kandanapp/kandan

/*
  Implement Github like autocomplete mentions
  http://ichord.github.com/At.js

  Copyright (c) 2013 chord.luo@gmail.com
  Licensed under the MIT license.
*/


/*
本插件操作 textarea 或者 input 内的插入符
只实现了获得插入符在文本框中的位置，我设置
插入符的位置.
*/


(function() {

  (function(factory) {
    if (typeof exports === 'object') {
      return factory(require('jquery'));
    } else if (typeof define === 'function' && define.amd) {
      return define(['jquery']);
    } else {
      return factory(window.jQuery);
    }
  })(function($) {
    var getCaretPos, setCaretPos;
    getCaretPos = function(inputor) {
      var end, endRange, len, normalizedValue, pos, range, start, textInputRange;
      if (document.selection) {
        /*
                #assume we select "HATE" in the inputor such as textarea -> { }.
                 *               start end-point.
                 *              /
                 * <  I really [HATE] IE   > between the brackets is the selection range.
                 *                   \
                 *                    end end-point.
        */

        range = document.selection.createRange();
        pos = 0;
        if (range && range.parentElement() === inputor) {
          normalizedValue = inputor.value.replace(/\r\n/g, "\n");
          /* SOMETIME !!!
           "/r/n" is counted as two char.
            one line is two, two will be four. balalala.
            so we have to using the normalized one's length.;
          */

          len = normalizedValue.length;
          /*
                       <[  I really HATE IE   ]>:
                        the whole content in the inputor will be the textInputRange.
          */

          textInputRange = inputor.createTextRange();
          /*                 _here must be the position of bookmark.
                           /
             <[  I really [HATE] IE   ]>
              [---------->[           ] : this is what moveToBookmark do.
             <   I really [[HATE] IE   ]> : here is result.
                            \ two brackets in should be in line.
          */

          textInputRange.moveToBookmark(range.getBookmark());
          endRange = inputor.createTextRange();
          /*  [--------------------->[] : if set false all end-point goto end.
            <  I really [[HATE] IE  []]>
          */

          endRange.collapse(false);
          /*
                                    ___VS____
                                   /         \
                     <   I really [[HATE] IE []]>
                                              \_endRange end-point.
          
                    " > -1" mean the start end-point will be the same or right to the end end-point
                   * simplelly, all in the end.
          */

          if (textInputRange.compareEndPoints("StartToEnd", endRange) > -1) {
            start = end = len;
          } else {
            /*
                                I really |HATE] IE   ]>
                                       <-|
                              I really[ [HATE] IE   ]>
                                    <-[
                            I reall[y  [HATE] IE   ]>
            
                          will return how many unit have moved.
            */

            start = -textInputRange.moveStart("character", -len);
            end = -textInputRange.moveEnd("character", -len);
          }
        }
      } else {
        start = inputor.selectionStart;
      }
      return start;
    };
    setCaretPos = function(inputor, pos) {
      var range;
      if (document.selection) {
        range = inputor.createTextRange();
        range.move("character", pos);
        return range.select();
      } else {
        return inputor.setSelectionRange(pos, pos);
      }
    };
    return $.fn.caretPos = function(pos) {
      var inputor;
      inputor = this[0];
      inputor.focus();
      if (pos) {
        return setCaretPos(inputor, pos);
      } else {
        return getCaretPos(inputor);
      }
    };
  });

}).call(this);