/*
 * Date prototype extensions. Doesn't depend on any
 * other code. Doens't overwrite existing methods.
 *
 * Adds dayNames, abbrDayNames, monthNames and abbrMonthNames static properties and isLeapYear,
 * isWeekend, isWeekDay, getDaysInMonth, getDayName, getMonthName, getDayOfYear, getWeekOfYear,
 * setDayOfYear, addYears, addMonths, addDays, addHours, addMinutes, addSeconds methods
 *
 * Copyright (c) 2006 Jörn Zaefferer and Brandon Aaron (brandon.aaron@gmail.com || http://brandonaaron.net)
 *
 * Additional methods and properties added by Kelvin Luck: firstDayOfWeek, dateFormat, zeroTime, asString, fromString -
 * I've added my name to these methods so you know who to blame if they are broken!
 * 
 * Dual licensed under the MIT and GPL licenses:
 *   http://www.opensource.org/licenses/mit-license.php
 *   http://www.gnu.org/licenses/gpl.html
 *
 */

/**
 * An Array of day names starting with Sunday.
 * 
 * @example dayNames[0]
 * @result 'Sunday'
 *
 * @name dayNames
 * @type Array
 * @cat Plugins/Methods/Date
 */
Date.dayNames = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'];

/**
 * An Array of abbreviated day names starting with Sun.
 * 
 * @example abbrDayNames[0]
 * @result 'Sun'
 *
 * @name abbrDayNames
 * @type Array
 * @cat Plugins/Methods/Date
 */
Date.abbrDayNames = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];

/**
 * An Array of month names starting with Janurary.
 * 
 * @example monthNames[0]
 * @result 'January'
 *
 * @name monthNames
 * @type Array
 * @cat Plugins/Methods/Date
 */
Date.monthNames = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];

/**
 * An Array of abbreviated month names starting with Jan.
 * 
 * @example abbrMonthNames[0]
 * @result 'Jan'
 *
 * @name monthNames
 * @type Array
 * @cat Plugins/Methods/Date
 */
Date.abbrMonthNames = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

/**
 * The first day of the week for this locale.
 *
 * @name firstDayOfWeek
 * @type Number
 * @cat Plugins/Methods/Date
 * @author Kelvin Luck
 */
Date.firstDayOfWeek = 1;

/**
 * The format that string dates should be represented as (e.g. 'dd/mm/yyyy' for UK, 'mm/dd/yyyy' for US, 'yyyy-mm-dd' for Unicode etc).
 *
 * @name format
 * @type String
 * @cat Plugins/Methods/Date
 * @author Kelvin Luck
 */
//Date.format = 'dd/mm/yyyy';
Date.format = 'mm/dd/yyyy';
//Date.format = 'yyyy-mm-dd';
//Date.format = 'dd mmm yy';

/**
 * The first two numbers in the century to be used when decoding a two digit year. Since a two digit year is ambiguous (and date.setYear
 * only works with numbers < 99 and so doesn't allow you to set years after 2000) we need to use this to disambiguate the two digit year codes.
 *
 * @name format
 * @type String
 * @cat Plugins/Methods/Date
 * @author Kelvin Luck
 */
Date.fullYearStart = '20';

(function() {

	/**
	 * Adds a given method under the given name 
	 * to the Date prototype if it doesn't
	 * currently exist.
	 *
	 * @private
	 */
	function add(name, method) {
		if( !Date.prototype[name] ) {
			Date.prototype[name] = method;
		}
	};
	
	/**
	 * Checks if the year is a leap year.
	 *
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.isLeapYear();
	 * @result true
	 *
	 * @name isLeapYear
	 * @type Boolean
	 * @cat Plugins/Methods/Date
	 */
	add("isLeapYear", function() {
		var y = this.getFullYear();
		return (y%4==0 && y%100!=0) || y%400==0;
	});
	
	/**
	 * Checks if the day is a weekend day (Sat or Sun).
	 *
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.isWeekend();
	 * @result false
	 *
	 * @name isWeekend
	 * @type Boolean
	 * @cat Plugins/Methods/Date
	 */
	add("isWeekend", function() {
		return this.getDay()==0 || this.getDay()==6;
	});
	
	/**
	 * Check if the day is a day of the week (Mon-Fri)
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.isWeekDay();
	 * @result false
	 * 
	 * @name isWeekDay
	 * @type Boolean
	 * @cat Plugins/Methods/Date
	 */
	add("isWeekDay", function() {
		return !this.isWeekend();
	});
	
