frisb/timeously

import pad from './pad';

let moment = require('moment-timezone');

let localOffsetMinutes = -new Date().getTimezoneOffset();

export default class TimeBucket {
    constructor(date) {
        if (!date) {
            date = new Date();
        }
        else if (typeof(date) === 'string') {
            date = new Date(date);
        }
        else {
            date = date;
        }

        this.date = date;
        this._tzOffsetMinutes = -date.getTimezoneOffset();
    }

    static get MonthNames() {
        return ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
    }

    static get DayNames() {
        return ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];
    }

    get offsetString() {
        let tzo = this.tzOffsetMinutes;

        if (tzo === 0) {
            return 'Z';
        }
        else {
            let diff = tzo >= 0 ? '+' : '-';
            return `${diff}${pad(Math.floor(Math.abs(tzo / 60)))}:${pad(Math.abs(tzo % 60))}`;
        }
    }

    tz(timezone) {
        if (!timezone)
            timezone = 'GMT';

        this.tzOffsetMinutes = moment.tz(timezone).utcOffset();
        this.minute += this.tzOffsetMinutes - localOffsetMinutes;
        return this;
    }

    /**
     * returns the different in milliseconds between this and timeBucket date
     * @param timeBucket
     * @returns {number}
   */
    subtract(timeBucket) {
        return this - timeBucket;
    }

    toString(format) {
        if (format) {
            return format
                .replace('yyyy', this.year.toString())
                .replace('yy', this.year.toString().substr(2))
                .replace('MM', pad(this.month + 1))
                .replace('dd', pad(this.day))
                .replace('HH', pad(this.hour))
                .replace('mm', pad(this.minute))
                .replace('ss', pad(this.second))
                .replace('SSS', pad(this.millisecond, 3))
                .replace('Z', this.offsetString);
        }
        else {
            return this.toISOString(true);
        }
    }

    valueOf() {
        return this.date.getTime();
    }

    toUTCDate() {
        let d = new Date(this.date);
        d.setMinutes(d.getMinutes() - this.tzOffsetMinutes + localOffsetMinutes);
        return d;
    }

    toISOString(withTimeZoneOffset) {
        if (withTimeZoneOffset) {
                return this.year
                    + '-' + pad(this.month + 1)
                    + '-' + pad(this.day)
                    + 'T' + pad(this.hour)
                    + ':' + pad(this.minute)
                    + ':' + pad(this.second)
                    + '.' + pad(this.millisecond, 3)
                    + this.offsetString;
        }
        else {
            return this.toUTCDate().toISOString();
        }
    }

    get millisecond() { return this.date.getMilliseconds(); }
    set millisecond(val) { this.date.setMilliseconds(val); }

    get second() { return this.date.getSeconds(); }
    set second(val) { this.date.setSeconds(val); }

    get minute() { return this.date.getMinutes(); }
    set minute(val) { this.date.setMinutes(val); }

    get hour() { return this.date.getHours(); }
    set hour(val) { this.date.setHours(val); }

    get day() { return this.date.getDate(); }
    set day(val) { this.date.setDate(val); }

    get dayOfWeek() { return this.date.getDay(); }
    set dayOfWeek(val) { this.date.setDay(val); }

    get dayName() {
        return TimeBucket.DayNames[this.dayOfWeek];
    }

    get month() { return this.date.getMonth(); }
    set month(val) { this.date.setMonth(val); }

    get monthName() { return TimeBucket.MonthNames[this.month]; }

    get year() { return this.date.getFullYear(); }
    set year(val) { this.date.setFullYear(val); }

    get tzOffsetMinutes() { return this._tzOffsetMinutes; }
    set tzOffsetMinutes(val) { this._tzOffsetMinutes = val; }

    get daysInMonth() {
        return new Date(this.year, this.month + 1, 0).getDate();
    }
}