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/*!
 * FullCalendar v3.0.0
 * Docs & License: http://fullcalendar.io/
 * (c) 2016 Adam Shaw
 */


(function(factory) {
    if (typeof define === 'function' && define.amd) {
        define([ 'jquery', 'moment' ], factory);
    }
    else if (typeof exports === 'object') { // Node/CommonJS
        module.exports = factory(require('jquery'), require('moment'));
    }
    else {
        factory(jQuery, moment);
    }
})(function($, moment) {

;;

var FC = $.fullCalendar = {
    version: "3.0.0",
    internalApiVersion: 6
};
var fcViews = FC.views = {};


$.fn.fullCalendar = function(options) {
    var args = Array.prototype.slice.call(arguments, 1); // for a possible method call
    var res = this; // what this function will return (this jQuery object by default)

    this.each(function(i, _element) { // loop each DOM element involved
        var element = $(_element);
        var calendar = element.data('fullCalendar'); // get the existing calendar object (if any)
        var singleRes; // the returned value of this single method call

        // a method call
        if (typeof options === 'string') {
            if (calendar && $.isFunction(calendar[options])) {
                singleRes = calendar[options].apply(calendar, args);
                if (!i) {
                    res = singleRes; // record the first method call result
                }
                if (options === 'destroy') { // for the destroy method, must remove Calendar object data
                    element.removeData('fullCalendar');
                }
            }
        }
        // a new calendar initialization
        else if (!calendar) { // don't initialize twice
            calendar = new Calendar(element, options);
            element.data('fullCalendar', calendar);
            calendar.render();
        }
    });
    
    return res;
};


var complexOptions = [ // names of options that are objects whose properties should be combined
    'header',
    'buttonText',
    'buttonIcons',
    'themeButtonIcons'
];


// Merges an array of option objects into a single object
function mergeOptions(optionObjs) {
    return mergeProps(optionObjs, complexOptions);
}

;;

// exports
FC.intersectRanges = intersectRanges;
FC.applyAll = applyAll;
FC.debounce = debounce;
FC.isInt = isInt;
FC.htmlEscape = htmlEscape;
FC.cssToStr = cssToStr;
FC.proxy = proxy;
FC.capitaliseFirstLetter = capitaliseFirstLetter;


/* FullCalendar-specific DOM Utilities
----------------------------------------------------------------------------------------------------------------------*/


// Given the scrollbar widths of some other container, create borders/margins on rowEls in order to match the left
// and right space that was offset by the scrollbars. A 1-pixel border first, then margin beyond that.
function compensateScroll(rowEls, scrollbarWidths) {
    if (scrollbarWidths.left) {
        rowEls.css({
            'border-left-width': 1,
            'margin-left': scrollbarWidths.left - 1
        });
    }
    if (scrollbarWidths.right) {
        rowEls.css({
            'border-right-width': 1,
            'margin-right': scrollbarWidths.right - 1
        });
    }
}


// Undoes compensateScroll and restores all borders/margins
function uncompensateScroll(rowEls) {
    rowEls.css({
        'margin-left': '',
        'margin-right': '',
        'border-left-width': '',
        'border-right-width': ''
    });
}


// Make the mouse cursor express that an event is not allowed in the current area
function disableCursor() {
    $('body').addClass('fc-not-allowed');
}


// Returns the mouse cursor to its original look
function enableCursor() {
    $('body').removeClass('fc-not-allowed');
}


// Given a total available height to fill, have `els` (essentially child rows) expand to accomodate.
// By default, all elements that are shorter than the recommended height are expanded uniformly, not considering
// any other els that are already too tall. if `shouldRedistribute` is on, it considers these tall rows and 
// reduces the available height.
function distributeHeight(els, availableHeight, shouldRedistribute) {

    // *FLOORING NOTE*: we floor in certain places because zoom can give inaccurate floating-point dimensions,
    // and it is better to be shorter than taller, to avoid creating unnecessary scrollbars.

    var minOffset1 = Math.floor(availableHeight / els.length); // for non-last element
    var minOffset2 = Math.floor(availableHeight - minOffset1 * (els.length - 1)); // for last element *FLOORING NOTE*
    var flexEls = []; // elements that are allowed to expand. array of DOM nodes
    var flexOffsets = []; // amount of vertical space it takes up
    var flexHeights = []; // actual css height
    var usedHeight = 0;

    undistributeHeight(els); // give all elements their natural height

    // find elements that are below the recommended height (expandable).
    // important to query for heights in a single first pass (to avoid reflow oscillation).
    els.each(function(i, el) {
        var minOffset = i === els.length - 1 ? minOffset2 : minOffset1;
        var naturalOffset = $(el).outerHeight(true);

        if (naturalOffset < minOffset) {
            flexEls.push(el);
            flexOffsets.push(naturalOffset);
            flexHeights.push($(el).height());
        }
        else {
            // this element stretches past recommended height (non-expandable). mark the space as occupied.
            usedHeight += naturalOffset;
        }
    });

    // readjust the recommended height to only consider the height available to non-maxed-out rows.
    if (shouldRedistribute) {
        availableHeight -= usedHeight;
        minOffset1 = Math.floor(availableHeight / flexEls.length);
        minOffset2 = Math.floor(availableHeight - minOffset1 * (flexEls.length - 1)); // *FLOORING NOTE*
    }

    // assign heights to all expandable elements
    $(flexEls).each(function(i, el) {
        var minOffset = i === flexEls.length - 1 ? minOffset2 : minOffset1;
        var naturalOffset = flexOffsets[i];
        var naturalHeight = flexHeights[i];
        var newHeight = minOffset - (naturalOffset - naturalHeight); // subtract the margin/padding

        if (naturalOffset < minOffset) { // we check this again because redistribution might have changed things
            $(el).height(newHeight);
        }
    });
}


// Undoes distrubuteHeight, restoring all els to their natural height
function undistributeHeight(els) {
    els.height('');
}


// Given `els`, a jQuery set of <td> cells, find the cell with the largest natural width and set the widths of all the
// cells to be that width.
// PREREQUISITE: if you want a cell to take up width, it needs to have a single inner element w/ display:inline
function matchCellWidths(els) {
    var maxInnerWidth = 0;

    els.find('> *').each(function(i, innerEl) {
        var innerWidth = $(innerEl).outerWidth();
        if (innerWidth > maxInnerWidth) {
            maxInnerWidth = innerWidth;
        }
    });

    maxInnerWidth++; // sometimes not accurate of width the text needs to stay on one line. insurance

    els.width(maxInnerWidth);

    return maxInnerWidth;
}


// Given one element that resides inside another,
// Subtracts the height of the inner element from the outer element.
function subtractInnerElHeight(outerEl, innerEl) {
    var both = outerEl.add(innerEl);
    var diff;

    // effin' IE8/9/10/11 sometimes returns 0 for dimensions. this weird hack was the only thing that worked
    both.css({
        position: 'relative', // cause a reflow, which will force fresh dimension recalculation
        left: -1 // ensure reflow in case the el was already relative. negative is less likely to cause new scroll
    });
    diff = outerEl.outerHeight() - innerEl.outerHeight(); // grab the dimensions
    both.css({ position: '', left: '' }); // undo hack

    return diff;
}


/* Element Geom Utilities
----------------------------------------------------------------------------------------------------------------------*/

FC.getOuterRect = getOuterRect;
FC.getClientRect = getClientRect;
FC.getContentRect = getContentRect;
FC.getScrollbarWidths = getScrollbarWidths;


// borrowed from https://github.com/jquery/jquery-ui/blob/1.11.0/ui/core.js#L51
function getScrollParent(el) {
    var position = el.css('position'),
        scrollParent = el.parents().filter(function() {
            var parent = $(this);
            return (/(auto|scroll)/).test(
                parent.css('overflow') + parent.css('overflow-y') + parent.css('overflow-x')
            );
        }).eq(0);

    return position === 'fixed' || !scrollParent.length ? $(el[0].ownerDocument || document) : scrollParent;
}


// Queries the outer bounding area of a jQuery element.
// Returns a rectangle with absolute coordinates: left, right (exclusive), top, bottom (exclusive).
// Origin is optional.
function getOuterRect(el, origin) {
    var offset = el.offset();
    var left = offset.left - (origin ? origin.left : 0);
    var top = offset.top - (origin ? origin.top : 0);

    return {
        left: left,
        right: left + el.outerWidth(),
        top: top,
        bottom: top + el.outerHeight()
    };
}


// Queries the area within the margin/border/scrollbars of a jQuery element. Does not go within the padding.
// Returns a rectangle with absolute coordinates: left, right (exclusive), top, bottom (exclusive).
// Origin is optional.
// NOTE: should use clientLeft/clientTop, but very unreliable cross-browser.
function getClientRect(el, origin) {
    var offset = el.offset();
    var scrollbarWidths = getScrollbarWidths(el);
    var left = offset.left + getCssFloat(el, 'border-left-width') + scrollbarWidths.left - (origin ? origin.left : 0);
    var top = offset.top + getCssFloat(el, 'border-top-width') + scrollbarWidths.top - (origin ? origin.top : 0);

    return {
        left: left,
        right: left + el[0].clientWidth, // clientWidth includes padding but NOT scrollbars
        top: top,
        bottom: top + el[0].clientHeight // clientHeight includes padding but NOT scrollbars
    };
}


// Queries the area within the margin/border/padding of a jQuery element. Assumed not to have scrollbars.
// Returns a rectangle with absolute coordinates: left, right (exclusive), top, bottom (exclusive).
// Origin is optional.
function getContentRect(el, origin) {
    var offset = el.offset(); // just outside of border, margin not included
    var left = offset.left + getCssFloat(el, 'border-left-width') + getCssFloat(el, 'padding-left') -
        (origin ? origin.left : 0);
    var top = offset.top + getCssFloat(el, 'border-top-width') + getCssFloat(el, 'padding-top') -
        (origin ? origin.top : 0);

    return {
        left: left,
        right: left + el.width(),
        top: top,
        bottom: top + el.height()
    };
}


// Returns the computed left/right/top/bottom scrollbar widths for the given jQuery element.
// NOTE: should use clientLeft/clientTop, but very unreliable cross-browser.
function getScrollbarWidths(el) {
    var leftRightWidth = el.innerWidth() - el[0].clientWidth; // the paddings cancel out, leaving the scrollbars
    var widths = {
        left: 0,
        right: 0,
        top: 0,
        bottom: el.innerHeight() - el[0].clientHeight // the paddings cancel out, leaving the bottom scrollbar
    };

    if (getIsLeftRtlScrollbars() && el.css('direction') == 'rtl') { // is the scrollbar on the left side?
        widths.left = leftRightWidth;
    }
    else {
        widths.right = leftRightWidth;
    }

    return widths;
}


// Logic for determining if, when the element is right-to-left, the scrollbar appears on the left side

var _isLeftRtlScrollbars = null;

function getIsLeftRtlScrollbars() { // responsible for caching the computation
    if (_isLeftRtlScrollbars === null) {
        _isLeftRtlScrollbars = computeIsLeftRtlScrollbars();
    }
    return _isLeftRtlScrollbars;
}

function computeIsLeftRtlScrollbars() { // creates an offscreen test element, then removes it
    var el = $('<div><div/></div>')
        .css({
            position: 'absolute',
            top: -1000,
            left: 0,
            border: 0,
            padding: 0,
            overflow: 'scroll',
            direction: 'rtl'
        })
        .appendTo('body');
    var innerEl = el.children();
    var res = innerEl.offset().left > el.offset().left; // is the inner div shifted to accommodate a left scrollbar?
    el.remove();
    return res;
}


// Retrieves a jQuery element's computed CSS value as a floating-point number.
// If the queried value is non-numeric (ex: IE can return "medium" for border width), will just return zero.
function getCssFloat(el, prop) {
    return parseFloat(el.css(prop)) || 0;
}


/* Mouse / Touch Utilities
----------------------------------------------------------------------------------------------------------------------*/

FC.preventDefault = preventDefault;


// Returns a boolean whether this was a left mouse click and no ctrl key (which means right click on Mac)
function isPrimaryMouseButton(ev) {
    return ev.which == 1 && !ev.ctrlKey;
}


function getEvX(ev) {
    if (ev.pageX !== undefined) {
        return ev.pageX;
    }
    var touches = ev.originalEvent.touches;
    if (touches) {
        return touches[0].pageX;
    }
}


function getEvY(ev) {
    if (ev.pageY !== undefined) {
        return ev.pageY;
    }
    var touches = ev.originalEvent.touches;
    if (touches) {
        return touches[0].pageY;
    }
}


function getEvIsTouch(ev) {
    return /^touch/.test(ev.type);
}


function preventSelection(el) {
    el.addClass('fc-unselectable')
        .on('selectstart', preventDefault);
}


// Stops a mouse/touch event from doing it's native browser action
function preventDefault(ev) {
    ev.preventDefault();
}


// attach a handler to get called when ANY scroll action happens on the page.
// this was impossible to do with normal on/off because 'scroll' doesn't bubble.
// http://stackoverflow.com/a/32954565/96342
// returns `true` on success.
function bindAnyScroll(handler) {
    if (window.addEventListener) {
        window.addEventListener('scroll', handler, true); // useCapture=true
        return true;
    }
    return false;
}


// undoes bindAnyScroll. must pass in the original function.
// returns `true` on success.
function unbindAnyScroll(handler) {
    if (window.removeEventListener) {
        window.removeEventListener('scroll', handler, true); // useCapture=true
        return true;
    }
    return false;
}


/* General Geometry Utils
----------------------------------------------------------------------------------------------------------------------*/

FC.intersectRects = intersectRects;

// Returns a new rectangle that is the intersection of the two rectangles. If they don't intersect, returns false
function intersectRects(rect1, rect2) {
    var res = {
        left: Math.max(rect1.left, rect2.left),
        right: Math.min(rect1.right, rect2.right),
        top: Math.max(rect1.top, rect2.top),
        bottom: Math.min(rect1.bottom, rect2.bottom)
    };

    if (res.left < res.right && res.top < res.bottom) {
        return res;
    }
    return false;
}


// Returns a new point that will have been moved to reside within the given rectangle
function constrainPoint(point, rect) {
    return {
        left: Math.min(Math.max(point.left, rect.left), rect.right),
        top: Math.min(Math.max(point.top, rect.top), rect.bottom)
    };
}


// Returns a point that is the center of the given rectangle
function getRectCenter(rect) {
    return {
        left: (rect.left + rect.right) / 2,
        top: (rect.top + rect.bottom) / 2
    };
}


// Subtracts point2's coordinates from point1's coordinates, returning a delta
function diffPoints(point1, point2) {
    return {
        left: point1.left - point2.left,
        top: point1.top - point2.top
    };
}


/* Object Ordering by Field
----------------------------------------------------------------------------------------------------------------------*/

FC.parseFieldSpecs = parseFieldSpecs;
FC.compareByFieldSpecs = compareByFieldSpecs;
FC.compareByFieldSpec = compareByFieldSpec;
FC.flexibleCompare = flexibleCompare;


function parseFieldSpecs(input) {
    var specs = [];
    var tokens = [];
    var i, token;

    if (typeof input === 'string') {
        tokens = input.split(/\s*,\s*/);
    }
    else if (typeof input === 'function') {
        tokens = [ input ];
    }
    else if ($.isArray(input)) {
        tokens = input;
    }

    for (i = 0; i < tokens.length; i++) {
        token = tokens[i];

        if (typeof token === 'string') {
            specs.push(
                token.charAt(0) == '-' ?
                    { field: token.substring(1), order: -1 } :
                    { field: token, order: 1 }
            );
        }
        else if (typeof token === 'function') {
            specs.push({ func: token });
        }
    }

    return specs;
}


function compareByFieldSpecs(obj1, obj2, fieldSpecs) {
    var i;
    var cmp;

    for (i = 0; i < fieldSpecs.length; i++) {
        cmp = compareByFieldSpec(obj1, obj2, fieldSpecs[i]);
        if (cmp) {
            return cmp;
        }
    }

    return 0;
}


function compareByFieldSpec(obj1, obj2, fieldSpec) {
    if (fieldSpec.func) {
        return fieldSpec.func(obj1, obj2);
    }
    return flexibleCompare(obj1[fieldSpec.field], obj2[fieldSpec.field]) *
        (fieldSpec.order || 1);
}


function flexibleCompare(a, b) {
    if (!a && !b) {
        return 0;
    }
    if (b == null) {
        return -1;
    }
    if (a == null) {
        return 1;
    }
    if ($.type(a) === 'string' || $.type(b) === 'string') {
        return String(a).localeCompare(String(b));
    }
    return a - b;
}


/* FullCalendar-specific Misc Utilities
----------------------------------------------------------------------------------------------------------------------*/


// Computes the intersection of the two ranges. Will return fresh date clones in a range.
// Returns undefined if no intersection.
// Expects all dates to be normalized to the same timezone beforehand.
// TODO: move to date section?
function intersectRanges(subjectRange, constraintRange) {
    var subjectStart = subjectRange.start;
    var subjectEnd = subjectRange.end;
    var constraintStart = constraintRange.start;
    var constraintEnd = constraintRange.end;
    var segStart, segEnd;
    var isStart, isEnd;

    if (subjectEnd > constraintStart && subjectStart < constraintEnd) { // in bounds at all?

        if (subjectStart >= constraintStart) {
            segStart = subjectStart.clone();
            isStart = true;
        }
        else {
            segStart = constraintStart.clone();
            isStart =  false;
        }

        if (subjectEnd <= constraintEnd) {
            segEnd = subjectEnd.clone();
            isEnd = true;
        }
        else {
            segEnd = constraintEnd.clone();
            isEnd = false;
        }

        return {
            start: segStart,
            end: segEnd,
            isStart: isStart,
            isEnd: isEnd
        };
    }
}


/* Date Utilities
----------------------------------------------------------------------------------------------------------------------*/

FC.computeIntervalUnit = computeIntervalUnit;
FC.divideRangeByDuration = divideRangeByDuration;
FC.divideDurationByDuration = divideDurationByDuration;
FC.multiplyDuration = multiplyDuration;
FC.durationHasTime = durationHasTime;

var dayIDs = [ 'sun', 'mon', 'tue', 'wed', 'thu', 'fri', 'sat' ];
var intervalUnits = [ 'year', 'month', 'week', 'day', 'hour', 'minute', 'second', 'millisecond' ];


// Diffs the two moments into a Duration where full-days are recorded first, then the remaining time.
// Moments will have their timezones normalized.
function diffDayTime(a, b) {
    return moment.duration({
        days: a.clone().stripTime().diff(b.clone().stripTime(), 'days'),
        ms: a.time() - b.time() // time-of-day from day start. disregards timezone
    });
}


// Diffs the two moments via their start-of-day (regardless of timezone). Produces whole-day durations.
function diffDay(a, b) {
    return moment.duration({
        days: a.clone().stripTime().diff(b.clone().stripTime(), 'days')
    });
}


// Diffs two moments, producing a duration, made of a whole-unit-increment of the given unit. Uses rounding.
function diffByUnit(a, b, unit) {
    return moment.duration(
        Math.round(a.diff(b, unit, true)), // returnFloat=true
        unit
    );
}


// Computes the unit name of the largest whole-unit period of time.
// For example, 48 hours will be "days" whereas 49 hours will be "hours".
// Accepts start/end, a range object, or an original duration object.
function computeIntervalUnit(start, end) {
    var i, unit;
    var val;

    for (i = 0; i < intervalUnits.length; i++) {
        unit = intervalUnits[i];
        val = computeRangeAs(unit, start, end);

        if (val >= 1 && isInt(val)) {
            break;
        }
    }

    return unit; // will be "milliseconds" if nothing else matches
}


// Computes the number of units (like "hours") in the given range.
// Range can be a {start,end} object, separate start/end args, or a Duration.
// Results are based on Moment's .as() and .diff() methods, so results can depend on internal handling
// of month-diffing logic (which tends to vary from version to version).
function computeRangeAs(unit, start, end) {

    if (end != null) { // given start, end
        return end.diff(start, unit, true);
    }
    else if (moment.isDuration(start)) { // given duration
        return start.as(unit);
    }
    else { // given { start, end } range object
        return start.end.diff(start.start, unit, true);
    }
}


// Intelligently divides a range (specified by a start/end params) by a duration
function divideRangeByDuration(start, end, dur) {
    var months;

    if (durationHasTime(dur)) {
        return (end - start) / dur;
    }
    months = dur.asMonths();
    if (Math.abs(months) >= 1 && isInt(months)) {
        return end.diff(start, 'months', true) / months;
    }
    return end.diff(start, 'days', true) / dur.asDays();
}


// Intelligently divides one duration by another
function divideDurationByDuration(dur1, dur2) {
    var months1, months2;

    if (durationHasTime(dur1) || durationHasTime(dur2)) {
        return dur1 / dur2;
    }
    months1 = dur1.asMonths();
    months2 = dur2.asMonths();
    if (
        Math.abs(months1) >= 1 && isInt(months1) &&
        Math.abs(months2) >= 1 && isInt(months2)
    ) {
        return months1 / months2;
    }
    return dur1.asDays() / dur2.asDays();
}


// Intelligently multiplies a duration by a number
function multiplyDuration(dur, n) {
    var months;

    if (durationHasTime(dur)) {
        return moment.duration(dur * n);
    }
    months = dur.asMonths();
    if (Math.abs(months) >= 1 && isInt(months)) {
        return moment.duration({ months: months * n });
    }
    return moment.duration({ days: dur.asDays() * n });
}


// Returns a boolean about whether the given duration has any time parts (hours/minutes/seconds/ms)
function durationHasTime(dur) {
    return Boolean(dur.hours() || dur.minutes() || dur.seconds() || dur.milliseconds());
}


function isNativeDate(input) {
    return  Object.prototype.toString.call(input) === '[object Date]' || input instanceof Date;
}


// Returns a boolean about whether the given input is a time string, like "06:40:00" or "06:00"
function isTimeString(str) {
    return /^\d+\:\d+(?:\:\d+\.?(?:\d{3})?)?$/.test(str);
}


/* Logging and Debug
----------------------------------------------------------------------------------------------------------------------*/

FC.log = function() {
    var console = window.console;

    if (console && console.log) {
        return console.log.apply(console, arguments);
    }
};

FC.warn = function() {
    var console = window.console;

    if (console && console.warn) {
        return console.warn.apply(console, arguments);
    }
    else {
        return FC.log.apply(FC, arguments);
    }
};


/* General Utilities
----------------------------------------------------------------------------------------------------------------------*/

var hasOwnPropMethod = {}.hasOwnProperty;


// Merges an array of objects into a single object.
// The second argument allows for an array of property names who's object values will be merged together.
function mergeProps(propObjs, complexProps) {
    var dest = {};
    var i, name;
    var complexObjs;
    var j, val;
    var props;

    if (complexProps) {
        for (i = 0; i < complexProps.length; i++) {
            name = complexProps[i];
            complexObjs = [];

            // collect the trailing object values, stopping when a non-object is discovered
            for (j = propObjs.length - 1; j >= 0; j--) {
                val = propObjs[j][name];

                if (typeof val === 'object') {
                    complexObjs.unshift(val);
                }
                else if (val !== undefined) {
                    dest[name] = val; // if there were no objects, this value will be used
                    break;
                }
            }

            // if the trailing values were objects, use the merged value
            if (complexObjs.length) {
                dest[name] = mergeProps(complexObjs);
            }
        }
    }

    // copy values into the destination, going from last to first
    for (i = propObjs.length - 1; i >= 0; i--) {
        props = propObjs[i];

        for (name in props) {
            if (!(name in dest)) { // if already assigned by previous props or complex props, don't reassign
                dest[name] = props[name];
            }
        }
    }

    return dest;
}


// Create an object that has the given prototype. Just like Object.create
function createObject(proto) {
    var f = function() {};
    f.prototype = proto;
    return new f();
}


function copyOwnProps(src, dest) {
    for (var name in src) {
        if (hasOwnProp(src, name)) {
            dest[name] = src[name];
        }
    }
}


function hasOwnProp(obj, name) {
    return hasOwnPropMethod.call(obj, name);
}


// Is the given value a non-object non-function value?
function isAtomic(val) {
    return /undefined|null|boolean|number|string/.test($.type(val));
}


function applyAll(functions, thisObj, args) {
    if ($.isFunction(functions)) {
        functions = [ functions ];
    }
    if (functions) {
        var i;
        var ret;
        for (i=0; i<functions.length; i++) {
            ret = functions[i].apply(thisObj, args) || ret;
        }
        return ret;
    }
}


function firstDefined() {
    for (var i=0; i<arguments.length; i++) {
        if (arguments[i] !== undefined) {
            return arguments[i];
        }
    }
}


function htmlEscape(s) {
    return (s + '').replace(/&/g, '&amp;')
        .replace(/</g, '&lt;')
        .replace(/>/g, '&gt;')
        .replace(/'/g, '&#039;')
        .replace(/"/g, '&quot;')
        .replace(/\n/g, '<br />');
}


function stripHtmlEntities(text) {
    return text.replace(/&.*?;/g, '');
}


// Given a hash of CSS properties, returns a string of CSS.
// Uses property names as-is (no camel-case conversion). Will not make statements for null/undefined values.
function cssToStr(cssProps) {
    var statements = [];

    $.each(cssProps, function(name, val) {
        if (val != null) {
            statements.push(name + ':' + val);
        }
    });

    return statements.join(';');
}


// Given an object hash of HTML attribute names to values,
// generates a string that can be injected between < > in HTML
function attrsToStr(attrs) {
    var parts = [];

    $.each(attrs, function(name, val) {
        if (val != null) {
            parts.push(name + '="' + htmlEscape(val) + '"');
        }
    });

    return parts.join(' ');
}


function capitaliseFirstLetter(str) {
    return str.charAt(0).toUpperCase() + str.slice(1);
}


function compareNumbers(a, b) { // for .sort()
    return a - b;
}


function isInt(n) {
    return n % 1 === 0;
}


// Returns a method bound to the given object context.
// Just like one of the jQuery.proxy signatures, but without the undesired behavior of treating the same method with
// different contexts as identical when binding/unbinding events.
function proxy(obj, methodName) {
    var method = obj[methodName];

    return function() {
        return method.apply(obj, arguments);
    };
}


// Returns a function, that, as long as it continues to be invoked, will not
// be triggered. The function will be called after it stops being called for
// N milliseconds. If `immediate` is passed, trigger the function on the
// leading edge, instead of the trailing.
// https://github.com/jashkenas/underscore/blob/1.6.0/underscore.js#L714
function debounce(func, wait, immediate) {
    var timeout, args, context, timestamp, result;

    var later = function() {
        var last = +new Date() - timestamp;
        if (last < wait) {
            timeout = setTimeout(later, wait - last);
        }
        else {
            timeout = null;
            if (!immediate) {
                result = func.apply(context, args);
                context = args = null;
            }
        }
    };

    return function() {
        context = this;
        args = arguments;
        timestamp = +new Date();
        var callNow = immediate && !timeout;
        if (!timeout) {
            timeout = setTimeout(later, wait);
        }
        if (callNow) {
            result = func.apply(context, args);
            context = args = null;
        }
        return result;
    };
}


// HACK around jQuery's now A+ promises: execute callback synchronously if already resolved.
// thenFunc shouldn't accept args.
// similar to whenResources in Scheduler plugin.
function syncThen(promise, thenFunc) {
    // not a promise, or an already-resolved promise?
    if (!promise || !promise.then || promise.state() === 'resolved') {
        return $.when(thenFunc()); // resolve immediately
    }
    else if (thenFunc) {
        return promise.then(thenFunc);
    }
}

;;

/*
GENERAL NOTE on moments throughout the *entire rest* of the codebase:
All moments are assumed to be ambiguously-zoned unless otherwise noted,
with the NOTABLE EXCEOPTION of start/end dates that live on *Event Objects*.
Ambiguously-TIMED moments are assumed to be ambiguously-zoned by nature.
*/

var ambigDateOfMonthRegex = /^\s*\d{4}-\d\d$/;
var ambigTimeOrZoneRegex =
    /^\s*\d{4}-(?:(\d\d-\d\d)|(W\d\d$)|(W\d\d-\d)|(\d\d\d))((T| )(\d\d(:\d\d(:\d\d(\.\d+)?)?)?)?)?$/;
var newMomentProto = moment.fn; // where we will attach our new methods
var oldMomentProto = $.extend({}, newMomentProto); // copy of original moment methods

// tell momentjs to transfer these properties upon clone
var momentProperties = moment.momentProperties;
momentProperties.push('_fullCalendar');
momentProperties.push('_ambigTime');
momentProperties.push('_ambigZone');


// Creating
// -------------------------------------------------------------------------------------------------

// Creates a new moment, similar to the vanilla moment(...) constructor, but with
// extra features (ambiguous time, enhanced formatting). When given an existing moment,
// it will function as a clone (and retain the zone of the moment). Anything else will
// result in a moment in the local zone.
FC.moment = function() {
    return makeMoment(arguments);
};

// Sames as FC.moment, but forces the resulting moment to be in the UTC timezone.
FC.moment.utc = function() {
    var mom = makeMoment(arguments, true);

    // Force it into UTC because makeMoment doesn't guarantee it
    // (if given a pre-existing moment for example)
    if (mom.hasTime()) { // don't give ambiguously-timed moments a UTC zone
        mom.utc();
    }

    return mom;
};

// Same as FC.moment, but when given an ISO8601 string, the timezone offset is preserved.
// ISO8601 strings with no timezone offset will become ambiguously zoned.
FC.moment.parseZone = function() {
    return makeMoment(arguments, true, true);
};

// Builds an enhanced moment from args. When given an existing moment, it clones. When given a
// native Date, or called with no arguments (the current time), the resulting moment will be local.
// Anything else needs to be "parsed" (a string or an array), and will be affected by:
//    parseAsUTC - if there is no zone information, should we parse the input in UTC?
//    parseZone - if there is zone information, should we force the zone of the moment?
function makeMoment(args, parseAsUTC, parseZone) {
    var input = args[0];
    var isSingleString = args.length == 1 && typeof input === 'string';
    var isAmbigTime;
    var isAmbigZone;
    var ambigMatch;
    var mom;

    if (moment.isMoment(input) || isNativeDate(input) || input === undefined) {
        mom = moment.apply(null, args);
    }
    else { // "parsing" is required
        isAmbigTime = false;
        isAmbigZone = false;

        if (isSingleString) {
            if (ambigDateOfMonthRegex.test(input)) {
                // accept strings like '2014-05', but convert to the first of the month
                input += '-01';
                args = [ input ]; // for when we pass it on to moment's constructor
                isAmbigTime = true;
                isAmbigZone = true;
            }
            else if ((ambigMatch = ambigTimeOrZoneRegex.exec(input))) {
                isAmbigTime = !ambigMatch[5]; // no time part?
                isAmbigZone = true;
            }
        }
        else if ($.isArray(input)) {
            // arrays have no timezone information, so assume ambiguous zone
            isAmbigZone = true;
        }
        // otherwise, probably a string with a format

        if (parseAsUTC || isAmbigTime) {
            mom = moment.utc.apply(moment, args);
        }
        else {
            mom = moment.apply(null, args);
        }

        if (isAmbigTime) {
            mom._ambigTime = true;
            mom._ambigZone = true; // ambiguous time always means ambiguous zone
        }
        else if (parseZone) { // let's record the inputted zone somehow
            if (isAmbigZone) {
                mom._ambigZone = true;
            }
            else if (isSingleString) {
                mom.utcOffset(input); // if not a valid zone, will assign UTC
            }
        }
    }

    mom._fullCalendar = true; // flag for extended functionality

    return mom;
}


// Week Number
// -------------------------------------------------------------------------------------------------


// Returns the week number, considering the locale's custom week number calcuation
// `weeks` is an alias for `week`
newMomentProto.week = newMomentProto.weeks = function(input) {
    var weekCalc = this._locale._fullCalendar_weekCalc;

    if (input == null && typeof weekCalc === 'function') { // custom function only works for getter
        return weekCalc(this);
    }
    else if (weekCalc === 'ISO') {
        return oldMomentProto.isoWeek.apply(this, arguments); // ISO getter/setter
    }

    return oldMomentProto.week.apply(this, arguments); // local getter/setter
};


// Time-of-day
// -------------------------------------------------------------------------------------------------

// GETTER
// Returns a Duration with the hours/minutes/seconds/ms values of the moment.
// If the moment has an ambiguous time, a duration of 00:00 will be returned.
//
// SETTER
// You can supply a Duration, a Moment, or a Duration-like argument.
// When setting the time, and the moment has an ambiguous time, it then becomes unambiguous.
newMomentProto.time = function(time) {

    // Fallback to the original method (if there is one) if this moment wasn't created via FullCalendar.
    // `time` is a generic enough method name where this precaution is necessary to avoid collisions w/ other plugins.
    if (!this._fullCalendar) {
        return oldMomentProto.time.apply(this, arguments);
    }

    if (time == null) { // getter
        return moment.duration({
            hours: this.hours(),
            minutes: this.minutes(),
            seconds: this.seconds(),
            milliseconds: this.milliseconds()
        });
    }
    else { // setter

        this._ambigTime = false; // mark that the moment now has a time

        if (!moment.isDuration(time) && !moment.isMoment(time)) {
            time = moment.duration(time);
        }

        // The day value should cause overflow (so 24 hours becomes 00:00:00 of next day).
        // Only for Duration times, not Moment times.
        var dayHours = 0;
        if (moment.isDuration(time)) {
            dayHours = Math.floor(time.asDays()) * 24;
        }

        // We need to set the individual fields.
        // Can't use startOf('day') then add duration. In case of DST at start of day.
        return this.hours(dayHours + time.hours())
            .minutes(time.minutes())
            .seconds(time.seconds())
            .milliseconds(time.milliseconds());
    }
};

// Converts the moment to UTC, stripping out its time-of-day and timezone offset,
// but preserving its YMD. A moment with a stripped time will display no time
// nor timezone offset when .format() is called.
newMomentProto.stripTime = function() {

    if (!this._ambigTime) {

        this.utc(true); // keepLocalTime=true (for keeping *date* value)

        // set time to zero
        this.set({
            hours: 0,
            minutes: 0,
            seconds: 0,
            ms: 0
        });

        // Mark the time as ambiguous. This needs to happen after the .utc() call, which might call .utcOffset(),
        // which clears all ambig flags.
        this._ambigTime = true;
        this._ambigZone = true; // if ambiguous time, also ambiguous timezone offset
    }

    return this; // for chaining
};

// Returns if the moment has a non-ambiguous time (boolean)
newMomentProto.hasTime = function() {
    return !this._ambigTime;
};


// Timezone
// -------------------------------------------------------------------------------------------------

// Converts the moment to UTC, stripping out its timezone offset, but preserving its
// YMD and time-of-day. A moment with a stripped timezone offset will display no
// timezone offset when .format() is called.
newMomentProto.stripZone = function() {
    var wasAmbigTime;

    if (!this._ambigZone) {

        wasAmbigTime = this._ambigTime;

        this.utc(true); // keepLocalTime=true (for keeping date and time values)

        // the above call to .utc()/.utcOffset() unfortunately might clear the ambig flags, so restore
        this._ambigTime = wasAmbigTime || false;

        // Mark the zone as ambiguous. This needs to happen after the .utc() call, which might call .utcOffset(),
        // which clears the ambig flags.
        this._ambigZone = true;
    }

    return this; // for chaining
};

// Returns of the moment has a non-ambiguous timezone offset (boolean)
newMomentProto.hasZone = function() {
    return !this._ambigZone;
};


// implicitly marks a zone
newMomentProto.local = function(keepLocalTime) {

    // for when converting from ambiguously-zoned to local,
    // keep the time values when converting from UTC -> local
    oldMomentProto.local.call(this, this._ambigZone || keepLocalTime);

    // ensure non-ambiguous
    // this probably already happened via local() -> utcOffset(), but don't rely on Moment's internals
    this._ambigTime = false;
    this._ambigZone = false;

    return this; // for chaining
};


// implicitly marks a zone
newMomentProto.utc = function(keepLocalTime) {

    oldMomentProto.utc.call(this, keepLocalTime);

    // ensure non-ambiguous
    // this probably already happened via utc() -> utcOffset(), but don't rely on Moment's internals
    this._ambigTime = false;
    this._ambigZone = false;

    return this;
};


// implicitly marks a zone (will probably get called upon .utc() and .local())
newMomentProto.utcOffset = function(tzo) {

    if (tzo != null) { // setter
        // these assignments needs to happen before the original zone method is called.
        // I forget why, something to do with a browser crash.
        this._ambigTime = false;
        this._ambigZone = false;
    }

    return oldMomentProto.utcOffset.apply(this, arguments);
};


// Formatting
// -------------------------------------------------------------------------------------------------

newMomentProto.format = function() {
    if (this._fullCalendar && arguments[0]) { // an enhanced moment? and a format string provided?
        return formatDate(this, arguments[0]); // our extended formatting
    }
    if (this._ambigTime) {
        return oldMomentFormat(this, 'YYYY-MM-DD');
    }
    if (this._ambigZone) {
        return oldMomentFormat(this, 'YYYY-MM-DD[T]HH:mm:ss');
    }
    return oldMomentProto.format.apply(this, arguments);
};

newMomentProto.toISOString = function() {
    if (this._ambigTime) {
        return oldMomentFormat(this, 'YYYY-MM-DD');
    }
    if (this._ambigZone) {
        return oldMomentFormat(this, 'YYYY-MM-DD[T]HH:mm:ss');
    }
    return oldMomentProto.toISOString.apply(this, arguments);
};

;;

// Single Date Formatting
// -------------------------------------------------------------------------------------------------


// call this if you want Moment's original format method to be used
function oldMomentFormat(mom, formatStr) {
    return oldMomentProto.format.call(mom, formatStr); // oldMomentProto defined in moment-ext.js
}


// Formats `date` with a Moment formatting string, but allow our non-zero areas and
// additional token.
function formatDate(date, formatStr) {
    return formatDateWithChunks(date, getFormatStringChunks(formatStr));
}


function formatDateWithChunks(date, chunks) {
    var s = '';
    var i;

    for (i=0; i<chunks.length; i++) {
        s += formatDateWithChunk(date, chunks[i]);
    }

    return s;
}


// addition formatting tokens we want recognized
var tokenOverrides = {
    t: function(date) { // "a" or "p"
        return oldMomentFormat(date, 'a').charAt(0);
    },
    T: function(date) { // "A" or "P"
        return oldMomentFormat(date, 'A').charAt(0);
    }
};


function formatDateWithChunk(date, chunk) {
    var token;
    var maybeStr;

    if (typeof chunk === 'string') { // a literal string
        return chunk;
    }
    else if ((token = chunk.token)) { // a token, like "YYYY"
        if (tokenOverrides[token]) {
            return tokenOverrides[token](date); // use our custom token
        }
        return oldMomentFormat(date, token);
    }
    else if (chunk.maybe) { // a grouping of other chunks that must be non-zero
        maybeStr = formatDateWithChunks(date, chunk.maybe);
        if (maybeStr.match(/[1-9]/)) {
            return maybeStr;
        }
    }

    return '';
}


// Date Range Formatting
// -------------------------------------------------------------------------------------------------
// TODO: make it work with timezone offset

// Using a formatting string meant for a single date, generate a range string, like
// "Sep 2 - 9 2013", that intelligently inserts a separator where the dates differ.
// If the dates are the same as far as the format string is concerned, just return a single
// rendering of one date, without any separator.
function formatRange(date1, date2, formatStr, separator, isRTL) {
    var localeData;

    date1 = FC.moment.parseZone(date1);
    date2 = FC.moment.parseZone(date2);

    localeData = date1.localeData();

    // Expand localized format strings, like "LL" -> "MMMM D YYYY"
    formatStr = localeData.longDateFormat(formatStr) || formatStr;
    // BTW, this is not important for `formatDate` because it is impossible to put custom tokens
    // or non-zero areas in Moment's localized format strings.

    separator = separator || ' - ';

    return formatRangeWithChunks(
        date1,
        date2,
        getFormatStringChunks(formatStr),
        separator,
        isRTL
    );
}
FC.formatRange = formatRange; // expose


function formatRangeWithChunks(date1, date2, chunks, separator, isRTL) {
    var unzonedDate1 = date1.clone().stripZone(); // for formatSimilarChunk
    var unzonedDate2 = date2.clone().stripZone(); // "
    var chunkStr; // the rendering of the chunk
    var leftI;
    var leftStr = '';
    var rightI;
    var rightStr = '';
    var middleI;
    var middleStr1 = '';
    var middleStr2 = '';
    var middleStr = '';

    // Start at the leftmost side of the formatting string and continue until you hit a token
    // that is not the same between dates.
    for (leftI=0; leftI<chunks.length; leftI++) {
        chunkStr = formatSimilarChunk(date1, date2, unzonedDate1, unzonedDate2, chunks[leftI]);
        if (chunkStr === false) {
            break;
        }
        leftStr += chunkStr;
    }

    // Similarly, start at the rightmost side of the formatting string and move left
    for (rightI=chunks.length-1; rightI>leftI; rightI--) {
        chunkStr = formatSimilarChunk(date1, date2, unzonedDate1, unzonedDate2,  chunks[rightI]);
        if (chunkStr === false) {
            break;
        }
        rightStr = chunkStr + rightStr;
    }

    // The area in the middle is different for both of the dates.
    // Collect them distinctly so we can jam them together later.
    for (middleI=leftI; middleI<=rightI; middleI++) {
        middleStr1 += formatDateWithChunk(date1, chunks[middleI]);
        middleStr2 += formatDateWithChunk(date2, chunks[middleI]);
    }

    if (middleStr1 || middleStr2) {
        if (isRTL) {
            middleStr = middleStr2 + separator + middleStr1;
        }
        else {
            middleStr = middleStr1 + separator + middleStr2;
        }
    }

    return leftStr + middleStr + rightStr;
}


var similarUnitMap = {
    Y: 'year',
    M: 'month',
    D: 'day', // day of month
    d: 'day', // day of week
    // prevents a separator between anything time-related...
    A: 'second', // AM/PM
    a: 'second', // am/pm
    T: 'second', // A/P
    t: 'second', // a/p
    H: 'second', // hour (24)
    h: 'second', // hour (12)
    m: 'second', // minute
    s: 'second' // second
};
// TODO: week maybe?


