/* http://keith-wood.name/calendars.html
   Calendars for jQuery v2.0.0.
   Written by Keith Wood (kbwood{at}iinet.com.au) August 2009.
   Available under the MIT (https://github.com/jquery/jquery/blob/master/MIT-LICENSE.txt) license. 
   Please attribute the author if you use it. */

(function($) { // Hide scope, no $ conflict

	function Calendars() {
		this.regionalOptions = [];
		this.regionalOptions[''] = {
			invalidCalendar: 'Calendar {0} not found',
			invalidDate: 'Invalid {0} date',
			invalidMonth: 'Invalid {0} month',
			invalidYear: 'Invalid {0} year',
			differentCalendars: 'Cannot mix {0} and {1} dates'
		};
		this.local = this.regionalOptions[''];
		this.calendars = {};
		this._localCals = {};
	}

	/** Create the calendars plugin.
		<p>Provides support for various world calendars in a consistent manner.</p>
	 	@class Calendars
		@example $.calendars.instance('julian').newDate(2014, 12, 25) */
	$.extend(Calendars.prototype, {

		/** Obtain a calendar implementation and localisation.
			@memberof Calendars
			@param [name='gregorian'] {string} The name of the calendar, e.g. 'gregorian', 'persian', 'islamic'.
			@param [language=''] {string} The language code to use for localisation (default is English).
			@return {Calendar} The calendar and localisation.
			@throws Error if calendar not found. */
		instance: function(name, language) {
			name = (name || 'gregorian').toLowerCase();
			language = language || '';
			var cal = this._localCals[name + '-' + language];
			if (!cal && this.calendars[name]) {
				cal = new this.calendars[name](language);
				this._localCals[name + '-' + language] = cal;
			}
			if (!cal) {
				throw (this.local.invalidCalendar || this.regionalOptions[''].invalidCalendar).
					replace(/\{0\}/, name);
			}
			return cal;
		},

		/** Create a new date - for today if no other parameters given.
			@memberof Calendars
			@param year {CDate|number} The date to copy or the year for the date.
			@param [month] {number} The month for the date.
			@param [day] {number} The day for the date.
			@param [calendar='gregorian'] {BaseCalendar|string} The underlying calendar or the name of the calendar.
			@param [language=''] {string} The language to use for localisation (default English).
			@return {CDate} The new date.
			@throws Error if an invalid date. */
		newDate: function(year, month, day, calendar, language) {
			calendar = (year != null && year.year ? year.calendar() : (typeof calendar === 'string' ?
				this.instance(calendar, language) : calendar)) || this.instance();
			return calendar.newDate(year, month, day);
		}
	});

	/** Generic date, based on a particular calendar.
		@class CDate
		@param calendar {BaseCalendar} The underlying calendar implementation.
		@param year {number} The year for this date.
		@param month {number} The month for this date.
		@param day {number} The day for this date.
		@return {CDate} The date object.
		@throws Error if an invalid date. */
	function CDate(calendar, year, month, day) {
		this._calendar = calendar;
		this._year = year;
		this._month = month;
		this._day = day;
		if (this._calendar._validateLevel === 0 &&
				!this._calendar.isValid(this._year, this._month, this._day)) {
			throw ($.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate).
				replace(/\{0\}/, this._calendar.local.name);
		}
	}

	/** Pad a numeric value with leading zeroes.
		@private
		@param value {number} The number to format.
		@param length {number} The minimum length.
		@return {string} The formatted number. */
	function pad(value, length) {
		value = '' + value;
		return '000000'.substring(0, length - value.length) + value;
	}

	$.extend(CDate.prototype, {

		/** Create a new date.
			@memberof CDate
			@param [year] {CDate|number} The date to copy or the year for the date (default this date).
			@param [month] {number} The month for the date.
			@param [day] {number} The day for the date.
			@return {CDate} The new date.
			@throws Error if an invalid date. */
		newDate: function(year, month, day) {
			return this._calendar.newDate((year == null ? this : year), month, day);
		},

		/** Set or retrieve the year for this date.
			@memberof CDate
			@param [year] {number} The year for the date.
			@return {number|CDate} The date's year (if no parameter) or the updated date.
			@throws Error if an invalid date. */
		year: function(year) {
			return (arguments.length === 0 ? this._year : this.set(year, 'y'));
		},

		/** Set or retrieve the month for this date.
			@memberof CDate
			@param [month] {number} The month for the date.
			@return {number|CDate} The date's month (if no parameter) or the updated date.
			@throws Error if an invalid date. */
		month: function(month) {
			return (arguments.length === 0 ? this._month : this.set(month, 'm'));
		},

		/** Set or retrieve the day for this date.
			@memberof CDate
			@param [day] {number} The day for the date.
			@return {number|CData} The date's day (if no parameter) or the updated date.
			@throws Error if an invalid date. */
		day: function(day) {
			return (arguments.length === 0 ? this._day : this.set(day, 'd'));
		},

		/** Set new values for this date.
			@memberof CDate
			@param year {number} The year for the date.
			@param month {number} The month for the date.
			@param day {number} The day for the date.
			@return {CDate} The updated date.
			@throws Error if an invalid date. */
		date: function(year, month, day) {
			if (!this._calendar.isValid(year, month, day)) {
				throw ($.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate).
					replace(/\{0\}/, this._calendar.local.name);
			}
			this._year = year;
			this._month = month;
			this._day = day;
			return this;
		},

		/** Determine whether this date is in a leap year.
			@memberof CDate
			@return {boolean} <code>true</code> if this is a leap year, <code>false</code> if not. */
		leapYear: function() {
			return this._calendar.leapYear(this);
		},

		/** Retrieve the epoch designator for this date, e.g. BCE or CE.
			@memberof CDate
			@return {string} The current epoch. */
		epoch: function() {
			return this._calendar.epoch(this);
		},

		/** Format the year, if not a simple sequential number.
			@memberof CDate
			@return {string} The formatted year. */
		formatYear: function() {
			return this._calendar.formatYear(this);
		},

		/** Retrieve the month of the year for this date,
			i.e. the month's position within a numbered year.
			@memberof CDate
			@return {number} The month of the year: <code>minMonth</code> to months per year. */
		monthOfYear: function() {
			return this._calendar.monthOfYear(this);
		},

		/** Retrieve the week of the year for this date.
			@memberof CDate
			@return {number} The week of the year: 1 to weeks per year. */
		weekOfYear: function() {
			return this._calendar.weekOfYear(this);
		},

		/** Retrieve the number of days in the year for this date.
			@memberof CDate
			@return {number} The number of days in this year. */
		daysInYear: function() {
			return this._calendar.daysInYear(this);
		},

		/** Retrieve the day of the year for this date.
			@memberof CDate
			@return {number} The day of the year: 1 to days per year. */
		dayOfYear: function() {
			return this._calendar.dayOfYear(this);
		},

		/** Retrieve the number of days in the month for this date.
			@memberof CDate
			@return {number} The number of days. */
		daysInMonth: function() {
			return this._calendar.daysInMonth(this);
		},

		/** Retrieve the day of the week for this date.
			@memberof CDate
			@return {number} The day of the week: 0 to number of days - 1. */
		dayOfWeek: function() {
			return this._calendar.dayOfWeek(this);
		},

		/** Determine whether this date is a week day.
			@memberof CDate
			@return {boolean} <code>true</code> if a week day, <code>false</code> if not. */
		weekDay: function() {
			return this._calendar.weekDay(this);
		},

		/** Retrieve additional information about this date.
			@memberof CDate
			@return {object} Additional information - contents depends on calendar. */
		extraInfo: function() {
			return this._calendar.extraInfo(this);
		},

		/** Add period(s) to a date.
			@memberof CDate
			@param offset {number} The number of periods to adjust by.
			@param period {string} One of 'y' for year, 'm' for month, 'w' for week, 'd' for day.
			@return {CDate} The updated date. */
		add: function(offset, period) {
			return this._calendar.add(this, offset, period);
		},

		/** Set a portion of the date.
			@memberof CDate
			@param value {number} The new value for the period.
			@param period {string} One of 'y' for year, 'm' for month, 'd' for day.
			@return {CDate} The updated date.
			@throws Error if not a valid date. */
		set: function(value, period) {
			return this._calendar.set(this, value, period);
		},

		/** Compare this date to another date.
			@memberof CDate
			@param date {CDate} The other date.
			@return {number} -1 if this date is before the other date,
					0 if they are equal, or +1 if this date is after the other date. */
		compareTo: function(date) {
			if (this._calendar.name !== date._calendar.name) {
				throw ($.calendars.local.differentCalendars || $.calendars.regionalOptions[''].differentCalendars).
					replace(/\{0\}/, this._calendar.local.name).replace(/\{1\}/, date._calendar.local.name);
			}
			var c = (this._year !== date._year ? this._year - date._year :
				this._month !== date._month ? this.monthOfYear() - date.monthOfYear() :
				this._day - date._day);
			return (c === 0 ? 0 : (c < 0 ? -1 : +1));
		},

		/** Retrieve the calendar backing this date.
			@memberof CDate
			@return {BaseCalendar} The calendar implementation. */
		calendar: function() {
			return this._calendar;
		},

		/** Retrieve the Julian date equivalent for this date,
			i.e. days since January 1, 4713 BCE Greenwich noon.
			@memberof CDate
			@return {number} The equivalent Julian date. */
		toJD: function() {
			return this._calendar.toJD(this);
		},

		/** Create a new date from a Julian date.
			@memberof CDate
			@param jd {number} The Julian date to convert.
			@return {CDate} The equivalent date. */
		fromJD: function(jd) {
			return this._calendar.fromJD(jd);
		},

		/** Convert this date to a standard (Gregorian) JavaScript Date.
			@memberof CDate
			@return {Date} The equivalent JavaScript date. */
		toJSDate: function() {
			return this._calendar.toJSDate(this);
		},

		/** Create a new date from a standard (Gregorian) JavaScript Date.
			@memberof CDate
			@param jsd {Date} The JavaScript date to convert.
			@return {CDate} The equivalent date. */
		fromJSDate: function(jsd) {
			return this._calendar.fromJSDate(jsd);
		},

		/** Convert to a string for display.
			@memberof CDate
			@return {string} This date as a string. */
		toString: function() {
			return (this.year() < 0 ? '-' : '') + pad(Math.abs(this.year()), 4) +
				'-' + pad(this.month(), 2) + '-' + pad(this.day(), 2);
		}
	});

	/** Basic functionality for all calendars.
		Other calendars should extend this:
		<pre>OtherCalendar.prototype = new BaseCalendar;</pre>
		@class BaseCalendar */
	function BaseCalendar() {
		this.shortYearCutoff = '+10';
	}

	$.extend(BaseCalendar.prototype, {
		_validateLevel: 0, // "Stack" to turn validation on/off

		/** Create a new date within this calendar - today if no parameters given.
			@memberof BaseCalendar
			@param year {CDate|number} The date to duplicate or the year for the date.
			@param [month] {number} The month for the date.
			@param [day] {number} The day for the date.
			@return {CDate} The new date.
			@throws Error if not a valid date or a different calendar used. */
		newDate: function(year, month, day) {
			if (year == null) {
				return this.today();
			}
			if (year.year) {
				this._validate(year, month, day,
					$.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate);
				day = year.day();
				month = year.month();
				year = year.year();
			}
			return new CDate(this, year, month, day);
		},

		/** Create a new date for today.
			@memberof BaseCalendar
			@return {CDate} Today's date. */
		today: function() {
			return this.fromJSDate(new Date());
		},

		/** Retrieve the epoch designator for this date.
			@memberof BaseCalendar
			@param year {CDate|number} The date to examine or the year to examine.
			@return {string} The current epoch.
			@throws Error if an invalid year or a different calendar used. */
		epoch: function(year) {
			var date = this._validate(year, this.minMonth, this.minDay,
				$.calendars.local.invalidYear || $.calendars.regionalOptions[''].invalidYear);
			return (date.year() < 0 ? this.local.epochs[0] : this.local.epochs[1]);
		},

		/** Format the year, if not a simple sequential number
			@memberof BaseCalendar
			@param year {CDate|number} The date to format or the year to format.
			@return {string} The formatted year.
			@throws Error if an invalid year or a different calendar used. */
		formatYear: function(year) {
			var date = this._validate(year, this.minMonth, this.minDay,
				$.calendars.local.invalidYear || $.calendars.regionalOptions[''].invalidYear);
			return (date.year() < 0 ? '-' : '') + pad(Math.abs(date.year()), 4)
		},

		/** Retrieve the number of months in a year.
			@memberof BaseCalendar
			@param year {CDate|number} The date to examine or the year to examine.
			@return {number} The number of months.
			@throws Error if an invalid year or a different calendar used. */
		monthsInYear: function(year) {
			this._validate(year, this.minMonth, this.minDay,
				$.calendars.local.invalidYear || $.calendars.regionalOptions[''].invalidYear);
			return 12;
		},

		/** Calculate the month's ordinal position within the year -
			for those calendars that don't start at month 1!
			@memberof BaseCalendar
			@param year {CDate|number} The date to examine or the year to examine.
			@param month {number} The month to examine.
			@return {number} The ordinal position, starting from <code>minMonth</code>.
			@throws Error if an invalid year/month or a different calendar used. */
		monthOfYear: function(year, month) {
			var date = this._validate(year, month, this.minDay,
				$.calendars.local.invalidMonth || $.calendars.regionalOptions[''].invalidMonth);
			return (date.month() + this.monthsInYear(date) - this.firstMonth) %
				this.monthsInYear(date) + this.minMonth;
		},

		/** Calculate actual month from ordinal position, starting from minMonth.
			@memberof BaseCalendar
			@param year {number} The year to examine.
			@param ord {number} The month's ordinal position.
			@return {number} The month's number.
			@throws Error if an invalid year/month. */
		fromMonthOfYear: function(year, ord) {
			var m = (ord + this.firstMonth - 2 * this.minMonth) %
				this.monthsInYear(year) + this.minMonth;
			this._validate(year, m, this.minDay,
				$.calendars.local.invalidMonth || $.calendars.regionalOptions[''].invalidMonth);
			return m;
		},

		/** Retrieve the number of days in a year.
			@memberof BaseCalendar
			@param year {CDate|number} The date to examine or the year to examine.
			@return {number} The number of days.
			@throws Error if an invalid year or a different calendar used. */
		daysInYear: function(year) {
			var date = this._validate(year, this.minMonth, this.minDay,
				$.calendars.local.invalidYear || $.calendars.regionalOptions[''].invalidYear);
			return (this.leapYear(date) ? 366 : 365);
		},

		/** Retrieve the day of the year for a date.
			@memberof BaseCalendar
			@param year {CDate|number} The date to convert or the year to convert.
			@param [month] {number} The month to convert.
			@param [day] {number} The day to convert.
			@return {number} The day of the year.
			@throws Error if an invalid date or a different calendar used. */
		dayOfYear: function(year, month, day) {
			var date = this._validate(year, month, day,
				$.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate);
			return date.toJD() - this.newDate(date.year(),
				this.fromMonthOfYear(date.year(), this.minMonth), this.minDay).toJD() + 1;
		},

		/** Retrieve the number of days in a week.
			@memberof BaseCalendar
			@return {number} The number of days. */
		daysInWeek: function() {
			return 7;
		},

		/** Retrieve the day of the week for a date.
			@memberof BaseCalendar
			@param year {CDate|number} The date to examine or the year to examine.
			@param [month] {number} The month to examine.
			@param [day] {number} The day to examine.
			@return {number} The day of the week: 0 to number of days - 1.
			@throws Error if an invalid date or a different calendar used. */
		dayOfWeek: function(year, month, day) {
			var date = this._validate(year, month, day,
				$.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate);
			return (Math.floor(this.toJD(date)) + 2) % this.daysInWeek();
		},

		/** Retrieve additional information about a date.
			@memberof BaseCalendar
			@param year {CDate|number} The date to examine or the year to examine.
			@param [month] {number} The month to examine.
			@param [day] {number} The day to examine.
			@return {object} Additional information - contents depends on calendar.
			@throws Error if an invalid date or a different calendar used. */
		extraInfo: function(year, month, day) {
			this._validate(year, month, day,
				$.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate);
			return {};
		},

		/** Add period(s) to a date.
			Cater for no year zero.
			@memberof BaseCalendar
			@param date {CDate} The starting date.
			@param offset {number} The number of periods to adjust by.
			@param period {string} One of 'y' for year, 'm' for month, 'w' for week, 'd' for day.
			@return {CDate} The updated date.
			@throws Error if a different calendar used. */
		add: function(date, offset, period) {
			this._validate(date, this.minMonth, this.minDay,
				$.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate);
			return this._correctAdd(date, this._add(date, offset, period), offset, period);
		},

		/** