Date.js

/*
---

script: Date.js

name: Date

description: Extends the Date native object to include methods useful in managing dates.

license: MIT-style license

authors:
  - Aaron Newton
  - Nicholas Barthelemy - https://svn.nbarthelemy.com/date-js/
  - Harald Kirshner - mail [at] digitarald.de; http://digitarald.de
  - Scott Kyle - scott [at] appden.com; http://appden.com

requires:
  - Core/Array
  - Core/String
  - Core/Number
  - MooTools.More
  - Locale
  - Locale.en-US.Date

provides: [Date]

...
*/

(function(){

var Date = this.Date;

var DateMethods = Date.Methods = {
	ms: 'Milliseconds',
	year: 'FullYear',
	min: 'Minutes',
	mo: 'Month',
	sec: 'Seconds',
	hr: 'Hours'
};

[
	'Date', 'Day', 'FullYear', 'Hours', 'Milliseconds', 'Minutes', 'Month', 'Seconds', 'Time', 'TimezoneOffset',
	'Week', 'Timezone', 'GMTOffset', 'DayOfYear', 'LastMonth', 'LastDayOfMonth', 'UTCDate', 'UTCDay', 'UTCFullYear',
	'AMPM', 'Ordinal', 'UTCHours', 'UTCMilliseconds', 'UTCMinutes', 'UTCMonth', 'UTCSeconds', 'UTCMilliseconds'
].each(function(method){
	Date.Methods[method.toLowerCase()] = method;
});

var pad = function(n, digits, string){
	if (digits == 1) return n;
	return n < Math.pow(10, digits - 1) ? (string || '0') + pad(n, digits - 1, string) : n;
};

Date.implement({

	set: function(prop, value){
		prop = prop.toLowerCase();
		var method = DateMethods[prop] && 'set' + DateMethods[prop];
		if (method && this[method]) this[method](value);
		return this;
	}.overloadSetter(),

	get: function(prop){
		prop = prop.toLowerCase();
		var method = DateMethods[prop] && 'get' + DateMethods[prop];
		if (method && this[method]) return this[method]();
		return null;
	}.overloadGetter(),

	clone: function(){
		return new Date(this.get('time'));
	},

	increment: function(interval, times){
		interval = interval || 'day';
		times = times != null ? times : 1;

		switch (interval){
			case 'year':
				return this.increment('month', times * 12);
			case 'month':
				var d = this.get('date');
				this.set('date', 1).set('mo', this.get('mo') + times);
				return this.set('date', d.min(this.get('lastdayofmonth')));
			case 'week':
				return this.increment('day', times * 7);
			case 'day':
				return this.set('date', this.get('date') + times);
		}

		if (!Date.units[interval]) throw new Error(interval + ' is not a supported interval');

		return this.set('time', this.get('time') + times * Date.units[interval]());
	},

	decrement: function(interval, times){
		return this.increment(interval, -1 * (times != null ? times : 1));
	},

	isLeapYear: function(){
		return Date.isLeapYear(this.get('year'));
	},

	clearTime: function(){
		return this.set({hr: 0, min: 0, sec: 0, ms: 0});
	},

	diff: function(date, resolution){
		if (typeOf(date) == 'string') date = Date.parse(date);

		return ((date - this) / Date.units[resolution || 'day'](3, 3)).round(); // non-leap year, 30-day month
	},

	getLastDayOfMonth: function(){
		return Date.daysInMonth(this.get('mo'), this.get('year'));
	},

	getDayOfYear: function(){
		return (Date.UTC(this.get('year'), this.get('mo'), this.get('date') + 1)
			- Date.UTC(this.get('year'), 0, 1)) / Date.units.day();
	},

	setDay: function(day, firstDayOfWeek){
		if (firstDayOfWeek == null){
			firstDayOfWeek = Date.getMsg('firstDayOfWeek');
			if (firstDayOfWeek === '') firstDayOfWeek = 1;
		}

		day = (7 + Date.parseDay(day, true) - firstDayOfWeek) % 7;
		var currentDay = (7 + this.get('day') - firstDayOfWeek) % 7;

		return this.increment('day', day - currentDay);
	},

	getWeek: function(firstDayOfWeek){
		if (firstDayOfWeek == null){
			firstDayOfWeek = Date.getMsg('firstDayOfWeek');
			if (firstDayOfWeek === '') firstDayOfWeek = 1;
		}

		var date = this,
			dayOfWeek = (7 + date.get('day') - firstDayOfWeek) % 7,
			dividend = 0,
			firstDayOfYear;

		if (firstDayOfWeek == 1){
			// ISO-8601, week belongs to year that has the most days of the week (i.e. has the thursday of the week)
			var month = date.get('month'),
				startOfWeek = date.get('date') - dayOfWeek;