// Given a formatting chunk, and given that both dates are similar in the regard the
// formatting chunk is concerned, format date1 against `chunk`. Otherwise, return `false`.
function formatSimilarChunk(date1, date2, unzonedDate1, unzonedDate2, chunk) {
    var token;
    var unit;

    if (typeof chunk === 'string') { // a literal string
        return chunk;
    }
    else if ((token = chunk.token)) {
        unit = similarUnitMap[token.charAt(0)];

        // are the dates the same for this unit of measurement?
        // use the unzoned dates for this calculation because unreliable when near DST (bug #2396)
        if (unit && unzonedDate1.isSame(unzonedDate2, unit)) {
            return oldMomentFormat(date1, token); // would be the same if we used `date2`
            // BTW, don't support custom tokens
        }
    }

    return false; // the chunk is NOT the same for the two dates
    // BTW, don't support splitting on non-zero areas
}


// Chunking Utils
// -------------------------------------------------------------------------------------------------


var formatStringChunkCache = {};


function getFormatStringChunks(formatStr) {
    if (formatStr in formatStringChunkCache) {
        return formatStringChunkCache[formatStr];
    }
    return (formatStringChunkCache[formatStr] = chunkFormatString(formatStr));
}


// Break the formatting string into an array of chunks
function chunkFormatString(formatStr) {
    var chunks = [];
    var chunker = /\[([^\]]*)\]|\(([^\)]*)\)|(LTS|LT|(\w)\4*o?)|([^\w\[\(]+)/g; // TODO: more descrimination
    var match;

    while ((match = chunker.exec(formatStr))) {
        if (match[1]) { // a literal string inside [ ... ]
            chunks.push(match[1]);
        }
        else if (match[2]) { // non-zero formatting inside ( ... )
            chunks.push({ maybe: chunkFormatString(match[2]) });
        }
        else if (match[3]) { // a formatting token
            chunks.push({ token: match[3] });
        }
        else if (match[5]) { // an unenclosed literal string
            chunks.push(match[5]);
        }
    }

    return chunks;
}

;;

FC.Class = Class; // export

// Class that all other classes will inherit from
function Class() { }


// Called on a class to create a subclass.
// Last argument contains instance methods. Any argument before the last are considered mixins.
Class.extend = function() {
    var len = arguments.length;
    var i;
    var members;

    for (i = 0; i < len; i++) {
        members = arguments[i];
        if (i < len - 1) { // not the last argument?
            mixIntoClass(this, members);
        }
    }

    return extendClass(this, members || {}); // members will be undefined if no arguments
};


// Adds new member variables/methods to the class's prototype.
// Can be called with another class, or a plain object hash containing new members.
Class.mixin = function(members) {
    mixIntoClass(this, members);
};


function extendClass(superClass, members) {
    var subClass;

    // ensure a constructor for the subclass, forwarding all arguments to the super-constructor if it doesn't exist
    if (hasOwnProp(members, 'constructor')) {
        subClass = members.constructor;
    }
    if (typeof subClass !== 'function') {
        subClass = members.constructor = function() {
            superClass.apply(this, arguments);
        };
    }

    // build the base prototype for the subclass, which is an new object chained to the superclass's prototype
    subClass.prototype = createObject(superClass.prototype);

    // copy each member variable/method onto the the subclass's prototype
    copyOwnProps(members, subClass.prototype);

    // copy over all class variables/methods to the subclass, such as `extend` and `mixin`
    copyOwnProps(superClass, subClass);

    return subClass;
}


function mixIntoClass(theClass, members) {
    copyOwnProps(members, theClass.prototype);
}
;;

var EmitterMixin = FC.EmitterMixin = {

    // jQuery-ification via $(this) allows a non-DOM object to have
    // the same event handling capabilities (including namespaces).


    on: function(types, handler) {

        // handlers are always called with an "event" object as their first param.
        // sneak the `this` context and arguments into the extra parameter object
        // and forward them on to the original handler.
        var intercept = function(ev, extra) {
            return handler.apply(
                extra.context || this,
                extra.args || []
            );
        };

        // mimick jQuery's internal "proxy" system (risky, I know)
        // causing all functions with the same .guid to appear to be the same.
        // https://github.com/jquery/jquery/blob/2.2.4/src/core.js#L448
        // this is needed for calling .off with the original non-intercept handler.
        if (!handler.guid) {
            handler.guid = $.guid++;
        }
        intercept.guid = handler.guid;

        $(this).on(types, intercept);

        return this; // for chaining
    },


    off: function(types, handler) {
        $(this).off(types, handler);

        return this; // for chaining
    },


    trigger: function(types) {
        var args = Array.prototype.slice.call(arguments, 1); // arguments after the first

        // pass in "extra" info to the intercept
        $(this).triggerHandler(types, { args: args });

        return this; // for chaining
    },


    triggerWith: function(types, context, args) {

        // `triggerHandler` is less reliant on the DOM compared to `trigger`.
        // pass in "extra" info to the intercept.
        $(this).triggerHandler(types, { context: context, args: args });

        return this; // for chaining
    }

};

;;

/*
Utility methods for easily listening to events on another object,
and more importantly, easily unlistening from them.
*/
var ListenerMixin = FC.ListenerMixin = (function() {
    var guid = 0;
    var ListenerMixin = {

        listenerId: null,

        /*
        Given an `other` object that has on/off methods, bind the given `callback` to an event by the given name.
        The `callback` will be called with the `this` context of the object that .listenTo is being called on.
        Can be called:
            .listenTo(other, eventName, callback)
        OR
            .listenTo(other, {
                eventName1: callback1,
                eventName2: callback2
            })
        */
        listenTo: function(other, arg, callback) {
            if (typeof arg === 'object') { // given dictionary of callbacks
                for (var eventName in arg) {
                    if (arg.hasOwnProperty(eventName)) {
                        this.listenTo(other, eventName, arg[eventName]);
                    }
                }
            }
            else if (typeof arg === 'string') {
                other.on(
                    arg + '.' + this.getListenerNamespace(), // use event namespacing to identify this object
                    $.proxy(callback, this) // always use `this` context
                        // the usually-undesired jQuery guid behavior doesn't matter,
                        // because we always unbind via namespace
                );
            }
        },

        /*
        Causes the current object to stop listening to events on the `other` object.
        `eventName` is optional. If omitted, will stop listening to ALL events on `other`.
        */
        stopListeningTo: function(other, eventName) {
            other.off((eventName || '') + '.' + this.getListenerNamespace());
        },

        /*
        Returns a string, unique to this object, to be used for event namespacing
        */
        getListenerNamespace: function() {
            if (this.listenerId == null) {
                this.listenerId = guid++;
            }
            return '_listener' + this.listenerId;
        }

    };
    return ListenerMixin;
})();
;;

// simple class for toggle a `isIgnoringMouse` flag on delay
// initMouseIgnoring must first be called, with a millisecond delay setting.
var MouseIgnorerMixin = {

    isIgnoringMouse: false, // bool
    delayUnignoreMouse: null, // method


    initMouseIgnoring: function(delay) {
        this.delayUnignoreMouse = debounce(proxy(this, 'unignoreMouse'), delay || 1000);
    },


    // temporarily ignore mouse actions on segments
    tempIgnoreMouse: function() {
        this.isIgnoringMouse = true;
        this.delayUnignoreMouse();
    },


    // delayUnignoreMouse eventually calls this
    unignoreMouse: function() {
        this.isIgnoringMouse = false;
    }

};

;;

/* A rectangular panel that is absolutely positioned over other content
------------------------------------------------------------------------------------------------------------------------
Options:
    - className (string)
    - content (HTML string or jQuery element set)
    - parentEl
    - top
    - left
    - right (the x coord of where the right edge should be. not a "CSS" right)
    - autoHide (boolean)
    - show (callback)
    - hide (callback)
*/

var Popover = Class.extend(ListenerMixin, {

    isHidden: true,
    options: null,
    el: null, // the container element for the popover. generated by this object
    margin: 10, // the space required between the popover and the edges of the scroll container


    constructor: function(options) {
        this.options = options || {};
    },


    // Shows the popover on the specified position. Renders it if not already
    show: function() {
        if (this.isHidden) {
            if (!this.el) {
                this.render();
            }
            this.el.show();
            this.position();
            this.isHidden = false;
            this.trigger('show');
        }
    },


    // Hides the popover, through CSS, but does not remove it from the DOM
    hide: function() {
        if (!this.isHidden) {
            this.el.hide();
            this.isHidden = true;
            this.trigger('hide');
        }
    },


    // Creates `this.el` and renders content inside of it
    render: function() {
        var _this = this;
        var options = this.options;

        this.el = $('<div class="fc-popover"/>')
            .addClass(options.className || '')
            .css({
                // position initially to the top left to avoid creating scrollbars
                top: 0,
                left: 0
            })
            .append(options.content)
            .appendTo(options.parentEl);

        // when a click happens on anything inside with a 'fc-close' className, hide the popover
        this.el.on('click', '.fc-close', function() {
            _this.hide();
        });

        if (options.autoHide) {
            this.listenTo($(document), 'mousedown', this.documentMousedown);
        }
    },


    // Triggered when the user clicks *anywhere* in the document, for the autoHide feature
    documentMousedown: function(ev) {
        // only hide the popover if the click happened outside the popover
        if (this.el && !$(ev.target).closest(this.el).length) {
            this.hide();
        }
    },


    // Hides and unregisters any handlers
    removeElement: function() {
        this.hide();

        if (this.el) {
            this.el.remove();
            this.el = null;
        }

        this.stopListeningTo($(document), 'mousedown');
    },


    // Positions the popover optimally, using the top/left/right options
    position: function() {
        var options = this.options;
        var origin = this.el.offsetParent().offset();
        var width = this.el.outerWidth();
        var height = this.el.outerHeight();
        var windowEl = $(window);
        var viewportEl = getScrollParent(this.el);
        var viewportTop;
        var viewportLeft;
        var viewportOffset;
        var top; // the "position" (not "offset") values for the popover
        var left; //

        // compute top and left
        top = options.top || 0;
        if (options.left !== undefined) {
            left = options.left;
        }
        else if (options.right !== undefined) {
            left = options.right - width; // derive the left value from the right value
        }
        else {
            left = 0;
        }

        if (viewportEl.is(window) || viewportEl.is(document)) { // normalize getScrollParent's result
            viewportEl = windowEl;
            viewportTop = 0; // the window is always at the top left
            viewportLeft = 0; // (and .offset() won't work if called here)
        }
        else {
            viewportOffset = viewportEl.offset();
            viewportTop = viewportOffset.top;
            viewportLeft = viewportOffset.left;
        }

        // if the window is scrolled, it causes the visible area to be further down
        viewportTop += windowEl.scrollTop();
        viewportLeft += windowEl.scrollLeft();

        // constrain to the view port. if constrained by two edges, give precedence to top/left
        if (options.viewportConstrain !== false) {
            top = Math.min(top, viewportTop + viewportEl.outerHeight() - height - this.margin);
            top = Math.max(top, viewportTop + this.margin);
            left = Math.min(left, viewportLeft + viewportEl.outerWidth() - width - this.margin);
            left = Math.max(left, viewportLeft + this.margin);
        }

        this.el.css({
            top: top - origin.top,
            left: left - origin.left
        });
    },


    // Triggers a callback. Calls a function in the option hash of the same name.
    // Arguments beyond the first `name` are forwarded on.
    // TODO: better code reuse for this. Repeat code
    trigger: function(name) {
        if (this.options[name]) {
            this.options[name].apply(this, Array.prototype.slice.call(arguments, 1));
        }
    }

});

;;

/*
A cache for the left/right/top/bottom/width/height values for one or more elements.
Works with both offset (from topleft document) and position (from offsetParent).

options:
- els
- isHorizontal
- isVertical
*/
var CoordCache = FC.CoordCache = Class.extend({

    els: null, // jQuery set (assumed to be siblings)
    forcedOffsetParentEl: null, // options can override the natural offsetParent
    origin: null, // {left,top} position of offsetParent of els
    boundingRect: null, // constrain cordinates to this rectangle. {left,right,top,bottom} or null
    isHorizontal: false, // whether to query for left/right/width
    isVertical: false, // whether to query for top/bottom/height

    // arrays of coordinates (offsets from topleft of document)
    lefts: null,
    rights: null,
    tops: null,
    bottoms: null,


    constructor: function(options) {
        this.els = $(options.els);
        this.isHorizontal = options.isHorizontal;
        this.isVertical = options.isVertical;
        this.forcedOffsetParentEl = options.offsetParent ? $(options.offsetParent) : null;
    },


    // Queries the els for coordinates and stores them.
    // Call this method before using and of the get* methods below.
    build: function() {
        var offsetParentEl = this.forcedOffsetParentEl || this.els.eq(0).offsetParent();

        this.origin = offsetParentEl.offset();
        this.boundingRect = this.queryBoundingRect();

        if (this.isHorizontal) {
            this.buildElHorizontals();
        }
        if (this.isVertical) {
            this.buildElVerticals();
        }
    },


    // Destroys all internal data about coordinates, freeing memory
    clear: function() {
        this.origin = null;
        this.boundingRect = null;
        this.lefts = null;
        this.rights = null;
        this.tops = null;
        this.bottoms = null;
    },


    // When called, if coord caches aren't built, builds them
    ensureBuilt: function() {
        if (!this.origin) {
            this.build();
        }
    },


    // Populates the left/right internal coordinate arrays
    buildElHorizontals: function() {
        var lefts = [];
        var rights = [];

        this.els.each(function(i, node) {
            var el = $(node);
            var left = el.offset().left;
            var width = el.outerWidth();

            lefts.push(left);
            rights.push(left + width);
        });

        this.lefts = lefts;
        this.rights = rights;
    },


    // Populates the top/bottom internal coordinate arrays
    buildElVerticals: function() {
        var tops = [];
        var bottoms = [];

        this.els.each(function(i, node) {
            var el = $(node);
            var top = el.offset().top;
            var height = el.outerHeight();

            tops.push(top);
            bottoms.push(top + height);
        });

        this.tops = tops;
        this.bottoms = bottoms;
    },


    // Given a left offset (from document left), returns the index of the el that it horizontally intersects.
    // If no intersection is made, returns undefined.
    getHorizontalIndex: function(leftOffset) {
        this.ensureBuilt();

        var lefts = this.lefts;
        var rights = this.rights;
        var len = lefts.length;
        var i;

        for (i = 0; i < len; i++) {
            if (leftOffset >= lefts[i] && leftOffset < rights[i]) {
                return i;
            }
        }
    },


    // Given a top offset (from document top), returns the index of the el that it vertically intersects.
    // If no intersection is made, returns undefined.
    getVerticalIndex: function(topOffset) {
        this.ensureBuilt();

        var tops = this.tops;
        var bottoms = this.bottoms;
        var len = tops.length;
        var i;

        for (i = 0; i < len; i++) {
            if (topOffset >= tops[i] && topOffset < bottoms[i]) {
                return i;
            }
        }
    },


    // Gets the left offset (from document left) of the element at the given index
    getLeftOffset: function(leftIndex) {
        this.ensureBuilt();
        return this.lefts[leftIndex];
    },


    // Gets the left position (from offsetParent left) of the element at the given index
    getLeftPosition: function(leftIndex) {
        this.ensureBuilt();
        return this.lefts[leftIndex] - this.origin.left;
    },


    // Gets the right offset (from document left) of the element at the given index.
    // This value is NOT relative to the document's right edge, like the CSS concept of "right" would be.
    getRightOffset: function(leftIndex) {
        this.ensureBuilt();
        return this.rights[leftIndex];
    },


    // Gets the right position (from offsetParent left) of the element at the given index.
    // This value is NOT relative to the offsetParent's right edge, like the CSS concept of "right" would be.
    getRightPosition: function(leftIndex) {
        this.ensureBuilt();
        return this.rights[leftIndex] - this.origin.left;
    },


    // Gets the width of the element at the given index
    getWidth: function(leftIndex) {
        this.ensureBuilt();
        return this.rights[leftIndex] - this.lefts[leftIndex];
    },


    // Gets the top offset (from document top) of the element at the given index
    getTopOffset: function(topIndex) {
        this.ensureBuilt();
        return this.tops[topIndex];
    },


    // Gets the top position (from offsetParent top) of the element at the given position
    getTopPosition: function(topIndex) {
        this.ensureBuilt();
        return this.tops[topIndex] - this.origin.top;
    },

    // Gets the bottom offset (from the document top) of the element at the given index.
    // This value is NOT relative to the offsetParent's bottom edge, like the CSS concept of "bottom" would be.
    getBottomOffset: function(topIndex) {
        this.ensureBuilt();
        return this.bottoms[topIndex];
    },


    // Gets the bottom position (from the offsetParent top) of the element at the given index.
    // This value is NOT relative to the offsetParent's bottom edge, like the CSS concept of "bottom" would be.
    getBottomPosition: function(topIndex) {
        this.ensureBuilt();
        return this.bottoms[topIndex] - this.origin.top;
    },


    // Gets the height of the element at the given index
    getHeight: function(topIndex) {
        this.ensureBuilt();
        return this.bottoms[topIndex] - this.tops[topIndex];
    },


    // Bounding Rect
    // TODO: decouple this from CoordCache

    // Compute and return what the elements' bounding rectangle is, from the user's perspective.
    // Right now, only returns a rectangle if constrained by an overflow:scroll element.
    queryBoundingRect: function() {
        var scrollParentEl = getScrollParent(this.els.eq(0));

        if (!scrollParentEl.is(document)) {
            return getClientRect(scrollParentEl);
        }
    },

    isPointInBounds: function(leftOffset, topOffset) {
        return this.isLeftInBounds(leftOffset) && this.isTopInBounds(topOffset);
    },

    isLeftInBounds: function(leftOffset) {
        return !this.boundingRect || (leftOffset >= this.boundingRect.left && leftOffset < this.boundingRect.right);
    },

    isTopInBounds: function(topOffset) {
        return !this.boundingRect || (topOffset >= this.boundingRect.top && topOffset < this.boundingRect.bottom);
    }

});

;;

/* Tracks a drag's mouse movement, firing various handlers
----------------------------------------------------------------------------------------------------------------------*/
// TODO: use Emitter

var DragListener = FC.DragListener = Class.extend(ListenerMixin, MouseIgnorerMixin, {

    options: null,
    subjectEl: null,

    // coordinates of the initial mousedown
    originX: null,
    originY: null,

    // the wrapping element that scrolls, or MIGHT scroll if there's overflow.
    // TODO: do this for wrappers that have overflow:hidden as well.
    scrollEl: null,

    isInteracting: false,
    isDistanceSurpassed: false,
    isDelayEnded: false,
    isDragging: false,
    isTouch: false,

    delay: null,
    delayTimeoutId: null,
    minDistance: null,

    handleTouchScrollProxy: null, // calls handleTouchScroll, always bound to `this`


    constructor: function(options) {
        this.options = options || {};
        this.handleTouchScrollProxy = proxy(this, 'handleTouchScroll');
        this.initMouseIgnoring(500);
    },


    // Interaction (high-level)
    // -----------------------------------------------------------------------------------------------------------------


    startInteraction: function(ev, extraOptions) {
        var isTouch = getEvIsTouch(ev);

        if (ev.type === 'mousedown') {
            if (this.isIgnoringMouse) {
                return;
            }
            else if (!isPrimaryMouseButton(ev)) {
                return;
            }
            else {
                ev.preventDefault(); // prevents native selection in most browsers
            }
        }

        if (!this.isInteracting) {

            // process options
            extraOptions = extraOptions || {};
            this.delay = firstDefined(extraOptions.delay, this.options.delay, 0);
            this.minDistance = firstDefined(extraOptions.distance, this.options.distance, 0);
            this.subjectEl = this.options.subjectEl;

            this.isInteracting = true;
            this.isTouch = isTouch;
            this.isDelayEnded = false;
            this.isDistanceSurpassed = false;

            this.originX = getEvX(ev);
            this.originY = getEvY(ev);
            this.scrollEl = getScrollParent($(ev.target));

            this.bindHandlers();
            this.initAutoScroll();
            this.handleInteractionStart(ev);
            this.startDelay(ev);

            if (!this.minDistance) {
                this.handleDistanceSurpassed(ev);
            }
        }
    },


    handleInteractionStart: function(ev) {
        this.trigger('interactionStart', ev);
    },


    endInteraction: function(ev, isCancelled) {
        if (this.isInteracting) {
            this.endDrag(ev);

            if (this.delayTimeoutId) {
                clearTimeout(this.delayTimeoutId);
                this.delayTimeoutId = null;
            }

            this.destroyAutoScroll();
            this.unbindHandlers();

            this.isInteracting = false;
            this.handleInteractionEnd(ev, isCancelled);

            // a touchstart+touchend on the same element will result in the following addition simulated events:
            // mouseover + mouseout + click
            // let's ignore these bogus events
            if (this.isTouch) {
                this.tempIgnoreMouse();
            }
        }
    },


    handleInteractionEnd: function(ev, isCancelled) {
        this.trigger('interactionEnd', ev, isCancelled || false);
    },


    // Binding To DOM
    // -----------------------------------------------------------------------------------------------------------------


    bindHandlers: function() {
        var _this = this;
        var touchStartIgnores = 1;

        if (this.isTouch) {
            this.listenTo($(document), {
                touchmove: this.handleTouchMove,
                touchend: this.endInteraction,
                touchcancel: this.endInteraction,

                // Sometimes touchend doesn't fire
                // (can't figure out why. touchcancel doesn't fire either. has to do with scrolling?)
                // If another touchstart happens, we know it's bogus, so cancel the drag.
                // touchend will continue to be broken until user does a shorttap/scroll, but this is best we can do.
                touchstart: function(ev) {
                    if (touchStartIgnores) { // bindHandlers is called from within a touchstart,
                        touchStartIgnores--; // and we don't want this to fire immediately, so ignore.
                    }
                    else {
                        _this.endInteraction(ev, true); // isCancelled=true
                    }
                }
            });

            // listen to ALL scroll actions on the page
            if (
                !bindAnyScroll(this.handleTouchScrollProxy) && // hopefully this works and short-circuits the rest
                this.scrollEl // otherwise, attach a single handler to this
            ) {
                this.listenTo(this.scrollEl, 'scroll', this.handleTouchScroll);
            }
        }
        else {
            this.listenTo($(document), {
                mousemove: this.handleMouseMove,
                mouseup: this.endInteraction
            });
        }

        this.listenTo($(document), {
            selectstart: preventDefault, // don't allow selection while dragging
            contextmenu: preventDefault // long taps would open menu on Chrome dev tools
        });
    },


    unbindHandlers: function() {
        this.stopListeningTo($(document));

        // unbind scroll listening
        unbindAnyScroll(this.handleTouchScrollProxy);
        if (this.scrollEl) {
            this.stopListeningTo(this.scrollEl, 'scroll');
        }
    },


    // Drag (high-level)
    // -----------------------------------------------------------------------------------------------------------------


    // extraOptions ignored if drag already started
    startDrag: function(ev, extraOptions) {
        this.startInteraction(ev, extraOptions); // ensure interaction began

        if (!this.isDragging) {
            this.isDragging = true;
            this.handleDragStart(ev);
        }
    },


    handleDragStart: function(ev) {
        this.trigger('dragStart', ev);
    },


    handleMove: function(ev) {
        var dx = getEvX(ev) - this.originX;
        var dy = getEvY(ev) - this.originY;
        var minDistance = this.minDistance;
        var distanceSq; // current distance from the origin, squared

        if (!this.isDistanceSurpassed) {
            distanceSq = dx * dx + dy * dy;
            if (distanceSq >= minDistance * minDistance) { // use pythagorean theorem
                this.handleDistanceSurpassed(ev);
            }
        }

        if (this.isDragging) {
            this.handleDrag(dx, dy, ev);
        }
    },


    // Called while the mouse is being moved and when we know a legitimate drag is taking place
    handleDrag: function(dx, dy, ev) {
        this.trigger('drag', dx, dy, ev);
        this.updateAutoScroll(ev); // will possibly cause scrolling
    },


    endDrag: function(ev) {
        if (this.isDragging) {
            this.isDragging = false;
            this.handleDragEnd(ev);
        }
    },


    handleDragEnd: function(ev) {
        this.trigger('dragEnd', ev);
    },


    // Delay
    // -----------------------------------------------------------------------------------------------------------------


    startDelay: function(initialEv) {
        var _this = this;

        if (this.delay) {
            this.delayTimeoutId = setTimeout(function() {
                _this.handleDelayEnd(initialEv);
            }, this.delay);
        }
        else {
            this.handleDelayEnd(initialEv);
        }
    },


    handleDelayEnd: function(initialEv) {
        this.isDelayEnded = true;

        if (this.isDistanceSurpassed) {
            this.startDrag(initialEv);
        }
    },


    // Distance
    // -----------------------------------------------------------------------------------------------------------------


    handleDistanceSurpassed: function(ev) {
        this.isDistanceSurpassed = true;

        if (this.isDelayEnded) {
            this.startDrag(ev);
        }
    },


    // Mouse / Touch
    // -----------------------------------------------------------------------------------------------------------------


    handleTouchMove: function(ev) {
        // prevent inertia and touchmove-scrolling while dragging
        if (this.isDragging) {
            ev.preventDefault();
        }

        this.handleMove(ev);
    },


    handleMouseMove: function(ev) {
        this.handleMove(ev);
    },


    // Scrolling (unrelated to auto-scroll)
    // -----------------------------------------------------------------------------------------------------------------


    handleTouchScroll: function(ev) {
        // if the drag is being initiated by touch, but a scroll happens before
        // the drag-initiating delay is over, cancel the drag
        if (!this.isDragging) {
            this.endInteraction(ev, true); // isCancelled=true
        }
    },


    // Utils
    // -----------------------------------------------------------------------------------------------------------------


    // Triggers a callback. Calls a function in the option hash of the same name.
    // Arguments beyond the first `name` are forwarded on.
    trigger: function(name) {
        if (this.options[name]) {
            this.options[name].apply(this, Array.prototype.slice.call(arguments, 1));
        }
        // makes _methods callable by event name. TODO: kill this
        if (this['_' + name]) {
            this['_' + name].apply(this, Array.prototype.slice.call(arguments, 1));
        }
    }


});

;;
/*
this.scrollEl is set in DragListener
*/
DragListener.mixin({

    isAutoScroll: false,

    scrollBounds: null, // { top, bottom, left, right }
    scrollTopVel: null, // pixels per second
    scrollLeftVel: null, // pixels per second
    scrollIntervalId: null, // ID of setTimeout for scrolling animation loop

    // defaults
    scrollSensitivity: 30, // pixels from edge for scrolling to start
    scrollSpeed: 200, // pixels per second, at maximum speed
    scrollIntervalMs: 50, // millisecond wait between scroll increment


    initAutoScroll: function() {
        var scrollEl = this.scrollEl;

        this.isAutoScroll =
            this.options.scroll &&
            scrollEl &&
            !scrollEl.is(window) &&
            !scrollEl.is(document);

        if (this.isAutoScroll) {
            // debounce makes sure rapid calls don't happen
            this.listenTo(scrollEl, 'scroll', debounce(this.handleDebouncedScroll, 100));
        }
    },


    destroyAutoScroll: function() {
        this.endAutoScroll(); // kill any animation loop

        // remove the scroll handler if there is a scrollEl
        if (this.isAutoScroll) {
            this.stopListeningTo(this.scrollEl, 'scroll'); // will probably get removed by unbindHandlers too :(
        }
    },


    // Computes and stores the bounding rectangle of scrollEl
    computeScrollBounds: function() {
        if (this.isAutoScroll) {
            this.scrollBounds = getOuterRect(this.scrollEl);
            // TODO: use getClientRect in future. but prevents auto scrolling when on top of scrollbars
        }
    },


    // Called when the dragging is in progress and scrolling should be updated
    updateAutoScroll: function(ev) {
        var sensitivity = this.scrollSensitivity;
        var bounds = this.scrollBounds;
        var topCloseness, bottomCloseness;
        var leftCloseness, rightCloseness;
        var topVel = 0;
        var leftVel = 0;

        if (bounds) { // only scroll if scrollEl exists

            // compute closeness to edges. valid range is from 0.0 - 1.0
            topCloseness = (sensitivity - (getEvY(ev) - bounds.top)) / sensitivity;
            bottomCloseness = (sensitivity - (bounds.bottom - getEvY(ev))) / sensitivity;
            leftCloseness = (sensitivity - (getEvX(ev) - bounds.left)) / sensitivity;
            rightCloseness = (sensitivity - (bounds.right - getEvX(ev))) / sensitivity;

            // translate vertical closeness into velocity.
            // mouse must be completely in bounds for velocity to happen.
            if (topCloseness >= 0 && topCloseness <= 1) {
                topVel = topCloseness * this.scrollSpeed * -1; // negative. for scrolling up
            }
            else if (bottomCloseness >= 0 && bottomCloseness <= 1) {
                topVel = bottomCloseness * this.scrollSpeed;
            }

            // translate horizontal closeness into velocity
            if (leftCloseness >= 0 && leftCloseness <= 1) {
                leftVel = leftCloseness * this.scrollSpeed * -1; // negative. for scrolling left
            }
            else if (rightCloseness >= 0 && rightCloseness <= 1) {
                leftVel = rightCloseness * this.scrollSpeed;
            }
        }

        this.setScrollVel(topVel, leftVel);
    },


    // Sets the speed-of-scrolling for the scrollEl
    setScrollVel: function(topVel, leftVel) {

        this.scrollTopVel = topVel;
        this.scrollLeftVel = leftVel;

        this.constrainScrollVel(); // massages into realistic values

        // if there is non-zero velocity, and an animation loop hasn't already started, then START
        if ((this.scrollTopVel || this.scrollLeftVel) && !this.scrollIntervalId) {
            this.scrollIntervalId = setInterval(
                proxy(this, 'scrollIntervalFunc'), // scope to `this`
                this.scrollIntervalMs
            );
        }
    },


    // Forces scrollTopVel and scrollLeftVel to be zero if scrolling has already gone all the way
    constrainScrollVel: function() {
        var el = this.scrollEl;

        if (this.scrollTopVel < 0) { // scrolling up?
            if (el.scrollTop() <= 0) { // already scrolled all the way up?
                this.scrollTopVel = 0;
            }
        }
        else if (this.scrollTopVel > 0) { // scrolling down?
            if (el.scrollTop() + el[0].clientHeight >= el[0].scrollHeight) { // already scrolled all the way down?
                this.scrollTopVel = 0;
            }
        }

        if (this.scrollLeftVel < 0) { // scrolling left?
            if (el.scrollLeft() <= 0) { // already scrolled all the left?
                this.scrollLeftVel = 0;
            }
        }
        else if (this.scrollLeftVel > 0) { // scrolling right?
            if (el.scrollLeft() + el[0].clientWidth >= el[0].scrollWidth) { // already scrolled all the way right?
                this.scrollLeftVel = 0;
            }
        }
    },


    // This function gets called during every iteration of the scrolling animation loop
    scrollIntervalFunc: function() {
        var el = this.scrollEl;
        var frac = this.scrollIntervalMs / 1000; // considering animation frequency, what the vel should be mult'd by

        // change the value of scrollEl's scroll
        if (this.scrollTopVel) {
            el.scrollTop(el.scrollTop() + this.scrollTopVel * frac);
        }
        if (this.scrollLeftVel) {
            el.scrollLeft(el.scrollLeft() + this.scrollLeftVel * frac);
        }

        this.constrainScrollVel(); // since the scroll values changed, recompute the velocities

        // if scrolled all the way, which causes the vels to be zero, stop the animation loop
        if (!this.scrollTopVel && !this.scrollLeftVel) {
            this.endAutoScroll();
        }
    },


    // Kills any existing scrolling animation loop
    endAutoScroll: function() {
        if (this.scrollIntervalId) {
            clearInterval(this.scrollIntervalId);
            this.scrollIntervalId = null;

            this.handleScrollEnd();
        }
    },


    // Get called when the scrollEl is scrolled (NOTE: this is delayed via debounce)
    handleDebouncedScroll: function() {
        // recompute all coordinates, but *only* if this is *not* part of our scrolling animation
        if (!this.scrollIntervalId) {
            this.handleScrollEnd();
        }
    },


    // Called when scrolling has stopped, whether through auto scroll, or the user scrolling
    handleScrollEnd: function() {
    }

});
;;

/* Tracks mouse movements over a component and raises events about which hit the mouse is over.
------------------------------------------------------------------------------------------------------------------------
options:
- subjectEl
- subjectCenter
*/

var HitDragListener = DragListener.extend({

    component: null, // converts coordinates to hits
        // methods: prepareHits, releaseHits, queryHit

    origHit: null, // the hit the mouse was over when listening started
    hit: null, // the hit the mouse is over
    coordAdjust: null, // delta that will be added to the mouse coordinates when computing collisions


    constructor: function(component, options) {
        DragListener.call(this, options); // call the super-constructor

        this.component = component;
    },


    // Called when drag listening starts (but a real drag has not necessarily began).
    // ev might be undefined if dragging was started manually.
    handleInteractionStart: function(ev) {
        var subjectEl = this.subjectEl;
        var subjectRect;
        var origPoint;
        var point;

        this.computeCoords();

        if (ev) {
            origPoint = { left: getEvX(ev), top: getEvY(ev) };
            point = origPoint;

            // constrain the point to bounds of the element being dragged
            if (subjectEl) {
                subjectRect = getOuterRect(subjectEl); // used for centering as well
                point = constrainPoint(point, subjectRect);
            }

            this.origHit = this.queryHit(point.left, point.top);

            // treat the center of the subject as the collision point?
            if (subjectEl && this.options.subjectCenter) {

                // only consider the area the subject overlaps the hit. best for large subjects.
                // TODO: skip this if hit didn't supply left/right/top/bottom
                if (this.origHit) {
                    subjectRect = intersectRects(this.origHit, subjectRect) ||
                        subjectRect; // in case there is no intersection
                }

                point = getRectCenter(subjectRect);
            }

            this.coordAdjust = diffPoints(point, origPoint); // point - origPoint
        }
        else {
            this.origHit = null;
            this.coordAdjust = null;
        }

        // call the super-method. do it after origHit has been computed
        DragListener.prototype.handleInteractionStart.apply(this, arguments);
    },


    // Recomputes the drag-critical positions of elements
    computeCoords: function() {
        this.component.prepareHits();
        this.computeScrollBounds(); // why is this here??????
    },


    // Called when the actual drag has started
    handleDragStart: function(ev) {
        var hit;

        DragListener.prototype.handleDragStart.apply(this, arguments); // call the super-method

        // might be different from this.origHit if the min-distance is large
        hit = this.queryHit(getEvX(ev), getEvY(ev));

        // report the initial hit the mouse is over
        // especially important if no min-distance and drag starts immediately
        if (hit) {
            this.handleHitOver(hit);
        }
    },


    // Called when the drag moves
    handleDrag: function(dx, dy, ev) {
        var hit;

        DragListener.prototype.handleDrag.apply(this, arguments); // call the super-method

        hit = this.queryHit(getEvX(ev), getEvY(ev));

        if (!isHitsEqual(hit, this.hit)) { // a different hit than before?
            if (this.hit) {
                this.handleHitOut();
            }
            if (hit) {
                this.handleHitOver(hit);
            }
        }
    },


    // Called when dragging has been stopped
    handleDragEnd: function() {
        this.handleHitDone();
        DragListener.prototype.handleDragEnd.apply(this, arguments); // call the super-method
    },


    // Called when a the mouse has just moved over a new hit
    handleHitOver: function(hit) {
        var isOrig = isHitsEqual(hit, this.origHit);

        this.hit = hit;

        this.trigger('hitOver', this.hit, isOrig, this.origHit);
    },


    // Called when the mouse has just moved out of a hit
    handleHitOut: function() {
        if (this.hit) {
            this.trigger('hitOut', this.hit);
            this.handleHitDone();
            this.hit = null;
        }
    },


    // Called after a hitOut. Also called before a dragStop
    handleHitDone: function() {
        if (this.hit) {
            this.trigger('hitDone', this.hit);
        }
    },


    // Called when the interaction ends, whether there was a real drag or not
    handleInteractionEnd: function() {
        DragListener.prototype.handleInteractionEnd.apply(this, arguments); // call the super-method

        this.origHit = null;
        this.hit = null;

        this.component.releaseHits();
    },


    // Called when scrolling has stopped, whether through auto scroll, or the user scrolling
    handleScrollEnd: function() {
        DragListener.prototype.handleScrollEnd.apply(this, arguments); // call the super-method

        this.computeCoords(); // hits' absolute positions will be in new places. recompute
    },


    // Gets the hit underneath the coordinates for the given mouse event
    queryHit: function(left, top) {

        if (this.coordAdjust) {
            left += this.coordAdjust.left;
            top += this.coordAdjust.top;
        }

        return this.component.queryHit(left, top);
    }

});


// Returns `true` if the hits are identically equal. `false` otherwise. Must be from the same component.
// Two null values will be considered equal, as two "out of the component" states are the same.
function isHitsEqual(hit0, hit1) {

    if (!hit0 && !hit1) {
        return true;
    }

    if (hit0 && hit1) {
        return hit0.component === hit1.component &&
            isHitPropsWithin(hit0, hit1) &&
            isHitPropsWithin(hit1, hit0); // ensures all props are identical
    }

    return false;
}


// Returns true if all of subHit's non-standard properties are within superHit
function isHitPropsWithin(subHit, superHit) {
    for (var propName in subHit) {
        if (!/^(component|left|right|top|bottom)$/.test(propName)) {
            if (subHit[propName] !== superHit[propName]) {
                return false;
            }
        }
    }
    return true;
}

;;

/* Creates a clone of an element and lets it track the mouse as it moves
----------------------------------------------------------------------------------------------------------------------*/

var MouseFollower = Class.extend(ListenerMixin, {

    options: null,

    sourceEl: null, // the element that will be cloned and made to look like it is dragging
    el: null, // the clone of `sourceEl` that will track the mouse
    parentEl: null, // the element that `el` (the clone) will be attached to

    // the initial position of el, relative to the offset parent. made to match the initial offset of sourceEl
    top0: null,
    left0: null,

    // the absolute coordinates of the initiating touch/mouse action
    y0: null,
    x0: null,

    // the number of pixels the mouse has moved from its initial position
    topDelta: null,
    leftDelta: null,

    isFollowing: false,
    isHidden: false,
    isAnimating: false, // doing the revert animation?

    constructor: function(sourceEl, options) {
        this.options = options = options || {};
        this.sourceEl = sourceEl;
        this.parentEl = options.parentEl ? $(options.parentEl) : sourceEl.parent(); // default to sourceEl's parent
    },


    // Causes the element to start following the mouse
    start: function(ev) {
        if (!this.isFollowing) {
            this.isFollowing = true;

            this.y0 = getEvY(ev);
            this.x0 = getEvX(ev);
            this.topDelta = 0;
            this.leftDelta = 0;

            if (!this.isHidden) {
                this.updatePosition();
            }

            if (getEvIsTouch(ev)) {
                this.listenTo($(document), 'touchmove', this.handleMove);
            }
            else {
                this.listenTo($(document), 'mousemove', this.handleMove);
            }
        }
    },


    // Causes the element to stop following the mouse. If shouldRevert is true, will animate back to original position.
    // `callback` gets invoked when the animation is complete. If no animation, it is invoked immediately.
    stop: function(shouldRevert, callback) {
        var _this = this;
        var revertDuration = this.options.revertDuration;

        function complete() { // might be called by .animate(), which might change `this` context
            _this.isAnimating = false;
            _this.removeElement();

            _this.top0 = _this.left0 = null; // reset state for future updatePosition calls

            if (callback) {
                callback();
            }
        }

        if (this.isFollowing && !this.isAnimating) { // disallow more than one stop animation at a time
            this.isFollowing = false;

            this.stopListeningTo($(document));

            if (shouldRevert && revertDuration && !this.isHidden) { // do a revert animation?
                this.isAnimating = true;
                this.el.animate({
                    top: this.top0,
                    left: this.left0
                }, {
                    duration: revertDuration,
                    complete: complete
                });
            }
            else {
                complete();
            }
        }
    },


    // Gets the tracking element. Create it if necessary
    getEl: function() {
        var el = this.el;

        if (!el) {
            el = this.el = this.sourceEl.clone()
                .addClass(this.options.additionalClass || '')
                .css({
                    position: 'absolute',
                    visibility: '', // in case original element was hidden (commonly through hideEvents())
                    display: this.isHidden ? 'none' : '', // for when initially hidden
                    margin: 0,
                    right: 'auto', // erase and set width instead
                    bottom: 'auto', // erase and set height instead
                    width: this.sourceEl.width(), // explicit height in case there was a 'right' value
                    height: this.sourceEl.height(), // explicit width in case there was a 'bottom' value
                    opacity: this.options.opacity || '',
                    zIndex: this.options.zIndex
                });

            // we don't want long taps or any mouse interaction causing selection/menus.
            // would use preventSelection(), but that prevents selectstart, causing problems.
            el.addClass('fc-unselectable');

            el.appendTo(this.parentEl);
        }

        return el;
    },


    // Removes the tracking element if it has already been created
    removeElement: function() {
        if (this.el) {
            this.el.remove();
            this.el = null;
        }
    },


    // Update the CSS position of the tracking element
    updatePosition: function() {
        var sourceOffset;
        var origin;

        this.getEl(); // ensure this.el

        // make sure origin info was computed
        if (this.top0 === null) {
            sourceOffset = this.sourceEl.offset();
            origin = this.el.offsetParent().offset();
            this.top0 = sourceOffset.top - origin.top;
            this.left0 = sourceOffset.left - origin.left;
        }

        this.el.css({
            top: this.top0 + this.topDelta,
            left: this.left0 + this.leftDelta
        });
    },


    // Gets called when the user moves the mouse
    handleMove: function(ev) {
        this.topDelta = getEvY(ev) - this.y0;
        this.leftDelta = getEvX(ev) - this.x0;

        if (!this.isHidden) {
            this.updatePosition();
        }
    },


    // Temporarily makes the tracking element invisible. Can be called before following starts
    hide: function() {
        if (!this.isHidden) {
            this.isHidden = true;
            if (this.el) {
                this.el.hide();
            }
        }
    },


    // Show the tracking element after it has been temporarily hidden
    show: function() {
        if (this.isHidden) {
            this.isHidden = false;
            this.updatePosition();
            this.getEl().show();
        }
    }

});

;;

/* An abstract class comprised of a "grid" of areas that each represent a specific datetime
----------------------------------------------------------------------------------------------------------------------*/

var Grid = FC.Grid = Class.extend(ListenerMixin, MouseIgnorerMixin, {

    // self-config, overridable by subclasses
    hasDayInteractions: true, // can user click/select ranges of time?

    view: null, // a View object
    isRTL: null, // shortcut to the view's isRTL option

    start: null,
    end: null,

    el: null, // the containing element
    elsByFill: null, // a hash of jQuery element sets used for rendering each fill. Keyed by fill name.

    // derived from options
    eventTimeFormat: null,
    displayEventTime: null,
    displayEventEnd: null,

    minResizeDuration: null, // TODO: hack. set by subclasses. minumum event resize duration

    // if defined, holds the unit identified (ex: "year" or "month") that determines the level of granularity
    // of the date areas. if not defined, assumes to be day and time granularity.
    // TODO: port isTimeScale into same system?
    largeUnit: null,

    dayDragListener: null,
    segDragListener: null,
    segResizeListener: null,
    externalDragListener: null,


    constructor: function(view) {
        this.view = view;
        this.isRTL = view.opt('isRTL');
        this.elsByFill = {};

        this.dayDragListener = this.buildDayDragListener();
        this.initMouseIgnoring();
    },


    /* Options
    ------------------------------------------------------------------------------------------------------------------*/


    // Generates the format string used for event time text, if not explicitly defined by 'timeFormat'
    computeEventTimeFormat: function() {
        return this.view.opt('smallTimeFormat');
    },


    // Determines whether events should have their end times displayed, if not explicitly defined by 'displayEventTime'.
    // Only applies to non-all-day events.
    computeDisplayEventTime: function() {
        return true;
    },


    // Determines whether events should have their end times displayed, if not explicitly defined by 'displayEventEnd'
    computeDisplayEventEnd: function() {
        return true;
    },


    /* Dates
    ------------------------------------------------------------------------------------------------------------------*/


    // Tells the grid about what period of time to display.
    // Any date-related internal data should be generated.
    setRange: function(range) {
        this.start = range.start.clone();
        this.end = range.end.clone();

        this.rangeUpdated();
        this.processRangeOptions();
    },


    // Called when internal variables that rely on the range should be updated
    rangeUpdated: function() {
    },


    // Updates values that rely on options and also relate to range
    processRangeOptions: function() {
        var view = this.view;
        var displayEventTime;
        var displayEventEnd;

        this.eventTimeFormat =
            view.opt('eventTimeFormat') ||
            view.opt('timeFormat') || // deprecated
            this.computeEventTimeFormat();

        displayEventTime = view.opt('displayEventTime');
        if (displayEventTime == null) {
            displayEventTime = this.computeDisplayEventTime(); // might be based off of range
        }

        displayEventEnd = view.opt('displayEventEnd');
        if (displayEventEnd == null) {
            displayEventEnd = this.computeDisplayEventEnd(); // might be based off of range
        }

        this.displayEventTime = displayEventTime;
        this.displayEventEnd = displayEventEnd;
    },


    // Converts a span (has unzoned start/end and any other grid-specific location information)
    // into an array of segments (pieces of events whose format is decided by the grid).
    spanToSegs: function(span) {
        // subclasses must implement
    },


    // Diffs the two dates, returning a duration, based on granularity of the grid
    // TODO: port isTimeScale into this system?
    diffDates: function(a, b) {
        if (this.largeUnit) {
            return diffByUnit(a, b, this.largeUnit);
        }
        else {
            return diffDayTime(a, b);
        }
    },


    /* Hit Area
    ------------------------------------------------------------------------------------------------------------------*/


    // Called before one or more queryHit calls might happen. Should prepare any cached coordinates for queryHit
    prepareHits: function() {
    },


    // Called when queryHit calls have subsided. Good place to clear any coordinate caches.
    releaseHits: function() {
    },


    // Given coordinates from the topleft of the document, return data about the date-related area underneath.
    // Can return an object with arbitrary properties (although top/right/left/bottom are encouraged).
    // Must have a `grid` property, a reference to this current grid. TODO: avoid this
    // The returned object will be processed by getHitSpan and getHitEl.
    queryHit: function(leftOffset, topOffset) {
    },


    // Given position-level information about a date-related area within the grid,
    // should return an object with at least a start/end date. Can provide other information as well.
    getHitSpan: function(hit) {
    },


    // Given position-level information about a date-related area within the grid,
    // should return a jQuery element that best represents it. passed to dayClick callback.
    getHitEl: function(hit) {
    },


    /* Rendering
    ------------------------------------------------------------------------------------------------------------------*/


    // Sets the container element that the grid should render inside of.
    // Does other DOM-related initializations.
    setElement: function(el) {
        this.el = el;

        if (this.hasDayInteractions) {
            preventSelection(el);

            this.bindDayHandler('touchstart', this.dayTouchStart);
            this.bindDayHandler('mousedown', this.dayMousedown);
        }

        // attach event-element-related handlers. in Grid.events
        // same garbage collection note as above.
        this.bindSegHandlers();

        this.bindGlobalHandlers();
    },


    bindDayHandler: function(name, handler) {
        var _this = this;

        // attach a handler to the grid's root element.
        // jQuery will take care of unregistering them when removeElement gets called.
        this.el.on(name, function(ev) {
            if (
                !$(ev.target).is(
                    _this.segSelector + ',' + // directly on an event element
                    _this.segSelector + ' *,' + // within an event element
                    '.fc-more,' + // a "more.." link
                    'a[data-goto]' // a clickable nav link
                )
            ) {
                return handler.call(_this, ev);
            }
        });
    },


    // Removes the grid's container element from the DOM. Undoes any other DOM-related attachments.
    // DOES NOT remove any content beforehand (doesn't clear events or call unrenderDates), unlike View
    removeElement: function() {
        this.unbindGlobalHandlers();
        this.clearDragListeners();

        this.el.remove();

        // NOTE: we don't null-out this.el for the same reasons we don't do it within View::removeElement
    },


    // Renders the basic structure of grid view before any content is rendered
    renderSkeleton: function() {
        // subclasses should implement
    },


    // Renders the grid's date-related content (like areas that represent days/times).
    // Assumes setRange has already been called and the skeleton has already been rendered.
    renderDates: function() {
        // subclasses should implement
    },


    // Unrenders the grid's date-related content
    unrenderDates: function() {
        // subclasses should implement
    },


    /* Handlers
    ------------------------------------------------------------------------------------------------------------------*/


    // Binds DOM handlers to elements that reside outside the grid, such as the document
    bindGlobalHandlers: function() {
        this.listenTo($(document), {
            dragstart: this.externalDragStart, // jqui
            sortstart: this.externalDragStart // jqui
        });
    },


    // Unbinds DOM handlers from elements that reside outside the grid
    unbindGlobalHandlers: function() {
        this.stopListeningTo($(document));
    },


    // Process a mousedown on an element that represents a day. For day clicking and selecting.
    dayMousedown: function(ev) {
        if (!this.isIgnoringMouse) {
            this.dayDragListener.startInteraction(ev, {
                //distance: 5, // needs more work if we want dayClick to fire correctly
            });
        }
    },


    dayTouchStart: function(ev) {
        var view = this.view;

        // HACK to prevent a user's clickaway for unselecting a range or an event
        // from causing a dayClick.
        if (view.isSelected || view.selectedEvent) {
            this.tempIgnoreMouse();
        }

        this.dayDragListener.startInteraction(ev, {
            delay: this.view.opt('longPressDelay')
        });
    },