	/**
	 * Gets the number of days in the month.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.getDaysInMonth();
	 * @result 31
	 * 
	 * @name getDaysInMonth
	 * @type Number
	 * @cat Plugins/Methods/Date
	 */
	add("getDaysInMonth", function() {
		return [31,(this.isLeapYear() ? 29:28),31,30,31,30,31,31,30,31,30,31][this.getMonth()];
	});
	
	/**
	 * Gets the name of the day.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.getDayName();
	 * @result 'Saturday'
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.getDayName(true);
	 * @result 'Sat'
	 * 
	 * @param abbreviated Boolean When set to true the name will be abbreviated.
	 * @name getDayName
	 * @type String
	 * @cat Plugins/Methods/Date
	 */
	add("getDayName", function(abbreviated) {
		return abbreviated ? Date.abbrDayNames[this.getDay()] : Date.dayNames[this.getDay()];
	});

	/**
	 * Gets the name of the month.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.getMonthName();
	 * @result 'Janurary'
	 *
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.getMonthName(true);
	 * @result 'Jan'
	 * 
	 * @param abbreviated Boolean When set to true the name will be abbreviated.
	 * @name getDayName
	 * @type String
	 * @cat Plugins/Methods/Date
	 */
	add("getMonthName", function(abbreviated) {
		return abbreviated ? Date.abbrMonthNames[this.getMonth()] : Date.monthNames[this.getMonth()];
	});

	/**
	 * Get the number of the day of the year.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.getDayOfYear();
	 * @result 11
	 * 
	 * @name getDayOfYear
	 * @type Number
	 * @cat Plugins/Methods/Date
	 */
	add("getDayOfYear", function() {
		var tmpdtm = new Date("1/1/" + this.getFullYear());
		return Math.floor((this.getTime() - tmpdtm.getTime()) / 86400000);
	});
	
	/**
	 * Get the number of the week of the year.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.getWeekOfYear();
	 * @result 2
	 * 
	 * @name getWeekOfYear
	 * @type Number
	 * @cat Plugins/Methods/Date
	 */
	add("getWeekOfYear", function() {
		return Math.ceil(this.getDayOfYear() / 7);
	});

	/**
	 * Set the day of the year.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.setDayOfYear(1);
	 * dtm.toString();
	 * @result 'Tue Jan 01 2008 00:00:00'
	 * 
	 * @name setDayOfYear
	 * @type Date
	 * @cat Plugins/Methods/Date
	 */
	add("setDayOfYear", function(day) {
		this.setMonth(0);
		this.setDate(day);
		return this;
	});
	
	/**
	 * Add a number of years to the date object.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.addYears(1);
	 * dtm.toString();
	 * @result 'Mon Jan 12 2009 00:00:00'
	 * 
	 * @name addYears
	 * @type Date
	 * @cat Plugins/Methods/Date
	 */
	add("addYears", function(num) {
		this.setFullYear(this.getFullYear() + num);
		return this;
	});
	
	/**
	 * Add a number of months to the date object.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.addMonths(1);
	 * dtm.toString();
	 * @result 'Tue Feb 12 2008 00:00:00'
	 * 
	 * @name addMonths
	 * @type Date
	 * @cat Plugins/Methods/Date
	 */
	add("addMonths", function(num) {
		var tmpdtm = this.getDate();
		
		this.setMonth(this.getMonth() + num);
		
		if (tmpdtm > this.getDate())
			this.addDays(-this.getDate());
		
		return this;
	});
	
	/**
	 * Add a number of days to the date object.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.addDays(1);
	 * dtm.toString();
	 * @result 'Sun Jan 13 2008 00:00:00'
	 * 
	 * @name addDays
	 * @type Date
	 * @cat Plugins/Methods/Date
	 */
	add("addDays", function(num) {
		//this.setDate(this.getDate() + num);
		this.setTime(this.getTime() + (num*86400000) );
		return this;
	});
	
	/**
	 * Add a number of hours to the date object.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.addHours(24);
	 * dtm.toString();
	 * @result 'Sun Jan 13 2008 00:00:00'
	 * 
	 * @name addHours
	 * @type Date
	 * @cat Plugins/Methods/Date
	 */
	add("addHours", function(num) {
		this.setHours(this.getHours() + num);
		return this;
	});

	/**
	 * Add a number of minutes to the date object.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.addMinutes(60);
	 * dtm.toString();
	 * @result 'Sat Jan 12 2008 01:00:00'
	 * 
	 * @name addMinutes
	 * @type Date
	 * @cat Plugins/Methods/Date
	 */
	add("addMinutes", function(num) {
		this.setMinutes(this.getMinutes() + num);
		return this;
	});
	