			if (month == 11 && startOfWeek > 28) return 1; // Week 1 of next year

			if (month == 0 && startOfWeek < -2){
				// Use a date from last year to determine the week
				date = new Date(date).decrement('day', dayOfWeek);
				dayOfWeek = 0;
			}

			firstDayOfYear = new Date(date.get('year'), 0, 1).get('day') || 7;
			if (firstDayOfYear > 4) dividend = -7; // First week of the year is not week 1
		} else {
			// In other cultures the first week of the year is always week 1 and the last week always 53 or 54.
			// Days in the same week can have a different weeknumber if the week spreads across two years.
			firstDayOfYear = new Date(date.get('year'), 0, 1).get('day');
		}

		dividend += date.get('dayofyear');
		dividend += 6 - dayOfWeek; // Add days so we calculate the current date's week as a full week
		dividend += (7 + firstDayOfYear - firstDayOfWeek) % 7; // Make up for first week of the year not being a full week

		return (dividend / 7);
	},

	getOrdinal: function(day){
		return Date.getMsg('ordinal', day || this.get('date'));
	},

	getTimezone: function(){
		return this.toString()
			.replace(/^.*? ([A-Z]{3}).[0-9]{4}.*$/, '$1')
			.replace(/^.*?\(([A-Z])[a-z]+ ([A-Z])[a-z]+ ([A-Z])[a-z]+\)$/, '$1$2$3');
	},

	getGMTOffset: function(){
		var off = this.get('timezoneOffset');
		return ((off > 0) ? '-' : '+') + pad((off.abs() / 60).floor(), 2) + pad(off % 60, 2);
	},

	setAMPM: function(ampm){
		ampm = ampm.toUpperCase();
		var hr = this.get('hr');
		if (hr > 11 && ampm == 'AM') return this.decrement('hour', 12);
		else if (hr < 12 && ampm == 'PM') return this.increment('hour', 12);
		return this;
	},

	getAMPM: function(){
		return (this.get('hr') < 12) ? 'AM' : 'PM';
	},

	parse: function(str){
		this.set('time', Date.parse(str));
		return this;
	},

	isValid: function(date){
		if (!date) date = this;
		return typeOf(date) == 'date' && !isNaN(date.valueOf());
	},

	format: function(format){
		if (!this.isValid()) return 'invalid date';

		if (!format) format = '%x %X';
		if (typeof format == 'string') format = formats[format.toLowerCase()] || format;
		if (typeof format == 'function') return format(this);

		var d = this;
		return format.replace(/%([a-z%])/gi,
			function($0, $1){
				switch ($1){
					case 'a': return Date.getMsg('days_abbr')[d.get('day')];
					case 'A': return Date.getMsg('days')[d.get('day')];
					case 'b': return Date.getMsg('months_abbr')[d.get('month')];
					case 'B': return Date.getMsg('months')[d.get('month')];
					case 'c': return d.format('%a %b %d %H:%M:%S %Y');
					case 'd': return pad(d.get('date'), 2);
					case 'e': return pad(d.get('date'), 2, ' ');
					case 'H': return pad(d.get('hr'), 2);
					case 'I': return pad((d.get('hr') % 12) || 12, 2);
					case 'j': return pad(d.get('dayofyear'), 3);
					case 'k': return pad(d.get('hr'), 2, ' ');
					case 'l': return pad((d.get('hr') % 12) || 12, 2, ' ');
					case 'L': return pad(d.get('ms'), 3);
					case 'm': return pad((d.get('mo') + 1), 2);
					case 'M': return pad(d.get('min'), 2);
					case 'o': return d.get('ordinal');
					case 'p': return Date.getMsg(d.get('ampm'));
					case 's': return Math.round(d / 1000);
					case 'S': return pad(d.get('seconds'), 2);
					case 'T': return d.format('%H:%M:%S');
					case 'U': return pad(d.get('week'), 2);
					case 'w': return d.get('day');
					case 'x': return d.format(Date.getMsg('shortDate'));
					case 'X': return d.format(Date.getMsg('shortTime'));
					case 'y': return d.get('year').toString().substr(2);
					case 'Y': return d.get('year');
					case 'z': return d.get('GMTOffset');
					case 'Z': return d.get('Timezone');
				}
				return $1;
			}
		);
	},

	toISOString: function(){
		return this.format('iso8601');
	}

}).alias({
	toJSON: 'toISOString',
	compare: 'diff',
	strftime: 'format'
});