    // Creates a listener that tracks the user's drag across day elements.
    // For day clicking and selecting.
    buildDayDragListener: function() {
        var _this = this;
        var view = this.view;
        var isSelectable = view.opt('selectable');
        var dayClickHit; // null if invalid dayClick
        var selectionSpan; // null if invalid selection

        // this listener tracks a mousedown on a day element, and a subsequent drag.
        // if the drag ends on the same day, it is a 'dayClick'.
        // if 'selectable' is enabled, this listener also detects selections.
        var dragListener = new HitDragListener(this, {
            scroll: view.opt('dragScroll'),
            interactionStart: function() {
                dayClickHit = dragListener.origHit; // for dayClick, where no dragging happens
                selectionSpan = null;
            },
            dragStart: function() {
                view.unselect(); // since we could be rendering a new selection, we want to clear any old one
            },
            hitOver: function(hit, isOrig, origHit) {
                if (origHit) { // click needs to have started on a hit

                    // if user dragged to another cell at any point, it can no longer be a dayClick
                    if (!isOrig) {
                        dayClickHit = null;
                    }

                    if (isSelectable) {
                        selectionSpan = _this.computeSelection(
                            _this.getHitSpan(origHit),
                            _this.getHitSpan(hit)
                        );
                        if (selectionSpan) {
                            _this.renderSelection(selectionSpan);
                        }
                        else if (selectionSpan === false) {
                            disableCursor();
                        }
                    }
                }
            },
            hitOut: function() { // called before mouse moves to a different hit OR moved out of all hits
                dayClickHit = null;
                selectionSpan = null;
                _this.unrenderSelection();
            },
            hitDone: function() { // called after a hitOut OR before a dragEnd
                enableCursor();
            },
            interactionEnd: function(ev, isCancelled) {
                if (!isCancelled) {
                    if (
                        dayClickHit &&
                        !_this.isIgnoringMouse // see hack in dayTouchStart
                    ) {
                        view.triggerDayClick(
                            _this.getHitSpan(dayClickHit),
                            _this.getHitEl(dayClickHit),
                            ev
                        );
                    }
                    if (selectionSpan) {
                        // the selection will already have been rendered. just report it
                        view.reportSelection(selectionSpan, ev);
                    }
                }
            }
        });

        return dragListener;
    },


    // Kills all in-progress dragging.
    // Useful for when public API methods that result in re-rendering are invoked during a drag.
    // Also useful for when touch devices misbehave and don't fire their touchend.
    clearDragListeners: function() {
        this.dayDragListener.endInteraction();

        if (this.segDragListener) {
            this.segDragListener.endInteraction(); // will clear this.segDragListener
        }
        if (this.segResizeListener) {
            this.segResizeListener.endInteraction(); // will clear this.segResizeListener
        }
        if (this.externalDragListener) {
            this.externalDragListener.endInteraction(); // will clear this.externalDragListener
        }
    },


    /* Event Helper
    ------------------------------------------------------------------------------------------------------------------*/
    // TODO: should probably move this to Grid.events, like we did event dragging / resizing


    // Renders a mock event at the given event location, which contains zoned start/end properties.
    // Returns all mock event elements.
    renderEventLocationHelper: function(eventLocation, sourceSeg) {
        var fakeEvent = this.fabricateHelperEvent(eventLocation, sourceSeg);

        return this.renderHelper(fakeEvent, sourceSeg); // do the actual rendering
    },


    // Builds a fake event given zoned event date properties and a segment is should be inspired from.
    // The range's end can be null, in which case the mock event that is rendered will have a null end time.
    // `sourceSeg` is the internal segment object involved in the drag. If null, something external is dragging.
    fabricateHelperEvent: function(eventLocation, sourceSeg) {
        var fakeEvent = sourceSeg ? createObject(sourceSeg.event) : {}; // mask the original event object if possible

        fakeEvent.start = eventLocation.start.clone();
        fakeEvent.end = eventLocation.end ? eventLocation.end.clone() : null;
        fakeEvent.allDay = null; // force it to be freshly computed by normalizeEventDates
        this.view.calendar.normalizeEventDates(fakeEvent);

        // this extra className will be useful for differentiating real events from mock events in CSS
        fakeEvent.className = (fakeEvent.className || []).concat('fc-helper');

        // if something external is being dragged in, don't render a resizer
        if (!sourceSeg) {
            fakeEvent.editable = false;
        }

        return fakeEvent;
    },


    // Renders a mock event. Given zoned event date properties.
    // Must return all mock event elements.
    renderHelper: function(eventLocation, sourceSeg) {
        // subclasses must implement
    },


    // Unrenders a mock event
    unrenderHelper: function() {
        // subclasses must implement
    },


    /* Selection
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a visual indication of a selection. Will highlight by default but can be overridden by subclasses.
    // Given a span (unzoned start/end and other misc data)
    renderSelection: function(span) {
        this.renderHighlight(span);
    },


    // Unrenders any visual indications of a selection. Will unrender a highlight by default.
    unrenderSelection: function() {
        this.unrenderHighlight();
    },


    // Given the first and last date-spans of a selection, returns another date-span object.
    // Subclasses can override and provide additional data in the span object. Will be passed to renderSelection().
    // Will return false if the selection is invalid and this should be indicated to the user.
    // Will return null/undefined if a selection invalid but no error should be reported.
    computeSelection: function(span0, span1) {
        var span = this.computeSelectionSpan(span0, span1);

        if (span && !this.view.calendar.isSelectionSpanAllowed(span)) {
            return false;
        }

        return span;
    },


    // Given two spans, must return the combination of the two.
    // TODO: do this separation of concerns (combining VS validation) for event dnd/resize too.
    computeSelectionSpan: function(span0, span1) {
        var dates = [ span0.start, span0.end, span1.start, span1.end ];

        dates.sort(compareNumbers); // sorts chronologically. works with Moments

        return { start: dates[0].clone(), end: dates[3].clone() };
    },


    /* Highlight
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders an emphasis on the given date range. Given a span (unzoned start/end and other misc data)
    renderHighlight: function(span) {
        this.renderFill('highlight', this.spanToSegs(span));
    },


    // Unrenders the emphasis on a date range
    unrenderHighlight: function() {
        this.unrenderFill('highlight');
    },


    // Generates an array of classNames for rendering the highlight. Used by the fill system.
    highlightSegClasses: function() {
        return [ 'fc-highlight' ];
    },


    /* Business Hours
    ------------------------------------------------------------------------------------------------------------------*/


    renderBusinessHours: function() {
    },


    unrenderBusinessHours: function() {
    },


    /* Now Indicator
    ------------------------------------------------------------------------------------------------------------------*/


    getNowIndicatorUnit: function() {
    },


    renderNowIndicator: function(date) {
    },


    unrenderNowIndicator: function() {
    },


    /* Fill System (highlight, background events, business hours)
    --------------------------------------------------------------------------------------------------------------------
    TODO: remove this system. like we did in TimeGrid
    */


    // Renders a set of rectangles over the given segments of time.
    // MUST RETURN a subset of segs, the segs that were actually rendered.
    // Responsible for populating this.elsByFill. TODO: better API for expressing this requirement
    renderFill: function(type, segs) {
        // subclasses must implement
    },


    // Unrenders a specific type of fill that is currently rendered on the grid
    unrenderFill: function(type) {
        var el = this.elsByFill[type];

        if (el) {
            el.remove();
            delete this.elsByFill[type];
        }
    },


    // Renders and assigns an `el` property for each fill segment. Generic enough to work with different types.
    // Only returns segments that successfully rendered.
    // To be harnessed by renderFill (implemented by subclasses).
    // Analagous to renderFgSegEls.
    renderFillSegEls: function(type, segs) {
        var _this = this;
        var segElMethod = this[type + 'SegEl'];
        var html = '';
        var renderedSegs = [];
        var i;

        if (segs.length) {

            // build a large concatenation of segment HTML
            for (i = 0; i < segs.length; i++) {
                html += this.fillSegHtml(type, segs[i]);
            }

            // Grab individual elements from the combined HTML string. Use each as the default rendering.
            // Then, compute the 'el' for each segment.
            $(html).each(function(i, node) {
                var seg = segs[i];
                var el = $(node);

                // allow custom filter methods per-type
                if (segElMethod) {
                    el = segElMethod.call(_this, seg, el);
                }

                if (el) { // custom filters did not cancel the render
                    el = $(el); // allow custom filter to return raw DOM node

                    // correct element type? (would be bad if a non-TD were inserted into a table for example)
                    if (el.is(_this.fillSegTag)) {
                        seg.el = el;
                        renderedSegs.push(seg);
                    }
                }
            });
        }

        return renderedSegs;
    },


    fillSegTag: 'div', // subclasses can override


    // Builds the HTML needed for one fill segment. Generic enough to work with different types.
    fillSegHtml: function(type, seg) {

        // custom hooks per-type
        var classesMethod = this[type + 'SegClasses'];
        var cssMethod = this[type + 'SegCss'];

        var classes = classesMethod ? classesMethod.call(this, seg) : [];
        var css = cssToStr(cssMethod ? cssMethod.call(this, seg) : {});

        return '<' + this.fillSegTag +
            (classes.length ? ' class="' + classes.join(' ') + '"' : '') +
            (css ? ' style="' + css + '"' : '') +
            ' />';
    },



    /* Generic rendering utilities for subclasses
    ------------------------------------------------------------------------------------------------------------------*/


    // Computes HTML classNames for a single-day element
    getDayClasses: function(date) {
        var view = this.view;
        var today = view.calendar.getNow();
        var classes = [ 'fc-' + dayIDs[date.day()] ];

        if (
            view.intervalDuration.as('months') == 1 &&
            date.month() != view.intervalStart.month()
        ) {
            classes.push('fc-other-month');
        }

        if (date.isSame(today, 'day')) {
            classes.push(
                'fc-today',
                view.highlightStateClass
            );
        }
        else if (date < today) {
            classes.push('fc-past');
        }
        else {
            classes.push('fc-future');
        }

        return classes;
    }

});

;;

/* Event-rendering and event-interaction methods for the abstract Grid class
----------------------------------------------------------------------------------------------------------------------*/

Grid.mixin({

    // self-config, overridable by subclasses
    segSelector: '.fc-event-container > *', // what constitutes an event element?

    mousedOverSeg: null, // the segment object the user's mouse is over. null if over nothing
    isDraggingSeg: false, // is a segment being dragged? boolean
    isResizingSeg: false, // is a segment being resized? boolean
    isDraggingExternal: false, // jqui-dragging an external element? boolean
    segs: null, // the *event* segments currently rendered in the grid. TODO: rename to `eventSegs`


    // Renders the given events onto the grid
    renderEvents: function(events) {
        var bgEvents = [];
        var fgEvents = [];
        var i;

        for (i = 0; i < events.length; i++) {
            (isBgEvent(events[i]) ? bgEvents : fgEvents).push(events[i]);
        }

        this.segs = [].concat( // record all segs
            this.renderBgEvents(bgEvents),
            this.renderFgEvents(fgEvents)
        );
    },


    renderBgEvents: function(events) {
        var segs = this.eventsToSegs(events);

        // renderBgSegs might return a subset of segs, segs that were actually rendered
        return this.renderBgSegs(segs) || segs;
    },


    renderFgEvents: function(events) {
        var segs = this.eventsToSegs(events);

        // renderFgSegs might return a subset of segs, segs that were actually rendered
        return this.renderFgSegs(segs) || segs;
    },


    // Unrenders all events currently rendered on the grid
    unrenderEvents: function() {
        this.handleSegMouseout(); // trigger an eventMouseout if user's mouse is over an event
        this.clearDragListeners();

        this.unrenderFgSegs();
        this.unrenderBgSegs();

        this.segs = null;
    },


    // Retrieves all rendered segment objects currently rendered on the grid
    getEventSegs: function() {
        return this.segs || [];
    },


    /* Foreground Segment Rendering
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders foreground event segments onto the grid. May return a subset of segs that were rendered.
    renderFgSegs: function(segs) {
        // subclasses must implement
    },


    // Unrenders all currently rendered foreground segments
    unrenderFgSegs: function() {
        // subclasses must implement
    },


    // Renders and assigns an `el` property for each foreground event segment.
    // Only returns segments that successfully rendered.
    // A utility that subclasses may use.
    renderFgSegEls: function(segs, disableResizing) {
        var view = this.view;
        var html = '';
        var renderedSegs = [];
        var i;

        if (segs.length) { // don't build an empty html string

            // build a large concatenation of event segment HTML
            for (i = 0; i < segs.length; i++) {
                html += this.fgSegHtml(segs[i], disableResizing);
            }

            // Grab individual elements from the combined HTML string. Use each as the default rendering.
            // Then, compute the 'el' for each segment. An el might be null if the eventRender callback returned false.
            $(html).each(function(i, node) {
                var seg = segs[i];
                var el = view.resolveEventEl(seg.event, $(node));

                if (el) {
                    el.data('fc-seg', seg); // used by handlers
                    seg.el = el;
                    renderedSegs.push(seg);
                }
            });
        }

        return renderedSegs;
    },


    // Generates the HTML for the default rendering of a foreground event segment. Used by renderFgSegEls()
    fgSegHtml: function(seg, disableResizing) {
        // subclasses should implement
    },


    /* Background Segment Rendering
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders the given background event segments onto the grid.
    // Returns a subset of the segs that were actually rendered.
    renderBgSegs: function(segs) {
        return this.renderFill('bgEvent', segs);
    },


    // Unrenders all the currently rendered background event segments
    unrenderBgSegs: function() {
        this.unrenderFill('bgEvent');
    },


    // Renders a background event element, given the default rendering. Called by the fill system.
    bgEventSegEl: function(seg, el) {
        return this.view.resolveEventEl(seg.event, el); // will filter through eventRender
    },


    // Generates an array of classNames to be used for the default rendering of a background event.
    // Called by fillSegHtml.
    bgEventSegClasses: function(seg) {
        var event = seg.event;
        var source = event.source || {};

        return [ 'fc-bgevent' ].concat(
            event.className,
            source.className || []
        );
    },


    // Generates a semicolon-separated CSS string to be used for the default rendering of a background event.
    // Called by fillSegHtml.
    bgEventSegCss: function(seg) {
        return {
            'background-color': this.getSegSkinCss(seg)['background-color']
        };
    },


    // Generates an array of classNames to be used for the rendering business hours overlay. Called by the fill system.
    // Called by fillSegHtml.
    businessHoursSegClasses: function(seg) {
        return [ 'fc-nonbusiness', 'fc-bgevent' ];
    },


    /* Business Hours
    ------------------------------------------------------------------------------------------------------------------*/


    // Compute business hour segs for the grid's current date range.
    // Caller must ask if whole-day business hours are needed.
    buildBusinessHourSegs: function(wholeDay) {
        var events = this.view.calendar.getCurrentBusinessHourEvents(wholeDay);

        // HACK. Eventually refactor business hours "events" system.
        // If no events are given, but businessHours is activated, this means the entire visible range should be
        // marked as *not* business-hours, via inverse-background rendering.
        if (
            !events.length &&
            this.view.calendar.options.businessHours // don't access view option. doesn't update with dynamic options
        ) {
            events = [
                $.extend({}, BUSINESS_HOUR_EVENT_DEFAULTS, {
                    start: this.view.end, // guaranteed out-of-range
                    end: this.view.end,   // "
                    dow: null
                })
            ];
        }

        return this.eventsToSegs(events);
    },


    /* Handlers
    ------------------------------------------------------------------------------------------------------------------*/


    // Attaches event-element-related handlers for *all* rendered event segments of the view.
    bindSegHandlers: function() {
        this.bindSegHandlersToEl(this.el);
    },


    // Attaches event-element-related handlers to an arbitrary container element. leverages bubbling.
    bindSegHandlersToEl: function(el) {
        this.bindSegHandlerToEl(el, 'touchstart', this.handleSegTouchStart);
        this.bindSegHandlerToEl(el, 'touchend', this.handleSegTouchEnd);
        this.bindSegHandlerToEl(el, 'mouseenter', this.handleSegMouseover);
        this.bindSegHandlerToEl(el, 'mouseleave', this.handleSegMouseout);
        this.bindSegHandlerToEl(el, 'mousedown', this.handleSegMousedown);
        this.bindSegHandlerToEl(el, 'click', this.handleSegClick);
    },


    // Executes a handler for any a user-interaction on a segment.
    // Handler gets called with (seg, ev), and with the `this` context of the Grid
    bindSegHandlerToEl: function(el, name, handler) {
        var _this = this;

        el.on(name, this.segSelector, function(ev) {
            var seg = $(this).data('fc-seg'); // grab segment data. put there by View::renderEvents

            // only call the handlers if there is not a drag/resize in progress
            if (seg && !_this.isDraggingSeg && !_this.isResizingSeg) {
                return handler.call(_this, seg, ev); // context will be the Grid
            }
        });
    },


    handleSegClick: function(seg, ev) {
        var res = this.view.trigger('eventClick', seg.el[0], seg.event, ev); // can return `false` to cancel
        if (res === false) {
            ev.preventDefault();
        }
    },


    // Updates internal state and triggers handlers for when an event element is moused over
    handleSegMouseover: function(seg, ev) {
        if (
            !this.isIgnoringMouse &&
            !this.mousedOverSeg
        ) {
            this.mousedOverSeg = seg;
            if (this.view.isEventResizable(seg.event)) {
                seg.el.addClass('fc-allow-mouse-resize');
            }
            this.view.trigger('eventMouseover', seg.el[0], seg.event, ev);
        }
    },


    // Updates internal state and triggers handlers for when an event element is moused out.
    // Can be given no arguments, in which case it will mouseout the segment that was previously moused over.
    handleSegMouseout: function(seg, ev) {
        ev = ev || {}; // if given no args, make a mock mouse event

        if (this.mousedOverSeg) {
            seg = seg || this.mousedOverSeg; // if given no args, use the currently moused-over segment
            this.mousedOverSeg = null;
            if (this.view.isEventResizable(seg.event)) {
                seg.el.removeClass('fc-allow-mouse-resize');
            }
            this.view.trigger('eventMouseout', seg.el[0], seg.event, ev);
        }
    },


    handleSegMousedown: function(seg, ev) {
        var isResizing = this.startSegResize(seg, ev, { distance: 5 });

        if (!isResizing && this.view.isEventDraggable(seg.event)) {
            this.buildSegDragListener(seg)
                .startInteraction(ev, {
                    distance: 5
                });
        }
    },


    handleSegTouchStart: function(seg, ev) {
        var view = this.view;
        var event = seg.event;
        var isSelected = view.isEventSelected(event);
        var isDraggable = view.isEventDraggable(event);
        var isResizable = view.isEventResizable(event);
        var isResizing = false;
        var dragListener;

        if (isSelected && isResizable) {
            // only allow resizing of the event is selected
            isResizing = this.startSegResize(seg, ev);
        }

        if (!isResizing && (isDraggable || isResizable)) { // allowed to be selected?

            dragListener = isDraggable ?
                this.buildSegDragListener(seg) :
                this.buildSegSelectListener(seg); // seg isn't draggable, but still needs to be selected

            dragListener.startInteraction(ev, { // won't start if already started
                delay: isSelected ? 0 : this.view.opt('longPressDelay') // do delay if not already selected
            });
        }

        // a long tap simulates a mouseover. ignore this bogus mouseover.
        this.tempIgnoreMouse();
    },


    handleSegTouchEnd: function(seg, ev) {
        // touchstart+touchend = click, which simulates a mouseover.
        // ignore this bogus mouseover.
        this.tempIgnoreMouse();
    },


    // returns boolean whether resizing actually started or not.
    // assumes the seg allows resizing.
    // `dragOptions` are optional.
    startSegResize: function(seg, ev, dragOptions) {
        if ($(ev.target).is('.fc-resizer')) {
            this.buildSegResizeListener(seg, $(ev.target).is('.fc-start-resizer'))
                .startInteraction(ev, dragOptions);
            return true;
        }
        return false;
    },



    /* Event Dragging
    ------------------------------------------------------------------------------------------------------------------*/


    // Builds a listener that will track user-dragging on an event segment.
    // Generic enough to work with any type of Grid.
    // Has side effect of setting/unsetting `segDragListener`
    buildSegDragListener: function(seg) {
        var _this = this;
        var view = this.view;
        var calendar = view.calendar;
        var el = seg.el;
        var event = seg.event;
        var isDragging;
        var mouseFollower; // A clone of the original element that will move with the mouse
        var dropLocation; // zoned event date properties

        if (this.segDragListener) {
            return this.segDragListener;
        }

        // Tracks mouse movement over the *view's* coordinate map. Allows dragging and dropping between subcomponents
        // of the view.
        var dragListener = this.segDragListener = new HitDragListener(view, {
            scroll: view.opt('dragScroll'),
            subjectEl: el,
            subjectCenter: true,
            interactionStart: function(ev) {
                seg.component = _this; // for renderDrag
                isDragging = false;
                mouseFollower = new MouseFollower(seg.el, {
                    additionalClass: 'fc-dragging',
                    parentEl: view.el,
                    opacity: dragListener.isTouch ? null : view.opt('dragOpacity'),
                    revertDuration: view.opt('dragRevertDuration'),
                    zIndex: 2 // one above the .fc-view
                });
                mouseFollower.hide(); // don't show until we know this is a real drag
                mouseFollower.start(ev);
            },
            dragStart: function(ev) {
                if (dragListener.isTouch && !view.isEventSelected(event)) {
                    // if not previously selected, will fire after a delay. then, select the event
                    view.selectEvent(event);
                }
                isDragging = true;
                _this.handleSegMouseout(seg, ev); // ensure a mouseout on the manipulated event has been reported
                _this.segDragStart(seg, ev);
                view.hideEvent(event); // hide all event segments. our mouseFollower will take over
            },
            hitOver: function(hit, isOrig, origHit) {
                var dragHelperEls;

                // starting hit could be forced (DayGrid.limit)
                if (seg.hit) {
                    origHit = seg.hit;
                }

                // since we are querying the parent view, might not belong to this grid
                dropLocation = _this.computeEventDrop(
                    origHit.component.getHitSpan(origHit),
                    hit.component.getHitSpan(hit),
                    event
                );

                if (dropLocation && !calendar.isEventSpanAllowed(_this.eventToSpan(dropLocation), event)) {
                    disableCursor();
                    dropLocation = null;
                }

                // if a valid drop location, have the subclass render a visual indication
                if (dropLocation && (dragHelperEls = view.renderDrag(dropLocation, seg))) {

                    dragHelperEls.addClass('fc-dragging');
                    if (!dragListener.isTouch) {
                        _this.applyDragOpacity(dragHelperEls);
                    }

                    mouseFollower.hide(); // if the subclass is already using a mock event "helper", hide our own
                }
                else {
                    mouseFollower.show(); // otherwise, have the helper follow the mouse (no snapping)
                }

                if (isOrig) {
                    dropLocation = null; // needs to have moved hits to be a valid drop
                }
            },
            hitOut: function() { // called before mouse moves to a different hit OR moved out of all hits
                view.unrenderDrag(); // unrender whatever was done in renderDrag
                mouseFollower.show(); // show in case we are moving out of all hits
                dropLocation = null;
            },
            hitDone: function() { // Called after a hitOut OR before a dragEnd
                enableCursor();
            },
            interactionEnd: function(ev) {
                delete seg.component; // prevent side effects

                // do revert animation if hasn't changed. calls a callback when finished (whether animation or not)
                mouseFollower.stop(!dropLocation, function() {
                    if (isDragging) {
                        view.unrenderDrag();
                        view.showEvent(event);
                        _this.segDragStop(seg, ev);
                    }
                    if (dropLocation) {
                        view.reportEventDrop(event, dropLocation, this.largeUnit, el, ev);
                    }
                });
                _this.segDragListener = null;
            }
        });

        return dragListener;
    },


    // seg isn't draggable, but let's use a generic DragListener
    // simply for the delay, so it can be selected.
    // Has side effect of setting/unsetting `segDragListener`
    buildSegSelectListener: function(seg) {
        var _this = this;
        var view = this.view;
        var event = seg.event;

        if (this.segDragListener) {
            return this.segDragListener;
        }

        var dragListener = this.segDragListener = new DragListener({
            dragStart: function(ev) {
                if (dragListener.isTouch && !view.isEventSelected(event)) {
                    // if not previously selected, will fire after a delay. then, select the event
                    view.selectEvent(event);
                }
            },
            interactionEnd: function(ev) {
                _this.segDragListener = null;
            }
        });

        return dragListener;
    },


    // Called before event segment dragging starts
    segDragStart: function(seg, ev) {
        this.isDraggingSeg = true;
        this.view.trigger('eventDragStart', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
    },


    // Called after event segment dragging stops
    segDragStop: function(seg, ev) {
        this.isDraggingSeg = false;
        this.view.trigger('eventDragStop', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
    },


    // Given the spans an event drag began, and the span event was dropped, calculates the new zoned start/end/allDay
    // values for the event. Subclasses may override and set additional properties to be used by renderDrag.
    // A falsy returned value indicates an invalid drop.
    // DOES NOT consider overlap/constraint.
    computeEventDrop: function(startSpan, endSpan, event) {
        var calendar = this.view.calendar;
        var dragStart = startSpan.start;
        var dragEnd = endSpan.start;
        var delta;
        var dropLocation; // zoned event date properties

        if (dragStart.hasTime() === dragEnd.hasTime()) {
            delta = this.diffDates(dragEnd, dragStart);

            // if an all-day event was in a timed area and it was dragged to a different time,
            // guarantee an end and adjust start/end to have times
            if (event.allDay && durationHasTime(delta)) {
                dropLocation = {
                    start: event.start.clone(),
                    end: calendar.getEventEnd(event), // will be an ambig day
                    allDay: false // for normalizeEventTimes
                };
                calendar.normalizeEventTimes(dropLocation);
            }
            // othewise, work off existing values
            else {
                dropLocation = pluckEventDateProps(event);
            }

            dropLocation.start.add(delta);
            if (dropLocation.end) {
                dropLocation.end.add(delta);
            }
        }
        else {
            // if switching from day <-> timed, start should be reset to the dropped date, and the end cleared
            dropLocation = {
                start: dragEnd.clone(),
                end: null, // end should be cleared
                allDay: !dragEnd.hasTime()
            };
        }

        return dropLocation;
    },


    // Utility for apply dragOpacity to a jQuery set
    applyDragOpacity: function(els) {
        var opacity = this.view.opt('dragOpacity');

        if (opacity != null) {
            els.css('opacity', opacity);
        }
    },


    /* External Element Dragging
    ------------------------------------------------------------------------------------------------------------------*/


    // Called when a jQuery UI drag is initiated anywhere in the DOM
    externalDragStart: function(ev, ui) {
        var view = this.view;
        var el;
        var accept;

        if (view.opt('droppable')) { // only listen if this setting is on
            el = $((ui ? ui.item : null) || ev.target);

            // Test that the dragged element passes the dropAccept selector or filter function.
            // FYI, the default is "*" (matches all)
            accept = view.opt('dropAccept');
            if ($.isFunction(accept) ? accept.call(el[0], el) : el.is(accept)) {
                if (!this.isDraggingExternal) { // prevent double-listening if fired twice
                    this.listenToExternalDrag(el, ev, ui);
                }
            }
        }
    },


    // Called when a jQuery UI drag starts and it needs to be monitored for dropping
    listenToExternalDrag: function(el, ev, ui) {
        var _this = this;
        var calendar = this.view.calendar;
        var meta = getDraggedElMeta(el); // extra data about event drop, including possible event to create
        var dropLocation; // a null value signals an unsuccessful drag

        // listener that tracks mouse movement over date-associated pixel regions
        var dragListener = _this.externalDragListener = new HitDragListener(this, {
            interactionStart: function() {
                _this.isDraggingExternal = true;
            },
            hitOver: function(hit) {
                dropLocation = _this.computeExternalDrop(
                    hit.component.getHitSpan(hit), // since we are querying the parent view, might not belong to this grid
                    meta
                );

                if ( // invalid hit?
                    dropLocation &&
                    !calendar.isExternalSpanAllowed(_this.eventToSpan(dropLocation), dropLocation, meta.eventProps)
                ) {
                    disableCursor();
                    dropLocation = null;
                }

                if (dropLocation) {
                    _this.renderDrag(dropLocation); // called without a seg parameter
                }
            },
            hitOut: function() {
                dropLocation = null; // signal unsuccessful
            },
            hitDone: function() { // Called after a hitOut OR before a dragEnd
                enableCursor();
                _this.unrenderDrag();
            },
            interactionEnd: function(ev) {
                if (dropLocation) { // element was dropped on a valid hit
                    _this.view.reportExternalDrop(meta, dropLocation, el, ev, ui);
                }
                _this.isDraggingExternal = false;
                _this.externalDragListener = null;
            }
        });

        dragListener.startDrag(ev); // start listening immediately
    },


    // Given a hit to be dropped upon, and misc data associated with the jqui drag (guaranteed to be a plain object),
    // returns the zoned start/end dates for the event that would result from the hypothetical drop. end might be null.
    // Returning a null value signals an invalid drop hit.
    // DOES NOT consider overlap/constraint.
    computeExternalDrop: function(span, meta) {
        var calendar = this.view.calendar;
        var dropLocation = {
            start: calendar.applyTimezone(span.start), // simulate a zoned event start date
            end: null
        };

        // if dropped on an all-day span, and element's metadata specified a time, set it
        if (meta.startTime && !dropLocation.start.hasTime()) {
            dropLocation.start.time(meta.startTime);
        }

        if (meta.duration) {
            dropLocation.end = dropLocation.start.clone().add(meta.duration);
        }

        return dropLocation;
    },



    /* Drag Rendering (for both events and an external elements)
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a visual indication of an event or external element being dragged.
    // `dropLocation` contains hypothetical start/end/allDay values the event would have if dropped. end can be null.
    // `seg` is the internal segment object that is being dragged. If dragging an external element, `seg` is null.
    // A truthy returned value indicates this method has rendered a helper element.
    // Must return elements used for any mock events.
    renderDrag: function(dropLocation, seg) {
        // subclasses must implement
    },


    // Unrenders a visual indication of an event or external element being dragged
    unrenderDrag: function() {
        // subclasses must implement
    },


    /* Resizing
    ------------------------------------------------------------------------------------------------------------------*/


    // Creates a listener that tracks the user as they resize an event segment.
    // Generic enough to work with any type of Grid.
    buildSegResizeListener: function(seg, isStart) {
        var _this = this;
        var view = this.view;
        var calendar = view.calendar;
        var el = seg.el;
        var event = seg.event;
        var eventEnd = calendar.getEventEnd(event);
        var isDragging;
        var resizeLocation; // zoned event date properties. falsy if invalid resize

        // Tracks mouse movement over the *grid's* coordinate map
        var dragListener = this.segResizeListener = new HitDragListener(this, {
            scroll: view.opt('dragScroll'),
            subjectEl: el,
            interactionStart: function() {
                isDragging = false;
            },
            dragStart: function(ev) {
                isDragging = true;
                _this.handleSegMouseout(seg, ev); // ensure a mouseout on the manipulated event has been reported
                _this.segResizeStart(seg, ev);
            },
            hitOver: function(hit, isOrig, origHit) {
                var origHitSpan = _this.getHitSpan(origHit);
                var hitSpan = _this.getHitSpan(hit);

                resizeLocation = isStart ?
                    _this.computeEventStartResize(origHitSpan, hitSpan, event) :
                    _this.computeEventEndResize(origHitSpan, hitSpan, event);

                if (resizeLocation) {
                    if (!calendar.isEventSpanAllowed(_this.eventToSpan(resizeLocation), event)) {
                        disableCursor();
                        resizeLocation = null;
                    }
                    // no change? (FYI, event dates might have zones)
                    else if (
                        resizeLocation.start.isSame(event.start.clone().stripZone()) &&
                        resizeLocation.end.isSame(eventEnd.clone().stripZone())
                    ) {
                        resizeLocation = null;
                    }
                }

                if (resizeLocation) {
                    view.hideEvent(event);
                    _this.renderEventResize(resizeLocation, seg);
                }
            },
            hitOut: function() { // called before mouse moves to a different hit OR moved out of all hits
                resizeLocation = null;
            },
            hitDone: function() { // resets the rendering to show the original event
                _this.unrenderEventResize();
                view.showEvent(event);
                enableCursor();
            },
            interactionEnd: function(ev) {
                if (isDragging) {
                    _this.segResizeStop(seg, ev);
                }
                if (resizeLocation) { // valid date to resize to?
                    view.reportEventResize(event, resizeLocation, this.largeUnit, el, ev);
                }
                _this.segResizeListener = null;
            }
        });

        return dragListener;
    },


    // Called before event segment resizing starts
    segResizeStart: function(seg, ev) {
        this.isResizingSeg = true;
        this.view.trigger('eventResizeStart', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
    },


    // Called after event segment resizing stops
    segResizeStop: function(seg, ev) {
        this.isResizingSeg = false;
        this.view.trigger('eventResizeStop', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
    },


    // Returns new date-information for an event segment being resized from its start
    computeEventStartResize: function(startSpan, endSpan, event) {
        return this.computeEventResize('start', startSpan, endSpan, event);
    },


    // Returns new date-information for an event segment being resized from its end
    computeEventEndResize: function(startSpan, endSpan, event) {
        return this.computeEventResize('end', startSpan, endSpan, event);
    },


    // Returns new zoned date information for an event segment being resized from its start OR end
    // `type` is either 'start' or 'end'.
    // DOES NOT consider overlap/constraint.
    computeEventResize: function(type, startSpan, endSpan, event) {
        var calendar = this.view.calendar;
        var delta = this.diffDates(endSpan[type], startSpan[type]);
        var resizeLocation; // zoned event date properties
        var defaultDuration;

        // build original values to work from, guaranteeing a start and end
        resizeLocation = {
            start: event.start.clone(),
            end: calendar.getEventEnd(event),
            allDay: event.allDay
        };

        // if an all-day event was in a timed area and was resized to a time, adjust start/end to have times
        if (resizeLocation.allDay && durationHasTime(delta)) {
            resizeLocation.allDay = false;
            calendar.normalizeEventTimes(resizeLocation);
        }

        resizeLocation[type].add(delta); // apply delta to start or end

        // if the event was compressed too small, find a new reasonable duration for it
        if (!resizeLocation.start.isBefore(resizeLocation.end)) {

            defaultDuration =
                this.minResizeDuration || // TODO: hack
                (event.allDay ?
                    calendar.defaultAllDayEventDuration :
                    calendar.defaultTimedEventDuration);

            if (type == 'start') { // resizing the start?
                resizeLocation.start = resizeLocation.end.clone().subtract(defaultDuration);
            }
            else { // resizing the end?
                resizeLocation.end = resizeLocation.start.clone().add(defaultDuration);
            }
        }

        return resizeLocation;
    },


    // Renders a visual indication of an event being resized.
    // `range` has the updated dates of the event. `seg` is the original segment object involved in the drag.
    // Must return elements used for any mock events.
    renderEventResize: function(range, seg) {
        // subclasses must implement
    },


    // Unrenders a visual indication of an event being resized.
    unrenderEventResize: function() {
        // subclasses must implement
    },


    /* Rendering Utils
    ------------------------------------------------------------------------------------------------------------------*/


    // Compute the text that should be displayed on an event's element.
    // `range` can be the Event object itself, or something range-like, with at least a `start`.
    // If event times are disabled, or the event has no time, will return a blank string.
    // If not specified, formatStr will default to the eventTimeFormat setting,
    // and displayEnd will default to the displayEventEnd setting.
    getEventTimeText: function(range, formatStr, displayEnd) {

        if (formatStr == null) {
            formatStr = this.eventTimeFormat;
        }

        if (displayEnd == null) {
            displayEnd = this.displayEventEnd;
        }

        if (this.displayEventTime && range.start.hasTime()) {
            if (displayEnd && range.end) {
                return this.view.formatRange(range, formatStr);
            }
            else {
                return range.start.format(formatStr);
            }
        }

        return '';
    },


    // Generic utility for generating the HTML classNames for an event segment's element
    getSegClasses: function(seg, isDraggable, isResizable) {
        var view = this.view;
        var classes = [
            'fc-event',
            seg.isStart ? 'fc-start' : 'fc-not-start',
            seg.isEnd ? 'fc-end' : 'fc-not-end'
        ].concat(this.getSegCustomClasses(seg));

        if (isDraggable) {
            classes.push('fc-draggable');
        }
        if (isResizable) {
            classes.push('fc-resizable');
        }

        // event is currently selected? attach a className.
        if (view.isEventSelected(seg.event)) {
            classes.push('fc-selected');
        }

        return classes;
    },


    // List of classes that were defined by the caller of the API in some way
    getSegCustomClasses: function(seg) {
        var event = seg.event;

        return [].concat(
            event.className, // guaranteed to be an array
            event.source ? event.source.className : []
        );
    },


    // Utility for generating event skin-related CSS properties
    getSegSkinCss: function(seg) {
        return {
            'background-color': this.getSegBackgroundColor(seg),
            'border-color': this.getSegBorderColor(seg),
            color: this.getSegTextColor(seg)
        };
    },


    // Queries for caller-specified color, then falls back to default
    getSegBackgroundColor: function(seg) {
        return seg.event.backgroundColor ||
            seg.event.color ||
            this.getSegDefaultBackgroundColor(seg);
    },


    getSegDefaultBackgroundColor: function(seg) {
        var source = seg.event.source || {};

        return source.backgroundColor ||
            source.color ||
            this.view.opt('eventBackgroundColor') ||
            this.view.opt('eventColor');
    },


    // Queries for caller-specified color, then falls back to default
    getSegBorderColor: function(seg) {
        return seg.event.borderColor ||
            seg.event.color ||
            this.getSegDefaultBorderColor(seg);
    },


    getSegDefaultBorderColor: function(seg) {
        var source = seg.event.source || {};

        return source.borderColor ||
            source.color ||
            this.view.opt('eventBorderColor') ||
            this.view.opt('eventColor');
    },


    // Queries for caller-specified color, then falls back to default
    getSegTextColor: function(seg) {
        return seg.event.textColor ||
            this.getSegDefaultTextColor(seg);
    },


    getSegDefaultTextColor: function(seg) {
        var source = seg.event.source || {};

        return source.textColor ||
            this.view.opt('eventTextColor');
    },


    /* Converting events -> eventRange -> eventSpan -> eventSegs
    ------------------------------------------------------------------------------------------------------------------*/


    // Generates an array of segments for the given single event
    // Can accept an event "location" as well (which only has start/end and no allDay)
    eventToSegs: function(event) {
        return this.eventsToSegs([ event ]);
    },


    eventToSpan: function(event) {
        return this.eventToSpans(event)[0];
    },


    // Generates spans (always unzoned) for the given event.
    // Does not do any inverting for inverse-background events.
    // Can accept an event "location" as well (which only has start/end and no allDay)
    eventToSpans: function(event) {
        var range = this.eventToRange(event);
        return this.eventRangeToSpans(range, event);
    },



    // Converts an array of event objects into an array of event segment objects.
    // A custom `segSliceFunc` may be given for arbitrarily slicing up events.
    // Doesn't guarantee an order for the resulting array.
    eventsToSegs: function(allEvents, segSliceFunc) {
        var _this = this;
        var eventsById = groupEventsById(allEvents);
        var segs = [];

        $.each(eventsById, function(id, events) {
            var ranges = [];
            var i;

            for (i = 0; i < events.length; i++) {
                ranges.push(_this.eventToRange(events[i]));
            }

            // inverse-background events (utilize only the first event in calculations)
            if (isInverseBgEvent(events[0])) {
                ranges = _this.invertRanges(ranges);

                for (i = 0; i < ranges.length; i++) {
                    segs.push.apply(segs, // append to
                        _this.eventRangeToSegs(ranges[i], events[0], segSliceFunc));
                }
            }
            // normal event ranges
            else {
                for (i = 0; i < ranges.length; i++) {
                    segs.push.apply(segs, // append to
                        _this.eventRangeToSegs(ranges[i], events[i], segSliceFunc));
                }
            }
        });

        return segs;
    },


    // Generates the unzoned start/end dates an event appears to occupy
    // Can accept an event "location" as well (which only has start/end and no allDay)
    eventToRange: function(event) {
        var calendar = this.view.calendar;
        var start = event.start.clone().stripZone();
        var end = (
                event.end ?
                    event.end.clone() :
                    // derive the end from the start and allDay. compute allDay if necessary
                    calendar.getDefaultEventEnd(
                        event.allDay != null ?
                            event.allDay :
                            !event.start.hasTime(),
                        event.start
                    )
            ).stripZone();

        // hack: dynamic locale change forgets to upate stored event localed
        calendar.localizeMoment(start);
        calendar.localizeMoment(end);

        return { start: start, end: end };
    },


    // Given an event's range (unzoned start/end), and the event itself,
    // slice into segments (using the segSliceFunc function if specified)
    eventRangeToSegs: function(range, event, segSliceFunc) {
        var spans = this.eventRangeToSpans(range, event);
        var segs = [];
        var i;

        for (i = 0; i < spans.length; i++) {
            segs.push.apply(segs, // append to
                this.eventSpanToSegs(spans[i], event, segSliceFunc));
        }

        return segs;
    },


    // Given an event's unzoned date range, return an array of "span" objects.
    // Subclasses can override.
    eventRangeToSpans: function(range, event) {
        return [ $.extend({}, range) ]; // copy into a single-item array
    },


    // Given an event's span (unzoned start/end and other misc data), and the event itself,
    // slices into segments and attaches event-derived properties to them.
    eventSpanToSegs: function(span, event, segSliceFunc) {
        var segs = segSliceFunc ? segSliceFunc(span) : this.spanToSegs(span);
        var i, seg;

        for (i = 0; i < segs.length; i++) {
            seg = segs[i];
            seg.event = event;
            seg.eventStartMS = +span.start; // TODO: not the best name after making spans unzoned
            seg.eventDurationMS = span.end - span.start;
        }

        return segs;
    },


    // Produces a new array of range objects that will cover all the time NOT covered by the given ranges.
    // SIDE EFFECT: will mutate the given array and will use its date references.
    invertRanges: function(ranges) {
        var view = this.view;
        var viewStart = view.start.clone(); // need a copy
        var viewEnd = view.end.clone(); // need a copy
        var inverseRanges = [];
        var start = viewStart; // the end of the previous range. the start of the new range
        var i, range;

        // ranges need to be in order. required for our date-walking algorithm
        ranges.sort(compareRanges);

        for (i = 0; i < ranges.length; i++) {
            range = ranges[i];

            // add the span of time before the event (if there is any)
            if (range.start > start) { // compare millisecond time (skip any ambig logic)
                inverseRanges.push({
                    start: start,
                    end: range.start
                });
            }

            start = range.end;
        }

        // add the span of time after the last event (if there is any)
        if (start < viewEnd) { // compare millisecond time (skip any ambig logic)
            inverseRanges.push({
                start: start,
                end: viewEnd
            });
        }

        return inverseRanges;
    },


    sortEventSegs: function(segs) {
        segs.sort(proxy(this, 'compareEventSegs'));
    },


    // A cmp function for determining which segments should take visual priority
    compareEventSegs: function(seg1, seg2) {
        return seg1.eventStartMS - seg2.eventStartMS || // earlier events go first
            seg2.eventDurationMS - seg1.eventDurationMS || // tie? longer events go first
            seg2.event.allDay - seg1.event.allDay || // tie? put all-day events first (booleans cast to 0/1)
            compareByFieldSpecs(seg1.event, seg2.event, this.view.eventOrderSpecs);
    }

});


/* Utilities
----------------------------------------------------------------------------------------------------------------------*/


function pluckEventDateProps(event) {
    return {
        start: event.start.clone(),
        end: event.end ? event.end.clone() : null,
        allDay: event.allDay // keep it the same
    };
}
FC.pluckEventDateProps = pluckEventDateProps;


function isBgEvent(event) { // returns true if background OR inverse-background
    var rendering = getEventRendering(event);
    return rendering === 'background' || rendering === 'inverse-background';
}
FC.isBgEvent = isBgEvent; // export


function isInverseBgEvent(event) {
    return getEventRendering(event) === 'inverse-background';
}


function getEventRendering(event) {
    return firstDefined((event.source || {}).rendering, event.rendering);
}


function groupEventsById(events) {
    var eventsById = {};
    var i, event;

    for (i = 0; i < events.length; i++) {
        event = events[i];
        (eventsById[event._id] || (eventsById[event._id] = [])).push(event);
    }

    return eventsById;
}


// A cmp function for determining which non-inverted "ranges" (see above) happen earlier
function compareRanges(range1, range2) {
    return range1.start - range2.start; // earlier ranges go first
}


/* External-Dragging-Element Data
----------------------------------------------------------------------------------------------------------------------*/

// Require all HTML5 data-* attributes used by FullCalendar to have this prefix.
// A value of '' will query attributes like data-event. A value of 'fc' will query attributes like data-fc-event.
FC.dataAttrPrefix = '';

// Given a jQuery element that might represent a dragged FullCalendar event, returns an intermediate data structure
// to be used for Event Object creation.
// A defined `.eventProps`, even when empty, indicates that an event should be created.
function getDraggedElMeta(el) {
    var prefix = FC.dataAttrPrefix;
    var eventProps; // properties for creating the event, not related to date/time
    var startTime; // a Duration
    var duration;
    var stick;

    if (prefix) { prefix += '-'; }
    eventProps = el.data(prefix + 'event') || null;

    if (eventProps) {
        if (typeof eventProps === 'object') {
            eventProps = $.extend({}, eventProps); // make a copy
        }
        else { // something like 1 or true. still signal event creation
            eventProps = {};
        }

        // pluck special-cased date/time properties
        startTime = eventProps.start;
        if (startTime == null) { startTime = eventProps.time; } // accept 'time' as well
        duration = eventProps.duration;
        stick = eventProps.stick;
        delete eventProps.start;
        delete eventProps.time;
        delete eventProps.duration;
        delete eventProps.stick;
    }

    // fallback to standalone attribute values for each of the date/time properties
    if (startTime == null) { startTime = el.data(prefix + 'start'); }
    if (startTime == null) { startTime = el.data(prefix + 'time'); } // accept 'time' as well
    if (duration == null) { duration = el.data(prefix + 'duration'); }
    if (stick == null) { stick = el.data(prefix + 'stick'); }

    // massage into correct data types
    startTime = startTime != null ? moment.duration(startTime) : null;
    duration = duration != null ? moment.duration(duration) : null;
    stick = Boolean(stick);

    return { eventProps: eventProps, startTime: startTime, duration: duration, stick: stick };
}


;;

/*
A set of rendering and date-related methods for a visual component comprised of one or more rows of day columns.
Prerequisite: the object being mixed into needs to be a *Grid*
*/
var DayTableMixin = FC.DayTableMixin = {

    breakOnWeeks: false, // should create a new row for each week?
    dayDates: null, // whole-day dates for each column. left to right
    dayIndices: null, // for each day from start, the offset
    daysPerRow: null,
    rowCnt: null,
    colCnt: null,
    colHeadFormat: null,


    // Populates internal variables used for date calculation and rendering
    updateDayTable: function() {
        var view = this.view;
        var date = this.start.clone();
        var dayIndex = -1;
        var dayIndices = [];
        var dayDates = [];
        var daysPerRow;
        var firstDay;
        var rowCnt;

        while (date.isBefore(this.end)) { // loop each day from start to end
            if (view.isHiddenDay(date)) {
                dayIndices.push(dayIndex + 0.5); // mark that it's between indices
            }
            else {
                dayIndex++;
                dayIndices.push(dayIndex);
                dayDates.push(date.clone());
            }
            date.add(1, 'days');
        }

        if (this.breakOnWeeks) {
            // count columns until the day-of-week repeats
            firstDay = dayDates[0].day();
            for (daysPerRow = 1; daysPerRow < dayDates.length; daysPerRow++) {
                if (dayDates[daysPerRow].day() == firstDay) {
                    break;
                }
            }
            rowCnt = Math.ceil(dayDates.length / daysPerRow);
        }
        else {
            rowCnt = 1;
            daysPerRow = dayDates.length;
        }

        this.dayDates = dayDates;
        this.dayIndices = dayIndices;
        this.daysPerRow = daysPerRow;
        this.rowCnt = rowCnt;
        
        this.updateDayTableCols();
    },


    // Computes and assigned the colCnt property and updates any options that may be computed from it
    updateDayTableCols: function() {
        this.colCnt = this.computeColCnt();
        this.colHeadFormat = this.view.opt('columnFormat') || this.computeColHeadFormat();
    },


    // Determines how many columns there should be in the table
    computeColCnt: function() {
        return this.daysPerRow;
    },


    // Computes the ambiguously-timed moment for the given cell
    getCellDate: function(row, col) {
        return this.dayDates[
                this.getCellDayIndex(row, col)
            ].clone();
    },


    // Computes the ambiguously-timed date range for the given cell
    getCellRange: function(row, col) {
        var start = this.getCellDate(row, col);
        var end = start.clone().add(1, 'days');

        return { start: start, end: end };
    },


    // Returns the number of day cells, chronologically, from the first of the grid (0-based)
    getCellDayIndex: function(row, col) {
        return row * this.daysPerRow + this.getColDayIndex(col);
    },


    // Returns the numner of day cells, chronologically, from the first cell in *any given row*
    getColDayIndex: function(col) {
        if (this.isRTL) {
            return this.colCnt - 1 - col;
        }
        else {
            return col;
        }
    },


    // Given a date, returns its chronolocial cell-index from the first cell of the grid.
    // If the date lies between cells (because of hiddenDays), returns a floating-point value between offsets.
    // If before the first offset, returns a negative number.
    // If after the last offset, returns an offset past the last cell offset.
    // Only works for *start* dates of cells. Will not work for exclusive end dates for cells.
    getDateDayIndex: function(date) {
        var dayIndices = this.dayIndices;
        var dayOffset = date.diff(this.start, 'days');

        if (dayOffset < 0) {
            return dayIndices[0] - 1;
        }
        else if (dayOffset >= dayIndices.length) {
            return dayIndices[dayIndices.length - 1] + 1;
        }
        else {
            return dayIndices[dayOffset];
        }
    },


    /* Options
    ------------------------------------------------------------------------------------------------------------------*/


    // Computes a default column header formatting string if `colFormat` is not explicitly defined
    computeColHeadFormat: function() {
        // if more than one week row, or if there are a lot of columns with not much space,
        // put just the day numbers will be in each cell
        if (this.rowCnt > 1 || this.colCnt > 10) {
            return 'ddd'; // "Sat"
        }
        // multiple days, so full single date string WON'T be in title text
        else if (this.colCnt > 1) {
            return this.view.opt('dayOfMonthFormat'); // "Sat 12/10"
        }
        // single day, so full single date string will probably be in title text
        else {
            return 'dddd'; // "Saturday"
        }
    },


    /* Slicing
    ------------------------------------------------------------------------------------------------------------------*/


    // Slices up a date range into a segment for every week-row it intersects with
    sliceRangeByRow: function(range) {
        var daysPerRow = this.daysPerRow;
        var normalRange = this.view.computeDayRange(range); // make whole-day range, considering nextDayThreshold
        var rangeFirst = this.getDateDayIndex(normalRange.start); // inclusive first index
        var rangeLast = this.getDateDayIndex(normalRange.end.clone().subtract(1, 'days')); // inclusive last index
        var segs = [];
        var row;
        var rowFirst, rowLast; // inclusive day-index range for current row
        var segFirst, segLast; // inclusive day-index range for segment

        for (row = 0; row < this.rowCnt; row++) {
            rowFirst = row * daysPerRow;
            rowLast = rowFirst + daysPerRow - 1;

            // intersect segment's offset range with the row's
            segFirst = Math.max(rangeFirst, rowFirst);
            segLast = Math.min(rangeLast, rowLast);

            // deal with in-between indices
            segFirst = Math.ceil(segFirst); // in-between starts round to next cell
            segLast = Math.floor(segLast); // in-between ends round to prev cell

            if (segFirst <= segLast) { // was there any intersection with the current row?
                segs.push({
                    row: row,

                    // normalize to start of row
                    firstRowDayIndex: segFirst - rowFirst,
                    lastRowDayIndex: segLast - rowFirst,

                    // must be matching integers to be the segment's start/end
                    isStart: segFirst === rangeFirst,
                    isEnd: segLast === rangeLast
                });
            }
        }

        return segs;
    },


    // Slices up a date range into a segment for every day-cell it intersects with.
    // TODO: make more DRY with sliceRangeByRow somehow.
    sliceRangeByDay: function(range) {
        var daysPerRow = this.daysPerRow;
        var normalRange = this.view.computeDayRange(range); // make whole-day range, considering nextDayThreshold
        var rangeFirst = this.getDateDayIndex(normalRange.start); // inclusive first index
        var rangeLast = this.getDateDayIndex(normalRange.end.clone().subtract(1, 'days')); // inclusive last index
        var segs = [];
        var row;
        var rowFirst, rowLast; // inclusive day-index range for current row
        var i;
        var segFirst, segLast; // inclusive day-index range for segment

        for (row = 0; row < this.rowCnt; row++) {
            rowFirst = row * daysPerRow;
            rowLast = rowFirst + daysPerRow - 1;

            for (i = rowFirst; i <= rowLast; i++) {

                // intersect segment's offset range with the row's
                segFirst = Math.max(rangeFirst, i);
                segLast = Math.min(rangeLast, i);

                // deal with in-between indices
                segFirst = Math.ceil(segFirst); // in-between starts round to next cell
                segLast = Math.floor(segLast); // in-between ends round to prev cell

                if (segFirst <= segLast) { // was there any intersection with the current row?
                    segs.push({
                        row: row,

                        // normalize to start of row
                        firstRowDayIndex: segFirst - rowFirst,
                        lastRowDayIndex: segLast - rowFirst,

                        // must be matching integers to be the segment's start/end
                        isStart: segFirst === rangeFirst,
                        isEnd: segLast === rangeLast
                    });
                }
            }
        }

        return segs;
    },


    /* Header Rendering
    ------------------------------------------------------------------------------------------------------------------*/


    renderHeadHtml: function() {
        var view = this.view;

        return '' +
            '<div class="fc-row ' + view.widgetHeaderClass + '">' +
                '<table>' +
                    '<thead>' +
                        this.renderHeadTrHtml() +
                    '</thead>' +
                '</table>' +
            '</div>';
    },


    renderHeadIntroHtml: function() {
        return this.renderIntroHtml(); // fall back to generic
    },


    renderHeadTrHtml: function() {
        return '' +
            '<tr>' +
                (this.isRTL ? '' : this.renderHeadIntroHtml()) +
                this.renderHeadDateCellsHtml() +
                (this.isRTL ? this.renderHeadIntroHtml() : '') +
            '</tr>';
    },


    renderHeadDateCellsHtml: function() {
        var htmls = [];
        var col, date;

        for (col = 0; col < this.colCnt; col++) {
            date = this.getCellDate(0, col);
            htmls.push(this.renderHeadDateCellHtml(date));
        }

        return htmls.join('');
    },


    // TODO: when internalApiVersion, accept an object for HTML attributes
    // (colspan should be no different)
    renderHeadDateCellHtml: function(date, colspan, otherAttrs) {
        var view = this.view;

        return '' +
            '<th class="fc-day-header ' + view.widgetHeaderClass + ' fc-' + dayIDs[date.day()] + '"' +
                (this.rowCnt === 1 ?
                    ' data-date="' + date.format('YYYY-MM-DD') + '"' :
                    '') +
                (colspan > 1 ?
                    ' colspan="' + colspan + '"' :
                    '') +
                (otherAttrs ?
                    ' ' + otherAttrs :
                    '') +
                '>' +
                // don't make a link if the heading could represent multiple days, or if there's only one day (forceOff)
                view.buildGotoAnchorHtml(
                    { date: date, forceOff: this.rowCnt > 1 || this.colCnt === 1 },
                    htmlEscape(date.format(this.colHeadFormat)) // inner HTML
                ) +
            '</th>';
    },


    /* Background Rendering
    ------------------------------------------------------------------------------------------------------------------*/


    renderBgTrHtml: function(row) {
        return '' +
            '<tr>' +
                (this.isRTL ? '' : this.renderBgIntroHtml(row)) +
                this.renderBgCellsHtml(row) +
                (this.isRTL ? this.renderBgIntroHtml(row) : '') +
            '</tr>';
    },


    renderBgIntroHtml: function(row) {
        return this.renderIntroHtml(); // fall back to generic
    },


    renderBgCellsHtml: function(row) {
        var htmls = [];
        var col, date;

        for (col = 0; col < this.colCnt; col++) {
            date = this.getCellDate(row, col);
            htmls.push(this.renderBgCellHtml(date));
        }

        return htmls.join('');
    },


    renderBgCellHtml: function(date, otherAttrs) {
        var view = this.view;
        var classes = this.getDayClasses(date);

        classes.unshift('fc-day', view.widgetContentClass);

        return '<td class="' + classes.join(' ') + '"' +
            ' data-date="' + date.format('YYYY-MM-DD') + '"' + // if date has a time, won't format it
            (otherAttrs ?
                ' ' + otherAttrs :
                '') +
            '></td>';
    },


    /* Generic
    ------------------------------------------------------------------------------------------------------------------*/


    // Generates the default HTML intro for any row. User classes should override
    renderIntroHtml: function() {
    },


    // TODO: a generic method for dealing with <tr>, RTL, intro
    // when increment internalApiVersion
    // wrapTr (scheduler)


    /* Utils
    ------------------------------------------------------------------------------------------------------------------*/


    // Applies the generic "intro" and "outro" HTML to the given cells.
    // Intro means the leftmost cell when the calendar is LTR and the rightmost cell when RTL. Vice-versa for outro.
    bookendCells: function(trEl) {
        var introHtml = this.renderIntroHtml();

        if (introHtml) {
            if (this.isRTL) {
                trEl.append(introHtml);
            }
            else {
                trEl.prepend(introHtml);
            }
        }
    }

};

;;

/* A component that renders a grid of whole-days that runs horizontally. There can be multiple rows, one per week.
----------------------------------------------------------------------------------------------------------------------*/

var DayGrid = FC.DayGrid = Grid.extend(DayTableMixin, {

    numbersVisible: false, // should render a row for day/week numbers? set by outside view. TODO: make internal
    bottomCoordPadding: 0, // hack for extending the hit area for the last row of the coordinate grid

    rowEls: null, // set of fake row elements
    cellEls: null, // set of whole-day elements comprising the row's background
    helperEls: null, // set of cell skeleton elements for rendering the mock event "helper"

    rowCoordCache: null,
    colCoordCache: null,


    // Renders the rows and columns into the component's `this.el`, which should already be assigned.
    // isRigid determins whether the individual rows should ignore the contents and be a constant height.
    // Relies on the view's colCnt and rowCnt. In the future, this component should probably be self-sufficient.
    renderDates: function(isRigid) {
        var view = this.view;
        var rowCnt = this.rowCnt;
        var colCnt = this.colCnt;
        var html = '';
        var row;
        var col;

        for (row = 0; row < rowCnt; row++) {
            html += this.renderDayRowHtml(row, isRigid);
        }
        this.el.html(html);

        this.rowEls = this.el.find('.fc-row');
        this.cellEls = this.el.find('.fc-day');

        this.rowCoordCache = new CoordCache({
            els: this.rowEls,
            isVertical: true
        });
        this.colCoordCache = new CoordCache({
            els: this.cellEls.slice(0, this.colCnt), // only the first row
            isHorizontal: true
        });

        // trigger dayRender with each cell's element
        for (row = 0; row < rowCnt; row++) {
            for (col = 0; col < colCnt; col++) {
                view.trigger(
                    'dayRender',
                    null,
                    this.getCellDate(row, col),
                    this.getCellEl(row, col)
                );
            }
        }
    },


    unrenderDates: function() {
        this.removeSegPopover();
    },


    renderBusinessHours: function() {
        var segs = this.buildBusinessHourSegs(true); // wholeDay=true
        this.renderFill('businessHours', segs, 'bgevent');
    },


    unrenderBusinessHours: function() {
        this.unrenderFill('businessHours');
    },


    // Generates the HTML for a single row, which is a div that wraps a table.
    // `row` is the row number.
    renderDayRowHtml: function(row, isRigid) {
        var view = this.view;
        var classes = [ 'fc-row', 'fc-week', view.widgetContentClass ];

        if (isRigid) {
            classes.push('fc-rigid');
        }

        return '' +
            '<div class="' + classes.join(' ') + '">' +
                '<div class="fc-bg">' +
                    '<table>' +
                        this.renderBgTrHtml(row) +
                    '</table>' +
                '</div>' +
                '<div class="fc-content-skeleton">' +
                    '<table>' +
                        (this.numbersVisible ?
                            '<thead>' +
                                this.renderNumberTrHtml(row) +
                            '</thead>' :
                            ''
                            ) +
                    '</table>' +
                '</div>' +
            '</div>';
    },


    /* Grid Number Rendering
    ------------------------------------------------------------------------------------------------------------------*/


    renderNumberTrHtml: function(row) {
        return '' +
            '<tr>' +
                (this.isRTL ? '' : this.renderNumberIntroHtml(row)) +
                this.renderNumberCellsHtml(row) +
                (this.isRTL ? this.renderNumberIntroHtml(row) : '') +
            '</tr>';
    },


    renderNumberIntroHtml: function(row) {
        return this.renderIntroHtml();
    },


    renderNumberCellsHtml: function(row) {
        var htmls = [];
        var col, date;

        for (col = 0; col < this.colCnt; col++) {
            date = this.getCellDate(row, col);
            htmls.push(this.renderNumberCellHtml(date));
        }

        return htmls.join('');
    },


    // Generates the HTML for the <td>s of the "number" row in the DayGrid's content skeleton.
    // The number row will only exist if either day numbers or week numbers are turned on.
    renderNumberCellHtml: function(date) {
        var html = '';
        var classes;
        var weekCalcFirstDoW;

        if (!this.view.dayNumbersVisible && !this.view.cellWeekNumbersVisible) {
            // no numbers in day cell (week number must be along the side)
            return '<td/>'; //  will create an empty space above events :(
        }

        classes = this.getDayClasses(date);
        classes.unshift('fc-day-top');

        if (this.view.cellWeekNumbersVisible) {
            // To determine the day of week number change under ISO, we cannot
            // rely on moment.js methods such as firstDayOfWeek() or weekday(),
            // because they rely on the locale's dow (possibly overridden by
            // our firstDay option), which may not be Monday. We cannot change
            // dow, because that would affect the calendar start day as well.
            if (date._locale._fullCalendar_weekCalc === 'ISO') {
                weekCalcFirstDoW = 1;  // Monday by ISO 8601 definition
            }
            else {
                weekCalcFirstDoW = date._locale.firstDayOfWeek();
            }
        }

        html += '<td class="' + classes.join(' ') + '" data-date="' + date.format() + '">';

        if (this.view.cellWeekNumbersVisible && (date.day() == weekCalcFirstDoW)) {
            html += this.view.buildGotoAnchorHtml(
                { date: date, type: 'week' },
                { 'class': 'fc-week-number' },
                date.format('w') // inner HTML
            );
        }

        if (this.view.dayNumbersVisible) {
            html += this.view.buildGotoAnchorHtml(
                date,
                { 'class': 'fc-day-number' },
                date.date() // inner HTML
            );
        }

        html += '</td>';

        return html;
    },


    /* Options
    ------------------------------------------------------------------------------------------------------------------*/


    // Computes a default event time formatting string if `timeFormat` is not explicitly defined
    computeEventTimeFormat: function() {
        return this.view.opt('extraSmallTimeFormat'); // like "6p" or "6:30p"
    },


    // Computes a default `displayEventEnd` value if one is not expliclty defined
    computeDisplayEventEnd: function() {
        return this.colCnt == 1; // we'll likely have space if there's only one day
    },


    /* Dates
    ------------------------------------------------------------------------------------------------------------------*/


    rangeUpdated: function() {
        this.updateDayTable();
    },


    // Slices up the given span (unzoned start/end with other misc data) into an array of segments
    spanToSegs: function(span) {
        var segs = this.sliceRangeByRow(span);
        var i, seg;

        for (i = 0; i < segs.length; i++) {
            seg = segs[i];
            if (this.isRTL) {
                seg.leftCol = this.daysPerRow - 1 - seg.lastRowDayIndex;
                seg.rightCol = this.daysPerRow - 1 - seg.firstRowDayIndex;
            }
            else {
                seg.leftCol = seg.firstRowDayIndex;
                seg.rightCol = seg.lastRowDayIndex;
            }
        }

        return segs;
    },


    /* Hit System
    ------------------------------------------------------------------------------------------------------------------*/


    prepareHits: function() {
        this.colCoordCache.build();
        this.rowCoordCache.build();
        this.rowCoordCache.bottoms[this.rowCnt - 1] += this.bottomCoordPadding; // hack
    },


    releaseHits: function() {
        this.colCoordCache.clear();
        this.rowCoordCache.clear();
    },


    queryHit: function(leftOffset, topOffset) {
        if (this.colCoordCache.isLeftInBounds(leftOffset) && this.rowCoordCache.isTopInBounds(topOffset)) {
            var col = this.colCoordCache.getHorizontalIndex(leftOffset);
            var row = this.rowCoordCache.getVerticalIndex(topOffset);

            if (row != null && col != null) {
                return this.getCellHit(row, col);
            }
        }
    },


    getHitSpan: function(hit) {
        return this.getCellRange(hit.row, hit.col);
    },


    getHitEl: function(hit) {
        return this.getCellEl(hit.row, hit.col);
    },


    /* Cell System
    ------------------------------------------------------------------------------------------------------------------*/
    // FYI: the first column is the leftmost column, regardless of date


    getCellHit: function(row, col) {
        return {
            row: row,
            col: col,
            component: this, // needed unfortunately :(
            left: this.colCoordCache.getLeftOffset(col),
            right: this.colCoordCache.getRightOffset(col),
            top: this.rowCoordCache.getTopOffset(row),
            bottom: this.rowCoordCache.getBottomOffset(row)
        };
    },


    getCellEl: function(row, col) {
        return this.cellEls.eq(row * this.colCnt + col);
    },


    /* Event Drag Visualization
    ------------------------------------------------------------------------------------------------------------------*/
    // TODO: move to DayGrid.event, similar to what we did with Grid's drag methods


    // Renders a visual indication of an event or external element being dragged.
    // `eventLocation` has zoned start and end (optional)
    renderDrag: function(eventLocation, seg) {

        // always render a highlight underneath
        this.renderHighlight(this.eventToSpan(eventLocation));

        // if a segment from the same calendar but another component is being dragged, render a helper event
        if (seg && seg.component !== this) {
            return this.renderEventLocationHelper(eventLocation, seg); // returns mock event elements
        }
    },


    // Unrenders any visual indication of a hovering event
    unrenderDrag: function() {
        this.unrenderHighlight();
        this.unrenderHelper();
    },


    /* Event Resize Visualization
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a visual indication of an event being resized
    renderEventResize: function(eventLocation, seg) {
        this.renderHighlight(this.eventToSpan(eventLocation));
        return this.renderEventLocationHelper(eventLocation, seg); // returns mock event elements
    },


    // Unrenders a visual indication of an event being resized
    unrenderEventResize: function() {
        this.unrenderHighlight();
        this.unrenderHelper();
    },


    /* Event Helper
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a mock "helper" event. `sourceSeg` is the associated internal segment object. It can be null.
    renderHelper: function(event, sourceSeg) {
        var helperNodes = [];
        var segs = this.eventToSegs(event);
        var rowStructs;

        segs = this.renderFgSegEls(segs); // assigns each seg's el and returns a subset of segs that were rendered
        rowStructs = this.renderSegRows(segs);

        // inject each new event skeleton into each associated row
        this.rowEls.each(function(row, rowNode) {
            var rowEl = $(rowNode); // the .fc-row
            var skeletonEl = $('<div class="fc-helper-skeleton"><table/></div>'); // will be absolutely positioned
            var skeletonTop;

            // If there is an original segment, match the top position. Otherwise, put it at the row's top level
            if (sourceSeg && sourceSeg.row === row) {
                skeletonTop = sourceSeg.el.position().top;
            }
            else {
                skeletonTop = rowEl.find('.fc-content-skeleton tbody').position().top;
            }

            skeletonEl.css('top', skeletonTop)
                .find('table')
                    .append(rowStructs[row].tbodyEl);

            rowEl.append(skeletonEl);
            helperNodes.push(skeletonEl[0]);
        });

        return ( // must return the elements rendered
            this.helperEls = $(helperNodes) // array -> jQuery set
        );
    },


    // Unrenders any visual indication of a mock helper event
    unrenderHelper: function() {
        if (this.helperEls) {
            this.helperEls.remove();
            this.helperEls = null;
        }
    },


    /* Fill System (highlight, background events, business hours)
    ------------------------------------------------------------------------------------------------------------------*/


    fillSegTag: 'td', // override the default tag name


    // Renders a set of rectangles over the given segments of days.
    // Only returns segments that successfully rendered.
    renderFill: function(type, segs, className) {
        var nodes = [];
        var i, seg;
        var skeletonEl;

        segs = this.renderFillSegEls(type, segs); // assignes `.el` to each seg. returns successfully rendered segs

        for (i = 0; i < segs.length; i++) {
            seg = segs[i];
            skeletonEl = this.renderFillRow(type, seg, className);
            this.rowEls.eq(seg.row).append(skeletonEl);
            nodes.push(skeletonEl[0]);
        }

        this.elsByFill[type] = $(nodes);

        return segs;
    },


    // Generates the HTML needed for one row of a fill. Requires the seg's el to be rendered.
    renderFillRow: function(type, seg, className) {
        var colCnt = this.colCnt;
        var startCol = seg.leftCol;
        var endCol = seg.rightCol + 1;
        var skeletonEl;
        var trEl;

        className = className || type.toLowerCase();

        skeletonEl = $(
            '<div class="fc-' + className + '-skeleton">' +
                '<table><tr/></table>' +
            '</div>'
        );
        trEl = skeletonEl.find('tr');

        if (startCol > 0) {
            trEl.append('<td colspan="' + startCol + '"/>');
        }

        trEl.append(
            seg.el.attr('colspan', endCol - startCol)
        );

        if (endCol < colCnt) {
            trEl.append('<td colspan="' + (colCnt - endCol) + '"/>');
        }

        this.bookendCells(trEl);

        return skeletonEl;
    }

});

;;

/* Event-rendering methods for the DayGrid class
----------------------------------------------------------------------------------------------------------------------*/

DayGrid.mixin({

    rowStructs: null, // an array of objects, each holding information about a row's foreground event-rendering


    // Unrenders all events currently rendered on the grid
    unrenderEvents: function() {
        this.removeSegPopover(); // removes the "more.." events popover
        Grid.prototype.unrenderEvents.apply(this, arguments); // calls the super-method
    },


    // Retrieves all rendered segment objects currently rendered on the grid
    getEventSegs: function() {
        return Grid.prototype.getEventSegs.call(this) // get the segments from the super-method
            .concat(this.popoverSegs || []); // append the segments from the "more..." popover
    },


    // Renders the given background event segments onto the grid
    renderBgSegs: function(segs) {

        // don't render timed background events
        var allDaySegs = $.grep(segs, function(seg) {
            return seg.event.allDay;
        });

        return Grid.prototype.renderBgSegs.call(this, allDaySegs); // call the super-method
    },


    // Renders the given foreground event segments onto the grid
    renderFgSegs: function(segs) {
        var rowStructs;

        // render an `.el` on each seg
        // returns a subset of the segs. segs that were actually rendered
        segs = this.renderFgSegEls(segs);

        rowStructs = this.rowStructs = this.renderSegRows(segs);

        // append to each row's content skeleton
        this.rowEls.each(function(i, rowNode) {
            $(rowNode).find('.fc-content-skeleton > table').append(
                rowStructs[i].tbodyEl
            );
        });

        return segs; // return only the segs that were actually rendered
    },


    // Unrenders all currently rendered foreground event segments
    unrenderFgSegs: function() {
        var rowStructs = this.rowStructs || [];
        var rowStruct;

        while ((rowStruct = rowStructs.pop())) {
            rowStruct.tbodyEl.remove();
        }

        this.rowStructs = null;
    },


    // Uses the given events array to generate <tbody> elements that should be appended to each row's content skeleton.
    // Returns an array of rowStruct objects (see the bottom of `renderSegRow`).
    // PRECONDITION: each segment shoud already have a rendered and assigned `.el`
    renderSegRows: function(segs) {
        var rowStructs = [];
        var segRows;
        var row;

        segRows = this.groupSegRows(segs); // group into nested arrays

        // iterate each row of segment groupings
        for (row = 0; row < segRows.length; row++) {
            rowStructs.push(
                this.renderSegRow(row, segRows[row])
            );
        }

        return rowStructs;
    },


    // Builds the HTML to be used for the default element for an individual segment
    fgSegHtml: function(seg, disableResizing) {
        var view = this.view;
        var event = seg.event;
        var isDraggable = view.isEventDraggable(event);
        var isResizableFromStart = !disableResizing && event.allDay &&
            seg.isStart && view.isEventResizableFromStart(event);
        var isResizableFromEnd = !disableResizing && event.allDay &&
            seg.isEnd && view.isEventResizableFromEnd(event);
        var classes = this.getSegClasses(seg, isDraggable, isResizableFromStart || isResizableFromEnd);
        var skinCss = cssToStr(this.getSegSkinCss(seg));
        var timeHtml = '';
        var timeText;
        var titleHtml;

        classes.unshift('fc-day-grid-event', 'fc-h-event');

        // Only display a timed events time if it is the starting segment
        if (seg.isStart) {
            timeText = this.getEventTimeText(event);
            if (timeText) {
                timeHtml = '<span class="fc-time">' + htmlEscape(timeText) + '</span>';
            }
        }

        titleHtml =
            '<span class="fc-title">' +
                (htmlEscape(event.title || '') || '&nbsp;') + // we always want one line of height
            '</span>';
        
        return '<a class="' + classes.join(' ') + '"' +
                (event.url ?
                    ' href="' + htmlEscape(event.url) + '"' :
                    ''
                    ) +
                (skinCss ?
                    ' style="' + skinCss + '"' :
                    ''
                    ) +
            '>' +
                '<div class="fc-content">' +
                    (this.isRTL ?
                        titleHtml + ' ' + timeHtml : // put a natural space in between
                        timeHtml + ' ' + titleHtml   //
                        ) +
                '</div>' +
                (isResizableFromStart ?
                    '<div class="fc-resizer fc-start-resizer" />' :
                    ''
                    ) +
                (isResizableFromEnd ?
                    '<div class="fc-resizer fc-end-resizer" />' :
                    ''
                    ) +
            '</a>';
    },


    // Given a row # and an array of segments all in the same row, render a <tbody> element, a skeleton that contains
    // the segments. Returns object with a bunch of internal data about how the render was calculated.
    // NOTE: modifies rowSegs
    renderSegRow: function(row, rowSegs) {
        var colCnt = this.colCnt;
        var segLevels = this.buildSegLevels(rowSegs); // group into sub-arrays of levels
        var levelCnt = Math.max(1, segLevels.length); // ensure at least one level
        var tbody = $('<tbody/>');
        var segMatrix = []; // lookup for which segments are rendered into which level+col cells
        var cellMatrix = []; // lookup for all <td> elements of the level+col matrix
        var loneCellMatrix = []; // lookup for <td> elements that only take up a single column
        var i, levelSegs;
        var col;
        var tr;
        var j, seg;
        var td;

        // populates empty cells from the current column (`col`) to `endCol`
        function emptyCellsUntil(endCol) {
            while (col < endCol) {
                // try to grab a cell from the level above and extend its rowspan. otherwise, create a fresh cell
                td = (loneCellMatrix[i - 1] || [])[col];
                if (td) {
                    td.attr(
                        'rowspan',
                        parseInt(td.attr('rowspan') || 1, 10) + 1
                    );
                }
                else {
                    td = $('<td/>');
                    tr.append(td);
                }
                cellMatrix[i][col] = td;
                loneCellMatrix[i][col] = td;
                col++;
            }
        }

        for (i = 0; i < levelCnt; i++) { // iterate through all levels
            levelSegs = segLevels[i];
            col = 0;
            tr = $('<tr/>');

            segMatrix.push([]);
            cellMatrix.push([]);
            loneCellMatrix.push([]);

            // levelCnt might be 1 even though there are no actual levels. protect against this.
            // this single empty row is useful for styling.
            if (levelSegs) {
                for (j = 0; j < levelSegs.length; j++) { // iterate through segments in level
                    seg = levelSegs[j];

                    emptyCellsUntil(seg.leftCol);

                    // create a container that occupies or more columns. append the event element.
                    td = $('<td class="fc-event-container"/>').append(seg.el);
                    if (seg.leftCol != seg.rightCol) {
                        td.attr('colspan', seg.rightCol - seg.leftCol + 1);
                    }
                    else { // a single-column segment
                        loneCellMatrix[i][col] = td;
                    }

                    while (col <= seg.rightCol) {
                        cellMatrix[i][col] = td;
                        segMatrix[i][col] = seg;
                        col++;
                    }

                    tr.append(td);
                }
            }

            emptyCellsUntil(colCnt); // finish off the row
            this.bookendCells(tr);
            tbody.append(tr);
        }

        return { // a "rowStruct"
            row: row, // the row number
            tbodyEl: tbody,
            cellMatrix: cellMatrix,
            segMatrix: segMatrix,
            segLevels: segLevels,
            segs: rowSegs
        };
    },


    // Stacks a flat array of segments, which are all assumed to be in the same row, into subarrays of vertical levels.
    // NOTE: modifies segs
    buildSegLevels: function(segs) {
        var levels = [];
        var i, seg;
        var j;

        // Give preference to elements with certain criteria, so they have
        // a chance to be closer to the top.
        this.sortEventSegs(segs);
        
        for (i = 0; i < segs.length; i++) {
            seg = segs[i];

            // loop through levels, starting with the topmost, until the segment doesn't collide with other segments
            for (j = 0; j < levels.length; j++) {
                if (!isDaySegCollision(seg, levels[j])) {
                    break;
                }
            }
            // `j` now holds the desired subrow index
            seg.level = j;

            // create new level array if needed and append segment
            (levels[j] || (levels[j] = [])).push(seg);
        }

        // order segments left-to-right. very important if calendar is RTL
        for (j = 0; j < levels.length; j++) {
            levels[j].sort(compareDaySegCols);
        }

        return levels;
    },


    // Given a flat array of segments, return an array of sub-arrays, grouped by each segment's row
    groupSegRows: function(segs) {
        var segRows = [];
        var i;

        for (i = 0; i < this.rowCnt; i++) {
            segRows.push([]);
        }

        for (i = 0; i < segs.length; i++) {
            segRows[segs[i].row].push(segs[i]);
        }

        return segRows;
    }

});


// Computes whether two segments' columns collide. They are assumed to be in the same row.
function isDaySegCollision(seg, otherSegs) {
    var i, otherSeg;

    for (i = 0; i < otherSegs.length; i++) {
        otherSeg = otherSegs[i];

        if (
            otherSeg.leftCol <= seg.rightCol &&
            otherSeg.rightCol >= seg.leftCol
        ) {
            return true;
        }
    }

    return false;
}


// A cmp function for determining the leftmost event
function compareDaySegCols(a, b) {
    return a.leftCol - b.leftCol;
}

;;

/* Methods relate to limiting the number events for a given day on a DayGrid
----------------------------------------------------------------------------------------------------------------------*/
// NOTE: all the segs being passed around in here are foreground segs

DayGrid.mixin({

    segPopover: null, // the Popover that holds events that can't fit in a cell. null when not visible
    popoverSegs: null, // an array of segment objects that the segPopover holds. null when not visible


    removeSegPopover: function() {
        if (this.segPopover) {
            this.segPopover.hide(); // in handler, will call segPopover's removeElement
        }
    },


    // Limits the number of "levels" (vertically stacking layers of events) for each row of the grid.
    // `levelLimit` can be false (don't limit), a number, or true (should be computed).
    limitRows: function(levelLimit) {
        var rowStructs = this.rowStructs || [];
        var row; // row #
        var rowLevelLimit;

        for (row = 0; row < rowStructs.length; row++) {
            this.unlimitRow(row);

            if (!levelLimit) {
                rowLevelLimit = false;
            }
            else if (typeof levelLimit === 'number') {
                rowLevelLimit = levelLimit;
            }
            else {
                rowLevelLimit = this.computeRowLevelLimit(row);
            }

            if (rowLevelLimit !== false) {
                this.limitRow(row, rowLevelLimit);
            }
        }
    },


    // Computes the number of levels a row will accomodate without going outside its bounds.
    // Assumes the row is "rigid" (maintains a constant height regardless of what is inside).
    // `row` is the row number.
    computeRowLevelLimit: function(row) {
        var rowEl = this.rowEls.eq(row); // the containing "fake" row div
        var rowHeight = rowEl.height(); // TODO: cache somehow?
        var trEls = this.rowStructs[row].tbodyEl.children();
        var i, trEl;
        var trHeight;

        function iterInnerHeights(i, childNode) {
            trHeight = Math.max(trHeight, $(childNode).outerHeight());
        }

        // Reveal one level <tr> at a time and stop when we find one out of bounds
        for (i = 0; i < trEls.length; i++) {
            trEl = trEls.eq(i).removeClass('fc-limited'); // reset to original state (reveal)

            // with rowspans>1 and IE8, trEl.outerHeight() would return the height of the largest cell,
            // so instead, find the tallest inner content element.
            trHeight = 0;
            trEl.find('> td > :first-child').each(iterInnerHeights);

            if (trEl.position().top + trHeight > rowHeight) {
                return i;
            }
        }

        return false; // should not limit at all
    },


    // Limits the given grid row to the maximum number of levels and injects "more" links if necessary.
    // `row` is the row number.
    // `levelLimit` is a number for the maximum (inclusive) number of levels allowed.
    limitRow: function(row, levelLimit) {
        var _this = this;
        var rowStruct = this.rowStructs[row];
        var moreNodes = []; // array of "more" <a> links and <td> DOM nodes
        var col = 0; // col #, left-to-right (not chronologically)
        var levelSegs; // array of segment objects in the last allowable level, ordered left-to-right
        var cellMatrix; // a matrix (by level, then column) of all <td> jQuery elements in the row
        var limitedNodes; // array of temporarily hidden level <tr> and segment <td> DOM nodes
        var i, seg;
        var segsBelow; // array of segment objects below `seg` in the current `col`
        var totalSegsBelow; // total number of segments below `seg` in any of the columns `seg` occupies
        var colSegsBelow; // array of segment arrays, below seg, one for each column (offset from segs's first column)
        var td, rowspan;
        var segMoreNodes; // array of "more" <td> cells that will stand-in for the current seg's cell
        var j;
        var moreTd, moreWrap, moreLink;

        // Iterates through empty level cells and places "more" links inside if need be
        function emptyCellsUntil(endCol) { // goes from current `col` to `endCol`
            while (col < endCol) {
                segsBelow = _this.getCellSegs(row, col, levelLimit);
                if (segsBelow.length) {
                    td = cellMatrix[levelLimit - 1][col];
                    moreLink = _this.renderMoreLink(row, col, segsBelow);
                    moreWrap = $('<div/>').append(moreLink);
                    td.append(moreWrap);
                    moreNodes.push(moreWrap[0]);
                }
                col++;
            }
        }

        if (levelLimit && levelLimit < rowStruct.segLevels.length) { // is it actually over the limit?
            levelSegs = rowStruct.segLevels[levelLimit - 1];
            cellMatrix = rowStruct.cellMatrix;

            limitedNodes = rowStruct.tbodyEl.children().slice(levelLimit) // get level <tr> elements past the limit
                .addClass('fc-limited').get(); // hide elements and get a simple DOM-nodes array

            // iterate though segments in the last allowable level
            for (i = 0; i < levelSegs.length; i++) {
                seg = levelSegs[i];
                emptyCellsUntil(seg.leftCol); // process empty cells before the segment

                // determine *all* segments below `seg` that occupy the same columns
                colSegsBelow = [];
                totalSegsBelow = 0;
                while (col <= seg.rightCol) {
                    segsBelow = this.getCellSegs(row, col, levelLimit);
                    colSegsBelow.push(segsBelow);
                    totalSegsBelow += segsBelow.length;
                    col++;
                }

                if (totalSegsBelow) { // do we need to replace this segment with one or many "more" links?
                    td = cellMatrix[levelLimit - 1][seg.leftCol]; // the segment's parent cell
                    rowspan = td.attr('rowspan') || 1;
                    segMoreNodes = [];

                    // make a replacement <td> for each column the segment occupies. will be one for each colspan
                    for (j = 0; j < colSegsBelow.length; j++) {
                        moreTd = $('<td class="fc-more-cell"/>').attr('rowspan', rowspan);
                        segsBelow = colSegsBelow[j];
                        moreLink = this.renderMoreLink(
                            row,
                            seg.leftCol + j,
                            [ seg ].concat(segsBelow) // count seg as hidden too
                        );
                        moreWrap = $('<div/>').append(moreLink);
                        moreTd.append(moreWrap);
                        segMoreNodes.push(moreTd[0]);
                        moreNodes.push(moreTd[0]);
                    }

                    td.addClass('fc-limited').after($(segMoreNodes)); // hide original <td> and inject replacements
                    limitedNodes.push(td[0]);
                }
            }

            emptyCellsUntil(this.colCnt); // finish off the level
            rowStruct.moreEls = $(moreNodes); // for easy undoing later
            rowStruct.limitedEls = $(limitedNodes); // for easy undoing later
        }
    },


    // Reveals all levels and removes all "more"-related elements for a grid's row.
    // `row` is a row number.
    unlimitRow: function(row) {
        var rowStruct = this.rowStructs[row];

        if (rowStruct.moreEls) {
            rowStruct.moreEls.remove();
            rowStruct.moreEls = null;
        }

        if (rowStruct.limitedEls) {
            rowStruct.limitedEls.removeClass('fc-limited');
            rowStruct.limitedEls = null;
        }
    },


    // Renders an <a> element that represents hidden event element for a cell.
    // Responsible for attaching click handler as well.
    renderMoreLink: function(row, col, hiddenSegs) {
        var _this = this;
        var view = this.view;

        return $('<a class="fc-more"/>')
            .text(
                this.getMoreLinkText(hiddenSegs.length)
            )
            .on('click', function(ev) {
                var clickOption = view.opt('eventLimitClick');
                var date = _this.getCellDate(row, col);
                var moreEl = $(this);
                var dayEl = _this.getCellEl(row, col);
                var allSegs = _this.getCellSegs(row, col);

                // rescope the segments to be within the cell's date
                var reslicedAllSegs = _this.resliceDaySegs(allSegs, date);
                var reslicedHiddenSegs = _this.resliceDaySegs(hiddenSegs, date);

                if (typeof clickOption === 'function') {
                    // the returned value can be an atomic option
                    clickOption = view.trigger('eventLimitClick', null, {
                        date: date,
                        dayEl: dayEl,
                        moreEl: moreEl,
                        segs: reslicedAllSegs,
                        hiddenSegs: reslicedHiddenSegs
                    }, ev);
                }

                if (clickOption === 'popover') {
                    _this.showSegPopover(row, col, moreEl, reslicedAllSegs);
                }
                else if (typeof clickOption === 'string') { // a view name
                    view.calendar.zoomTo(date, clickOption);
                }
            });
    },


    // Reveals the popover that displays all events within a cell
    showSegPopover: function(row, col, moreLink, segs) {
        var _this = this;
        var view = this.view;
        var moreWrap = moreLink.parent(); // the <div> wrapper around the <a>
        var topEl; // the element we want to match the top coordinate of
        var options;

        if (this.rowCnt == 1) {
            topEl = view.el; // will cause the popover to cover any sort of header
        }
        else {
            topEl = this.rowEls.eq(row); // will align with top of row
        }

        options = {
            className: 'fc-more-popover',
            content: this.renderSegPopoverContent(row, col, segs),
            parentEl: this.view.el, // attach to root of view. guarantees outside of scrollbars.
            top: topEl.offset().top,
            autoHide: true, // when the user clicks elsewhere, hide the popover
            viewportConstrain: view.opt('popoverViewportConstrain'),
            hide: function() {
                // kill everything when the popover is hidden
                _this.segPopover.removeElement();
                _this.segPopover = null;
                _this.popoverSegs = null;
            }
        };

        // Determine horizontal coordinate.
        // We use the moreWrap instead of the <td> to avoid border confusion.
        if (this.isRTL) {
            options.right = moreWrap.offset().left + moreWrap.outerWidth() + 1; // +1 to be over cell border
        }
        else {
            options.left = moreWrap.offset().left - 1; // -1 to be over cell border
        }

        this.segPopover = new Popover(options);
        this.segPopover.show();

        // the popover doesn't live within the grid's container element, and thus won't get the event
        // delegated-handlers for free. attach event-related handlers to the popover.
        this.bindSegHandlersToEl(this.segPopover.el);
    },


    // Builds the inner DOM contents of the segment popover
    renderSegPopoverContent: function(row, col, segs) {
        var view = this.view;
        var isTheme = view.opt('theme');
        var title = this.getCellDate(row, col).format(view.opt('dayPopoverFormat'));
        var content = $(
            '<div class="fc-header ' + view.widgetHeaderClass + '">' +
                '<span class="fc-close ' +
                    (isTheme ? 'ui-icon ui-icon-closethick' : 'fc-icon fc-icon-x') +
                '"></span>' +
                '<span class="fc-title">' +
                    htmlEscape(title) +
                '</span>' +
                '<div class="fc-clear"/>' +
            '</div>' +
            '<div class="fc-body ' + view.widgetContentClass + '">' +
                '<div class="fc-event-container"></div>' +
            '</div>'
        );
        var segContainer = content.find('.fc-event-container');
        var i;

        // render each seg's `el` and only return the visible segs
        segs = this.renderFgSegEls(segs, true); // disableResizing=true
        this.popoverSegs = segs;

        for (i = 0; i < segs.length; i++) {

            // because segments in the popover are not part of a grid coordinate system, provide a hint to any
            // grids that want to do drag-n-drop about which cell it came from
            this.prepareHits();
            segs[i].hit = this.getCellHit(row, col);
            this.releaseHits();

            segContainer.append(segs[i].el);
        }

        return content;
    },


    // Given the events within an array of segment objects, reslice them to be in a single day
    resliceDaySegs: function(segs, dayDate) {

        // build an array of the original events
        var events = $.map(segs, function(seg) {
            return seg.event;
        });

        var dayStart = dayDate.clone();
        var dayEnd = dayStart.clone().add(1, 'days');
        var dayRange = { start: dayStart, end: dayEnd };

        // slice the events with a custom slicing function
        segs = this.eventsToSegs(
            events,
            function(range) {
                var seg = intersectRanges(range, dayRange); // undefind if no intersection
                return seg ? [ seg ] : []; // must return an array of segments
            }
        );

        // force an order because eventsToSegs doesn't guarantee one
        this.sortEventSegs(segs);

        return segs;
    },


    // Generates the text that should be inside a "more" link, given the number of events it represents
    getMoreLinkText: function(num) {
        var opt = this.view.opt('eventLimitText');

        if (typeof opt === 'function') {
            return opt(num);
        }
        else {
            return '+' + num + ' ' + opt;
        }
    },


    // Returns segments within a given cell.
    // If `startLevel` is specified, returns only events including and below that level. Otherwise returns all segs.
    getCellSegs: function(row, col, startLevel) {
        var segMatrix = this.rowStructs[row].segMatrix;
        var level = startLevel || 0;
        var segs = [];
        var seg;

        while (level < segMatrix.length) {
            seg = segMatrix[level][col];
            if (seg) {
                segs.push(seg);
            }
            level++;
        }

        return segs;
    }

});

;;

/* A component that renders one or more columns of vertical time slots
----------------------------------------------------------------------------------------------------------------------*/
// We mixin DayTable, even though there is only a single row of days

var TimeGrid = FC.TimeGrid = Grid.extend(DayTableMixin, {

    slotDuration: null, // duration of a "slot", a distinct time segment on given day, visualized by lines
    snapDuration: null, // granularity of time for dragging and selecting
    snapsPerSlot: null,
    minTime: null, // Duration object that denotes the first visible time of any given day
    maxTime: null, // Duration object that denotes the exclusive visible end time of any given day
    labelFormat: null, // formatting string for times running along vertical axis
    labelInterval: null, // duration of how often a label should be displayed for a slot

    colEls: null, // cells elements in the day-row background
    slatContainerEl: null, // div that wraps all the slat rows
    slatEls: null, // elements running horizontally across all columns
    nowIndicatorEls: null,

    colCoordCache: null,
    slatCoordCache: null,


    constructor: function() {
        Grid.apply(this, arguments); // call the super-constructor

        this.processOptions();
    },


    // Renders the time grid into `this.el`, which should already be assigned.
    // Relies on the view's colCnt. In the future, this component should probably be self-sufficient.
    renderDates: function() {
        this.el.html(this.renderHtml());
        this.colEls = this.el.find('.fc-day');
        this.slatContainerEl = this.el.find('.fc-slats');
        this.slatEls = this.slatContainerEl.find('tr');

        this.colCoordCache = new CoordCache({
            els: this.colEls,
            isHorizontal: true
        });
        this.slatCoordCache = new CoordCache({
            els: this.slatEls,
            isVertical: true
        });

        this.renderContentSkeleton();
    },


    // Renders the basic HTML skeleton for the grid
    renderHtml: function() {
        return '' +
            '<div class="fc-bg">' +
                '<table>' +
                    this.renderBgTrHtml(0) + // row=0
                '</table>' +
            '</div>' +
            '<div class="fc-slats">' +
                '<table>' +
                    this.renderSlatRowHtml() +
                '</table>' +
            '</div>';
    },


    // Generates the HTML for the horizontal "slats" that run width-wise. Has a time axis on a side. Depends on RTL.
    renderSlatRowHtml: function() {
        var view = this.view;
        var isRTL = this.isRTL;
        var html = '';
        var slotTime = moment.duration(+this.minTime); // wish there was .clone() for durations
        var slotDate; // will be on the view's first day, but we only care about its time
        var isLabeled;
        var axisHtml;

        // Calculate the time for each slot
        while (slotTime < this.maxTime) {
            slotDate = this.start.clone().time(slotTime);
            isLabeled = isInt(divideDurationByDuration(slotTime, this.labelInterval));

            axisHtml =
                '<td class="fc-axis fc-time ' + view.widgetContentClass + '" ' + view.axisStyleAttr() + '>' +
                    (isLabeled ?
                        '<span>' + // for matchCellWidths
                            htmlEscape(slotDate.format(this.labelFormat)) +
                        '</span>' :
                        ''
                        ) +
                '</td>';

            html +=
                '<tr data-time="' + slotDate.format('HH:mm:ss') + '"' +
                    (isLabeled ? '' : ' class="fc-minor"') +
                    '>' +
                    (!isRTL ? axisHtml : '') +
                    '<td class="' + view.widgetContentClass + '"/>' +
                    (isRTL ? axisHtml : '') +
                "</tr>";

            slotTime.add(this.slotDuration);
        }

        return html;
    },


    /* Options
    ------------------------------------------------------------------------------------------------------------------*/


    // Parses various options into properties of this object
    processOptions: function() {
        var view = this.view;
        var slotDuration = view.opt('slotDuration');
        var snapDuration = view.opt('snapDuration');
        var input;

        slotDuration = moment.duration(slotDuration);
        snapDuration = snapDuration ? moment.duration(snapDuration) : slotDuration;

        this.slotDuration = slotDuration;
        this.snapDuration = snapDuration;
        this.snapsPerSlot = slotDuration / snapDuration; // TODO: ensure an integer multiple?

        this.minResizeDuration = snapDuration; // hack

        this.minTime = moment.duration(view.opt('minTime'));
        this.maxTime = moment.duration(view.opt('maxTime'));

        // might be an array value (for TimelineView).
        // if so, getting the most granular entry (the last one probably).
        input = view.opt('slotLabelFormat');
        if ($.isArray(input)) {
            input = input[input.length - 1];
        }

        this.labelFormat =
            input ||
            view.opt('smallTimeFormat'); // the computed default

        input = view.opt('slotLabelInterval');
        this.labelInterval = input ?
            moment.duration(input) :
            this.computeLabelInterval(slotDuration);
    },


    // Computes an automatic value for slotLabelInterval
    computeLabelInterval: function(slotDuration) {
        var i;
        var labelInterval;
        var slotsPerLabel;

        // find the smallest stock label interval that results in more than one slots-per-label
        for (i = AGENDA_STOCK_SUB_DURATIONS.length - 1; i >= 0; i--) {
            labelInterval = moment.duration(AGENDA_STOCK_SUB_DURATIONS[i]);
            slotsPerLabel = divideDurationByDuration(labelInterval, slotDuration);
            if (isInt(slotsPerLabel) && slotsPerLabel > 1) {
                return labelInterval;
            }
        }

        return moment.duration(slotDuration); // fall back. clone
    },


    // Computes a default event time formatting string if `timeFormat` is not explicitly defined
    computeEventTimeFormat: function() {
        return this.view.opt('noMeridiemTimeFormat'); // like "6:30" (no AM/PM)
    },


    // Computes a default `displayEventEnd` value if one is not expliclty defined
    computeDisplayEventEnd: function() {
        return true;
    },


    /* Hit System
    ------------------------------------------------------------------------------------------------------------------*/


    prepareHits: function() {
        this.colCoordCache.build();
        this.slatCoordCache.build();
    },


    releaseHits: function() {
        this.colCoordCache.clear();
        // NOTE: don't clear slatCoordCache because we rely on it for computeTimeTop
    },


    queryHit: function(leftOffset, topOffset) {
        var snapsPerSlot = this.snapsPerSlot;
        var colCoordCache = this.colCoordCache;
        var slatCoordCache = this.slatCoordCache;

        if (colCoordCache.isLeftInBounds(leftOffset) && slatCoordCache.isTopInBounds(topOffset)) {
            var colIndex = colCoordCache.getHorizontalIndex(leftOffset);
            var slatIndex = slatCoordCache.getVerticalIndex(topOffset);

            if (colIndex != null && slatIndex != null) {
                var slatTop = slatCoordCache.getTopOffset(slatIndex);
                var slatHeight = slatCoordCache.getHeight(slatIndex);
                var partial = (topOffset - slatTop) / slatHeight; // floating point number between 0 and 1
                var localSnapIndex = Math.floor(partial * snapsPerSlot); // the snap # relative to start of slat
                var snapIndex = slatIndex * snapsPerSlot + localSnapIndex;
                var snapTop = slatTop + (localSnapIndex / snapsPerSlot) * slatHeight;
                var snapBottom = slatTop + ((localSnapIndex + 1) / snapsPerSlot) * slatHeight;

                return {
                    col: colIndex,
                    snap: snapIndex,
                    component: this, // needed unfortunately :(
                    left: colCoordCache.getLeftOffset(colIndex),
                    right: colCoordCache.getRightOffset(colIndex),
                    top: snapTop,
                    bottom: snapBottom
                };
            }
        }
    },


    getHitSpan: function(hit) {
        var start = this.getCellDate(0, hit.col); // row=0
        var time = this.computeSnapTime(hit.snap); // pass in the snap-index
        var end;

        start.time(time);
        end = start.clone().add(this.snapDuration);

        return { start: start, end: end };
    },


    getHitEl: function(hit) {
        return this.colEls.eq(hit.col);
    },


    /* Dates
    ------------------------------------------------------------------------------------------------------------------*/


    rangeUpdated: function() {
        this.updateDayTable();
    },


    // Given a row number of the grid, representing a "snap", returns a time (Duration) from its start-of-day
    computeSnapTime: function(snapIndex) {
        return moment.duration(this.minTime + this.snapDuration * snapIndex);
    },


    // Slices up the given span (unzoned start/end with other misc data) into an array of segments
    spanToSegs: function(span) {
        var segs = this.sliceRangeByTimes(span);
        var i;

        for (i = 0; i < segs.length; i++) {
            if (this.isRTL) {
                segs[i].col = this.daysPerRow - 1 - segs[i].dayIndex;
            }
            else {
                segs[i].col = segs[i].dayIndex;
            }
        }

        return segs;
    },


    sliceRangeByTimes: function(range) {
        var segs = [];
        var seg;
        var dayIndex;
        var dayDate;
        var dayRange;

        for (dayIndex = 0; dayIndex < this.daysPerRow; dayIndex++) {
            dayDate = this.dayDates[dayIndex].clone(); // TODO: better API for this?
            dayRange = {
                start: dayDate.clone().time(this.minTime),
                end: dayDate.clone().time(this.maxTime)
            };
            seg = intersectRanges(range, dayRange); // both will be ambig timezone
            if (seg) {
                seg.dayIndex = dayIndex;
                segs.push(seg);
            }
        }

        return segs;
    },


    /* Coordinates
    ------------------------------------------------------------------------------------------------------------------*/


    updateSize: function(isResize) { // NOT a standard Grid method
        this.slatCoordCache.build();

        if (isResize) {
            this.updateSegVerticals(
                [].concat(this.fgSegs || [], this.bgSegs || [], this.businessSegs || [])
            );
        }
    },


    getTotalSlatHeight: function() {
        return this.slatContainerEl.outerHeight();
    },


    // Computes the top coordinate, relative to the bounds of the grid, of the given date.
    // A `startOfDayDate` must be given for avoiding ambiguity over how to treat midnight.
    computeDateTop: function(date, startOfDayDate) {
        return this.computeTimeTop(
            moment.duration(
                date - startOfDayDate.clone().stripTime()
            )
        );
    },


    // Computes the top coordinate, relative to the bounds of the grid, of the given time (a Duration).
    computeTimeTop: function(time) {
        var len = this.slatEls.length;
        var slatCoverage = (time - this.minTime) / this.slotDuration; // floating-point value of # of slots covered
        var slatIndex;
        var slatRemainder;

        // compute a floating-point number for how many slats should be progressed through.
        // from 0 to number of slats (inclusive)
        // constrained because minTime/maxTime might be customized.
        slatCoverage = Math.max(0, slatCoverage);
        slatCoverage = Math.min(len, slatCoverage);

        // an integer index of the furthest whole slat
        // from 0 to number slats (*exclusive*, so len-1)
        slatIndex = Math.floor(slatCoverage);
        slatIndex = Math.min(slatIndex, len - 1);

        // how much further through the slatIndex slat (from 0.0-1.0) must be covered in addition.
        // could be 1.0 if slatCoverage is covering *all* the slots
        slatRemainder = slatCoverage - slatIndex;

        return this.slatCoordCache.getTopPosition(slatIndex) +
            this.slatCoordCache.getHeight(slatIndex) * slatRemainder;
    },



    /* Event Drag Visualization
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a visual indication of an event being dragged over the specified date(s).
    // A returned value of `true` signals that a mock "helper" event has been rendered.
    renderDrag: function(eventLocation, seg) {

        if (seg) { // if there is event information for this drag, render a helper event

            // returns mock event elements
            // signal that a helper has been rendered
            return this.renderEventLocationHelper(eventLocation, seg);
        }
        else {
            // otherwise, just render a highlight
            this.renderHighlight(this.eventToSpan(eventLocation));
        }
    },


    // Unrenders any visual indication of an event being dragged
    unrenderDrag: function() {
        this.unrenderHelper();
        this.unrenderHighlight();
    },


    /* Event Resize Visualization
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a visual indication of an event being resized
    renderEventResize: function(eventLocation, seg) {
        return this.renderEventLocationHelper(eventLocation, seg); // returns mock event elements
    },


    // Unrenders any visual indication of an event being resized
    unrenderEventResize: function() {
        this.unrenderHelper();
    },


    /* Event Helper
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a mock "helper" event. `sourceSeg` is the original segment object and might be null (an external drag)
    renderHelper: function(event, sourceSeg) {
        return this.renderHelperSegs(this.eventToSegs(event), sourceSeg); // returns mock event elements
    },


    // Unrenders any mock helper event
    unrenderHelper: function() {
        this.unrenderHelperSegs();
    },


    /* Business Hours
    ------------------------------------------------------------------------------------------------------------------*/


    renderBusinessHours: function() {
        this.renderBusinessSegs(
            this.buildBusinessHourSegs()
        );
    },


    unrenderBusinessHours: function() {
        this.unrenderBusinessSegs();
    },


    /* Now Indicator
    ------------------------------------------------------------------------------------------------------------------*/


    getNowIndicatorUnit: function() {
        return 'minute'; // will refresh on the minute
    },


    renderNowIndicator: function(date) {
        // seg system might be overkill, but it handles scenario where line needs to be rendered
        //  more than once because of columns with the same date (resources columns for example)
        var segs = this.spanToSegs({ start: date, end: date });
        var top = this.computeDateTop(date, date);
        var nodes = [];
        var i;

        // render lines within the columns
        for (i = 0; i < segs.length; i++) {
            nodes.push($('<div class="fc-now-indicator fc-now-indicator-line"></div>')
                .css('top', top)
                .appendTo(this.colContainerEls.eq(segs[i].col))[0]);
        }

        // render an arrow over the axis
        if (segs.length > 0) { // is the current time in view?
            nodes.push($('<div class="fc-now-indicator fc-now-indicator-arrow"></div>')
                .css('top', top)
                .appendTo(this.el.find('.fc-content-skeleton'))[0]);
        }

        this.nowIndicatorEls = $(nodes);
    },


    unrenderNowIndicator: function() {
        if (this.nowIndicatorEls) {
            this.nowIndicatorEls.remove();
            this.nowIndicatorEls = null;
        }
    },


    /* Selection
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a visual indication of a selection. Overrides the default, which was to simply render a highlight.
    renderSelection: function(span) {
        if (this.view.opt('selectHelper')) { // this setting signals that a mock helper event should be rendered

            // normally acceps an eventLocation, span has a start/end, which is good enough
            this.renderEventLocationHelper(span);
        }
        else {
            this.renderHighlight(span);
        }
    },


    // Unrenders any visual indication of a selection
    unrenderSelection: function() {
        this.unrenderHelper();
        this.unrenderHighlight();
    },


    /* Highlight
    ------------------------------------------------------------------------------------------------------------------*/


    renderHighlight: function(span) {
        this.renderHighlightSegs(this.spanToSegs(span));
    },


    unrenderHighlight: function() {
        this.unrenderHighlightSegs();
    }

});

;;

/* Methods for rendering SEGMENTS, pieces of content that live on the view
 ( this file is no longer just for events )
----------------------------------------------------------------------------------------------------------------------*/

TimeGrid.mixin({

    colContainerEls: null, // containers for each column

    // inner-containers for each column where different types of segs live
    fgContainerEls: null,
    bgContainerEls: null,
    helperContainerEls: null,
    highlightContainerEls: null,
    businessContainerEls: null,

    // arrays of different types of displayed segments
    fgSegs: null,
    bgSegs: null,
    helperSegs: null,
    highlightSegs: null,
    businessSegs: null,


    // Renders the DOM that the view's content will live in
    renderContentSkeleton: function() {
        var cellHtml = '';
        var i;
        var skeletonEl;

        for (i = 0; i < this.colCnt; i++) {
            cellHtml +=
                '<td>' +
                    '<div class="fc-content-col">' +
                        '<div class="fc-event-container fc-helper-container"></div>' +
                        '<div class="fc-event-container"></div>' +
                        '<div class="fc-highlight-container"></div>' +
                        '<div class="fc-bgevent-container"></div>' +
                        '<div class="fc-business-container"></div>' +
                    '</div>' +
                '</td>';
        }

        skeletonEl = $(
            '<div class="fc-content-skeleton">' +
                '<table>' +
                    '<tr>' + cellHtml + '</tr>' +
                '</table>' +
            '</div>'
        );

        this.colContainerEls = skeletonEl.find('.fc-content-col');
        this.helperContainerEls = skeletonEl.find('.fc-helper-container');
        this.fgContainerEls = skeletonEl.find('.fc-event-container:not(.fc-helper-container)');
        this.bgContainerEls = skeletonEl.find('.fc-bgevent-container');
        this.highlightContainerEls = skeletonEl.find('.fc-highlight-container');
        this.businessContainerEls = skeletonEl.find('.fc-business-container');

        this.bookendCells(skeletonEl.find('tr')); // TODO: do this on string level
        this.el.append(skeletonEl);
    },


    /* Foreground Events
    ------------------------------------------------------------------------------------------------------------------*/


    renderFgSegs: function(segs) {
        segs = this.renderFgSegsIntoContainers(segs, this.fgContainerEls);
        this.fgSegs = segs;
        return segs; // needed for Grid::renderEvents
    },


    unrenderFgSegs: function() {
        this.unrenderNamedSegs('fgSegs');
    },


    /* Foreground Helper Events
    ------------------------------------------------------------------------------------------------------------------*/


    renderHelperSegs: function(segs, sourceSeg) {
        var helperEls = [];
        var i, seg;
        var sourceEl;

        segs = this.renderFgSegsIntoContainers(segs, this.helperContainerEls);

        // Try to make the segment that is in the same row as sourceSeg look the same
        for (i = 0; i < segs.length; i++) {
            seg = segs[i];
            if (sourceSeg && sourceSeg.col === seg.col) {
                sourceEl = sourceSeg.el;
                seg.el.css({
                    left: sourceEl.css('left'),
                    right: sourceEl.css('right'),
                    'margin-left': sourceEl.css('margin-left'),
                    'margin-right': sourceEl.css('margin-right')
                });
            }
            helperEls.push(seg.el[0]);
        }

        this.helperSegs = segs;

        return $(helperEls); // must return rendered helpers
    },


    unrenderHelperSegs: function() {
        this.unrenderNamedSegs('helperSegs');
    },


    /* Background Events
    ------------------------------------------------------------------------------------------------------------------*/


    renderBgSegs: function(segs) {
        segs = this.renderFillSegEls('bgEvent', segs); // TODO: old fill system
        this.updateSegVerticals(segs);
        this.attachSegsByCol(this.groupSegsByCol(segs), this.bgContainerEls);
        this.bgSegs = segs;
        return segs; // needed for Grid::renderEvents
    },


    unrenderBgSegs: function() {
        this.unrenderNamedSegs('bgSegs');
    },


    /* Highlight
    ------------------------------------------------------------------------------------------------------------------*/


    renderHighlightSegs: function(segs) {
        segs = this.renderFillSegEls('highlight', segs); // TODO: old fill system
        this.updateSegVerticals(segs);
        this.attachSegsByCol(this.groupSegsByCol(segs), this.highlightContainerEls);
        this.highlightSegs = segs;
    },


    unrenderHighlightSegs: function() {
        this.unrenderNamedSegs('highlightSegs');
    },


    /* Business Hours
    ------------------------------------------------------------------------------------------------------------------*/


    renderBusinessSegs: function(segs) {
        segs = this.renderFillSegEls('businessHours', segs); // TODO: old fill system
        this.updateSegVerticals(segs);
        this.attachSegsByCol(this.groupSegsByCol(segs), this.businessContainerEls);
        this.businessSegs = segs;
    },


    unrenderBusinessSegs: function() {
        this.unrenderNamedSegs('businessSegs');
    },


    /* Seg Rendering Utils
    ------------------------------------------------------------------------------------------------------------------*/


    // Given a flat array of segments, return an array of sub-arrays, grouped by each segment's col
    groupSegsByCol: function(segs) {
        var segsByCol = [];
        var i;

        for (i = 0; i < this.colCnt; i++) {
            segsByCol.push([]);
        }

        for (i = 0; i < segs.length; i++) {
            segsByCol[segs[i].col].push(segs[i]);
        }

        return segsByCol;
    },


    // Given segments grouped by column, insert the segments' elements into a parallel array of container
    // elements, each living within a column.
    attachSegsByCol: function(segsByCol, containerEls) {
        var col;
        var segs;
        var i;

        for (col = 0; col < this.colCnt; col++) { // iterate each column grouping
            segs = segsByCol[col];

            for (i = 0; i < segs.length; i++) {
                containerEls.eq(col).append(segs[i].el);
            }
        }
    },


    // Given the name of a property of `this` object, assumed to be an array of segments,
    // loops through each segment and removes from DOM. Will null-out the property afterwards.
    unrenderNamedSegs: function(propName) {
        var segs = this[propName];
        var i;

        if (segs) {
            for (i = 0; i < segs.length; i++) {
                segs[i].el.remove();
            }
            this[propName] = null;
        }
    },



    /* Foreground Event Rendering Utils
    ------------------------------------------------------------------------------------------------------------------*/


    // Given an array of foreground segments, render a DOM element for each, computes position,
    // and attaches to the column inner-container elements.
    renderFgSegsIntoContainers: function(segs, containerEls) {
        var segsByCol;
        var col;

        segs = this.renderFgSegEls(segs); // will call fgSegHtml
        segsByCol = this.groupSegsByCol(segs);

        for (col = 0; col < this.colCnt; col++) {
            this.updateFgSegCoords(segsByCol[col]);
        }

        this.attachSegsByCol(segsByCol, containerEls);

        return segs;
    },


    // Renders the HTML for a single event segment's default rendering
    fgSegHtml: function(seg, disableResizing) {
        var view = this.view;
        var event = seg.event;
        var isDraggable = view.isEventDraggable(event);
        var isResizableFromStart = !disableResizing && seg.isStart && view.isEventResizableFromStart(event);
        var isResizableFromEnd = !disableResizing && seg.isEnd && view.isEventResizableFromEnd(event);
        var classes = this.getSegClasses(seg, isDraggable, isResizableFromStart || isResizableFromEnd);
        var skinCss = cssToStr(this.getSegSkinCss(seg));
        var timeText;
        var fullTimeText; // more verbose time text. for the print stylesheet
        var startTimeText; // just the start time text

        classes.unshift('fc-time-grid-event', 'fc-v-event');

        if (view.isMultiDayEvent(event)) { // if the event appears to span more than one day...
            // Don't display time text on segments that run entirely through a day.
            // That would appear as midnight-midnight and would look dumb.
            // Otherwise, display the time text for the *segment's* times (like 6pm-midnight or midnight-10am)
            if (seg.isStart || seg.isEnd) {
                timeText = this.getEventTimeText(seg);
                fullTimeText = this.getEventTimeText(seg, 'LT');
                startTimeText = this.getEventTimeText(seg, null, false); // displayEnd=false
            }
        } else {
            // Display the normal time text for the *event's* times
            timeText = this.getEventTimeText(event);
            fullTimeText = this.getEventTimeText(event, 'LT');
            startTimeText = this.getEventTimeText(event, null, false); // displayEnd=false
        }

        return '<a class="' + classes.join(' ') + '"' +
            (event.url ?
                ' href="' + htmlEscape(event.url) + '"' :
                ''
                ) +
            (skinCss ?
                ' style="' + skinCss + '"' :
                ''
                ) +
            '>' +
                '<div class="fc-content">' +
                    (timeText ?
                        '<div class="fc-time"' +
                        ' data-start="' + htmlEscape(startTimeText) + '"' +
                        ' data-full="' + htmlEscape(fullTimeText) + '"' +
                        '>' +
                            '<span>' + htmlEscape(timeText) + '</span>' +
                        '</div>' :
                        ''
                        ) +
                    (event.title ?
                        '<div class="fc-title">' +
                            htmlEscape(event.title) +
                        '</div>' :
                        ''
                        ) +
                '</div>' +
                '<div class="fc-bg"/>' +
                /* TODO: write CSS for this
                (isResizableFromStart ?
                    '<div class="fc-resizer fc-start-resizer" />' :
                    ''
                    ) +
                */
                (isResizableFromEnd ?
                    '<div class="fc-resizer fc-end-resizer" />' :
                    ''
                    ) +
            '</a>';
    },


    /* Seg Position Utils
    ------------------------------------------------------------------------------------------------------------------*/


    // Refreshes the CSS top/bottom coordinates for each segment element.
    // Works when called after initial render, after a window resize/zoom for example.
    updateSegVerticals: function(segs) {
        this.computeSegVerticals(segs);
        this.assignSegVerticals(segs);
    },


    // For each segment in an array, computes and assigns its top and bottom properties
    computeSegVerticals: function(segs) {
        var i, seg;

        for (i = 0; i < segs.length; i++) {
            seg = segs[i];
            seg.top = this.computeDateTop(seg.start, seg.start);
            seg.bottom = this.computeDateTop(seg.end, seg.start);
        }
    },


    // Given segments that already have their top/bottom properties computed, applies those values to
    // the segments' elements.
    assignSegVerticals: function(segs) {
        var i, seg;

        for (i = 0; i < segs.length; i++) {
            seg = segs[i];
            seg.el.css(this.generateSegVerticalCss(seg));
        }
    },


    // Generates an object with CSS properties for the top/bottom coordinates of a segment element
    generateSegVerticalCss: function(seg) {
        return {
            top: seg.top,
            bottom: -seg.bottom // flipped because needs to be space beyond bottom edge of event container
        };
    },


    /* Foreground Event Positioning Utils
    ------------------------------------------------------------------------------------------------------------------*/


    // Given segments that are assumed to all live in the *same column*,
    // compute their verical/horizontal coordinates and assign to their elements.
    updateFgSegCoords: function(segs) {
        this.computeSegVerticals(segs); // horizontals relies on this
        this.computeFgSegHorizontals(segs); // compute horizontal coordinates, z-index's, and reorder the array
        this.assignSegVerticals(segs);
        this.assignFgSegHorizontals(segs);
    },


    // Given an array of segments that are all in the same column, sets the backwardCoord and forwardCoord on each.
    // NOTE: Also reorders the given array by date!
    computeFgSegHorizontals: function(segs) {
        var levels;
        var level0;
        var i;

        this.sortEventSegs(segs); // order by certain criteria
        levels = buildSlotSegLevels(segs);
        computeForwardSlotSegs(levels);

        if ((level0 = levels[0])) {

            for (i = 0; i < level0.length; i++) {
                computeSlotSegPressures(level0[i]);
            }

            for (i = 0; i < level0.length; i++) {
                this.computeFgSegForwardBack(level0[i], 0, 0);
            }
        }
    },


    // Calculate seg.forwardCoord and seg.backwardCoord for the segment, where both values range
    // from 0 to 1. If the calendar is left-to-right, the seg.backwardCoord maps to "left" and
    // seg.forwardCoord maps to "right" (via percentage). Vice-versa if the calendar is right-to-left.
    //
    // The segment might be part of a "series", which means consecutive segments with the same pressure
    // who's width is unknown until an edge has been hit. `seriesBackwardPressure` is the number of
    // segments behind this one in the current series, and `seriesBackwardCoord` is the starting
    // coordinate of the first segment in the series.
    computeFgSegForwardBack: function(seg, seriesBackwardPressure, seriesBackwardCoord) {
        var forwardSegs = seg.forwardSegs;
        var i;

        if (seg.forwardCoord === undefined) { // not already computed

            if (!forwardSegs.length) {

                // if there are no forward segments, this segment should butt up against the edge
                seg.forwardCoord = 1;
            }
            else {

                // sort highest pressure first
                this.sortForwardSegs(forwardSegs);

                // this segment's forwardCoord will be calculated from the backwardCoord of the
                // highest-pressure forward segment.
                this.computeFgSegForwardBack(forwardSegs[0], seriesBackwardPressure + 1, seriesBackwardCoord);
                seg.forwardCoord = forwardSegs[0].backwardCoord;
            }

            // calculate the backwardCoord from the forwardCoord. consider the series
            seg.backwardCoord = seg.forwardCoord -
                (seg.forwardCoord - seriesBackwardCoord) / // available width for series
                (seriesBackwardPressure + 1); // # of segments in the series

            // use this segment's coordinates to computed the coordinates of the less-pressurized
            // forward segments
            for (i=0; i<forwardSegs.length; i++) {
                this.computeFgSegForwardBack(forwardSegs[i], 0, seg.forwardCoord);
            }
        }
    },


    sortForwardSegs: function(forwardSegs) {
        forwardSegs.sort(proxy(this, 'compareForwardSegs'));
    },


    // A cmp function for determining which forward segment to rely on more when computing coordinates.
    compareForwardSegs: function(seg1, seg2) {
        // put higher-pressure first
        return seg2.forwardPressure - seg1.forwardPressure ||
            // put segments that are closer to initial edge first (and favor ones with no coords yet)
            (seg1.backwardCoord || 0) - (seg2.backwardCoord || 0) ||
            // do normal sorting...
            this.compareEventSegs(seg1, seg2);
    },


    // Given foreground event segments that have already had their position coordinates computed,
    // assigns position-related CSS values to their elements.
    assignFgSegHorizontals: function(segs) {
        var i, seg;

        for (i = 0; i < segs.length; i++) {
            seg = segs[i];
            seg.el.css(this.generateFgSegHorizontalCss(seg));

            // if the height is short, add a className for alternate styling
            if (seg.bottom - seg.top < 30) {
                seg.el.addClass('fc-short');
            }
        }
    },


    // Generates an object with CSS properties/values that should be applied to an event segment element.
    // Contains important positioning-related properties that should be applied to any event element, customized or not.
    generateFgSegHorizontalCss: function(seg) {
        var shouldOverlap = this.view.opt('slotEventOverlap');
        var backwardCoord = seg.backwardCoord; // the left side if LTR. the right side if RTL. floating-point
        var forwardCoord = seg.forwardCoord; // the right side if LTR. the left side if RTL. floating-point
        var props = this.generateSegVerticalCss(seg); // get top/bottom first
        var left; // amount of space from left edge, a fraction of the total width
        var right; // amount of space from right edge, a fraction of the total width

        if (shouldOverlap) {
            // double the width, but don't go beyond the maximum forward coordinate (1.0)
            forwardCoord = Math.min(1, backwardCoord + (forwardCoord - backwardCoord) * 2);
        }

        if (this.isRTL) {
            left = 1 - forwardCoord;
            right = backwardCoord;
        }
        else {
            left = backwardCoord;
            right = 1 - forwardCoord;
        }

        props.zIndex = seg.level + 1; // convert from 0-base to 1-based
        props.left = left * 100 + '%';
        props.right = right * 100 + '%';

        if (shouldOverlap && seg.forwardPressure) {
            // add padding to the edge so that forward stacked events don't cover the resizer's icon
            props[this.isRTL ? 'marginLeft' : 'marginRight'] = 10 * 2; // 10 is a guesstimate of the icon's width
        }

        return props;
    }

});


// Builds an array of segments "levels". The first level will be the leftmost tier of segments if the calendar is
// left-to-right, or the rightmost if the calendar is right-to-left. Assumes the segments are already ordered by date.
function buildSlotSegLevels(segs) {
    var levels = [];
    var i, seg;
    var j;

    for (i=0; i<segs.length; i++) {
        seg = segs[i];

        // go through all the levels and stop on the first level where there are no collisions
        for (j=0; j<levels.length; j++) {
            if (!computeSlotSegCollisions(seg, levels[j]).length) {
                break;
            }
        }

        seg.level = j;

        (levels[j] || (levels[j] = [])).push(seg);
    }

    return levels;
}


// For every segment, figure out the other segments that are in subsequent
// levels that also occupy the same vertical space. Accumulate in seg.forwardSegs
function computeForwardSlotSegs(levels) {
    var i, level;
    var j, seg;
    var k;

    for (i=0; i<levels.length; i++) {
        level = levels[i];

        for (j=0; j<level.length; j++) {
            seg = level[j];

            seg.forwardSegs = [];
            for (k=i+1; k<levels.length; k++) {
                computeSlotSegCollisions(seg, levels[k], seg.forwardSegs);
            }
        }
    }
}


// Figure out which path forward (via seg.forwardSegs) results in the longest path until
// the furthest edge is reached. The number of segments in this path will be seg.forwardPressure
function computeSlotSegPressures(seg) {
    var forwardSegs = seg.forwardSegs;
    var forwardPressure = 0;
    var i, forwardSeg;

    if (seg.forwardPressure === undefined) { // not already computed

        for (i=0; i<forwardSegs.length; i++) {
            forwardSeg = forwardSegs[i];

            // figure out the child's maximum forward path
            computeSlotSegPressures(forwardSeg);

            // either use the existing maximum, or use the child's forward pressure
            // plus one (for the forwardSeg itself)
            forwardPressure = Math.max(
                forwardPressure,
                1 + forwardSeg.forwardPressure
            );
        }

        seg.forwardPressure = forwardPressure;
    }
}


// Find all the segments in `otherSegs` that vertically collide with `seg`.
// Append into an optionally-supplied `results` array and return.
function computeSlotSegCollisions(seg, otherSegs, results) {
    results = results || [];

    for (var i=0; i<otherSegs.length; i++) {
        if (isSlotSegCollision(seg, otherSegs[i])) {
            results.push(otherSegs[i]);
        }
    }

    return results;
}


// Do these segments occupy the same vertical space?
function isSlotSegCollision(seg1, seg2) {
    return seg1.bottom > seg2.top && seg1.top < seg2.bottom;
}

;;

/* An abstract class from which other views inherit from
----------------------------------------------------------------------------------------------------------------------*/

var View = FC.View = Class.extend(EmitterMixin, ListenerMixin, {

    type: null, // subclass' view name (string)
    name: null, // deprecated. use `type` instead
    title: null, // the text that will be displayed in the header's title

    calendar: null, // owner Calendar object
    options: null, // hash containing all options. already merged with view-specific-options
    el: null, // the view's containing element. set by Calendar

    displaying: null, // a promise representing the state of rendering. null if no render requested
    isSkeletonRendered: false,
    isEventsRendered: false,

    // range the view is actually displaying (moments)
    start: null,
    end: null, // exclusive

    // range the view is formally responsible for (moments)
    // may be different from start/end. for example, a month view might have 1st-31st, excluding padded dates
    intervalStart: null,
    intervalEnd: null, // exclusive
    intervalDuration: null,
    intervalUnit: null, // name of largest unit being displayed, like "month" or "week"

    isRTL: false,
    isSelected: false, // boolean whether a range of time is user-selected or not
    selectedEvent: null,

    eventOrderSpecs: null, // criteria for ordering events when they have same date/time

    // classNames styled by jqui themes
    widgetHeaderClass: null,
    widgetContentClass: null,
    highlightStateClass: null,

    // for date utils, computed from options
    nextDayThreshold: null,
    isHiddenDayHash: null,

    // now indicator
    isNowIndicatorRendered: null,
    initialNowDate: null, // result first getNow call
    initialNowQueriedMs: null, // ms time the getNow was called
    nowIndicatorTimeoutID: null, // for refresh timing of now indicator
    nowIndicatorIntervalID: null, // "


    constructor: function(calendar, type, options, intervalDuration) {

        this.calendar = calendar;
        this.type = this.name = type; // .name is deprecated
        this.options = options;
        this.intervalDuration = intervalDuration || moment.duration(1, 'day');

        this.nextDayThreshold = moment.duration(this.opt('nextDayThreshold'));
        this.initThemingProps();
        this.initHiddenDays();
        this.isRTL = this.opt('isRTL');

        this.eventOrderSpecs = parseFieldSpecs(this.opt('eventOrder'));

        this.initialize();
    },


    // A good place for subclasses to initialize member variables
    initialize: function() {
        // subclasses can implement
    },


    // Retrieves an option with the given name
    opt: function(name) {
        return this.options[name];
    },


    // Triggers handlers that are view-related. Modifies args before passing to calendar.
    trigger: function(name, thisObj) { // arguments beyond thisObj are passed along
        var calendar = this.calendar;

        return calendar.trigger.apply(
            calendar,
            [name, thisObj || this].concat(
                Array.prototype.slice.call(arguments, 2), // arguments beyond thisObj
                [ this ] // always make the last argument a reference to the view. TODO: deprecate
            )
        );
    },


    /* Dates
    ------------------------------------------------------------------------------------------------------------------*/


    // Updates all internal dates to center around the given current unzoned date.
    setDate: function(date) {
        this.setRange(this.computeRange(date));
    },


    // Updates all internal dates for displaying the given unzoned range.
    setRange: function(range) {
        $.extend(this, range); // assigns every property to this object's member variables
        this.updateTitle();
    },


    // Given a single current unzoned date, produce information about what range to display.
    // Subclasses can override. Must return all properties.
    computeRange: function(date) {
        var intervalUnit = computeIntervalUnit(this.intervalDuration);
        var intervalStart = date.clone().startOf(intervalUnit);
        var intervalEnd = intervalStart.clone().add(this.intervalDuration);
        var start, end;

        // normalize the range's time-ambiguity
        if (/year|month|week|day/.test(intervalUnit)) { // whole-days?
            intervalStart.stripTime();
            intervalEnd.stripTime();
        }
        else { // needs to have a time?
            if (!intervalStart.hasTime()) {
                intervalStart = this.calendar.time(0); // give 00:00 time
            }
            if (!intervalEnd.hasTime()) {
                intervalEnd = this.calendar.time(0); // give 00:00 time
            }
        }

        start = intervalStart.clone();
        start = this.skipHiddenDays(start);
        end = intervalEnd.clone();
        end = this.skipHiddenDays(end, -1, true); // exclusively move backwards

        return {
            intervalUnit: intervalUnit,
            intervalStart: intervalStart,
            intervalEnd: intervalEnd,
            start: start,
            end: end
        };
    },


    // Computes the new date when the user hits the prev button, given the current date
    computePrevDate: function(date) {
        return this.massageCurrentDate(
            date.clone().startOf(this.intervalUnit).subtract(this.intervalDuration), -1
        );
    },


    // Computes the new date when the user hits the next button, given the current date
    computeNextDate: function(date) {
        return this.massageCurrentDate(
            date.clone().startOf(this.intervalUnit).add(this.intervalDuration)
        );
    },


    // Given an arbitrarily calculated current date of the calendar, returns a date that is ensured to be completely
    // visible. `direction` is optional and indicates which direction the current date was being
    // incremented or decremented (1 or -1).
    massageCurrentDate: function(date, direction) {
        if (this.intervalDuration.as('days') <= 1) { // if the view displays a single day or smaller
            if (this.isHiddenDay(date)) {
                date = this.skipHiddenDays(date, direction);
                date.startOf('day');
            }
        }

        return date;
    },


    /* Title and Date Formatting
    ------------------------------------------------------------------------------------------------------------------*/


    // Sets the view's title property to the most updated computed value
    updateTitle: function() {
        this.title = this.computeTitle();
    },


    // Computes what the title at the top of the calendar should be for this view
    computeTitle: function() {
        return this.formatRange(
            {
                // in case intervalStart/End has a time, make sure timezone is correct
                start: this.calendar.applyTimezone(this.intervalStart),
                end: this.calendar.applyTimezone(this.intervalEnd)
            },
            this.opt('titleFormat') || this.computeTitleFormat(),
            this.opt('titleRangeSeparator')
        );
    },


    // Generates the format string that should be used to generate the title for the current date range.
    // Attempts to compute the most appropriate format if not explicitly specified with `titleFormat`.
    computeTitleFormat: function() {
        if (this.intervalUnit == 'year') {
            return 'YYYY';
        }
        else if (this.intervalUnit == 'month') {
            return this.opt('monthYearFormat'); // like "September 2014"
        }
        else if (this.intervalDuration.as('days') > 1) {
            return 'll'; // multi-day range. shorter, like "Sep 9 - 10 2014"
        }
        else {
            return 'LL'; // one day. longer, like "September 9 2014"
        }
    },


    // Utility for formatting a range. Accepts a range object, formatting string, and optional separator.
    // Displays all-day ranges naturally, with an inclusive end. Takes the current isRTL into account.
    // The timezones of the dates within `range` will be respected.
    formatRange: function(range, formatStr, separator) {
        var end = range.end;

        if (!end.hasTime()) { // all-day?
            end = end.clone().subtract(1); // convert to inclusive. last ms of previous day
        }

        return formatRange(range.start, end, formatStr, separator, this.opt('isRTL'));
    },


    getAllDayHtml: function() {
        return this.opt('allDayHtml') || htmlEscape(this.opt('allDayText'));
    },


    /* Navigation
    ------------------------------------------------------------------------------------------------------------------*/


    // Generates HTML for an anchor to another view into the calendar.
    // Will either generate an <a> tag or a non-clickable <span> tag, depending on enabled settings.
    // `gotoOptions` can either be a moment input, or an object with the form:
    // { date, type, forceOff }
    // `type` is a view-type like "day" or "week". default value is "day".
    // `attrs` and `innerHtml` are use to generate the rest of the HTML tag.
    buildGotoAnchorHtml: function(gotoOptions, attrs, innerHtml) {
        var date, type, forceOff;
        var finalOptions;

        if ($.isPlainObject(gotoOptions)) {
            date = gotoOptions.date;
            type = gotoOptions.type;
            forceOff = gotoOptions.forceOff;
        }
        else {
            date = gotoOptions; // a single moment input
        }
        date = FC.moment(date); // if a string, parse it

        finalOptions = { // for serialization into the link
            date: date.format('YYYY-MM-DD'),
            type: type || 'day'
        };

        if (typeof attrs === 'string') {
            innerHtml = attrs;
            attrs = null;
        }

        attrs = attrs ? ' ' + attrsToStr(attrs) : ''; // will have a leading space
        innerHtml = innerHtml || '';

        if (!forceOff && this.opt('navLinks')) {
            return '<a' + attrs +
                ' data-goto="' + htmlEscape(JSON.stringify(finalOptions)) + '">' +
                innerHtml +
                '</a>';
        }
        else {
            return '<span' + attrs + '>' +
                innerHtml +
                '</span>';
        }
    },


    /* Rendering
    ------------------------------------------------------------------------------------------------------------------*/


    // Sets the container element that the view should render inside of.
    // Does other DOM-related initializations.
    setElement: function(el) {
        this.el = el;
        this.bindGlobalHandlers();
    },


    // Removes the view's container element from the DOM, clearing any content beforehand.
    // Undoes any other DOM-related attachments.
    removeElement: function() {
        this.clear(); // clears all content

        // clean up the skeleton
        if (this.isSkeletonRendered) {
            this.unrenderSkeleton();
            this.isSkeletonRendered = false;
        }

        this.unbindGlobalHandlers();

        this.el.remove();

        // NOTE: don't null-out this.el in case the View was destroyed within an API callback.
        // We don't null-out the View's other jQuery element references upon destroy,
        //  so we shouldn't kill this.el either.
    },


    // Does everything necessary to display the view centered around the given unzoned date.
    // Does every type of rendering EXCEPT rendering events.
    // Is asychronous and returns a promise.
    display: function(date, explicitScrollState) {
        var _this = this;
        var prevScrollState = null;

        if (explicitScrollState != null && this.displaying) { // don't need prevScrollState if explicitScrollState
            prevScrollState = this.queryScroll();
        }

        this.calendar.freezeContentHeight();

        return syncThen(this.clear(), function() { // clear the content first
            return (
                _this.displaying =
                    syncThen(_this.displayView(date), function() { // displayView might return a promise

                        // caller of display() wants a specific scroll state?
                        if (explicitScrollState != null) {
                            // we make an assumption that this is NOT the initial render,
                            // and thus don't need forceScroll (is inconveniently asynchronous)
                            _this.setScroll(explicitScrollState);
                        }
                        else {
                            _this.forceScroll(_this.computeInitialScroll(prevScrollState));
                        }

                        _this.calendar.unfreezeContentHeight();
                        _this.triggerRender();
                    })
            );
        });
    },


    // Does everything necessary to clear the content of the view.
    // Clears dates and events. Does not clear the skeleton.
    // Is asychronous and returns a promise.
    clear: function() {
        var _this = this;
        var displaying = this.displaying;

        if (displaying) { // previously displayed, or in the process of being displayed?
            return syncThen(displaying, function() { // wait for the display to finish
                _this.displaying = null;
                _this.clearEvents();
                return _this.clearView(); // might return a promise. chain it
            });
        }
        else {
            return $.when(); // an immediately-resolved promise
        }
    },


    // Displays the view's non-event content, such as date-related content or anything required by events.
    // Renders the view's non-content skeleton if necessary.
    // Can be asynchronous and return a promise.
    displayView: function(date) {
        if (!this.isSkeletonRendered) {
            this.renderSkeleton();
            this.isSkeletonRendered = true;
        }
        if (date) {
            this.setDate(date);
        }
        if (this.render) {
            this.render(); // TODO: deprecate
        }
        this.renderDates();
        this.updateSize();
        this.renderBusinessHours(); // might need coordinates, so should go after updateSize()
        this.startNowIndicator();
    },


    // Unrenders the view content that was rendered in displayView.
    // Can be asynchronous and return a promise.
    clearView: function() {
        this.unselect();
        this.stopNowIndicator();
        this.triggerUnrender();
        this.unrenderBusinessHours();
        this.unrenderDates();
        if (this.destroy) {
            this.destroy(); // TODO: deprecate
        }
    },


    // Renders the basic structure of the view before any content is rendered
    renderSkeleton: function() {
        // subclasses should implement
    },


    // Unrenders the basic structure of the view
    unrenderSkeleton: function() {
        // subclasses should implement
    },


    // Renders the view's date-related content.
    // Assumes setRange has already been called and the skeleton has already been rendered.
    renderDates: function() {
        // subclasses should implement
    },


    // Unrenders the view's date-related content
    unrenderDates: function() {
        // subclasses should override
    },


    // Signals that the view's content has been rendered
    triggerRender: function() {
        this.trigger('viewRender', this, this, this.el);
    },


    // Signals that the view's content is about to be unrendered
    triggerUnrender: function() {
        this.trigger('viewDestroy', this, this, this.el);
    },


    // Binds DOM handlers to elements that reside outside the view container, such as the document
    bindGlobalHandlers: function() {
        this.listenTo($(document), 'mousedown', this.handleDocumentMousedown);
        this.listenTo($(document), 'touchstart', this.processUnselect);
    },


    // Unbinds DOM handlers from elements that reside outside the view container
    unbindGlobalHandlers: function() {
        this.stopListeningTo($(document));
    },


    // Initializes internal variables related to theming
    initThemingProps: function() {
        var tm = this.opt('theme') ? 'ui' : 'fc';

        this.widgetHeaderClass = tm + '-widget-header';
        this.widgetContentClass = tm + '-widget-content';
        this.highlightStateClass = tm + '-state-highlight';
    },


    /* Business Hours
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders business-hours onto the view. Assumes updateSize has already been called.
    renderBusinessHours: function() {
        // subclasses should implement
    },


    // Unrenders previously-rendered business-hours
    unrenderBusinessHours: function() {
        // subclasses should implement
    },


    /* Now Indicator
    ------------------------------------------------------------------------------------------------------------------*/


    // Immediately render the current time indicator and begins re-rendering it at an interval,
    // which is defined by this.getNowIndicatorUnit().
    // TODO: somehow do this for the current whole day's background too
    startNowIndicator: function() {
        var _this = this;
        var unit;
        var update;
        var delay; // ms wait value

        if (this.opt('nowIndicator')) {
            unit = this.getNowIndicatorUnit();
            if (unit) {
                update = proxy(this, 'updateNowIndicator'); // bind to `this`

                this.initialNowDate = this.calendar.getNow();
                this.initialNowQueriedMs = +new Date();
                this.renderNowIndicator(this.initialNowDate);
                this.isNowIndicatorRendered = true;

                // wait until the beginning of the next interval
                delay = this.initialNowDate.clone().startOf(unit).add(1, unit) - this.initialNowDate;
                this.nowIndicatorTimeoutID = setTimeout(function() {
                    _this.nowIndicatorTimeoutID = null;
                    update();
                    delay = +moment.duration(1, unit);
                    delay = Math.max(100, delay); // prevent too frequent
                    _this.nowIndicatorIntervalID = setInterval(update, delay); // update every interval
                }, delay);
            }
        }
    },


    // rerenders the now indicator, computing the new current time from the amount of time that has passed
    // since the initial getNow call.
    updateNowIndicator: function() {
        if (this.isNowIndicatorRendered) {
            this.unrenderNowIndicator();
            this.renderNowIndicator(
                this.initialNowDate.clone().add(new Date() - this.initialNowQueriedMs) // add ms
            );
        }
    },


    // Immediately unrenders the view's current time indicator and stops any re-rendering timers.
    // Won't cause side effects if indicator isn't rendered.
    stopNowIndicator: function() {
        if (this.isNowIndicatorRendered) {

            if (this.nowIndicatorTimeoutID) {
                clearTimeout(this.nowIndicatorTimeoutID);
                this.nowIndicatorTimeoutID = null;
            }
            if (this.nowIndicatorIntervalID) {
                clearTimeout(this.nowIndicatorIntervalID);
                this.nowIndicatorIntervalID = null;
            }

            this.unrenderNowIndicator();
            this.isNowIndicatorRendered = false;
        }
    },


    // Returns a string unit, like 'second' or 'minute' that defined how often the current time indicator
    // should be refreshed. If something falsy is returned, no time indicator is rendered at all.
    getNowIndicatorUnit: function() {
        // subclasses should implement
    },


    // Renders a current time indicator at the given datetime
    renderNowIndicator: function(date) {
        // subclasses should implement
    },


    // Undoes the rendering actions from renderNowIndicator
    unrenderNowIndicator: function() {
        // subclasses should implement
    },


    /* Dimensions
    ------------------------------------------------------------------------------------------------------------------*/


    // Refreshes anything dependant upon sizing of the container element of the grid
    updateSize: function(isResize) {
        var scrollState;

        if (isResize) {
            scrollState = this.queryScroll();
        }

        this.updateHeight(isResize);
        this.updateWidth(isResize);
        this.updateNowIndicator();

        if (isResize) {
            this.setScroll(scrollState);
        }
    },


    // Refreshes the horizontal dimensions of the calendar
    updateWidth: function(isResize) {
        // subclasses should implement
    },


    // Refreshes the vertical dimensions of the calendar
    updateHeight: function(isResize) {
        var calendar = this.calendar; // we poll the calendar for height information

        this.setHeight(
            calendar.getSuggestedViewHeight(),
            calendar.isHeightAuto()
        );
    },


    // Updates the vertical dimensions of the calendar to the specified height.
    // if `isAuto` is set to true, height becomes merely a suggestion and the view should use its "natural" height.
    setHeight: function(height, isAuto) {
        // subclasses should implement
    },


    /* Scroller
    ------------------------------------------------------------------------------------------------------------------*/


    // Computes the initial pre-configured scroll state prior to allowing the user to change it.
    // Given the scroll state from the previous rendering. If first time rendering, given null.
    computeInitialScroll: function(previousScrollState) {
        return 0;
    },


    // Retrieves the view's current natural scroll state. Can return an arbitrary format.
    queryScroll: function() {
        // subclasses must implement
    },


    // Sets the view's scroll state. Will accept the same format computeInitialScroll and queryScroll produce.
    setScroll: function(scrollState) {
        // subclasses must implement
    },


    // Sets the scroll state, making sure to overcome any predefined scroll value the browser has in mind
    forceScroll: function(scrollState) {
        var _this = this;

        this.setScroll(scrollState);
        setTimeout(function() {
            _this.setScroll(scrollState);
        }, 0);
    },


    /* Event Elements / Segments
    ------------------------------------------------------------------------------------------------------------------*/


    // Does everything necessary to display the given events onto the current view
    displayEvents: function(events) {
        var scrollState = this.queryScroll();

        this.clearEvents();
        this.renderEvents(events);
        this.isEventsRendered = true;
        this.setScroll(scrollState);
        this.triggerEventRender();
    },


    // Does everything necessary to clear the view's currently-rendered events
    clearEvents: function() {
        var scrollState;

        if (this.isEventsRendered) {

            // TODO: optimize: if we know this is part of a displayEvents call, don't queryScroll/setScroll
            scrollState = this.queryScroll();

            this.triggerEventUnrender();
            if (this.destroyEvents) {
                this.destroyEvents(); // TODO: deprecate
            }
            this.unrenderEvents();
            this.setScroll(scrollState);
            this.isEventsRendered = false;
        }
    },


    // Renders the events onto the view.
    renderEvents: function(events) {
        // subclasses should implement
    },


    // Removes event elements from the view.
    unrenderEvents: function() {
        // subclasses should implement
    },


    // Signals that all events have been rendered
    triggerEventRender: function() {
        this.renderedEventSegEach(function(seg) {
            this.trigger('eventAfterRender', seg.event, seg.event, seg.el);
        });
        this.trigger('eventAfterAllRender');
    },


    // Signals that all event elements are about to be removed
    triggerEventUnrender: function() {
        this.renderedEventSegEach(function(seg) {
            this.trigger('eventDestroy', seg.event, seg.event, seg.el);
        });
    },


    // Given an event and the default element used for rendering, returns the element that should actually be used.
    // Basically runs events and elements through the eventRender hook.
    resolveEventEl: function(event, el) {
        var custom = this.trigger('eventRender', event, event, el);

        if (custom === false) { // means don't render at all
            el = null;
        }
        else if (custom && custom !== true) {
            el = $(custom);
        }

        return el;
    },


    // Hides all rendered event segments linked to the given event
    showEvent: function(event) {
        this.renderedEventSegEach(function(seg) {
            seg.el.css('visibility', '');
        }, event);
    },


    // Shows all rendered event segments linked to the given event
    hideEvent: function(event) {
        this.renderedEventSegEach(function(seg) {
            seg.el.css('visibility', 'hidden');
        }, event);
    },


    // Iterates through event segments that have been rendered (have an el). Goes through all by default.
    // If the optional `event` argument is specified, only iterates through segments linked to that event.
    // The `this` value of the callback function will be the view.
    renderedEventSegEach: function(func, event) {
        var segs = this.getEventSegs();
        var i;

        for (i = 0; i < segs.length; i++) {
            if (!event || segs[i].event._id === event._id) {
                if (segs[i].el) {
                    func.call(this, segs[i]);
                }
            }
        }
    },


    // Retrieves all the rendered segment objects for the view
    getEventSegs: function() {
        // subclasses must implement
        return [];
    },


    /* Event Drag-n-Drop
    ------------------------------------------------------------------------------------------------------------------*/


    // Computes if the given event is allowed to be dragged by the user
    isEventDraggable: function(event) {
        return this.isEventStartEditable(event);
    },


    isEventStartEditable: function(event) {
        return firstDefined(
            event.startEditable,
            (event.source || {}).startEditable,
            this.opt('eventStartEditable'),
            this.isEventGenerallyEditable(event)
        );
    },


    isEventGenerallyEditable: function(event) {
        return firstDefined(
            event.editable,
            (event.source || {}).editable,
            this.opt('editable')
        );
    },


    // Must be called when an event in the view is dropped onto new location.
    // `dropLocation` is an object that contains the new zoned start/end/allDay values for the event.
    reportEventDrop: function(event, dropLocation, largeUnit, el, ev) {
        var calendar = this.calendar;
        var mutateResult = calendar.mutateEvent(event, dropLocation, largeUnit);
        var undoFunc = function() {
            mutateResult.undo();
            calendar.reportEventChange();
        };

        this.triggerEventDrop(event, mutateResult.dateDelta, undoFunc, el, ev);
        calendar.reportEventChange(); // will rerender events
    },


    // Triggers event-drop handlers that have subscribed via the API
    triggerEventDrop: function(event, dateDelta, undoFunc, el, ev) {
        this.trigger('eventDrop', el[0], event, dateDelta, undoFunc, ev, {}); // {} = jqui dummy
    },


    /* External Element Drag-n-Drop
    ------------------------------------------------------------------------------------------------------------------*/


    // Must be called when an external element, via jQuery UI, has been dropped onto the calendar.
    // `meta` is the parsed data that has been embedded into the dragging event.
    // `dropLocation` is an object that contains the new zoned start/end/allDay values for the event.
    reportExternalDrop: function(meta, dropLocation, el, ev, ui) {
        var eventProps = meta.eventProps;
        var eventInput;
        var event;

        // Try to build an event object and render it. TODO: decouple the two
        if (eventProps) {
            eventInput = $.extend({}, eventProps, dropLocation);
            event = this.calendar.renderEvent(eventInput, meta.stick)[0]; // renderEvent returns an array
        }

        this.triggerExternalDrop(event, dropLocation, el, ev, ui);
    },


    // Triggers external-drop handlers that have subscribed via the API
    triggerExternalDrop: function(event, dropLocation, el, ev, ui) {

        // trigger 'drop' regardless of whether element represents an event
        this.trigger('drop', el[0], dropLocation.start, ev, ui);

        if (event) {
            this.trigger('eventReceive', null, event); // signal an external event landed
        }
    },


    /* Drag-n-Drop Rendering (for both events and external elements)
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a visual indication of a event or external-element drag over the given drop zone.
    // If an external-element, seg will be `null`.
    // Must return elements used for any mock events.
    renderDrag: function(dropLocation, seg) {
        // subclasses must implement
    },


    // Unrenders a visual indication of an event or external-element being dragged.
    unrenderDrag: function() {
        // subclasses must implement
    },


    /* Event Resizing
    ------------------------------------------------------------------------------------------------------------------*/


    // Computes if the given event is allowed to be resized from its starting edge
    isEventResizableFromStart: function(event) {
        return this.opt('eventResizableFromStart') && this.isEventResizable(event);
    },


    // Computes if the given event is allowed to be resized from its ending edge
    isEventResizableFromEnd: function(event) {
        return this.isEventResizable(event);
    },


    // Computes if the given event is allowed to be resized by the user at all
    isEventResizable: function(event) {
        var source = event.source || {};

        return firstDefined(
            event.durationEditable,
            source.durationEditable,
            this.opt('eventDurationEditable'),
            event.editable,
            source.editable,
            this.opt('editable')
        );
    },


    // Must be called when an event in the view has been resized to a new length
    reportEventResize: function(event, resizeLocation, largeUnit, el, ev) {
        var calendar = this.calendar;
        var mutateResult = calendar.mutateEvent(event, resizeLocation, largeUnit);
        var undoFunc = function() {
            mutateResult.undo();
            calendar.reportEventChange();
        };

        this.triggerEventResize(event, mutateResult.durationDelta, undoFunc, el, ev);
        calendar.reportEventChange(); // will rerender events
    },


    // Triggers event-resize handlers that have subscribed via the API
    triggerEventResize: function(event, durationDelta, undoFunc, el, ev) {
        this.trigger('eventResize', el[0], event, durationDelta, undoFunc, ev, {}); // {} = jqui dummy
    },


    /* Selection (time range)
    ------------------------------------------------------------------------------------------------------------------*/


    // Selects a date span on the view. `start` and `end` are both Moments.
    // `ev` is the native mouse event that begin the interaction.
    select: function(span, ev) {
        this.unselect(ev);
        this.renderSelection(span);
        this.reportSelection(span, ev);
    },


    // Renders a visual indication of the selection
    renderSelection: function(span) {
        // subclasses should implement
    },


    // Called when a new selection is made. Updates internal state and triggers handlers.
    reportSelection: function(span, ev) {
        this.isSelected = true;
        this.triggerSelect(span, ev);
    },


    // Triggers handlers to 'select'
    triggerSelect: function(span, ev) {
        this.trigger(
            'select',
            null,
            this.calendar.applyTimezone(span.start), // convert to calendar's tz for external API
            this.calendar.applyTimezone(span.end), // "
            ev
        );
    },


    // Undoes a selection. updates in the internal state and triggers handlers.
    // `ev` is the native mouse event that began the interaction.
    unselect: function(ev) {
        if (this.isSelected) {
            this.isSelected = false;
            if (this.destroySelection) {
                this.destroySelection(); // TODO: deprecate
            }
            this.unrenderSelection();
            this.trigger('unselect', null, ev);
        }
    },


    // Unrenders a visual indication of selection
    unrenderSelection: function() {
        // subclasses should implement
    },


    /* Event Selection
    ------------------------------------------------------------------------------------------------------------------*/


    selectEvent: function(event) {
        if (!this.selectedEvent || this.selectedEvent !== event) {
            this.unselectEvent();
            this.renderedEventSegEach(function(seg) {
                seg.el.addClass('fc-selected');
            }, event);
            this.selectedEvent = event;
        }
    },


    unselectEvent: function() {
        if (this.selectedEvent) {
            this.renderedEventSegEach(function(seg) {
                seg.el.removeClass('fc-selected');
            }, this.selectedEvent);
            this.selectedEvent = null;
        }
    },


    isEventSelected: function(event) {
        // event references might change on refetchEvents(), while selectedEvent doesn't,
        // so compare IDs
        return this.selectedEvent && this.selectedEvent._id === event._id;
    },


    /* Mouse / Touch Unselecting (time range & event unselection)
    ------------------------------------------------------------------------------------------------------------------*/
    // TODO: move consistently to down/start or up/end?
    // TODO: don't kill previous selection if touch scrolling


    handleDocumentMousedown: function(ev) {
        if (isPrimaryMouseButton(ev)) {
            this.processUnselect(ev);
        }
    },


    processUnselect: function(ev) {
        this.processRangeUnselect(ev);
        this.processEventUnselect(ev);
    },


    processRangeUnselect: function(ev) {
        var ignore;

        // is there a time-range selection?
        if (this.isSelected && this.opt('unselectAuto')) {
            // only unselect if the clicked element is not identical to or inside of an 'unselectCancel' element
            ignore = this.opt('unselectCancel');
            if (!ignore || !$(ev.target).closest(ignore).length) {
                this.unselect(ev);
            }
        }
    },


    processEventUnselect: function(ev) {
        if (this.selectedEvent) {
            if (!$(ev.target).closest('.fc-selected').length) {
                this.unselectEvent();
            }
        }
    },


    /* Day Click
    ------------------------------------------------------------------------------------------------------------------*/


    // Triggers handlers to 'dayClick'
    // Span has start/end of the clicked area. Only the start is useful.
    triggerDayClick: function(span, dayEl, ev) {
        this.trigger(
            'dayClick',
            dayEl,
            this.calendar.applyTimezone(span.start), // convert to calendar's timezone for external API
            ev
        );
    },


    /* Date Utils
    ------------------------------------------------------------------------------------------------------------------*/


    // Initializes internal variables related to calculating hidden days-of-week
    initHiddenDays: function() {
        var hiddenDays = this.opt('hiddenDays') || []; // array of day-of-week indices that are hidden
        var isHiddenDayHash = []; // is the day-of-week hidden? (hash with day-of-week-index -> bool)
        var dayCnt = 0;
        var i;

        if (this.opt('weekends') === false) {
            hiddenDays.push(0, 6); // 0=sunday, 6=saturday
        }

        for (i = 0; i < 7; i++) {
            if (
                !(isHiddenDayHash[i] = $.inArray(i, hiddenDays) !== -1)
            ) {
                dayCnt++;
            }
        }

        if (!dayCnt) {
            throw 'invalid hiddenDays'; // all days were hidden? bad.
        }

        this.isHiddenDayHash = isHiddenDayHash;
    },


    // Is the current day hidden?
    // `day` is a day-of-week index (0-6), or a Moment
    isHiddenDay: function(day) {
        if (moment.isMoment(day)) {
            day = day.day();
        }
        return this.isHiddenDayHash[day];
    },


    // Incrementing the current day until it is no longer a hidden day, returning a copy.
    // If the initial value of `date` is not a hidden day, don't do anything.
    // Pass `isExclusive` as `true` if you are dealing with an end date.
    // `inc` defaults to `1` (increment one day forward each time)
    skipHiddenDays: function(date, inc, isExclusive) {
        var out = date.clone();
        inc = inc || 1;
        while (
            this.isHiddenDayHash[(out.day() + (isExclusive ? inc : 0) + 7) % 7]
        ) {
            out.add(inc, 'days');
        }
        return out;
    },


    // Returns the date range of the full days the given range visually appears to occupy.
    // Returns a new range object.
    computeDayRange: function(range) {
        var startDay = range.start.clone().stripTime(); // the beginning of the day the range starts
        var end = range.end;
        var endDay = null;
        var endTimeMS;

        if (end) {
            endDay = end.clone().stripTime(); // the beginning of the day the range exclusively ends
            endTimeMS = +end.time(); // # of milliseconds into `endDay`

            // If the end time is actually inclusively part of the next day and is equal to or
            // beyond the next day threshold, adjust the end to be the exclusive end of `endDay`.
            // Otherwise, leaving it as inclusive will cause it to exclude `endDay`.
            if (endTimeMS && endTimeMS >= this.nextDayThreshold) {
                endDay.add(1, 'days');
            }
        }

        // If no end was specified, or if it is within `startDay` but not past nextDayThreshold,
        // assign the default duration of one day.
        if (!end || endDay <= startDay) {
            endDay = startDay.clone().add(1, 'days');
        }

        return { start: startDay, end: endDay };
    },


    // Does the given event visually appear to occupy more than one day?
    isMultiDayEvent: function(event) {
        var range = this.computeDayRange(event); // event is range-ish

        return range.end.diff(range.start, 'days') > 1;
    }

});

;;

/*
Embodies a div that has potential scrollbars
*/
var Scroller = FC.Scroller = Class.extend({

    el: null, // the guaranteed outer element
    scrollEl: null, // the element with the scrollbars
    overflowX: null,
    overflowY: null,


    constructor: function(options) {
        options = options || {};
        this.overflowX = options.overflowX || options.overflow || 'auto';
        this.overflowY = options.overflowY || options.overflow || 'auto';
    },


    render: function() {
        this.el = this.renderEl();
        this.applyOverflow();
    },


    renderEl: function() {
        return (this.scrollEl = $('<div class="fc-scroller"></div>'));
    },


    // sets to natural height, unlocks overflow
    clear: function() {
        this.setHeight('auto');
        this.applyOverflow();
    },


    destroy: function() {
        this.el.remove();
    },


    // Overflow
    // -----------------------------------------------------------------------------------------------------------------


    applyOverflow: function() {
        this.scrollEl.css({
            'overflow-x': this.overflowX,
            'overflow-y': this.overflowY
        });
    },


    // Causes any 'auto' overflow values to resolves to 'scroll' or 'hidden'.
    // Useful for preserving scrollbar widths regardless of future resizes.
    // Can pass in scrollbarWidths for optimization.
    lockOverflow: function(scrollbarWidths) {
        var overflowX = this.overflowX;
        var overflowY = this.overflowY;

        scrollbarWidths = scrollbarWidths || this.getScrollbarWidths();

        if (overflowX === 'auto') {
            overflowX = (
                    scrollbarWidths.top || scrollbarWidths.bottom || // horizontal scrollbars?
                    // OR scrolling pane with massless scrollbars?
                    this.scrollEl[0].scrollWidth - 1 > this.scrollEl[0].clientWidth
                        // subtract 1 because of IE off-by-one issue
                ) ? 'scroll' : 'hidden';
        }

        if (overflowY === 'auto') {
            overflowY = (
                    scrollbarWidths.left || scrollbarWidths.right || // vertical scrollbars?
                    // OR scrolling pane with massless scrollbars?
                    this.scrollEl[0].scrollHeight - 1 > this.scrollEl[0].clientHeight
                        // subtract 1 because of IE off-by-one issue
                ) ? 'scroll' : 'hidden';
        }

        this.scrollEl.css({ 'overflow-x': overflowX, 'overflow-y': overflowY });
    },


    // Getters / Setters
    // -----------------------------------------------------------------------------------------------------------------


    setHeight: function(height) {
        this.scrollEl.height(height);
    },


    getScrollTop: function() {
        return this.scrollEl.scrollTop();
    },


    setScrollTop: function(top) {
        this.scrollEl.scrollTop(top);
    },


    getClientWidth: function() {
        return this.scrollEl[0].clientWidth;
    },


    getClientHeight: function() {
        return this.scrollEl[0].clientHeight;
    },


    getScrollbarWidths: function() {
        return getScrollbarWidths(this.scrollEl);
    }

});

;;

var Calendar = FC.Calendar = Class.extend({

    dirDefaults: null, // option defaults related to LTR or RTL
    localeDefaults: null, // option defaults related to current locale
    overrides: null, // option overrides given to the fullCalendar constructor
    dynamicOverrides: null, // options set with dynamic setter method. higher precedence than view overrides.
    options: null, // all defaults combined with overrides
    viewSpecCache: null, // cache of view definitions
    view: null, // current View object
    header: null,
    loadingLevel: 0, // number of simultaneous loading tasks


    // a lot of this class' OOP logic is scoped within this constructor function,
    // but in the future, write individual methods on the prototype.
    constructor: Calendar_constructor,


    // Subclasses can override this for initialization logic after the constructor has been called
    initialize: function() {
    },


    // Computes the flattened options hash for the calendar and assigns to `this.options`.
    // Assumes this.overrides and this.dynamicOverrides have already been initialized.
    populateOptionsHash: function() {
        var locale, localeDefaults;
        var isRTL, dirDefaults;

        locale = firstDefined( // explicit locale option given?
            this.dynamicOverrides.locale,
            this.overrides.locale
        );
        localeDefaults = localeOptionHash[locale];
        if (!localeDefaults) { // explicit locale option not given or invalid?
            locale = Calendar.defaults.locale;
            localeDefaults = localeOptionHash[locale] || {};
        }

        isRTL = firstDefined( // based on options computed so far, is direction RTL?
            this.dynamicOverrides.isRTL,
            this.overrides.isRTL,
            localeDefaults.isRTL,
            Calendar.defaults.isRTL
        );
        dirDefaults = isRTL ? Calendar.rtlDefaults : {};

        this.dirDefaults = dirDefaults;
        this.localeDefaults = localeDefaults;
        this.options = mergeOptions([ // merge defaults and overrides. lowest to highest precedence
            Calendar.defaults, // global defaults
            dirDefaults,
            localeDefaults,
            this.overrides,
            this.dynamicOverrides
        ]);
        populateInstanceComputableOptions(this.options); // fill in gaps with computed options
    },


    // Gets information about how to create a view. Will use a cache.
    getViewSpec: function(viewType) {
        var cache = this.viewSpecCache;

        return cache[viewType] || (cache[viewType] = this.buildViewSpec(viewType));
    },


    // Given a duration singular unit, like "week" or "day", finds a matching view spec.
    // Preference is given to views that have corresponding buttons.
    getUnitViewSpec: function(unit) {
        var viewTypes;
        var i;
        var spec;

        if ($.inArray(unit, intervalUnits) != -1) {

            // put views that have buttons first. there will be duplicates, but oh well
            viewTypes = this.header.getViewsWithButtons();
            $.each(FC.views, function(viewType) { // all views
                viewTypes.push(viewType);
            });

            for (i = 0; i < viewTypes.length; i++) {
                spec = this.getViewSpec(viewTypes[i]);
                if (spec) {
                    if (spec.singleUnit == unit) {
                        return spec;
                    }
                }
            }
        }
    },


    // Builds an object with information on how to create a given view
    buildViewSpec: function(requestedViewType) {
        var viewOverrides = this.overrides.views || {};
        var specChain = []; // for the view. lowest to highest priority
        var defaultsChain = []; // for the view. lowest to highest priority
        var overridesChain = []; // for the view. lowest to highest priority
        var viewType = requestedViewType;
        var spec; // for the view
        var overrides; // for the view
        var duration;
        var unit;

        // iterate from the specific view definition to a more general one until we hit an actual View class
        while (viewType) {
            spec = fcViews[viewType];
            overrides = viewOverrides[viewType];
            viewType = null; // clear. might repopulate for another iteration

            if (typeof spec === 'function') { // TODO: deprecate
                spec = { 'class': spec };
            }

            if (spec) {
                specChain.unshift(spec);
                defaultsChain.unshift(spec.defaults || {});
                duration = duration || spec.duration;
                viewType = viewType || spec.type;
            }

            if (overrides) {
                overridesChain.unshift(overrides); // view-specific option hashes have options at zero-level
                duration = duration || overrides.duration;
                viewType = viewType || overrides.type;
            }
        }

        spec = mergeProps(specChain);
        spec.type = requestedViewType;
        if (!spec['class']) {
            return false;
        }

        if (duration) {
            duration = moment.duration(duration);
            if (duration.valueOf()) { // valid?
                spec.duration = duration;
                unit = computeIntervalUnit(duration);

                // view is a single-unit duration, like "week" or "day"
                // incorporate options for this. lowest priority
                if (duration.as(unit) === 1) {
                    spec.singleUnit = unit;
                    overridesChain.unshift(viewOverrides[unit] || {});
                }
            }
        }

        spec.defaults = mergeOptions(defaultsChain);
        spec.overrides = mergeOptions(overridesChain);

        this.buildViewSpecOptions(spec);
        this.buildViewSpecButtonText(spec, requestedViewType);

        return spec;
    },


    // Builds and assigns a view spec's options object from its already-assigned defaults and overrides
    buildViewSpecOptions: function(spec) {
        spec.options = mergeOptions([ // lowest to highest priority
            Calendar.defaults, // global defaults
            spec.defaults, // view's defaults (from ViewSubclass.defaults)
            this.dirDefaults,
            this.localeDefaults, // locale and dir take precedence over view's defaults!
            this.overrides, // calendar's overrides (options given to constructor)
            spec.overrides, // view's overrides (view-specific options)
            this.dynamicOverrides // dynamically set via setter. highest precedence
        ]);
        populateInstanceComputableOptions(spec.options);
    },


    // Computes and assigns a view spec's buttonText-related options
    buildViewSpecButtonText: function(spec, requestedViewType) {

        // given an options object with a possible `buttonText` hash, lookup the buttonText for the
        // requested view, falling back to a generic unit entry like "week" or "day"
        function queryButtonText(options) {
            var buttonText = options.buttonText || {};
            return buttonText[requestedViewType] ||
                // view can decide to look up a certain key
                (spec.buttonTextKey ? buttonText[spec.buttonTextKey] : null) ||
                // a key like "month"
                (spec.singleUnit ? buttonText[spec.singleUnit] : null);
        }

        // highest to lowest priority
        spec.buttonTextOverride =
            queryButtonText(this.dynamicOverrides) ||
            queryButtonText(this.overrides) || // constructor-specified buttonText lookup hash takes precedence
            spec.overrides.buttonText; // `buttonText` for view-specific options is a string

        // highest to lowest priority. mirrors buildViewSpecOptions
        spec.buttonTextDefault =
            queryButtonText(this.localeDefaults) ||
            queryButtonText(this.dirDefaults) ||
            spec.defaults.buttonText || // a single string. from ViewSubclass.defaults
            queryButtonText(Calendar.defaults) ||
            (spec.duration ? this.humanizeDuration(spec.duration) : null) || // like "3 days"
            requestedViewType; // fall back to given view name
    },


    // Given a view name for a custom view or a standard view, creates a ready-to-go View object
    instantiateView: function(viewType) {
        var spec = this.getViewSpec(viewType);

        return new spec['class'](this, viewType, spec.options, spec.duration);
    },


    // Returns a boolean about whether the view is okay to instantiate at some point
    isValidViewType: function(viewType) {
        return Boolean(this.getViewSpec(viewType));
    },


    // Should be called when any type of async data fetching begins
    pushLoading: function() {
        if (!(this.loadingLevel++)) {
            this.trigger('loading', null, true, this.view);
        }
    },


    // Should be called when any type of async data fetching completes
    popLoading: function() {
        if (!(--this.loadingLevel)) {
            this.trigger('loading', null, false, this.view);
        }
    },


    // Given arguments to the select method in the API, returns a span (unzoned start/end and other info)
    buildSelectSpan: function(zonedStartInput, zonedEndInput) {
        var start = this.moment(zonedStartInput).stripZone();
        var end;

        if (zonedEndInput) {
            end = this.moment(zonedEndInput).stripZone();
        }
        else if (start.hasTime()) {
            end = start.clone().add(this.defaultTimedEventDuration);
        }
        else {
            end = start.clone().add(this.defaultAllDayEventDuration);
        }

        return { start: start, end: end };
    }

});


Calendar.mixin(EmitterMixin);


function Calendar_constructor(element, overrides) {
    var t = this;


    // Exports
    // -----------------------------------------------------------------------------------

    t.render = render;
    t.destroy = destroy;
    t.refetchEvents = refetchEvents;
    t.refetchEventSources = refetchEventSources;
    t.reportEvents = reportEvents;
    t.reportEventChange = reportEventChange;
    t.rerenderEvents = renderEvents; // `renderEvents` serves as a rerender. an API method
    t.changeView = renderView; // `renderView` will switch to another view
    t.select = select;
    t.unselect = unselect;
    t.prev = prev;
    t.next = next;
    t.prevYear = prevYear;
    t.nextYear = nextYear;
    t.today = today;
    t.gotoDate = gotoDate;
    t.incrementDate = incrementDate;
    t.zoomTo = zoomTo;
    t.getDate = getDate;
    t.getCalendar = getCalendar;
    t.getView = getView;
    t.option = option; // getter/setter method
    t.trigger = trigger;


    // Options
    // -----------------------------------------------------------------------------------

    t.dynamicOverrides = {};
    t.viewSpecCache = {};
    t.optionHandlers = {}; // for Calendar.options.js
    t.overrides = $.extend({}, overrides); // make a copy

    t.populateOptionsHash(); // sets this.options



    // Locale-data Internals
    // -----------------------------------------------------------------------------------
    // Apply overrides to the current locale's data

    var localeData;

    // Called immediately, and when any of the options change.
    // Happens before any internal objects rebuild or rerender, because this is very core.
    t.bindOptions([
        'locale', 'monthNames', 'monthNamesShort', 'dayNames', 'dayNamesShort', 'firstDay', 'weekNumberCalculation'
    ], function(locale, monthNames, monthNamesShort, dayNames, dayNamesShort, firstDay, weekNumberCalculation) {

        // normalize
        if (weekNumberCalculation === 'iso') {
            weekNumberCalculation = 'ISO'; // normalize
        }

        localeData = createObject( // make a cheap copy
            getMomentLocaleData(locale) // will fall back to en
        );

        if (monthNames) {
            localeData._months = monthNames;
        }
        if (monthNamesShort) {
            localeData._monthsShort = monthNamesShort;
        }
        if (dayNames) {
            localeData._weekdays = dayNames;
        }
        if (dayNamesShort) {
            localeData._weekdaysShort = dayNamesShort;
        }

        if (firstDay == null && weekNumberCalculation === 'ISO') {
            firstDay = 1;
        }
        if (firstDay != null) {
            var _week = createObject(localeData._week); // _week: { dow: # }
            _week.dow = firstDay;
            localeData._week = _week;
        }

        if ( // whitelist certain kinds of input
            weekNumberCalculation === 'ISO' ||
            weekNumberCalculation === 'local' ||
            typeof weekNumberCalculation === 'function'
        ) {
            localeData._fullCalendar_weekCalc = weekNumberCalculation; // moment-ext will know what to do with it
        }

        // If the internal current date object already exists, move to new locale.
        // We do NOT need to do this technique for event dates, because this happens when converting to "segments".
        if (date) {
            localizeMoment(date); // sets to localeData
        }
    });


    // Calendar-specific Date Utilities
    // -----------------------------------------------------------------------------------


    t.defaultAllDayEventDuration = moment.duration(t.options.defaultAllDayEventDuration);
    t.defaultTimedEventDuration = moment.duration(t.options.defaultTimedEventDuration);


    // Builds a moment using the settings of the current calendar: timezone and locale.
    // Accepts anything the vanilla moment() constructor accepts.
    t.moment = function() {
        var mom;

        if (t.options.timezone === 'local') {
            mom = FC.moment.apply(null, arguments);

            // Force the moment to be local, because FC.moment doesn't guarantee it.
            if (mom.hasTime()) { // don't give ambiguously-timed moments a local zone
                mom.local();
            }
        }
        else if (t.options.timezone === 'UTC') {
            mom = FC.moment.utc.apply(null, arguments); // process as UTC
        }
        else {
            mom = FC.moment.parseZone.apply(null, arguments); // let the input decide the zone
        }

        localizeMoment(mom);

        return mom;
    };


    // Updates the given moment's locale settings to the current calendar locale settings.
    function localizeMoment(mom) {
        mom._locale = localeData;
    }
    t.localizeMoment = localizeMoment;


    // Returns a boolean about whether or not the calendar knows how to calculate
    // the timezone offset of arbitrary dates in the current timezone.
    t.getIsAmbigTimezone = function() {
        return t.options.timezone !== 'local' && t.options.timezone !== 'UTC';
    };


    // Returns a copy of the given date in the current timezone. Has no effect on dates without times.
    t.applyTimezone = function(date) {
        if (!date.hasTime()) {
            return date.clone();
        }

        var zonedDate = t.moment(date.toArray());
        var timeAdjust = date.time() - zonedDate.time();
        var adjustedZonedDate;

        // Safari sometimes has problems with this coersion when near DST. Adjust if necessary. (bug #2396)
        if (timeAdjust) { // is the time result different than expected?
            adjustedZonedDate = zonedDate.clone().add(timeAdjust); // add milliseconds
            if (date.time() - adjustedZonedDate.time() === 0) { // does it match perfectly now?
                zonedDate = adjustedZonedDate;
            }
        }

        return zonedDate;
    };


    // Returns a moment for the current date, as defined by the client's computer or from the `now` option.
    // Will return an moment with an ambiguous timezone.
    t.getNow = function() {
        var now = t.options.now;
        if (typeof now === 'function') {
            now = now();
        }
        return t.moment(now).stripZone();
    };


    // Get an event's normalized end date. If not present, calculate it from the defaults.
    t.getEventEnd = function(event) {
        if (event.end) {
            return event.end.clone();
        }
        else {
            return t.getDefaultEventEnd(event.allDay, event.start);
        }
    };


    // Given an event's allDay status and start date, return what its fallback end date should be.
    // TODO: rename to computeDefaultEventEnd
    t.getDefaultEventEnd = function(allDay, zonedStart) {
        var end = zonedStart.clone();

        if (allDay) {
            end.stripTime().add(t.defaultAllDayEventDuration);
        }
        else {
            end.add(t.defaultTimedEventDuration);
        }

        if (t.getIsAmbigTimezone()) {
            end.stripZone(); // we don't know what the tzo should be
        }

        return end;
    };


    // Produces a human-readable string for the given duration.
    // Side-effect: changes the locale of the given duration.
    t.humanizeDuration = function(duration) {
        return duration.locale(t.options.locale).humanize();
    };


    
    // Imports
    // -----------------------------------------------------------------------------------


    EventManager.call(t);
    var isFetchNeeded = t.isFetchNeeded;
    var fetchEvents = t.fetchEvents;
    var fetchEventSources = t.fetchEventSources;



    // Locals
    // -----------------------------------------------------------------------------------


    var _element = element[0];
    var header;
    var content;
    var tm; // for making theme classes
    var currentView; // NOTE: keep this in sync with this.view
    var viewsByType = {}; // holds all instantiated view instances, current or not
    var suggestedViewHeight;
    var windowResizeProxy; // wraps the windowResize function
    var ignoreWindowResize = 0;
    var events = [];
    var date; // unzoned
    
    
    
    // Main Rendering
    // -----------------------------------------------------------------------------------


    // compute the initial ambig-timezone date
    if (t.options.defaultDate != null) {
        date = t.moment(t.options.defaultDate).stripZone();
    }
    else {
        date = t.getNow(); // getNow already returns unzoned
    }
    
    
    function render() {
        if (!content) {
            initialRender();
        }
        else if (elementVisible()) {
            // mainly for the public API
            calcSize();
            renderView();
        }
    }
    
    
    function initialRender() {
        element.addClass('fc');

        // event delegation for nav links
        element.on('click.fc', 'a[data-goto]', function(ev) {
            var anchorEl = $(this);
            var gotoOptions = anchorEl.data('goto'); // will automatically parse JSON
            var date = t.moment(gotoOptions.date);
            var viewType = gotoOptions.type;

            // property like "navLinkDayClick". might be a string or a function
            var customAction = currentView.opt('navLink' + capitaliseFirstLetter(viewType) + 'Click');

            if (typeof customAction === 'function') {
                customAction(date, ev);
            }
            else {
                if (typeof customAction === 'string') {
                    viewType = customAction;
                }
                zoomTo(date, viewType);
            }
        });

        // called immediately, and upon option change
        t.bindOption('theme', function(theme) {
            tm = theme ? 'ui' : 'fc'; // affects a larger scope
            element.toggleClass('ui-widget', theme);
            element.toggleClass('fc-unthemed', !theme);
        });

        // called immediately, and upon option change.
        // HACK: locale often affects isRTL, so we explicitly listen to that too.
        t.bindOptions([ 'isRTL', 'locale' ], function(isRTL) {
            element.toggleClass('fc-ltr', !isRTL);
            element.toggleClass('fc-rtl', isRTL);
        });

        content = $("<div class='fc-view-container'/>").prependTo(element);

        header = t.header = new Header(t);
        renderHeader();

        renderView(t.options.defaultView);

        if (t.options.handleWindowResize) {
            windowResizeProxy = debounce(windowResize, t.options.windowResizeDelay); // prevents rapid calls
            $(window).resize(windowResizeProxy);
        }
    }


    // can be called repeatedly and Header will rerender
    function renderHeader() {
        header.render();
        if (header.el) {
            element.prepend(header.el);
        }
    }
    
    
    function destroy() {

        if (currentView) {
            currentView.removeElement();

            // NOTE: don't null-out currentView/t.view in case API methods are called after destroy.
            // It is still the "current" view, just not rendered.
        }

        header.removeElement();
        content.remove();
        element.removeClass('fc fc-ltr fc-rtl fc-unthemed ui-widget');

        element.off('.fc'); // unbind nav link handlers

        if (windowResizeProxy) {
            $(window).unbind('resize', windowResizeProxy);
        }
    }
    
    
    function elementVisible() {
        return element.is(':visible');
    }
    
    

    // View Rendering
    // -----------------------------------------------------------------------------------


    // Renders a view because of a date change, view-type change, or for the first time.
    // If not given a viewType, keep the current view but render different dates.
    // Accepts an optional scroll state to restore to.
    function renderView(viewType, explicitScrollState) {
        ignoreWindowResize++;

        // if viewType is changing, remove the old view's rendering
        if (currentView && viewType && currentView.type !== viewType) {
            freezeContentHeight(); // prevent a scroll jump when view element is removed
            clearView();
        }

        // if viewType changed, or the view was never created, create a fresh view
        if (!currentView && viewType) {
            currentView = t.view =
                viewsByType[viewType] ||
                (viewsByType[viewType] = t.instantiateView(viewType));

            currentView.setElement(
                $("<div class='fc-view fc-" + viewType + "-view' />").appendTo(content)
            );
            header.activateButton(viewType);
        }

        if (currentView) {

            // in case the view should render a period of time that is completely hidden
            date = currentView.massageCurrentDate(date);

            // render or rerender the view
            if (
                !currentView.displaying ||
                !( // NOT within interval range signals an implicit date window change
                    date >= currentView.intervalStart &&
                    date < currentView.intervalEnd
                )
            ) {
                if (elementVisible()) {

                    currentView.display(date, explicitScrollState); // will call freezeContentHeight
                    unfreezeContentHeight(); // immediately unfreeze regardless of whether display is async

                    // need to do this after View::render, so dates are calculated
                    updateHeaderTitle();
                    updateTodayButton();

                    getAndRenderEvents();
                }
            }
        }

        unfreezeContentHeight(); // undo any lone freezeContentHeight calls
        ignoreWindowResize--;
    }


    // Unrenders the current view and reflects this change in the Header.
    // Unregsiters the `currentView`, but does not remove from viewByType hash.
    function clearView() {
        header.deactivateButton(currentView.type);
        currentView.removeElement();
        currentView = t.view = null;
    }


    // Destroys the view, including the view object. Then, re-instantiates it and renders it.
    // Maintains the same scroll state.
    // TODO: maintain any other user-manipulated state.
    function reinitView() {
        ignoreWindowResize++;
        freezeContentHeight();

        var viewType = currentView.type;
        var scrollState = currentView.queryScroll();
        clearView();
        renderView(viewType, scrollState);

        unfreezeContentHeight();
        ignoreWindowResize--;
    }

    

    // Resizing
    // -----------------------------------------------------------------------------------


    t.getSuggestedViewHeight = function() {
        if (suggestedViewHeight === undefined) {
            calcSize();
        }
        return suggestedViewHeight;
    };


    t.isHeightAuto = function() {
        return t.options.contentHeight === 'auto' || t.options.height === 'auto';
    };
    
    
    function updateSize(shouldRecalc) {
        if (elementVisible()) {

            if (shouldRecalc) {
                _calcSize();
            }

            ignoreWindowResize++;
            currentView.updateSize(true); // isResize=true. will poll getSuggestedViewHeight() and isHeightAuto()
            ignoreWindowResize--;

            return true; // signal success
        }
    }


    function calcSize() {
        if (elementVisible()) {
            _calcSize();
        }
    }
    
    
    function _calcSize() { // assumes elementVisible
        var contentHeightInput = t.options.contentHeight;
        var heightInput = t.options.height;

        if (typeof contentHeightInput === 'number') { // exists and not 'auto'
            suggestedViewHeight = contentHeightInput;
        }
        else if (typeof contentHeightInput === 'function') { // exists and is a function
            suggestedViewHeight = contentHeightInput();
        }
        else if (typeof heightInput === 'number') { // exists and not 'auto'
            suggestedViewHeight = heightInput - queryHeaderHeight();
        }
        else if (typeof heightInput === 'function') { // exists and is a function
            suggestedViewHeight = heightInput() - queryHeaderHeight();
        }
        else if (heightInput === 'parent') { // set to height of parent element
            suggestedViewHeight = element.parent().height() - queryHeaderHeight();
        }
        else {
            suggestedViewHeight = Math.round(content.width() / Math.max(t.options.aspectRatio, .5));
        }
    }


    function queryHeaderHeight() {
        return header.el ? header.el.outerHeight(true) : 0; // includes margin
    }
    
    
    function windowResize(ev) {
        if (
            !ignoreWindowResize &&
            ev.target === window && // so we don't process jqui "resize" events that have bubbled up
            currentView.start // view has already been rendered
        ) {
            if (updateSize(true)) {
                currentView.trigger('windowResize', _element);
            }
        }
    }
    
    
    
    /* Event Fetching/Rendering
    -----------------------------------------------------------------------------*/
    // TODO: going forward, most of this stuff should be directly handled by the view


    function refetchEvents() { // can be called as an API method
        fetchAndRenderEvents();
    }


    // TODO: move this into EventManager?
    function refetchEventSources(matchInputs) {
        fetchEventSources(t.getEventSourcesByMatchArray(matchInputs));
    }


    function renderEvents() { // destroys old events if previously rendered
        if (elementVisible()) {
            freezeContentHeight();
            currentView.displayEvents(events);
            unfreezeContentHeight();
        }
    }
    

    function getAndRenderEvents() {
        if (!t.options.lazyFetching || isFetchNeeded(currentView.start, currentView.end)) {
            fetchAndRenderEvents();
        }
        else {
            renderEvents();
        }
    }


    function fetchAndRenderEvents() {
        fetchEvents(currentView.start, currentView.end);
            // ... will call reportEvents
            // ... which will call renderEvents
    }

    
    // called when event data arrives
    function reportEvents(_events) {
        events = _events;
        renderEvents();
    }


    // called when a single event's data has been changed
    function reportEventChange() {
        renderEvents();
    }



    /* Header Updating
    -----------------------------------------------------------------------------*/


    function updateHeaderTitle() {
        header.updateTitle(currentView.title);
    }


    function updateTodayButton() {
        var now = t.getNow();

        if (now >= currentView.intervalStart && now < currentView.intervalEnd) {
            header.disableButton('today');
        }
        else {
            header.enableButton('today');
        }
    }
    


    /* Selection
    -----------------------------------------------------------------------------*/
    

    // this public method receives start/end dates in any format, with any timezone
    function select(zonedStartInput, zonedEndInput) {
        currentView.select(
            t.buildSelectSpan.apply(t, arguments)
        );
    }
    

    function unselect() { // safe to be called before renderView
        if (currentView) {
            currentView.unselect();
        }
    }
    
    
    