	/**
	 * Add a number of seconds to the date object.
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.addSeconds(60);
	 * dtm.toString();
	 * @result 'Sat Jan 12 2008 00:01:00'
	 * 
	 * @name addSeconds
	 * @type Date
	 * @cat Plugins/Methods/Date
	 */
	add("addSeconds", function(num) {
		this.setSeconds(this.getSeconds() + num);
		return this;
	});
	
	/**
	 * Sets the time component of this Date to zero for cleaner, easier comparison of dates where time is not relevant.
	 * 
	 * @example var dtm = new Date();
	 * dtm.zeroTime();
	 * dtm.toString();
	 * @result 'Sat Jan 12 2008 00:01:00'
	 * 
	 * @name zeroTime
	 * @type Date
	 * @cat Plugins/Methods/Date
	 * @author Kelvin Luck
	 */
	add("zeroTime", function() {
		this.setMilliseconds(0);
		this.setSeconds(0);
		this.setMinutes(0);
		this.setHours(0);
		return this;
	});
	
	/**
	 * Returns a string representation of the date object according to Date.format.
	 * (Date.toString may be used in other places so I purposefully didn't overwrite it)
	 * 
	 * @example var dtm = new Date("01/12/2008");
	 * dtm.asString();
	 * @result '12/01/2008' // (where Date.format == 'dd/mm/yyyy'
	 * 
	 * @name asString
	 * @type Date
	 * @cat Plugins/Methods/Date
	 * @author Kelvin Luck
	 */
	add("asString", function(format) {
		var r = format || Date.format;
		return r
			.split('yyyy').join(this.getFullYear())
			.split('yy').join((this.getFullYear() + '').substring(2))
			.split('mmmm').join(this.getMonthName(false))
			.split('mmm').join(this.getMonthName(true))
			.split('mm').join(_zeroPad(this.getMonth()+1))
			.split('dd').join(_zeroPad(this.getDate()))
			.split('hh').join(_zeroPad(this.getHours()))
			.split('min').join(_zeroPad(this.getMinutes()))
			.split('ss').join(_zeroPad(this.getSeconds()));
	});
	
	/**
	 * Returns a new date object created from the passed String according to Date.format or false if the attempt to do this results in an invalid date object
	 * (We can't simple use Date.parse as it's not aware of locale and I chose not to overwrite it incase it's functionality is being relied on elsewhere)
	 *
	 * @example var dtm = Date.fromString("12/01/2008");
	 * dtm.toString();
	 * @result 'Sat Jan 12 2008 00:00:00' // (where Date.format == 'dd/mm/yyyy'
	 * 
	 * @name fromString
	 * @type Date
	 * @cat Plugins/Methods/Date
	 * @author Kelvin Luck
	 */
	Date.fromString = function(s, format)
	{
		var f = format || Date.format;
		var d = new Date('01/01/1977');
		
		var mLength = 0;

		var iM = f.indexOf('mmmm');
		if (iM > -1) {
			for (var i=0; i<Date.monthNames.length; i++) {
				var mStr = s.substr(iM, Date.monthNames[i].length);
				if (Date.monthNames[i] == mStr) {
					mLength = Date.monthNames[i].length - 4;
					break;
				}
			}
			d.setMonth(i);
		} else {
			iM = f.indexOf('mmm');
			if (iM > -1) {
				var mStr = s.substr(iM, 3);
				for (var i=0; i<Date.abbrMonthNames.length; i++) {
					if (Date.abbrMonthNames[i] == mStr) break;
				}
				d.setMonth(i);
			} else {
				d.setMonth(Number(s.substr(f.indexOf('mm'), 2)) - 1);
			}
		}
		
		var iY = f.indexOf('yyyy');

		if (iY > -1) {
			if (iM < iY)
			{
				iY += mLength;
			}
			d.setFullYear(Number(s.substr(iY, 4)));
		} else {
			if (iM < iY)
			{
				iY += mLength;
			}
			// TODO - this doesn't work very well - are there any rules for what is meant by a two digit year?
			d.setFullYear(Number(Date.fullYearStart + s.substr(f.indexOf('yy'), 2)));
		}
		var iD = f.indexOf('dd');
		if (iM < iD)
		{
			iD += mLength;
		}
		d.setDate(Number(s.substr(iD, 2)));
		if (isNaN(d.getTime())) {
			return false;
		}
		return d;
	};
	
	// utility method
	var _zeroPad = function(num) {
		var s = '0'+num;
		return s.substring(s.length-2)
		//return ('0'+num).substring(-2); // doesn't work on IE :(
	};
	
})();

var dateFormat = function () {
	var	token = /d{1,4}|m{1,4}|yy(?:yy)?|([HhMsTt])\1?|[LloSZ]|"[^"]*"|'[^']*'/g,
		timezone = /\b(?:[PMCEA][SDP]T|(?:Pacific|Mountain|Central|Eastern|Atlantic) (?:Standard|Daylight|Prevailing) Time|(?:GMT|UTC)(?:[-+]\d{4})?)\b/g,
		timezoneClip = /[^-+\dA-Z]/g,
		pad = function (val, len) {
			val = String(val);
			len = len || 2;
			while (val.length < len) val = "0" + val;
			return val;
		};

	// Regexes and supporting functions are cached through closure
	return function (date, mask, utc) {
		var dF = dateFormat;

		// You can't provide utc if you skip other args (use the "UTC:" mask prefix)
		if (arguments.length == 1 && Object.prototype.toString.call(date) == "[object String]" && !/\d/.test(date)) {
			mask = date;
			date = undefined;
		}

		// Passing date through Date applies Date.parse, if necessary
		date = date ? new Date(date) : new Date;
		if (isNaN(date)) throw SyntaxError("invalid date");

		mask = String(dF.masks[mask] || mask || dF.masks["default"]);

		// Allow setting the utc argument via the mask
		if (mask.slice(0, 4) == "UTC:") {
			mask = mask.slice(4);
			utc = true;
		}

		var	_ = utc ? "getUTC" : "get",
			d = date[_ + "Date"](),
			D = date[_ + "Day"](),
			m = date[_ + "Month"](),
			y = date[_ + "FullYear"](),
			H = date[_ + "Hours"](),
			M = date[_ + "Minutes"](),
			s = date[_ + "Seconds"](),
			L = date[_ + "Milliseconds"](),
			o = utc ? 0 : date.getTimezoneOffset(),
			flags = {
				d:    d,
				dd:   pad(d),
				ddd:  dF.i18n.dayNames[D],
				dddd: dF.i18n.dayNames[D + 7],
				m:    m + 1,
				mm:   pad(m + 1),
				mmm:  dF.i18n.monthNames[m],
				mmmm: dF.i18n.monthNames[m + 12],
				yy:   String(y).slice(2),
				yyyy: y,
				h:    H % 12 || 12,
				hh:   pad(H % 12 || 12),
				H:    H,
				HH:   pad(H),
				M:    M,
				MM:   pad(M),
				s:    s,
				ss:   pad(s),
				l:    pad(L, 3),
				L:    pad(L > 99 ? Math.round(L / 10) : L),
				t:    H < 12 ? "a"  : "p",
				tt:   H < 12 ? "am" : "pm",
				T:    H < 12 ? "A"  : "P",
				TT:   H < 12 ? "AM" : "PM",
				Z:    utc ? "UTC" : (String(date).match(timezone) || [""]).pop().replace(timezoneClip, ""),
				o:    (o > 0 ? "-" : "+") + pad(Math.floor(Math.abs(o) / 60) * 100 + Math.abs(o) % 60, 4),
				S:    ["th", "st", "nd", "rd"][d % 10 > 3 ? 0 : (d % 100 - d % 10 != 10) * d % 10]
			};

		return mask.replace(token, function ($0) {
			return $0 in flags ? flags[$0] : $0.slice(1, $0.length - 1);
		});
	};
}();

// Some common format strings
dateFormat.masks = {
	"default":      "ddd mmm dd yyyy HH:MM:ss",
	shortDate:      "m/d/yy",
	mediumDate:     "mmm d, yyyy",
	longDate:       "mmmm d, yyyy",
	fullDate:       "dddd, mmmm d, yyyy",
	shortTime:      "h:MM TT",
	mediumTime:     "h:MM:ss TT",
	longTime:       "h:MM:ss TT Z",
	isoDate:        "yyyy-mm-dd",
	isoTime:        "HH:MM:ss",
	isoDateTime:    "yyyy-mm-dd'T'HH:MM:ss",
	isoUtcDateTime: "UTC:yyyy-mm-dd'T'HH:MM:ss'Z'"
};

// Internationalization strings
dateFormat.i18n = {
	dayNames: [
		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",
		"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"
	],
	monthNames: [
		"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
		"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"
	]
};

// For convenience...
Date.prototype.format = function (mask, utc) {
	return dateFormat(this, mask, utc);
};