// The day and month abbreviations are standardized, so we cannot use simply %a and %b because they will get localized
var rfcDayAbbr = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'],
	rfcMonthAbbr = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

var formats = {
	db: '%Y-%m-%d %H:%M:%S',
	compact: '%Y%m%dT%H%M%S',
	'short': '%d %b %H:%M',
	'long': '%B %d, %Y %H:%M',
	rfc822: function(date){
		return rfcDayAbbr[date.get('day')] + date.format(', %d ') + rfcMonthAbbr[date.get('month')] + date.format(' %Y %H:%M:%S %Z');
	},
	rfc2822: function(date){
		return rfcDayAbbr[date.get('day')] + date.format(', %d ') + rfcMonthAbbr[date.get('month')] + date.format(' %Y %H:%M:%S %z');
	},
	iso8601: function(date){
		return (
			date.getUTCFullYear() + '-' +
			pad(date.getUTCMonth() + 1, 2) + '-' +
			pad(date.getUTCDate(), 2) + 'T' +
			pad(date.getUTCHours(), 2) + ':' +
			pad(date.getUTCMinutes(), 2) + ':' +
			pad(date.getUTCSeconds(), 2) + '.' +
			pad(date.getUTCMilliseconds(), 3) + 'Z'
		);
	}
};

var parsePatterns = [],
	nativeParse = Date.parse;

var parseWord = function(type, word, num){
	var ret = -1,
		translated = Date.getMsg(type + 's');
	switch (typeOf(word)){
		case 'object':
			ret = translated[word.get(type)];
			break;
		case 'number':
			ret = translated[word];
			if (!ret) throw new Error('Invalid ' + type + ' index: ' + word);
			break;
		case 'string':
			var match = translated.filter(function(name){
				return this.test(name);
			}, new RegExp('^' + word, 'i'));
			if (!match.length) throw new Error('Invalid ' + type + ' string');
			if (match.length > 1) throw new Error('Ambiguous ' + type);
			ret = match[0];
	}

	return (num) ? translated.indexOf(ret) : ret;
};

var startCentury = 1900,
	startYear = 70;

Date.extend({

	getMsg: function(key, args){
		return Locale.get('Date.' + key, args);
	},

	units: {
		ms: Function.convert(1),
		second: Function.convert(1000),
		minute: Function.convert(60000),
		hour: Function.convert(3600000),
		day: Function.convert(86400000),
		week: Function.convert(608400000),
		month: function(month, year){
			var d = new Date;
			return Date.daysInMonth(month != null ? month : d.get('mo'), year != null ? year : d.get('year')) * 86400000;
		},
		year: function(year){
			year = year || new Date().get('year');
			return Date.isLeapYear(year) ? 31622400000 : 31536000000;
		}
	},

	daysInMonth: function(month, year){
		return [31, Date.isLeapYear(year) ? 29 : 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31][month];
	},

	isLeapYear: function(year){
		return ((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0);
	},

	parse: function(from){
		var t = typeOf(from);
		if (t == 'number') return new Date(from);
		if (t != 'string') return from;
		from = from.clean();
		if (!from.length) return null;

		var parsed;
		parsePatterns.some(function(pattern){
			var bits = pattern.re.exec(from);
			return (bits) ? (parsed = pattern.handler(bits)) : false;
		});

		if (!(parsed && parsed.isValid())){
			parsed = new Date(nativeParse(from));
			if (!(parsed && parsed.isValid())) parsed = new Date(from.toInt());
		}
		return parsed;
	},

	parseDay: function(day, num){
		return parseWord('day', day, num);
	},

	parseMonth: function(month, num){
		return parseWord('month', month, num);
	},

	parseUTC: function(value){
		var localDate = new Date(value);
		var utcSeconds = Date.UTC(
			localDate.get('year'),
			localDate.get('mo'),
			localDate.get('date'),
			localDate.get('hr'),
			localDate.get('min'),
			localDate.get('sec'),
			localDate.get('ms')
		);
		return new Date(utcSeconds);
	},

	orderIndex: function(unit){
		return Date.getMsg('dateOrder').indexOf(unit) + 1;
	},

	defineFormat: function(name, format){
		formats[name] = format;
		return this;
	},

	//<1.2compat>
	parsePatterns: parsePatterns,
	//</1.2compat>

	defineParser: function(pattern){
		parsePatterns.push((pattern.re && pattern.handler) ? pattern : build(pattern));
		return this;
	},

	defineParsers: function(){
		Array.flatten(arguments).each(Date.defineParser);
		return this;
	},

	define2DigitYearStart: function(year){
		startYear = year % 100;
		startCentury = year - startYear;
		return this;
	}

}).extend({
	defineFormats: Date.defineFormat.overloadSetter()
});

var regexOf = function(type){
	return new RegExp('(?:' + Date.getMsg(type).map(function(name){
		return name.substr(0, 3);
	}).join('|') + ')[a-z]*');
};

var replacers = function(key){
	switch (key){
		case 'T':
			return '%H:%M:%S';
		case 'x': // iso8601 covers yyyy-mm-dd, so just check if month is first
			return ((Date.orderIndex('month') == 1) ? '%m[-./]%d' : '%d[-./]%m') + '([-./]%y)?';
		case 'X':
			return '%H([.:]%M)?([.:]%S([.:]%s)?)? ?%p? ?%z?';
	}
	return null;
};

var keys = {
	d: /[0-2]?[0-9]|3[01]/,
	H: /[01]?[0-9]|2[0-3]/,
	I: /0?[1-9]|1[0-2]/,
	M: /[0-5]?\d/,
	s: /\d+/,
	o: /[a-z]*/,
	p: /[ap]\.?m\.?/,
	y: /\d{2}|\d{4}/,
	Y: /\d{4}/,
	z: /Z|[+-]\d{2}(?::?\d{2})?/
};

keys.m = keys.I;
keys.S = keys.M;

var currentLanguage;

var recompile = function(language){
	currentLanguage = language;

	keys.a = keys.A = regexOf('days');
	keys.b = keys.B = regexOf('months');

	parsePatterns.each(function(pattern, i){
		if (pattern.format) parsePatterns[i] = build(pattern.format);
	});
};

var build = function(format){
	if (!currentLanguage) return {format: format};

	var parsed = [];
	var re = (format.source || format) // allow format to be regex
	.replace(/%([a-z])/gi,
		function($0, $1){
			return replacers($1) || $0;
		}
	).replace(/\((?!\?)/g, '(?:') // make all groups non-capturing
	.replace(/ (?!\?|\*)/g, ',? ') // be forgiving with spaces and commas
	.replace(/%([a-z%])/gi,
		function($0, $1){
			var p = keys[$1];
			if (!p) return $1;
			parsed.push($1);
			return '(' + p.source + ')';
		}
	).replace(/\[a-z\]/gi, '[a-z\\u00c0-\\uffff;\&]'); // handle unicode words

	return {
		format: format,
		re: new RegExp('^' + re + '$', 'i'),
		handler: function(bits){
			bits = bits.slice(1).associate(parsed);
			var date = new Date().clearTime(),
				year = bits.y || bits.Y;

			if (year != null) handle.call(date, 'y', year); // need to start in the right year
			if ('d' in bits) handle.call(date, 'd', 1);
			if ('m' in bits || bits.b || bits.B) handle.call(date, 'm', 1);

			for (var key in bits) handle.call(date, key, bits[key]);
			return date;
		}
	};
};

var handle = function(key, value){
	if (!value) return this;

	switch (key){
		case 'a': case 'A': return this.set('day', Date.parseDay(value, true));
		case 'b': case 'B': return this.set('mo', Date.parseMonth(value, true));
		case 'd': return this.set('date', value);
		case 'H': case 'I': return this.set('hr', value);
		case 'm': return this.set('mo', value - 1);
		case 'M': return this.set('min', value);
		case 'p': return this.set('ampm', value.replace(/\./g, ''));
		case 'S': return this.set('sec', value);
		case 's': return this.set('ms', ('0.' + value) * 1000);
		case 'w': return this.set('day', value);
		case 'Y': return this.set('year', value);
		case 'y':
			value = +value;
			if (value < 100) value += startCentury + (value < startYear ? 100 : 0);
			return this.set('year', value);
		case 'z':
			if (value == 'Z') value = '+00';
			var offset = value.match(/([+-])(\d{2}):?(\d{2})?/);
			offset = (offset[1] + '1') * (offset[2] * 60 + (+offset[3] || 0)) + this.getTimezoneOffset();
			return this.set('time', this - offset * 60000);
	}

	return this;
};

Date.defineParsers(
	'%Y([-./]%m([-./]%d((T| )%X)?)?)?', // "1999-12-31", "1999-12-31 11:59pm", "1999-12-31 23:59:59", ISO8601
	'%Y%m%d(T%H(%M%S?)?)?', // "19991231", "19991231T1159", compact
	'%x( %X)?', // "12/31", "12.31.99", "12-31-1999", "12/31/2008 11:59 PM"
	'%d%o( %b( %Y)?)?( %X)?', // "31st", "31st December", "31 Dec 1999", "31 Dec 1999 11:59pm"
	'%b( %d%o)?( %Y)?( %X)?', // Same as above with month and day switched
	'%Y %b( %d%o( %X)?)?', // Same as above with year coming first
	'%o %b %d %X %z %Y', // "Thu Oct 22 08:11:23 +0000 2009"
	'%T', // %H:%M:%S
	'%H:%M( ?%p)?' // "11:05pm", "11:05 am" and "11:05"
);

Locale.addEvent('change', function(language){
	if (Locale.get('Date')) recompile(language);
}).fireEvent('change', Locale.getCurrent());

})();