    /* Date
    -----------------------------------------------------------------------------*/
    
    
    function prev() {
        date = currentView.computePrevDate(date);
        renderView();
    }
    
    
    function next() {
        date = currentView.computeNextDate(date);
        renderView();
    }
    
    
    function prevYear() {
        date.add(-1, 'years');
        renderView();
    }
    
    
    function nextYear() {
        date.add(1, 'years');
        renderView();
    }
    
    
    function today() {
        date = t.getNow();
        renderView();
    }
    
    
    function gotoDate(zonedDateInput) {
        date = t.moment(zonedDateInput).stripZone();
        renderView();
    }
    
    
    function incrementDate(delta) {
        date.add(moment.duration(delta));
        renderView();
    }


    // Forces navigation to a view for the given date.
    // `viewType` can be a specific view name or a generic one like "week" or "day".
    function zoomTo(newDate, viewType) {
        var spec;

        viewType = viewType || 'day'; // day is default zoom
        spec = t.getViewSpec(viewType) || t.getUnitViewSpec(viewType);

        date = newDate.clone();
        renderView(spec ? spec.type : null);
    }
    
    
    // for external API
    function getDate() {
        return t.applyTimezone(date); // infuse the calendar's timezone
    }



    /* Height "Freezing"
    -----------------------------------------------------------------------------*/
    // TODO: move this into the view

    t.freezeContentHeight = freezeContentHeight;
    t.unfreezeContentHeight = unfreezeContentHeight;


    function freezeContentHeight() {
        content.css({
            width: '100%',
            height: content.height(),
            overflow: 'hidden'
        });
    }


    function unfreezeContentHeight() {
        content.css({
            width: '',
            height: '',
            overflow: ''
        });
    }
    
    
    
    /* Misc
    -----------------------------------------------------------------------------*/
    

    function getCalendar() {
        return t;
    }

    
    function getView() {
        return currentView;
    }
    
    
    function option(name, value) {
        var newOptionHash;

        if (typeof name === 'string') {
            if (value === undefined) { // getter
                return t.options[name];
            }
            else { // setter for individual option
                newOptionHash = {};
                newOptionHash[name] = value;
                setOptions(newOptionHash);
            }
        }
        else if (typeof name === 'object') { // compound setter with object input
            setOptions(name);
        }
    }


    function setOptions(newOptionHash) {
        var optionCnt = 0;
        var optionName;

        for (optionName in newOptionHash) {
            t.dynamicOverrides[optionName] = newOptionHash[optionName];
        }

        t.viewSpecCache = {}; // the dynamic override invalidates the options in this cache, so just clear it
        t.populateOptionsHash(); // this.options needs to be recomputed after the dynamic override

        // trigger handlers after this.options has been updated
        for (optionName in newOptionHash) {
            t.triggerOptionHandlers(optionName); // recall bindOption/bindOptions
            optionCnt++;
        }

        // special-case handling of single option change.
        // if only one option change, `optionName` will be its name.
        if (optionCnt === 1) {
            if (optionName === 'height' || optionName === 'contentHeight' || optionName === 'aspectRatio') {
                updateSize(true); // true = allow recalculation of height
                return;
            }
            else if (optionName === 'defaultDate') {
                return; // can't change date this way. use gotoDate instead
            }
            else if (optionName === 'businessHours') {
                if (currentView) {
                    currentView.unrenderBusinessHours();
                    currentView.renderBusinessHours();
                }
                return;
            }
            else if (optionName === 'timezone') {
                t.rezoneArrayEventSources();
                refetchEvents();
                return;
            }
        }

        // catch-all. rerender the header and rebuild/rerender the current view
        renderHeader();
        viewsByType = {}; // even non-current views will be affected by this option change. do before rerender
        reinitView();
    }
    
    
    function trigger(name, thisObj) { // overrides the Emitter's trigger method :(
        var args = Array.prototype.slice.call(arguments, 2);

        thisObj = thisObj || _element;
        this.triggerWith(name, thisObj, args); // Emitter's method

        if (t.options[name]) {
            return t.options[name].apply(thisObj, args);
        }
    }

    t.initialize();
}

;;
/*
Options binding/triggering system.
*/
Calendar.mixin({

    // A map of option names to arrays of handler objects. Initialized to {} in Calendar.
    // Format for a handler object:
    // {
    //   func // callback function to be called upon change
    //   names // option names whose values should be given to func
    // }
    optionHandlers: null, 

    // Calls handlerFunc immediately, and when the given option has changed.
    // handlerFunc will be given the option value.
    bindOption: function(optionName, handlerFunc) {
        this.bindOptions([ optionName ], handlerFunc);
    },

    // Calls handlerFunc immediately, and when any of the given options change.
    // handlerFunc will be given each option value as ordered function arguments.
    bindOptions: function(optionNames, handlerFunc) {
        var handlerObj = { func: handlerFunc, names: optionNames };
        var i;

        for (i = 0; i < optionNames.length; i++) {
            this.registerOptionHandlerObj(optionNames[i], handlerObj);
        }

        this.triggerOptionHandlerObj(handlerObj);
    },

    // Puts the given handler object into the internal hash
    registerOptionHandlerObj: function(optionName, handlerObj) {
        (this.optionHandlers[optionName] || (this.optionHandlers[optionName] = []))
            .push(handlerObj);
    },

    // Reports that the given option has changed, and calls all appropriate handlers.
    triggerOptionHandlers: function(optionName) {
        var handlerObjs = this.optionHandlers[optionName] || [];
        var i;

        for (i = 0; i < handlerObjs.length; i++) {
            this.triggerOptionHandlerObj(handlerObjs[i]);
        }
    },

    // Calls the callback for a specific handler object, passing in the appropriate arguments.
    triggerOptionHandlerObj: function(handlerObj) {
        var optionNames = handlerObj.names;
        var optionValues = [];
        var i;

        for (i = 0; i < optionNames.length; i++) {
            optionValues.push(this.options[optionNames[i]]);
        }

        handlerObj.func.apply(this, optionValues); // maintain the Calendar's `this` context
    }

});

;;

Calendar.defaults = {

    titleRangeSeparator: ' \u2013 ', // en dash
    monthYearFormat: 'MMMM YYYY', // required for en. other locales rely on datepicker computable option

    defaultTimedEventDuration: '02:00:00',
    defaultAllDayEventDuration: { days: 1 },
    forceEventDuration: false,
    nextDayThreshold: '09:00:00', // 9am

    // display
    defaultView: 'month',
    aspectRatio: 1.35,
    header: {
        left: 'title',
        center: '',
        right: 'today prev,next'
    },
    weekends: true,
    weekNumbers: false,

    weekNumberTitle: 'W',
    weekNumberCalculation: 'local',
    
    //editable: false,

    //nowIndicator: false,

    scrollTime: '06:00:00',
    
    // event ajax
    lazyFetching: true,
    startParam: 'start',
    endParam: 'end',
    timezoneParam: 'timezone',

    timezone: false,

    //allDayDefault: undefined,

    // locale
    isRTL: false,
    buttonText: {
        prev: "prev",
        next: "next",
        prevYear: "prev year",
        nextYear: "next year",
        year: 'year', // TODO: locale files need to specify this
        today: 'today',
        month: 'month',
        week: 'week',
        day: 'day'
    },

    buttonIcons: {
        prev: 'left-single-arrow',
        next: 'right-single-arrow',
        prevYear: 'left-double-arrow',
        nextYear: 'right-double-arrow'
    },

    allDayText: 'all-day',
    
    // jquery-ui theming
    theme: false,
    themeButtonIcons: {
        prev: 'circle-triangle-w',
        next: 'circle-triangle-e',
        prevYear: 'seek-prev',
        nextYear: 'seek-next'
    },

    //eventResizableFromStart: false,
    dragOpacity: .75,
    dragRevertDuration: 500,
    dragScroll: true,
    
    //selectable: false,
    unselectAuto: true,
    
    dropAccept: '*',

    eventOrder: 'title',

    eventLimit: false,
    eventLimitText: 'more',
    eventLimitClick: 'popover',
    dayPopoverFormat: 'LL',
    
    handleWindowResize: true,
    windowResizeDelay: 100, // milliseconds before an updateSize happens

    longPressDelay: 1000
    
};


Calendar.englishDefaults = { // used by locale.js
    dayPopoverFormat: 'dddd, MMMM D'
};


Calendar.rtlDefaults = { // right-to-left defaults
    header: { // TODO: smarter solution (first/center/last ?)
        left: 'next,prev today',
        center: '',
        right: 'title'
    },
    buttonIcons: {
        prev: 'right-single-arrow',
        next: 'left-single-arrow',
        prevYear: 'right-double-arrow',
        nextYear: 'left-double-arrow'
    },
    themeButtonIcons: {
        prev: 'circle-triangle-e',
        next: 'circle-triangle-w',
        nextYear: 'seek-prev',
        prevYear: 'seek-next'
    }
};

;;

var localeOptionHash = FC.locales = {}; // initialize and expose


// TODO: document the structure and ordering of a FullCalendar locale file


// Initialize jQuery UI datepicker translations while using some of the translations
// Will set this as the default locales for datepicker.
FC.datepickerLocale = function(localeCode, dpLocaleCode, dpOptions) {

    // get the FullCalendar internal option hash for this locale. create if necessary
    var fcOptions = localeOptionHash[localeCode] || (localeOptionHash[localeCode] = {});

    // transfer some simple options from datepicker to fc
    fcOptions.isRTL = dpOptions.isRTL;
    fcOptions.weekNumberTitle = dpOptions.weekHeader;

    // compute some more complex options from datepicker
    $.each(dpComputableOptions, function(name, func) {
        fcOptions[name] = func(dpOptions);
    });

    // is jQuery UI Datepicker is on the page?
    if ($.datepicker) {

        // Register the locale data.
        // FullCalendar and MomentJS use locale codes like "pt-br" but Datepicker
        // does it like "pt-BR" or if it doesn't have the locale, maybe just "pt".
        // Make an alias so the locale can be referenced either way.
        $.datepicker.regional[dpLocaleCode] =
            $.datepicker.regional[localeCode] = // alias
                dpOptions;

        // Alias 'en' to the default locale data. Do this every time.
        $.datepicker.regional.en = $.datepicker.regional[''];

        // Set as Datepicker's global defaults.
        $.datepicker.setDefaults(dpOptions);
    }
};


// Sets FullCalendar-specific translations. Will set the locales as the global default.
FC.locale = function(localeCode, newFcOptions) {
    var fcOptions;
    var momOptions;

    // get the FullCalendar internal option hash for this locale. create if necessary
    fcOptions = localeOptionHash[localeCode] || (localeOptionHash[localeCode] = {});

    // provided new options for this locales? merge them in
    if (newFcOptions) {
        fcOptions = localeOptionHash[localeCode] = mergeOptions([ fcOptions, newFcOptions ]);
    }

    // compute locale options that weren't defined.
    // always do this. newFcOptions can be undefined when initializing from i18n file,
    // so no way to tell if this is an initialization or a default-setting.
    momOptions = getMomentLocaleData(localeCode); // will fall back to en
    $.each(momComputableOptions, function(name, func) {
        if (fcOptions[name] == null) {
            fcOptions[name] = func(momOptions, fcOptions);
        }
    });

    // set it as the default locale for FullCalendar
    Calendar.defaults.locale = localeCode;
};


// NOTE: can't guarantee any of these computations will run because not every locale has datepicker
// configs, so make sure there are English fallbacks for these in the defaults file.
var dpComputableOptions = {

    buttonText: function(dpOptions) {
        return {
            // the translations sometimes wrongly contain HTML entities
            prev: stripHtmlEntities(dpOptions.prevText),
            next: stripHtmlEntities(dpOptions.nextText),
            today: stripHtmlEntities(dpOptions.currentText)
        };
    },

    // Produces format strings like "MMMM YYYY" -> "September 2014"
    monthYearFormat: function(dpOptions) {
        return dpOptions.showMonthAfterYear ?
            'YYYY[' + dpOptions.yearSuffix + '] MMMM' :
            'MMMM YYYY[' + dpOptions.yearSuffix + ']';
    }

};

var momComputableOptions = {

    // Produces format strings like "ddd M/D" -> "Fri 9/15"
    dayOfMonthFormat: function(momOptions, fcOptions) {
        var format = momOptions.longDateFormat('l'); // for the format like "M/D/YYYY"

        // strip the year off the edge, as well as other misc non-whitespace chars
        format = format.replace(/^Y+[^\w\s]*|[^\w\s]*Y+$/g, '');

        if (fcOptions.isRTL) {
            format += ' ddd'; // for RTL, add day-of-week to end
        }
        else {
            format = 'ddd ' + format; // for LTR, add day-of-week to beginning
        }
        return format;
    },

    // Produces format strings like "h:mma" -> "6:00pm"
    mediumTimeFormat: function(momOptions) { // can't be called `timeFormat` because collides with option
        return momOptions.longDateFormat('LT')
            .replace(/\s*a$/i, 'a'); // convert AM/PM/am/pm to lowercase. remove any spaces beforehand
    },

    // Produces format strings like "h(:mm)a" -> "6pm" / "6:30pm"
    smallTimeFormat: function(momOptions) {
        return momOptions.longDateFormat('LT')
            .replace(':mm', '(:mm)')
            .replace(/(\Wmm)$/, '($1)') // like above, but for foreign locales
            .replace(/\s*a$/i, 'a'); // convert AM/PM/am/pm to lowercase. remove any spaces beforehand
    },

    // Produces format strings like "h(:mm)t" -> "6p" / "6:30p"
    extraSmallTimeFormat: function(momOptions) {
        return momOptions.longDateFormat('LT')
            .replace(':mm', '(:mm)')
            .replace(/(\Wmm)$/, '($1)') // like above, but for foreign locales
            .replace(/\s*a$/i, 't'); // convert to AM/PM/am/pm to lowercase one-letter. remove any spaces beforehand
    },

    // Produces format strings like "ha" / "H" -> "6pm" / "18"
    hourFormat: function(momOptions) {
        return momOptions.longDateFormat('LT')
            .replace(':mm', '')
            .replace(/(\Wmm)$/, '') // like above, but for foreign locales
            .replace(/\s*a$/i, 'a'); // convert AM/PM/am/pm to lowercase. remove any spaces beforehand
    },

    // Produces format strings like "h:mm" -> "6:30" (with no AM/PM)
    noMeridiemTimeFormat: function(momOptions) {
        return momOptions.longDateFormat('LT')
            .replace(/\s*a$/i, ''); // remove trailing AM/PM
    }

};


// options that should be computed off live calendar options (considers override options)
// TODO: best place for this? related to locale?
// TODO: flipping text based on isRTL is a bad idea because the CSS `direction` might want to handle it
var instanceComputableOptions = {

    // Produces format strings for results like "Mo 16"
    smallDayDateFormat: function(options) {
        return options.isRTL ?
            'D dd' :
            'dd D';
    },

    // Produces format strings for results like "Wk 5"
    weekFormat: function(options) {
        return options.isRTL ?
            'w[ ' + options.weekNumberTitle + ']' :
            '[' + options.weekNumberTitle + ' ]w';
    },

    // Produces format strings for results like "Wk5"
    smallWeekFormat: function(options) {
        return options.isRTL ?
            'w[' + options.weekNumberTitle + ']' :
            '[' + options.weekNumberTitle + ']w';
    }

};

function populateInstanceComputableOptions(options) {
    $.each(instanceComputableOptions, function(name, func) {
        if (options[name] == null) {
            options[name] = func(options);
        }
    });
}


// Returns moment's internal locale data. If doesn't exist, returns English.
function getMomentLocaleData(localeCode) {
    return moment.localeData(localeCode) || moment.localeData('en');
}


// Initialize English by forcing computation of moment-derived options.
// Also, sets it as the default.
FC.locale('en', Calendar.englishDefaults);

;;

/* Top toolbar area with buttons and title
----------------------------------------------------------------------------------------------------------------------*/
// TODO: rename all header-related things to "toolbar"

function Header(calendar) {
    var t = this;
    
    // exports
    t.render = render;
    t.removeElement = removeElement;
    t.updateTitle = updateTitle;
    t.activateButton = activateButton;
    t.deactivateButton = deactivateButton;
    t.disableButton = disableButton;
    t.enableButton = enableButton;
    t.getViewsWithButtons = getViewsWithButtons;
    t.el = null; // mirrors local `el`
    
    // locals
    var el;
    var viewsWithButtons = [];
    var tm;


    // can be called repeatedly and will rerender
    function render() {
        var options = calendar.options;
        var sections = options.header;

        tm = options.theme ? 'ui' : 'fc';

        if (sections) {
            if (!el) {
                el = this.el = $("<div class='fc-toolbar'/>");
            }
            else {
                el.empty();
            }
            el.append(renderSection('left'))
                .append(renderSection('right'))
                .append(renderSection('center'))
                .append('<div class="fc-clear"/>');
        }
        else {
            removeElement();
        }
    }
    
    
    function removeElement() {
        if (el) {
            el.remove();
            el = t.el = null;
        }
    }
    
    
    function renderSection(position) {
        var sectionEl = $('<div class="fc-' + position + '"/>');
        var options = calendar.options;
        var buttonStr = options.header[position];

        if (buttonStr) {
            $.each(buttonStr.split(' '), function(i) {
                var groupChildren = $();
                var isOnlyButtons = true;
                var groupEl;

                $.each(this.split(','), function(j, buttonName) {
                    var customButtonProps;
                    var viewSpec;
                    var buttonClick;
                    var overrideText; // text explicitly set by calendar's constructor options. overcomes icons
                    var defaultText;
                    var themeIcon;
                    var normalIcon;
                    var innerHtml;
                    var classes;
                    var button; // the element

                    if (buttonName == 'title') {
                        groupChildren = groupChildren.add($('<h2>&nbsp;</h2>')); // we always want it to take up height
                        isOnlyButtons = false;
                    }
                    else {
                        if ((customButtonProps = (options.customButtons || {})[buttonName])) {
                            buttonClick = function(ev) {
                                if (customButtonProps.click) {
                                    customButtonProps.click.call(button[0], ev);
                                }
                            };
                            overrideText = ''; // icons will override text
                            defaultText = customButtonProps.text;
                        }
                        else if ((viewSpec = calendar.getViewSpec(buttonName))) {
                            buttonClick = function() {
                                calendar.changeView(buttonName);
                            };
                            viewsWithButtons.push(buttonName);
                            overrideText = viewSpec.buttonTextOverride;
                            defaultText = viewSpec.buttonTextDefault;
                        }
                        else if (calendar[buttonName]) { // a calendar method
                            buttonClick = function() {
                                calendar[buttonName]();
                            };
                            overrideText = (calendar.overrides.buttonText || {})[buttonName];
                            defaultText = options.buttonText[buttonName]; // everything else is considered default
                        }

                        if (buttonClick) {

                            themeIcon =
                                customButtonProps ?
                                    customButtonProps.themeIcon :
                                    options.themeButtonIcons[buttonName];

                            normalIcon =
                                customButtonProps ?
                                    customButtonProps.icon :
                                    options.buttonIcons[buttonName];

                            if (overrideText) {
                                innerHtml = htmlEscape(overrideText);
                            }
                            else if (themeIcon && options.theme) {
                                innerHtml = "<span class='ui-icon ui-icon-" + themeIcon + "'></span>";
                            }
                            else if (normalIcon && !options.theme) {
                                innerHtml = "<span class='fc-icon fc-icon-" + normalIcon + "'></span>";
                            }
                            else {
                                innerHtml = htmlEscape(defaultText);
                            }

                            classes = [
                                'fc-' + buttonName + '-button',
                                tm + '-button',
                                tm + '-state-default'
                            ];

                            button = $( // type="button" so that it doesn't submit a form
                                '<button type="button" class="' + classes.join(' ') + '">' +
                                    innerHtml +
                                '</button>'
                                )
                                .click(function(ev) {
                                    // don't process clicks for disabled buttons
                                    if (!button.hasClass(tm + '-state-disabled')) {

                                        buttonClick(ev);

                                        // after the click action, if the button becomes the "active" tab, or disabled,
                                        // it should never have a hover class, so remove it now.
                                        if (
                                            button.hasClass(tm + '-state-active') ||
                                            button.hasClass(tm + '-state-disabled')
                                        ) {
                                            button.removeClass(tm + '-state-hover');
                                        }
                                    }
                                })
                                .mousedown(function() {
                                    // the *down* effect (mouse pressed in).
                                    // only on buttons that are not the "active" tab, or disabled
                                    button
                                        .not('.' + tm + '-state-active')
                                        .not('.' + tm + '-state-disabled')
                                        .addClass(tm + '-state-down');
                                })
                                .mouseup(function() {
                                    // undo the *down* effect
                                    button.removeClass(tm + '-state-down');
                                })
                                .hover(
                                    function() {
                                        // the *hover* effect.
                                        // only on buttons that are not the "active" tab, or disabled
                                        button
                                            .not('.' + tm + '-state-active')
                                            .not('.' + tm + '-state-disabled')
                                            .addClass(tm + '-state-hover');
                                    },
                                    function() {
                                        // undo the *hover* effect
                                        button
                                            .removeClass(tm + '-state-hover')
                                            .removeClass(tm + '-state-down'); // if mouseleave happens before mouseup
                                    }
                                );

                            groupChildren = groupChildren.add(button);
                        }
                    }
                });

                if (isOnlyButtons) {
                    groupChildren
                        .first().addClass(tm + '-corner-left').end()
                        .last().addClass(tm + '-corner-right').end();
                }

                if (groupChildren.length > 1) {
                    groupEl = $('<div/>');
                    if (isOnlyButtons) {
                        groupEl.addClass('fc-button-group');
                    }
                    groupEl.append(groupChildren);
                    sectionEl.append(groupEl);
                }
                else {
                    sectionEl.append(groupChildren); // 1 or 0 children
                }
            });
        }

        return sectionEl;
    }
    
    
    function updateTitle(text) {
        if (el) {
            el.find('h2').text(text);
        }
    }
    
    
    function activateButton(buttonName) {
        if (el) {
            el.find('.fc-' + buttonName + '-button')
                .addClass(tm + '-state-active');
        }
    }
    
    
    function deactivateButton(buttonName) {
        if (el) {
            el.find('.fc-' + buttonName + '-button')
                .removeClass(tm + '-state-active');
        }
    }
    
    
    function disableButton(buttonName) {
        if (el) {
            el.find('.fc-' + buttonName + '-button')
                .prop('disabled', true)
                .addClass(tm + '-state-disabled');
        }
    }
    
    
    function enableButton(buttonName) {
        if (el) {
            el.find('.fc-' + buttonName + '-button')
                .prop('disabled', false)
                .removeClass(tm + '-state-disabled');
        }
    }


    function getViewsWithButtons() {
        return viewsWithButtons;
    }

}

;;

FC.sourceNormalizers = [];
FC.sourceFetchers = [];

var ajaxDefaults = {
    dataType: 'json',
    cache: false
};

var eventGUID = 1;


function EventManager() { // assumed to be a calendar
    var t = this;
    
    
    // exports
    t.isFetchNeeded = isFetchNeeded;
    t.fetchEvents = fetchEvents;
    t.fetchEventSources = fetchEventSources;
    t.getEventSources = getEventSources;
    t.getEventSourceById = getEventSourceById;
    t.getEventSourcesByMatchArray = getEventSourcesByMatchArray;
    t.getEventSourcesByMatch = getEventSourcesByMatch;
    t.addEventSource = addEventSource;
    t.removeEventSource = removeEventSource;
    t.removeEventSources = removeEventSources;
    t.updateEvent = updateEvent;
    t.renderEvent = renderEvent;
    t.removeEvents = removeEvents;
    t.clientEvents = clientEvents;
    t.mutateEvent = mutateEvent;
    t.normalizeEventDates = normalizeEventDates;
    t.normalizeEventTimes = normalizeEventTimes;
    
    
    // imports
    var reportEvents = t.reportEvents;
    
    
    // locals
    var stickySource = { events: [] };
    var sources = [ stickySource ];
    var rangeStart, rangeEnd;
    var pendingSourceCnt = 0; // outstanding fetch requests, max one per source
    var cache = []; // holds events that have already been expanded


    $.each(
        (t.options.events ? [ t.options.events ] : []).concat(t.options.eventSources || []),
        function(i, sourceInput) {
            var source = buildEventSource(sourceInput);
            if (source) {
                sources.push(source);
            }
        }
    );
    
    
    
    /* Fetching
    -----------------------------------------------------------------------------*/


    // start and end are assumed to be unzoned
    function isFetchNeeded(start, end) {
        return !rangeStart || // nothing has been fetched yet?
            start < rangeStart || end > rangeEnd; // is part of the new range outside of the old range?
    }
    
    
    function fetchEvents(start, end) {
        rangeStart = start;
        rangeEnd = end;
        fetchEventSources(sources, 'reset');
    }


    // expects an array of event source objects (the originals, not copies)
    // `specialFetchType` is an optimization parameter that affects purging of the event cache.
    function fetchEventSources(specificSources, specialFetchType) {
        var i, source;

        if (specialFetchType === 'reset') {
            cache = [];
        }
        else if (specialFetchType !== 'add') {
            cache = excludeEventsBySources(cache, specificSources);
        }

        for (i = 0; i < specificSources.length; i++) {
            source = specificSources[i];

            // already-pending sources have already been accounted for in pendingSourceCnt
            if (source._status !== 'pending') {
                pendingSourceCnt++;
            }

            source._fetchId = (source._fetchId || 0) + 1;
            source._status = 'pending';
        }

        for (i = 0; i < specificSources.length; i++) {
            source = specificSources[i];

            tryFetchEventSource(source, source._fetchId);
        }
    }


    // fetches an event source and processes its result ONLY if it is still the current fetch.
    // caller is responsible for incrementing pendingSourceCnt first.
    function tryFetchEventSource(source, fetchId) {
        _fetchEventSource(source, function(eventInputs) {
            var isArraySource = $.isArray(source.events);
            var i, eventInput;
            var abstractEvent;

            if (
                // is this the source's most recent fetch?
                // if not, rely on an upcoming fetch of this source to decrement pendingSourceCnt
                fetchId === source._fetchId &&
                // event source no longer valid?
                source._status !== 'rejected'
            ) {
                source._status = 'resolved';

                if (eventInputs) {
                    for (i = 0; i < eventInputs.length; i++) {
                        eventInput = eventInputs[i];

                        if (isArraySource) { // array sources have already been convert to Event Objects
                            abstractEvent = eventInput;
                        }
                        else {
                            abstractEvent = buildEventFromInput(eventInput, source);
                        }

                        if (abstractEvent) { // not false (an invalid event)
                            cache.push.apply(
                                cache,
                                expandEvent(abstractEvent) // add individual expanded events to the cache
                            );
                        }
                    }
                }

                decrementPendingSourceCnt();
            }
        });
    }


    function rejectEventSource(source) {
        var wasPending = source._status === 'pending';

        source._status = 'rejected';

        if (wasPending) {
            decrementPendingSourceCnt();
        }
    }


    function decrementPendingSourceCnt() {
        pendingSourceCnt--;
        if (!pendingSourceCnt) {
            reportEvents(cache);
        }
    }
    
    
    function _fetchEventSource(source, callback) {
        var i;
        var fetchers = FC.sourceFetchers;
        var res;

        for (i=0; i<fetchers.length; i++) {
            res = fetchers[i].call(
                t, // this, the Calendar object
                source,
                rangeStart.clone(),
                rangeEnd.clone(),
                t.options.timezone,
                callback
            );

            if (res === true) {
                // the fetcher is in charge. made its own async request
                return;
            }
            else if (typeof res == 'object') {
                // the fetcher returned a new source. process it
                _fetchEventSource(res, callback);
                return;
            }
        }

        var events = source.events;
        if (events) {
            if ($.isFunction(events)) {
                t.pushLoading();
                events.call(
                    t, // this, the Calendar object
                    rangeStart.clone(),
                    rangeEnd.clone(),
                    t.options.timezone,
                    function(events) {
                        callback(events);
                        t.popLoading();
                    }
                );
            }
            else if ($.isArray(events)) {
                callback(events);
            }
            else {
                callback();
            }
        }else{
            var url = source.url;
            if (url) {
                var success = source.success;
                var error = source.error;
                var complete = source.complete;

                // retrieve any outbound GET/POST $.ajax data from the options
                var customData;
                if ($.isFunction(source.data)) {
                    // supplied as a function that returns a key/value object
                    customData = source.data();
                }
                else {
                    // supplied as a straight key/value object
                    customData = source.data;
                }

                // use a copy of the custom data so we can modify the parameters
                // and not affect the passed-in object.
                var data = $.extend({}, customData || {});

                var startParam = firstDefined(source.startParam, t.options.startParam);
                var endParam = firstDefined(source.endParam, t.options.endParam);
                var timezoneParam = firstDefined(source.timezoneParam, t.options.timezoneParam);

                if (startParam) {
                    data[startParam] = rangeStart.format();
                }
                if (endParam) {
                    data[endParam] = rangeEnd.format();
                }
                if (t.options.timezone && t.options.timezone != 'local') {
                    data[timezoneParam] = t.options.timezone;
                }

                t.pushLoading();
                $.ajax($.extend({}, ajaxDefaults, source, {
                    data: data,
                    success: function(events) {
                        events = events || [];
                        var res = applyAll(success, this, arguments);
                        if ($.isArray(res)) {
                            events = res;
                        }
                        callback(events);
                    },
                    error: function() {
                        applyAll(error, this, arguments);
                        callback();
                    },
                    complete: function() {
                        applyAll(complete, this, arguments);
                        t.popLoading();
                    }
                }));
            }else{
                callback();
            }
        }
    }
    
    
    
    /* Sources
    -----------------------------------------------------------------------------*/


    function addEventSource(sourceInput) {
        var source = buildEventSource(sourceInput);
        if (source) {
            sources.push(source);
            fetchEventSources([ source ], 'add'); // will eventually call reportEvents
        }
    }


    function buildEventSource(sourceInput) { // will return undefined if invalid source
        var normalizers = FC.sourceNormalizers;
        var source;
        var i;

        if ($.isFunction(sourceInput) || $.isArray(sourceInput)) {
            source = { events: sourceInput };
        }
        else if (typeof sourceInput === 'string') {
            source = { url: sourceInput };
        }
        else if (typeof sourceInput === 'object') {
            source = $.extend({}, sourceInput); // shallow copy
        }

        if (source) {

            // TODO: repeat code, same code for event classNames
            if (source.className) {
                if (typeof source.className === 'string') {
                    source.className = source.className.split(/\s+/);
                }
                // otherwise, assumed to be an array
            }
            else {
                source.className = [];
            }

            // for array sources, we convert to standard Event Objects up front
            if ($.isArray(source.events)) {
                source.origArray = source.events; // for removeEventSource
                source.events = $.map(source.events, function(eventInput) {
                    return buildEventFromInput(eventInput, source);
                });
            }

            for (i=0; i<normalizers.length; i++) {
                normalizers[i].call(t, source);
            }

            return source;
        }
    }


    function removeEventSource(matchInput) {
        removeSpecificEventSources(
            getEventSourcesByMatch(matchInput)
        );
    }


    // if called with no arguments, removes all.
    function removeEventSources(matchInputs) {
        if (matchInputs == null) {
            removeSpecificEventSources(sources, true); // isAll=true
        }
        else {
            removeSpecificEventSources(
                getEventSourcesByMatchArray(matchInputs)
            );
        }
    }


    function removeSpecificEventSources(targetSources, isAll) {
        var i;

        // cancel pending requests
        for (i = 0; i < targetSources.length; i++) {
            rejectEventSource(targetSources[i]);
        }

        if (isAll) { // an optimization
            sources = [];
            cache = [];
        }
        else {
            // remove from persisted source list
            sources = $.grep(sources, function(source) {
                for (i = 0; i < targetSources.length; i++) {
                    if (source === targetSources[i]) {
                        return false; // exclude
                    }
                }
                return true; // include
            });

            cache = excludeEventsBySources(cache, targetSources);
        }

        reportEvents(cache);
    }


    function getEventSources() {
        return sources.slice(1); // returns a shallow copy of sources with stickySource removed
    }


    function getEventSourceById(id) {
        return $.grep(sources, function(source) {
            return source.id && source.id === id;
        })[0];
    }


    // like getEventSourcesByMatch, but accepts multple match criteria (like multiple IDs)
    function getEventSourcesByMatchArray(matchInputs) {

        // coerce into an array
        if (!matchInputs) {
            matchInputs = [];
        }
        else if (!$.isArray(matchInputs)) {
            matchInputs = [ matchInputs ];
        }

        var matchingSources = [];
        var i;

        // resolve raw inputs to real event source objects
        for (i = 0; i < matchInputs.length; i++) {
            matchingSources.push.apply( // append
                matchingSources,
                getEventSourcesByMatch(matchInputs[i])
            );
        }

        return matchingSources;
    }


    // matchInput can either by a real event source object, an ID, or the function/URL for the source.
    // returns an array of matching source objects.
    function getEventSourcesByMatch(matchInput) {
        var i, source;

        // given an proper event source object
        for (i = 0; i < sources.length; i++) {
            source = sources[i];
            if (source === matchInput) {
                return [ source ];
            }
        }

        // an ID match
        source = getEventSourceById(matchInput);
        if (source) {
            return [ source ];
        }

        return $.grep(sources, function(source) {
            return isSourcesEquivalent(matchInput, source);
        });
    }


    function isSourcesEquivalent(source1, source2) {
        return source1 && source2 && getSourcePrimitive(source1) == getSourcePrimitive(source2);
    }


    function getSourcePrimitive(source) {
        return (
            (typeof source === 'object') ? // a normalized event source?
                (source.origArray || source.googleCalendarId || source.url || source.events) : // get the primitive
                null
        ) ||
        source; // the given argument *is* the primitive
    }


    // util
    // returns a filtered array without events that are part of any of the given sources
    function excludeEventsBySources(specificEvents, specificSources) {
        return $.grep(specificEvents, function(event) {
            for (var i = 0; i < specificSources.length; i++) {
                if (event.source === specificSources[i]) {
                    return false; // exclude
                }
            }
            return true; // keep
        });
    }
    
    
    
    /* Manipulation
    -----------------------------------------------------------------------------*/


    // Only ever called from the externally-facing API
    function updateEvent(event) {

        // massage start/end values, even if date string values
        event.start = t.moment(event.start);
        if (event.end) {
            event.end = t.moment(event.end);
        }
        else {
            event.end = null;
        }

        mutateEvent(event, getMiscEventProps(event)); // will handle start/end/allDay normalization
        reportEvents(cache); // reports event modifications (so we can redraw)
    }


    // Returns a hash of misc event properties that should be copied over to related events.
    function getMiscEventProps(event) {
        var props = {};

        $.each(event, function(name, val) {
            if (isMiscEventPropName(name)) {
                if (val !== undefined && isAtomic(val)) { // a defined non-object
                    props[name] = val;
                }
            }
        });

        return props;
    }

    // non-date-related, non-id-related, non-secret
    function isMiscEventPropName(name) {
        return !/^_|^(id|allDay|start|end)$/.test(name);
    }

    
    // returns the expanded events that were created
    function renderEvent(eventInput, stick) {
        var abstractEvent = buildEventFromInput(eventInput);
        var events;
        var i, event;

        if (abstractEvent) { // not false (a valid input)
            events = expandEvent(abstractEvent);

            for (i = 0; i < events.length; i++) {
                event = events[i];

                if (!event.source) {
                    if (stick) {
                        stickySource.events.push(event);
                        event.source = stickySource;
                    }
                    cache.push(event);
                }
            }

            reportEvents(cache);

            return events;
        }

        return [];
    }
    
    
    function removeEvents(filter) {
        var eventID;
        var i;

        if (filter == null) { // null or undefined. remove all events
            filter = function() { return true; }; // will always match
        }
        else if (!$.isFunction(filter)) { // an event ID
            eventID = filter + '';
            filter = function(event) {
                return event._id == eventID;
            };
        }

        // Purge event(s) from our local cache
        cache = $.grep(cache, filter, true); // inverse=true

        // Remove events from array sources.
        // This works because they have been converted to official Event Objects up front.
        // (and as a result, event._id has been calculated).
        for (i=0; i<sources.length; i++) {
            if ($.isArray(sources[i].events)) {
                sources[i].events = $.grep(sources[i].events, filter, true);
            }
        }

        reportEvents(cache);
    }

    
    function clientEvents(filter) {
        if ($.isFunction(filter)) {
            return $.grep(cache, filter);
        }
        else if (filter != null) { // not null, not undefined. an event ID
            filter += '';
            return $.grep(cache, function(e) {
                return e._id == filter;
            });
        }
        return cache; // else, return all
    }


    // Makes sure all array event sources have their internal event objects
    // converted over to the Calendar's current timezone.
    t.rezoneArrayEventSources = function() {
        var i;
        var events;
        var j;

        for (i = 0; i < sources.length; i++) {
            events = sources[i].events;
            if ($.isArray(events)) {

                for (j = 0; j < events.length; j++) {
                    rezoneEventDates(events[j]);
                }
            }
        }
    };

    function rezoneEventDates(event) {
        event.start = t.moment(event.start);
        if (event.end) {
            event.end = t.moment(event.end);
        }
        backupEventDates(event);
    }
    
    
    /* Event Normalization
    -----------------------------------------------------------------------------*/


    // Given a raw object with key/value properties, returns an "abstract" Event object.
    // An "abstract" event is an event that, if recurring, will not have been expanded yet.
    // Will return `false` when input is invalid.
    // `source` is optional
    function buildEventFromInput(input, source) {
        var out = {};
        var start, end;
        var allDay;

        if (t.options.eventDataTransform) {
            input = t.options.eventDataTransform(input);
        }
        if (source && source.eventDataTransform) {
            input = source.eventDataTransform(input);
        }

        // Copy all properties over to the resulting object.
        // The special-case properties will be copied over afterwards.
        $.extend(out, input);

        if (source) {
            out.source = source;
        }

        out._id = input._id || (input.id === undefined ? '_fc' + eventGUID++ : input.id + '');

        if (input.className) {
            if (typeof input.className == 'string') {
                out.className = input.className.split(/\s+/);
            }
            else { // assumed to be an array
                out.className = input.className;
            }
        }
        else {
            out.className = [];
        }

        start = input.start || input.date; // "date" is an alias for "start"
        end = input.end;

        // parse as a time (Duration) if applicable
        if (isTimeString(start)) {
            start = moment.duration(start);
        }
        if (isTimeString(end)) {
            end = moment.duration(end);
        }

        if (input.dow || moment.isDuration(start) || moment.isDuration(end)) {

            // the event is "abstract" (recurring) so don't calculate exact start/end dates just yet
            out.start = start ? moment.duration(start) : null; // will be a Duration or null
            out.end = end ? moment.duration(end) : null; // will be a Duration or null
            out._recurring = true; // our internal marker
        }
        else {

            if (start) {
                start = t.moment(start);
                if (!start.isValid()) {
                    return false;
                }
            }

            if (end) {
                end = t.moment(end);
                if (!end.isValid()) {
                    end = null; // let defaults take over
                }
            }

            allDay = input.allDay;
            if (allDay === undefined) { // still undefined? fallback to default
                allDay = firstDefined(
                    source ? source.allDayDefault : undefined,
                    t.options.allDayDefault
                );
                // still undefined? normalizeEventDates will calculate it
            }

            assignDatesToEvent(start, end, allDay, out);
        }

        t.normalizeEvent(out); // hook for external use. a prototype method

        return out;
    }
    t.buildEventFromInput = buildEventFromInput;


    // Normalizes and assigns the given dates to the given partially-formed event object.
    // NOTE: mutates the given start/end moments. does not make a copy.
    function assignDatesToEvent(start, end, allDay, event) {
        event.start = start;
        event.end = end;
        event.allDay = allDay;
        normalizeEventDates(event);
        backupEventDates(event);
    }


    // Ensures proper values for allDay/start/end. Accepts an Event object, or a plain object with event-ish properties.
    // NOTE: Will modify the given object.
    function normalizeEventDates(eventProps) {

        normalizeEventTimes(eventProps);

        if (eventProps.end && !eventProps.end.isAfter(eventProps.start)) {
            eventProps.end = null;
        }

        if (!eventProps.end) {
            if (t.options.forceEventDuration) {
                eventProps.end = t.getDefaultEventEnd(eventProps.allDay, eventProps.start);
            }
            else {
                eventProps.end = null;
            }
        }
    }


    // Ensures the allDay property exists and the timeliness of the start/end dates are consistent
    function normalizeEventTimes(eventProps) {
        if (eventProps.allDay == null) {
            eventProps.allDay = !(eventProps.start.hasTime() || (eventProps.end && eventProps.end.hasTime()));
        }

        if (eventProps.allDay) {
            eventProps.start.stripTime();
            if (eventProps.end) {
                // TODO: consider nextDayThreshold here? If so, will require a lot of testing and adjustment
                eventProps.end.stripTime();
            }
        }
        else {
            if (!eventProps.start.hasTime()) {
                eventProps.start = t.applyTimezone(eventProps.start.time(0)); // will assign a 00:00 time
            }
            if (eventProps.end && !eventProps.end.hasTime()) {
                eventProps.end = t.applyTimezone(eventProps.end.time(0)); // will assign a 00:00 time
            }
        }
    }


    // If the given event is a recurring event, break it down into an array of individual instances.
    // If not a recurring event, return an array with the single original event.
    // If given a falsy input (probably because of a failed buildEventFromInput call), returns an empty array.
    // HACK: can override the recurring window by providing custom rangeStart/rangeEnd (for businessHours).
    function expandEvent(abstractEvent, _rangeStart, _rangeEnd) {
        var events = [];
        var dowHash;
        var dow;
        var i;
        var date;
        var startTime, endTime;
        var start, end;
        var event;

        _rangeStart = _rangeStart || rangeStart;
        _rangeEnd = _rangeEnd || rangeEnd;

        if (abstractEvent) {
            if (abstractEvent._recurring) {

                // make a boolean hash as to whether the event occurs on each day-of-week
                if ((dow = abstractEvent.dow)) {
                    dowHash = {};
                    for (i = 0; i < dow.length; i++) {
                        dowHash[dow[i]] = true;
                    }
                }

                // iterate through every day in the current range
                date = _rangeStart.clone().stripTime(); // holds the date of the current day
                while (date.isBefore(_rangeEnd)) {

                    if (!dowHash || dowHash[date.day()]) { // if everyday, or this particular day-of-week

                        startTime = abstractEvent.start; // the stored start and end properties are times (Durations)
                        endTime = abstractEvent.end; // "
                        start = date.clone();
                        end = null;

                        if (startTime) {
                            start = start.time(startTime);
                        }
                        if (endTime) {
                            end = date.clone().time(endTime);
                        }

                        event = $.extend({}, abstractEvent); // make a copy of the original
                        assignDatesToEvent(
                            start, end,
                            !startTime && !endTime, // allDay?
                            event
                        );
                        events.push(event);
                    }

                    date.add(1, 'days');
                }
            }
            else {
                events.push(abstractEvent); // return the original event. will be a one-item array
            }
        }

        return events;
    }
    t.expandEvent = expandEvent;



    /* Event Modification Math
    -----------------------------------------------------------------------------------------*/


    // Modifies an event and all related events by applying the given properties.
    // Special date-diffing logic is used for manipulation of dates.
    // If `props` does not contain start/end dates, the updated values are assumed to be the event's current start/end.
    // All date comparisons are done against the event's pristine _start and _end dates.
    // Returns an object with delta information and a function to undo all operations.
    // For making computations in a granularity greater than day/time, specify largeUnit.
    // NOTE: The given `newProps` might be mutated for normalization purposes.
    function mutateEvent(event, newProps, largeUnit) {
        var miscProps = {};
        var oldProps;
        var clearEnd;
        var startDelta;
        var endDelta;
        var durationDelta;
        var undoFunc;

        // diffs the dates in the appropriate way, returning a duration
        function diffDates(date1, date0) { // date1 - date0
            if (largeUnit) {
                return diffByUnit(date1, date0, largeUnit);
            }
            else if (newProps.allDay) {
                return diffDay(date1, date0);
            }
            else {
                return diffDayTime(date1, date0);
            }
        }

        newProps = newProps || {};

        // normalize new date-related properties
        if (!newProps.start) {
            newProps.start = event.start.clone();
        }
        if (newProps.end === undefined) {
            newProps.end = event.end ? event.end.clone() : null;
        }
        if (newProps.allDay == null) { // is null or undefined?
            newProps.allDay = event.allDay;
        }
        normalizeEventDates(newProps);

        // create normalized versions of the original props to compare against
        // need a real end value, for diffing
        oldProps = {
            start: event._start.clone(),
            end: event._end ? event._end.clone() : t.getDefaultEventEnd(event._allDay, event._start),
            allDay: newProps.allDay // normalize the dates in the same regard as the new properties
        };
        normalizeEventDates(oldProps);

        // need to clear the end date if explicitly changed to null
        clearEnd = event._end !== null && newProps.end === null;

        // compute the delta for moving the start date
        startDelta = diffDates(newProps.start, oldProps.start);

        // compute the delta for moving the end date
        if (newProps.end) {
            endDelta = diffDates(newProps.end, oldProps.end);
            durationDelta = endDelta.subtract(startDelta);
        }
        else {
            durationDelta = null;
        }

        // gather all non-date-related properties
        $.each(newProps, function(name, val) {
            if (isMiscEventPropName(name)) {
                if (val !== undefined) {
                    miscProps[name] = val;
                }
            }
        });

        // apply the operations to the event and all related events
        undoFunc = mutateEvents(
            clientEvents(event._id), // get events with this ID
            clearEnd,
            newProps.allDay,
            startDelta,
            durationDelta,
            miscProps
        );

        return {
            dateDelta: startDelta,
            durationDelta: durationDelta,
            undo: undoFunc
        };
    }


    // Modifies an array of events in the following ways (operations are in order):
    // - clear the event's `end`
    // - convert the event to allDay
    // - add `dateDelta` to the start and end
    // - add `durationDelta` to the event's duration
    // - assign `miscProps` to the event
    //
    // Returns a function that can be called to undo all the operations.
    //
    // TODO: don't use so many closures. possible memory issues when lots of events with same ID.
    //
    function mutateEvents(events, clearEnd, allDay, dateDelta, durationDelta, miscProps) {
        var isAmbigTimezone = t.getIsAmbigTimezone();
        var undoFunctions = [];

        // normalize zero-length deltas to be null
        if (dateDelta && !dateDelta.valueOf()) { dateDelta = null; }
        if (durationDelta && !durationDelta.valueOf()) { durationDelta = null; }

        $.each(events, function(i, event) {
            var oldProps;
            var newProps;

            // build an object holding all the old values, both date-related and misc.
            // for the undo function.
            oldProps = {
                start: event.start.clone(),
                end: event.end ? event.end.clone() : null,
                allDay: event.allDay
            };
            $.each(miscProps, function(name) {
                oldProps[name] = event[name];
            });

            // new date-related properties. work off the original date snapshot.
            // ok to use references because they will be thrown away when backupEventDates is called.
            newProps = {
                start: event._start,
                end: event._end,
                allDay: allDay // normalize the dates in the same regard as the new properties
            };
            normalizeEventDates(newProps); // massages start/end/allDay

            // strip or ensure the end date
            if (clearEnd) {
                newProps.end = null;
            }
            else if (durationDelta && !newProps.end) { // the duration translation requires an end date
                newProps.end = t.getDefaultEventEnd(newProps.allDay, newProps.start);
            }

            if (dateDelta) {
                newProps.start.add(dateDelta);
                if (newProps.end) {
                    newProps.end.add(dateDelta);
                }
            }

            if (durationDelta) {
                newProps.end.add(durationDelta); // end already ensured above
            }

            // if the dates have changed, and we know it is impossible to recompute the
            // timezone offsets, strip the zone.
            if (
                isAmbigTimezone &&
                !newProps.allDay &&
                (dateDelta || durationDelta)
            ) {
                newProps.start.stripZone();
                if (newProps.end) {
                    newProps.end.stripZone();
                }
            }

            $.extend(event, miscProps, newProps); // copy over misc props, then date-related props
            backupEventDates(event); // regenerate internal _start/_end/_allDay

            undoFunctions.push(function() {
                $.extend(event, oldProps);
                backupEventDates(event); // regenerate internal _start/_end/_allDay
            });
        });

        return function() {
            for (var i = 0; i < undoFunctions.length; i++) {
                undoFunctions[i]();
            }
        };
    }


    t.getEventCache = function() {
        return cache;
    };

}


// hook for external libs to manipulate event properties upon creation.
// should manipulate the event in-place.
Calendar.prototype.normalizeEvent = function(event) {
};


// Does the given span (start, end, and other location information)
// fully contain the other?
Calendar.prototype.spanContainsSpan = function(outerSpan, innerSpan) {
    var eventStart = outerSpan.start.clone().stripZone();
    var eventEnd = this.getEventEnd(outerSpan).stripZone();

    return innerSpan.start >= eventStart && innerSpan.end <= eventEnd;
};


// Returns a list of events that the given event should be compared against when being considered for a move to
// the specified span. Attached to the Calendar's prototype because EventManager is a mixin for a Calendar.
Calendar.prototype.getPeerEvents = function(span, event) {
    var cache = this.getEventCache();
    var peerEvents = [];
    var i, otherEvent;

    for (i = 0; i < cache.length; i++) {
        otherEvent = cache[i];
        if (
            !event ||
            event._id !== otherEvent._id // don't compare the event to itself or other related [repeating] events
        ) {
            peerEvents.push(otherEvent);
        }
    }

    return peerEvents;
};


// updates the "backup" properties, which are preserved in order to compute diffs later on.
function backupEventDates(event) {
    event._allDay = event.allDay;
    event._start = event.start.clone();
    event._end = event.end ? event.end.clone() : null;
}


/* Overlapping / Constraining
-----------------------------------------------------------------------------------------*/


// Determines if the given event can be relocated to the given span (unzoned start/end with other misc data)
Calendar.prototype.isEventSpanAllowed = function(span, event) {
    var source = event.source || {};

    var constraint = firstDefined(
        event.constraint,
        source.constraint,
        this.options.eventConstraint
    );

    var overlap = firstDefined(
        event.overlap,
        source.overlap,
        this.options.eventOverlap
    );

    return this.isSpanAllowed(span, constraint, overlap, event) &&
        (!this.options.eventAllow || this.options.eventAllow(span, event) !== false);
};


// Determines if an external event can be relocated to the given span (unzoned start/end with other misc data)
Calendar.prototype.isExternalSpanAllowed = function(eventSpan, eventLocation, eventProps) {
    var eventInput;
    var event;

    // note: very similar logic is in View's reportExternalDrop
    if (eventProps) {
        eventInput = $.extend({}, eventProps, eventLocation);
        event = this.expandEvent(
            this.buildEventFromInput(eventInput)
        )[0];
    }

    if (event) {
        return this.isEventSpanAllowed(eventSpan, event);
    }
    else { // treat it as a selection

        return this.isSelectionSpanAllowed(eventSpan);
    }
};


// Determines the given span (unzoned start/end with other misc data) can be selected.
Calendar.prototype.isSelectionSpanAllowed = function(span) {
    return this.isSpanAllowed(span, this.options.selectConstraint, this.options.selectOverlap) &&
        (!this.options.selectAllow || this.options.selectAllow(span) !== false);
};


// Returns true if the given span (caused by an event drop/resize or a selection) is allowed to exist
// according to the constraint/overlap settings.
// `event` is not required if checking a selection.
Calendar.prototype.isSpanAllowed = function(span, constraint, overlap, event) {
    var constraintEvents;
    var anyContainment;
    var peerEvents;
    var i, peerEvent;
    var peerOverlap;

    // the range must be fully contained by at least one of produced constraint events
    if (constraint != null) {

        // not treated as an event! intermediate data structure
        // TODO: use ranges in the future
        constraintEvents = this.constraintToEvents(constraint);
        if (constraintEvents) { // not invalid

            anyContainment = false;
            for (i = 0; i < constraintEvents.length; i++) {
                if (this.spanContainsSpan(constraintEvents[i], span)) {
                    anyContainment = true;
                    break;
                }
            }

            if (!anyContainment) {
                return false;
            }
        }
    }

    peerEvents = this.getPeerEvents(span, event);

    for (i = 0; i < peerEvents.length; i++)  {
        peerEvent = peerEvents[i];

        // there needs to be an actual intersection before disallowing anything
        if (this.eventIntersectsRange(peerEvent, span)) {

            // evaluate overlap for the given range and short-circuit if necessary
            if (overlap === false) {
                return false;
            }
            // if the event's overlap is a test function, pass the peer event in question as the first param
            else if (typeof overlap === 'function' && !overlap(peerEvent, event)) {
                return false;
            }

            // if we are computing if the given range is allowable for an event, consider the other event's
            // EventObject-specific or Source-specific `overlap` property
            if (event) {
                peerOverlap = firstDefined(
                    peerEvent.overlap,
                    (peerEvent.source || {}).overlap
                    // we already considered the global `eventOverlap`
                );
                if (peerOverlap === false) {
                    return false;
                }
                // if the peer event's overlap is a test function, pass the subject event as the first param
                if (typeof peerOverlap === 'function' && !peerOverlap(event, peerEvent)) {
                    return false;
                }
            }
        }
    }

    return true;
};


// Given an event input from the API, produces an array of event objects. Possible event inputs:
// 'businessHours'
// An event ID (number or string)
// An object with specific start/end dates or a recurring event (like what businessHours accepts)
Calendar.prototype.constraintToEvents = function(constraintInput) {

    if (constraintInput === 'businessHours') {
        return this.getCurrentBusinessHourEvents();
    }

    if (typeof constraintInput === 'object') {
        if (constraintInput.start != null) { // needs to be event-like input
            return this.expandEvent(this.buildEventFromInput(constraintInput));
        }
        else {
            return null; // invalid
        }
    }

    return this.clientEvents(constraintInput); // probably an ID
};


// Does the event's date range intersect with the given range?
// start/end already assumed to have stripped zones :(
Calendar.prototype.eventIntersectsRange = function(event, range) {
    var eventStart = event.start.clone().stripZone();
    var eventEnd = this.getEventEnd(event).stripZone();

    return range.start < eventEnd && range.end > eventStart;
};


/* Business Hours
-----------------------------------------------------------------------------------------*/

var BUSINESS_HOUR_EVENT_DEFAULTS = {
    id: '_fcBusinessHours', // will relate events from different calls to expandEvent
    start: '09:00',
    end: '17:00',
    dow: [ 1, 2, 3, 4, 5 ], // monday - friday
    rendering: 'inverse-background'
    // classNames are defined in businessHoursSegClasses
};

// Return events objects for business hours within the current view.
// Abuse of our event system :(
Calendar.prototype.getCurrentBusinessHourEvents = function(wholeDay) {
    return this.computeBusinessHourEvents(wholeDay, this.options.businessHours);
};

// Given a raw input value from options, return events objects for business hours within the current view.
Calendar.prototype.computeBusinessHourEvents = function(wholeDay, input) {
    if (input === true) {
        return this.expandBusinessHourEvents(wholeDay, [ {} ]);
    }
    else if ($.isPlainObject(input)) {
        return this.expandBusinessHourEvents(wholeDay, [ input ]);
    }
    else if ($.isArray(input)) {
        return this.expandBusinessHourEvents(wholeDay, input, true);
    }
    else {
        return [];
    }
};

// inputs expected to be an array of objects.
// if ignoreNoDow is true, will ignore entries that don't specify a day-of-week (dow) key.
Calendar.prototype.expandBusinessHourEvents = function(wholeDay, inputs, ignoreNoDow) {
    var view = this.getView();
    var events = [];
    var i, input;

    for (i = 0; i < inputs.length; i++) {
        input = inputs[i];

        if (ignoreNoDow && !input.dow) {
            continue;
        }

        // give defaults. will make a copy
        input = $.extend({}, BUSINESS_HOUR_EVENT_DEFAULTS, input);

        // if a whole-day series is requested, clear the start/end times
        if (wholeDay) {
            input.start = null;
            input.end = null;
        }

        events.push.apply(events, // append
            this.expandEvent(
                this.buildEventFromInput(input),
                view.start,
                view.end
            )
        );
    }

    return events;
};

;;

/* An abstract class for the "basic" views, as well as month view. Renders one or more rows of day cells.
----------------------------------------------------------------------------------------------------------------------*/
// It is a manager for a DayGrid subcomponent, which does most of the heavy lifting.
// It is responsible for managing width/height.

var BasicView = FC.BasicView = View.extend({

    scroller: null,

    dayGridClass: DayGrid, // class the dayGrid will be instantiated from (overridable by subclasses)
    dayGrid: null, // the main subcomponent that does most of the heavy lifting

    dayNumbersVisible: false, // display day numbers on each day cell?
    colWeekNumbersVisible: false, // display week numbers along the side?
    cellWeekNumbersVisible: false, // display week numbers in day cell?

    weekNumberWidth: null, // width of all the week-number cells running down the side

    headContainerEl: null, // div that hold's the dayGrid's rendered date header
    headRowEl: null, // the fake row element of the day-of-week header


    initialize: function() {
        this.dayGrid = this.instantiateDayGrid();

        this.scroller = new Scroller({
            overflowX: 'hidden',
            overflowY: 'auto'
        });
    },


    // Generates the DayGrid object this view needs. Draws from this.dayGridClass
    instantiateDayGrid: function() {
        // generate a subclass on the fly with BasicView-specific behavior
        // TODO: cache this subclass
        var subclass = this.dayGridClass.extend(basicDayGridMethods);

        return new subclass(this);
    },


    // Sets the display range and computes all necessary dates
    setRange: function(range) {
        View.prototype.setRange.call(this, range); // call the super-method

        this.dayGrid.breakOnWeeks = /year|month|week/.test(this.intervalUnit); // do before setRange
        this.dayGrid.setRange(range);
    },


    // Compute the value to feed into setRange. Overrides superclass.
    computeRange: function(date) {
        var range = View.prototype.computeRange.call(this, date); // get value from the super-method

        // year and month views should be aligned with weeks. this is already done for week
        if (/year|month/.test(range.intervalUnit)) {
            range.start.startOf('week');
            range.start = this.skipHiddenDays(range.start);

            // make end-of-week if not already
            if (range.end.weekday()) {
                range.end.add(1, 'week').startOf('week');
                range.end = this.skipHiddenDays(range.end, -1, true); // exclusively move backwards
            }
        }

        return range;
    },


    // Renders the view into `this.el`, which should already be assigned
    renderDates: function() {

        this.dayNumbersVisible = this.dayGrid.rowCnt > 1; // TODO: make grid responsible
        if (this.opt('weekNumbers')) {
            if (this.opt('weekNumbersWithinDays')) {
                this.cellWeekNumbersVisible = true;
                this.colWeekNumbersVisible = false;
            }
            else {
                this.cellWeekNumbersVisible = false;
                this.colWeekNumbersVisible = true;
            };
        }
        this.dayGrid.numbersVisible = this.dayNumbersVisible ||
            this.cellWeekNumbersVisible || this.colWeekNumbersVisible;

        this.el.addClass('fc-basic-view').html(this.renderSkeletonHtml());
        this.renderHead();

        this.scroller.render();
        var dayGridContainerEl = this.scroller.el.addClass('fc-day-grid-container');
        var dayGridEl = $('<div class="fc-day-grid" />').appendTo(dayGridContainerEl);
        this.el.find('.fc-body > tr > td').append(dayGridContainerEl);

        this.dayGrid.setElement(dayGridEl);
        this.dayGrid.renderDates(this.hasRigidRows());
    },


    // render the day-of-week headers
    renderHead: function() {
        this.headContainerEl =
            this.el.find('.fc-head-container')
                .html(this.dayGrid.renderHeadHtml());
        this.headRowEl = this.headContainerEl.find('.fc-row');
    },


    // Unrenders the content of the view. Since we haven't separated skeleton rendering from date rendering,
    // always completely kill the dayGrid's rendering.
    unrenderDates: function() {
        this.dayGrid.unrenderDates();
        this.dayGrid.removeElement();
        this.scroller.destroy();
    },


    renderBusinessHours: function() {
        this.dayGrid.renderBusinessHours();
    },


    unrenderBusinessHours: function() {
        this.dayGrid.unrenderBusinessHours();
    },


    // Builds the HTML skeleton for the view.
    // The day-grid component will render inside of a container defined by this HTML.
    renderSkeletonHtml: function() {
        return '' +
            '<table>' +
                '<thead class="fc-head">' +
                    '<tr>' +
                        '<td class="fc-head-container ' + this.widgetHeaderClass + '"></td>' +
                    '</tr>' +
                '</thead>' +
                '<tbody class="fc-body">' +
                    '<tr>' +
                        '<td class="' + this.widgetContentClass + '"></td>' +
                    '</tr>' +
                '</tbody>' +
            '</table>';
    },


    // Generates an HTML attribute string for setting the width of the week number column, if it is known
    weekNumberStyleAttr: function() {
        if (this.weekNumberWidth !== null) {
            return 'style="width:' + this.weekNumberWidth + 'px"';
        }
        return '';
    },


    // Determines whether each row should have a constant height
    hasRigidRows: function() {
        var eventLimit = this.opt('eventLimit');
        return eventLimit && typeof eventLimit !== 'number';
    },


    /* Dimensions
    ------------------------------------------------------------------------------------------------------------------*/


    // Refreshes the horizontal dimensions of the view
    updateWidth: function() {
        if (this.colWeekNumbersVisible) {
            // Make sure all week number cells running down the side have the same width.
            // Record the width for cells created later.
            this.weekNumberWidth = matchCellWidths(
                this.el.find('.fc-week-number')
            );
        }
    },


    // Adjusts the vertical dimensions of the view to the specified values
    setHeight: function(totalHeight, isAuto) {
        var eventLimit = this.opt('eventLimit');
        var scrollerHeight;
        var scrollbarWidths;

        // reset all heights to be natural
        this.scroller.clear();
        uncompensateScroll(this.headRowEl);

        this.dayGrid.removeSegPopover(); // kill the "more" popover if displayed

        // is the event limit a constant level number?
        if (eventLimit && typeof eventLimit === 'number') {
            this.dayGrid.limitRows(eventLimit); // limit the levels first so the height can redistribute after
        }

        // distribute the height to the rows
        // (totalHeight is a "recommended" value if isAuto)
        scrollerHeight = this.computeScrollerHeight(totalHeight);
        this.setGridHeight(scrollerHeight, isAuto);

        // is the event limit dynamically calculated?
        if (eventLimit && typeof eventLimit !== 'number') {
            this.dayGrid.limitRows(eventLimit); // limit the levels after the grid's row heights have been set
        }

        if (!isAuto) { // should we force dimensions of the scroll container?

            this.scroller.setHeight(scrollerHeight);
            scrollbarWidths = this.scroller.getScrollbarWidths();

            if (scrollbarWidths.left || scrollbarWidths.right) { // using scrollbars?

                compensateScroll(this.headRowEl, scrollbarWidths);

                // doing the scrollbar compensation might have created text overflow which created more height. redo
                scrollerHeight = this.computeScrollerHeight(totalHeight);
                this.scroller.setHeight(scrollerHeight);
            }

            // guarantees the same scrollbar widths
            this.scroller.lockOverflow(scrollbarWidths);
        }
    },


    // given a desired total height of the view, returns what the height of the scroller should be
    computeScrollerHeight: function(totalHeight) {
        return totalHeight -
            subtractInnerElHeight(this.el, this.scroller.el); // everything that's NOT the scroller
    },


    // Sets the height of just the DayGrid component in this view
    setGridHeight: function(height, isAuto) {
        if (isAuto) {
            undistributeHeight(this.dayGrid.rowEls); // let the rows be their natural height with no expanding
        }
        else {
            distributeHeight(this.dayGrid.rowEls, height, true); // true = compensate for height-hogging rows
        }
    },


    /* Scroll
    ------------------------------------------------------------------------------------------------------------------*/


    queryScroll: function() {
        return this.scroller.getScrollTop();
    },


    setScroll: function(top) {
        this.scroller.setScrollTop(top);
    },


    /* Hit Areas
    ------------------------------------------------------------------------------------------------------------------*/
    // forward all hit-related method calls to dayGrid


    prepareHits: function() {
        this.dayGrid.prepareHits();
    },


    releaseHits: function() {
        this.dayGrid.releaseHits();
    },


    queryHit: function(left, top) {
        return this.dayGrid.queryHit(left, top);
    },


    getHitSpan: function(hit) {
        return this.dayGrid.getHitSpan(hit);
    },


    getHitEl: function(hit) {
        return this.dayGrid.getHitEl(hit);
    },


    /* Events
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders the given events onto the view and populates the segments array
    renderEvents: function(events) {
        this.dayGrid.renderEvents(events);

        this.updateHeight(); // must compensate for events that overflow the row
    },


    // Retrieves all segment objects that are rendered in the view
    getEventSegs: function() {
        return this.dayGrid.getEventSegs();
    },


    // Unrenders all event elements and clears internal segment data
    unrenderEvents: function() {
        this.dayGrid.unrenderEvents();

        // we DON'T need to call updateHeight() because
        // a renderEvents() call always happens after this, which will eventually call updateHeight()
    },


    /* Dragging (for both events and external elements)
    ------------------------------------------------------------------------------------------------------------------*/


    // A returned value of `true` signals that a mock "helper" event has been rendered.
    renderDrag: function(dropLocation, seg) {
        return this.dayGrid.renderDrag(dropLocation, seg);
    },


    unrenderDrag: function() {
        this.dayGrid.unrenderDrag();
    },


    /* Selection
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a visual indication of a selection
    renderSelection: function(span) {
        this.dayGrid.renderSelection(span);
    },


    // Unrenders a visual indications of a selection
    unrenderSelection: function() {
        this.dayGrid.unrenderSelection();
    }

});


// Methods that will customize the rendering behavior of the BasicView's dayGrid
var basicDayGridMethods = {


    // Generates the HTML that will go before the day-of week header cells
    renderHeadIntroHtml: function() {
        var view = this.view;

        if (view.colWeekNumbersVisible) {
            return '' +
                '<th class="fc-week-number ' + view.widgetHeaderClass + '" ' + view.weekNumberStyleAttr() + '>' +
                    '<span>' + // needed for matchCellWidths
                        htmlEscape(view.opt('weekNumberTitle')) +
                    '</span>' +
                '</th>';
        }

        return '';
    },


    // Generates the HTML that will go before content-skeleton cells that display the day/week numbers
    renderNumberIntroHtml: function(row) {
        var view = this.view;
        var weekStart = this.getCellDate(row, 0);

        if (view.colWeekNumbersVisible) {
            return '' +
                '<td class="fc-week-number" ' + view.weekNumberStyleAttr() + '>' +
                    view.buildGotoAnchorHtml( // aside from link, important for matchCellWidths
                        { date: weekStart, type: 'week', forceOff: this.colCnt === 1 },
                        weekStart.format('w') // inner HTML
                    ) +
                '</td>';
        }

        return '';
    },


    // Generates the HTML that goes before the day bg cells for each day-row
    renderBgIntroHtml: function() {
        var view = this.view;

        if (view.colWeekNumbersVisible) {
            return '<td class="fc-week-number ' + view.widgetContentClass + '" ' +
                view.weekNumberStyleAttr() + '></td>';
        }

        return '';
    },


    // Generates the HTML that goes before every other type of row generated by DayGrid.
    // Affects helper-skeleton and highlight-skeleton rows.
    renderIntroHtml: function() {
        var view = this.view;

        if (view.colWeekNumbersVisible) {
            return '<td class="fc-week-number" ' + view.weekNumberStyleAttr() + '></td>';
        }

        return '';
    }

};

;;

/* A month view with day cells running in rows (one-per-week) and columns
----------------------------------------------------------------------------------------------------------------------*/

var MonthView = FC.MonthView = BasicView.extend({

    // Produces information about what range to display
    computeRange: function(date) {
        var range = BasicView.prototype.computeRange.call(this, date); // get value from super-method
        var rowCnt;

        // ensure 6 weeks
        if (this.isFixedWeeks()) {
            rowCnt = Math.ceil(range.end.diff(range.start, 'weeks', true)); // could be partial weeks due to hiddenDays
            range.end.add(6 - rowCnt, 'weeks');
        }

        return range;
    },


    // Overrides the default BasicView behavior to have special multi-week auto-height logic
    setGridHeight: function(height, isAuto) {

        // if auto, make the height of each row the height that it would be if there were 6 weeks
        if (isAuto) {
            height *= this.rowCnt / 6;
        }

        distributeHeight(this.dayGrid.rowEls, height, !isAuto); // if auto, don't compensate for height-hogging rows
    },


    isFixedWeeks: function() {
        return this.opt('fixedWeekCount');
    }

});

;;

fcViews.basic = {
    'class': BasicView
};

fcViews.basicDay = {
    type: 'basic',
    duration: { days: 1 }
};

fcViews.basicWeek = {
    type: 'basic',
    duration: { weeks: 1 }
};

fcViews.month = {
    'class': MonthView,
    duration: { months: 1 }, // important for prev/next
    defaults: {
        fixedWeekCount: true
    }
};
;;

/* An abstract class for all agenda-related views. Displays one more columns with time slots running vertically.
----------------------------------------------------------------------------------------------------------------------*/
// Is a manager for the TimeGrid subcomponent and possibly the DayGrid subcomponent (if allDaySlot is on).
// Responsible for managing width/height.

var AgendaView = FC.AgendaView = View.extend({

    scroller: null,

    timeGridClass: TimeGrid, // class used to instantiate the timeGrid. subclasses can override
    timeGrid: null, // the main time-grid subcomponent of this view

    dayGridClass: DayGrid, // class used to instantiate the dayGrid. subclasses can override
    dayGrid: null, // the "all-day" subcomponent. if all-day is turned off, this will be null

    axisWidth: null, // the width of the time axis running down the side

    headContainerEl: null, // div that hold's the timeGrid's rendered date header
    noScrollRowEls: null, // set of fake row elements that must compensate when scroller has scrollbars

    // when the time-grid isn't tall enough to occupy the given height, we render an <hr> underneath
    bottomRuleEl: null,


    initialize: function() {
        this.timeGrid = this.instantiateTimeGrid();

        if (this.opt('allDaySlot')) { // should we display the "all-day" area?
            this.dayGrid = this.instantiateDayGrid(); // the all-day subcomponent of this view
        }

        this.scroller = new Scroller({
            overflowX: 'hidden',
            overflowY: 'auto'
        });
    },


    // Instantiates the TimeGrid object this view needs. Draws from this.timeGridClass
    instantiateTimeGrid: function() {
        var subclass = this.timeGridClass.extend(agendaTimeGridMethods);

        return new subclass(this);
    },


    // Instantiates the DayGrid object this view might need. Draws from this.dayGridClass
    instantiateDayGrid: function() {
        var subclass = this.dayGridClass.extend(agendaDayGridMethods);

        return new subclass(this);
    },


    /* Rendering
    ------------------------------------------------------------------------------------------------------------------*/


    // Sets the display range and computes all necessary dates
    setRange: function(range) {
        View.prototype.setRange.call(this, range); // call the super-method

        this.timeGrid.setRange(range);
        if (this.dayGrid) {
            this.dayGrid.setRange(range);
        }
    },


    // Renders the view into `this.el`, which has already been assigned
    renderDates: function() {

        this.el.addClass('fc-agenda-view').html(this.renderSkeletonHtml());
        this.renderHead();

        this.scroller.render();
        var timeGridWrapEl = this.scroller.el.addClass('fc-time-grid-container');
        var timeGridEl = $('<div class="fc-time-grid" />').appendTo(timeGridWrapEl);
        this.el.find('.fc-body > tr > td').append(timeGridWrapEl);

        this.timeGrid.setElement(timeGridEl);
        this.timeGrid.renderDates();

        // the <hr> that sometimes displays under the time-grid
        this.bottomRuleEl = $('<hr class="fc-divider ' + this.widgetHeaderClass + '"/>')
            .appendTo(this.timeGrid.el); // inject it into the time-grid

        if (this.dayGrid) {
            this.dayGrid.setElement(this.el.find('.fc-day-grid'));
            this.dayGrid.renderDates();

            // have the day-grid extend it's coordinate area over the <hr> dividing the two grids
            this.dayGrid.bottomCoordPadding = this.dayGrid.el.next('hr').outerHeight();
        }

        this.noScrollRowEls = this.el.find('.fc-row:not(.fc-scroller *)'); // fake rows not within the scroller
    },


    // render the day-of-week headers
    renderHead: function() {
        this.headContainerEl =
            this.el.find('.fc-head-container')
                .html(this.timeGrid.renderHeadHtml());
    },


    // Unrenders the content of the view. Since we haven't separated skeleton rendering from date rendering,
    // always completely kill each grid's rendering.
    unrenderDates: function() {
        this.timeGrid.unrenderDates();
        this.timeGrid.removeElement();

        if (this.dayGrid) {
            this.dayGrid.unrenderDates();
            this.dayGrid.removeElement();
        }

        this.scroller.destroy();
    },


    // Builds the HTML skeleton for the view.
    // The day-grid and time-grid components will render inside containers defined by this HTML.
    renderSkeletonHtml: function() {
        return '' +
            '<table>' +
                '<thead class="fc-head">' +
                    '<tr>' +
                        '<td class="fc-head-container ' + this.widgetHeaderClass + '"></td>' +
                    '</tr>' +
                '</thead>' +
                '<tbody class="fc-body">' +
                    '<tr>' +
                        '<td class="' + this.widgetContentClass + '">' +
                            (this.dayGrid ?
                                '<div class="fc-day-grid"/>' +
                                '<hr class="fc-divider ' + this.widgetHeaderClass + '"/>' :
                                ''
                                ) +
                        '</td>' +
                    '</tr>' +
                '</tbody>' +
            '</table>';
    },


    // Generates an HTML attribute string for setting the width of the axis, if it is known
    axisStyleAttr: function() {
        if (this.axisWidth !== null) {
             return 'style="width:' + this.axisWidth + 'px"';
        }
        return '';
    },


    /* Business Hours
    ------------------------------------------------------------------------------------------------------------------*/


    renderBusinessHours: function() {
        this.timeGrid.renderBusinessHours();

        if (this.dayGrid) {
            this.dayGrid.renderBusinessHours();
        }
    },


    unrenderBusinessHours: function() {
        this.timeGrid.unrenderBusinessHours();

        if (this.dayGrid) {
            this.dayGrid.unrenderBusinessHours();
        }
    },


    /* Now Indicator
    ------------------------------------------------------------------------------------------------------------------*/


    getNowIndicatorUnit: function() {
        return this.timeGrid.getNowIndicatorUnit();
    },


    renderNowIndicator: function(date) {
        this.timeGrid.renderNowIndicator(date);
    },


    unrenderNowIndicator: function() {
        this.timeGrid.unrenderNowIndicator();
    },


    /* Dimensions
    ------------------------------------------------------------------------------------------------------------------*/


    updateSize: function(isResize) {
        this.timeGrid.updateSize(isResize);

        View.prototype.updateSize.call(this, isResize); // call the super-method
    },


    // Refreshes the horizontal dimensions of the view
    updateWidth: function() {
        // make all axis cells line up, and record the width so newly created axis cells will have it
        this.axisWidth = matchCellWidths(this.el.find('.fc-axis'));
    },


    // Adjusts the vertical dimensions of the view to the specified values
    setHeight: function(totalHeight, isAuto) {
        var eventLimit;
        var scrollerHeight;
        var scrollbarWidths;

        // reset all dimensions back to the original state
        this.bottomRuleEl.hide(); // .show() will be called later if this <hr> is necessary
        this.scroller.clear(); // sets height to 'auto' and clears overflow
        uncompensateScroll(this.noScrollRowEls);

        // limit number of events in the all-day area
        if (this.dayGrid) {
            this.dayGrid.removeSegPopover(); // kill the "more" popover if displayed

            eventLimit = this.opt('eventLimit');
            if (eventLimit && typeof eventLimit !== 'number') {
                eventLimit = AGENDA_ALL_DAY_EVENT_LIMIT; // make sure "auto" goes to a real number
            }
            if (eventLimit) {
                this.dayGrid.limitRows(eventLimit);
            }
        }

        if (!isAuto) { // should we force dimensions of the scroll container?

            scrollerHeight = this.computeScrollerHeight(totalHeight);
            this.scroller.setHeight(scrollerHeight);
            scrollbarWidths = this.scroller.getScrollbarWidths();

            if (scrollbarWidths.left || scrollbarWidths.right) { // using scrollbars?

                // make the all-day and header rows lines up
                compensateScroll(this.noScrollRowEls, scrollbarWidths);

                // the scrollbar compensation might have changed text flow, which might affect height, so recalculate
                // and reapply the desired height to the scroller.
                scrollerHeight = this.computeScrollerHeight(totalHeight);
                this.scroller.setHeight(scrollerHeight);
            }

            // guarantees the same scrollbar widths
            this.scroller.lockOverflow(scrollbarWidths);

            // if there's any space below the slats, show the horizontal rule.
            // this won't cause any new overflow, because lockOverflow already called.
            if (this.timeGrid.getTotalSlatHeight() < scrollerHeight) {
                this.bottomRuleEl.show();
            }
        }
    },


    // given a desired total height of the view, returns what the height of the scroller should be
    computeScrollerHeight: function(totalHeight) {
        return totalHeight -
            subtractInnerElHeight(this.el, this.scroller.el); // everything that's NOT the scroller
    },


    /* Scroll
    ------------------------------------------------------------------------------------------------------------------*/


    // Computes the initial pre-configured scroll state prior to allowing the user to change it
    computeInitialScroll: function() {
        var scrollTime = moment.duration(this.opt('scrollTime'));
        var top = this.timeGrid.computeTimeTop(scrollTime);

        // zoom can give weird floating-point values. rather scroll a little bit further
        top = Math.ceil(top);

        if (top) {
            top++; // to overcome top border that slots beyond the first have. looks better
        }

        return top;
    },


    queryScroll: function() {
        return this.scroller.getScrollTop();
    },


    setScroll: function(top) {
        this.scroller.setScrollTop(top);
    },


    /* Hit Areas
    ------------------------------------------------------------------------------------------------------------------*/
    // forward all hit-related method calls to the grids (dayGrid might not be defined)


    prepareHits: function() {
        this.timeGrid.prepareHits();
        if (this.dayGrid) {
            this.dayGrid.prepareHits();
        }
    },


    releaseHits: function() {
        this.timeGrid.releaseHits();
        if (this.dayGrid) {
            this.dayGrid.releaseHits();
        }
    },


    queryHit: function(left, top) {
        var hit = this.timeGrid.queryHit(left, top);

        if (!hit && this.dayGrid) {
            hit = this.dayGrid.queryHit(left, top);
        }

        return hit;
    },


    getHitSpan: function(hit) {
        // TODO: hit.component is set as a hack to identify where the hit came from
        return hit.component.getHitSpan(hit);
    },


    getHitEl: function(hit) {
        // TODO: hit.component is set as a hack to identify where the hit came from
        return hit.component.getHitEl(hit);
    },


    /* Events
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders events onto the view and populates the View's segment array
    renderEvents: function(events) {
        var dayEvents = [];
        var timedEvents = [];
        var daySegs = [];
        var timedSegs;
        var i;

        // separate the events into all-day and timed
        for (i = 0; i < events.length; i++) {
            if (events[i].allDay) {
                dayEvents.push(events[i]);
            }
            else {
                timedEvents.push(events[i]);
            }
        }

        // render the events in the subcomponents
        timedSegs = this.timeGrid.renderEvents(timedEvents);
        if (this.dayGrid) {
            daySegs = this.dayGrid.renderEvents(dayEvents);
        }

        // the all-day area is flexible and might have a lot of events, so shift the height
        this.updateHeight();
    },


    // Retrieves all segment objects that are rendered in the view
    getEventSegs: function() {
        return this.timeGrid.getEventSegs().concat(
            this.dayGrid ? this.dayGrid.getEventSegs() : []
        );
    },


    // Unrenders all event elements and clears internal segment data
    unrenderEvents: function() {

        // unrender the events in the subcomponents
        this.timeGrid.unrenderEvents();
        if (this.dayGrid) {
            this.dayGrid.unrenderEvents();
        }

        // we DON'T need to call updateHeight() because
        // a renderEvents() call always happens after this, which will eventually call updateHeight()
    },


    /* Dragging (for events and external elements)
    ------------------------------------------------------------------------------------------------------------------*/


    // A returned value of `true` signals that a mock "helper" event has been rendered.
    renderDrag: function(dropLocation, seg) {
        if (dropLocation.start.hasTime()) {
            return this.timeGrid.renderDrag(dropLocation, seg);
        }
        else if (this.dayGrid) {
            return this.dayGrid.renderDrag(dropLocation, seg);
        }
    },


    unrenderDrag: function() {
        this.timeGrid.unrenderDrag();
        if (this.dayGrid) {
            this.dayGrid.unrenderDrag();
        }
    },


    /* Selection
    ------------------------------------------------------------------------------------------------------------------*/


    // Renders a visual indication of a selection
    renderSelection: function(span) {
        if (span.start.hasTime() || span.end.hasTime()) {
            this.timeGrid.renderSelection(span);
        }
        else if (this.dayGrid) {
            this.dayGrid.renderSelection(span);
        }
    },


    // Unrenders a visual indications of a selection
    unrenderSelection: function() {
        this.timeGrid.unrenderSelection();
        if (this.dayGrid) {
            this.dayGrid.unrenderSelection();
        }
    }

});


// Methods that will customize the rendering behavior of the AgendaView's timeGrid
// TODO: move into TimeGrid
var agendaTimeGridMethods = {


    // Generates the HTML that will go before the day-of week header cells
    renderHeadIntroHtml: function() {
        var view = this.view;
        var weekText;

        if (view.opt('weekNumbers')) {
            weekText = this.start.format(view.opt('smallWeekFormat'));

            return '' +
                '<th class="fc-axis fc-week-number ' + view.widgetHeaderClass + '" ' + view.axisStyleAttr() + '>' +
                    view.buildGotoAnchorHtml( // aside from link, important for matchCellWidths
                        { date: this.start, type: 'week', forceOff: this.colCnt > 1 },
                        htmlEscape(weekText) // inner HTML
                    ) +
                '</th>';
        }
        else {
            return '<th class="fc-axis ' + view.widgetHeaderClass + '" ' + view.axisStyleAttr() + '></th>';
        }
    },


    // Generates the HTML that goes before the bg of the TimeGrid slot area. Long vertical column.
    renderBgIntroHtml: function() {
        var view = this.view;

        return '<td class="fc-axis ' + view.widgetContentClass + '" ' + view.axisStyleAttr() + '></td>';
    },


    // Generates the HTML that goes before all other types of cells.
    // Affects content-skeleton, helper-skeleton, highlight-skeleton for both the time-grid and day-grid.
    renderIntroHtml: function() {
        var view = this.view;

        return '<td class="fc-axis" ' + view.axisStyleAttr() + '></td>';
    }

};


// Methods that will customize the rendering behavior of the AgendaView's dayGrid
var agendaDayGridMethods = {


    // Generates the HTML that goes before the all-day cells
    renderBgIntroHtml: function() {
        var view = this.view;

        return '' +
            '<td class="fc-axis ' + view.widgetContentClass + '" ' + view.axisStyleAttr() + '>' +
                '<span>' + // needed for matchCellWidths
                    view.getAllDayHtml() +
                '</span>' +
            '</td>';
    },


    // Generates the HTML that goes before all other types of cells.
    // Affects content-skeleton, helper-skeleton, highlight-skeleton for both the time-grid and day-grid.
    renderIntroHtml: function() {
        var view = this.view;

        return '<td class="fc-axis" ' + view.axisStyleAttr() + '></td>';
    }

};

;;

var AGENDA_ALL_DAY_EVENT_LIMIT = 5;

// potential nice values for the slot-duration and interval-duration
// from largest to smallest
var AGENDA_STOCK_SUB_DURATIONS = [
    { hours: 1 },
    { minutes: 30 },
    { minutes: 15 },
    { seconds: 30 },
    { seconds: 15 }
];

fcViews.agenda = {
    'class': AgendaView,
    defaults: {
        allDaySlot: true,
        slotDuration: '00:30:00',
        minTime: '00:00:00',
        maxTime: '24:00:00',
        slotEventOverlap: true // a bad name. confused with overlap/constraint system
    }
};

fcViews.agendaDay = {
    type: 'agenda',
    duration: { days: 1 }
};

fcViews.agendaWeek = {
    type: 'agenda',
    duration: { weeks: 1 }
};
;;

/*
Responsible for the scroller, and forwarding event-related actions into the "grid"
*/
var ListView = View.extend({

    grid: null,
    scroller: null,

    initialize: function() {
        this.grid = new ListViewGrid(this);
        this.scroller = new Scroller({
            overflowX: 'hidden',
            overflowY: 'auto'
        });
    },

    setRange: function(range) {
        View.prototype.setRange.call(this, range); // super

        this.grid.setRange(range); // needs to process range-related options
    },

    renderSkeleton: function() {
        this.el.addClass(
            'fc-list-view ' +
            this.widgetContentClass
        );

        this.scroller.render();
        this.scroller.el.appendTo(this.el);

        this.grid.setElement(this.scroller.scrollEl);
    },

    unrenderSkeleton: function() {
        this.scroller.destroy(); // will remove the Grid too
    },

    setHeight: function(totalHeight, isAuto) {
        this.scroller.setHeight(this.computeScrollerHeight(totalHeight));
    },

    computeScrollerHeight: function(totalHeight) {
        return totalHeight -
            subtractInnerElHeight(this.el, this.scroller.el); // everything that's NOT the scroller
    },

    renderEvents: function(events) {
        this.grid.renderEvents(events);
    },

    unrenderEvents: function() {
        this.grid.unrenderEvents();
    },

    isEventResizable: function(event) {
        return false;
    },

    isEventDraggable: function(event) {
        return false;
    }

});

/*
Responsible for event rendering and user-interaction.
Its "el" is the inner-content of the above view's scroller.
*/
var ListViewGrid = Grid.extend({

    segSelector: '.fc-list-item', // which elements accept event actions
    hasDayInteractions: false, // no day selection or day clicking

    // slices by day
    spanToSegs: function(span) {
        var view = this.view;
        var dayStart = view.start.clone();
        var dayEnd;
        var seg;
        var segs = [];

        while (dayStart < view.end) {
            dayEnd = dayStart.clone().add(1, 'day');
            seg = intersectRanges(span, {
                start: dayStart,
                end: dayEnd
            });
            if (seg) {
                segs.push(seg);
            }
            dayStart = dayEnd;
        }

        return segs;
    },

    // like "4:00am"
    computeEventTimeFormat: function() {
        return this.view.opt('mediumTimeFormat');
    },

    // for events with a url, the whole <tr> should be clickable,
    // but it's impossible to wrap with an <a> tag. simulate this.
    handleSegClick: function(seg, ev) {
        var url;

        Grid.prototype.handleSegClick.apply(this, arguments); // super. might prevent the default action

        // not clicking on or within an <a> with an href
        if (!$(ev.target).closest('a[href]').length) {
            url = seg.event.url;
            if (url && !ev.isDefaultPrevented()) { // jsEvent not cancelled in handler
                window.location.href = url; // simulate link click
            }
        }
    },

    // returns list of foreground segs that were actually rendered
    renderFgSegs: function(segs) {
        segs = this.renderFgSegEls(segs); // might filter away hidden events

        if (!segs.length) {
            this.renderEmptyMessage();
            return segs;
        }
        else {
            return this.renderSegList(segs);
        }
    },

    renderEmptyMessage: function() {
        this.el.html(
            '<div class="fc-list-empty-wrap2">' + // TODO: try less wraps
            '<div class="fc-list-empty-wrap1">' +
            '<div class="fc-list-empty">' +
                htmlEscape(this.view.opt('noEventsMessage')) +
            '</div>' +
            '</div>' +
            '</div>'
        );
    },

    // render the event segments in the view. returns the mutated array.
    renderSegList: function(segs) {
        var tableEl = $('<table class="fc-list-table"><tbody/></table>');
        var tbodyEl = tableEl.find('tbody');
        var i, seg;
        var dayDate;

        this.sortEventSegs(segs);

        for (i = 0; i < segs.length; i++) {
            seg = segs[i];

            // append a day header
            if (!dayDate || !seg.start.isSame(dayDate, 'day')) {
                dayDate = seg.start.clone().stripTime();
                tbodyEl.append(this.dayHeaderHtml(dayDate));
            }

            tbodyEl.append(seg.el); // append event row
        }

        this.el.empty().append(tableEl);

        return segs; // return the sorted list
    },

    // generates the HTML for the day headers that live amongst the event rows
    dayHeaderHtml: function(dayDate) {
        var view = this.view;
        var mainFormat = view.opt('listDayFormat');
        var altFormat = view.opt('listDayAltFormat');

        return '<tr class="fc-list-heading" data-date="' + dayDate.format('YYYY-MM-DD') + '">' +
            '<td class="' + view.widgetHeaderClass + '" colspan="3">' +
                (mainFormat ?
                    view.buildGotoAnchorHtml(
                        dayDate,
                        { 'class': 'fc-list-heading-main' },
                        htmlEscape(dayDate.format(mainFormat)) // inner HTML
                    ) :
                    '') +
                (altFormat ?
                    view.buildGotoAnchorHtml(
                        dayDate,
                        { 'class': 'fc-list-heading-alt' },
                        htmlEscape(dayDate.format(altFormat)) // inner HTML
                    ) :
                    '') +
            '</td>' +
        '</tr>';
    },

    // generates the HTML for a single event row
    fgSegHtml: function(seg) {
        var view = this.view;
        var classes = [ 'fc-list-item' ].concat(this.getSegCustomClasses(seg));
        var bgColor = this.getSegBackgroundColor(seg);
        var event = seg.event;
        var url = event.url;
        var timeHtml;

        if (!seg.start.hasTime()) {
            if (this.displayEventTime) {
                timeHtml = view.getAllDayHtml();
            }
        }
        else {
            timeHtml = htmlEscape(this.getEventTimeText(event)); // might return empty
        }

        if (url) {
            classes.push('fc-has-url');
        }

        return '<tr class="' + classes.join(' ') + '">' +
            (timeHtml ?
                '<td class="fc-list-item-time ' + view.widgetContentClass + '">' +
                    timeHtml +
                '</td>' :
                '') +
            '<td class="fc-list-item-marker ' + view.widgetContentClass + '">' +
                '<span class="fc-event-dot"' +
                (bgColor ?
                    ' style="background-color:' + bgColor + '"' :
                    '') +
                '></span>' +
            '</td>' +
            '<td class="fc-list-item-title ' + view.widgetContentClass + '">' +
                '<a' + (url ? ' href="' + htmlEscape(url) + '"' : '') + '>' +
                    htmlEscape(seg.event.title) +
                '</a>' +
            '</td>' +
        '</tr>';
    }

});

;;

fcViews.list = {
    'class': ListView,
    buttonTextKey: 'list', // what to lookup in locale files
    defaults: {
        buttonText: 'list', // text to display for English
        listTime: true, // show the time column?
        listDayFormat: 'LL', // like "January 1, 2016"
        noEventsMessage: 'No events to display'
    }
};

fcViews.listDay = {
    type: 'list',
    duration: { days: 1 },
    defaults: {
        listDayFormat: 'dddd' // day-of-week is all we need. full date is probably in header
    }
};

fcViews.listWeek = {
    type: 'list',
    duration: { weeks: 1 },
    defaults: {
        listDayFormat: 'dddd', // day-of-week is more important
        listDayAltFormat: 'LL'
    }
};

fcViews.listMonth = {
    type: 'list',
    duration: { month: 1 },
    defaults: {
        listDayAltFormat: 'dddd' // day-of-week is nice-to-have
    }
};

fcViews.listYear = {
    type: 'list',
    duration: { year: 1 },
    defaults: {
        listDayAltFormat: 'dddd' // day-of-week is nice-to-have
    }
};

;;

return FC; // export for Node/CommonJS
});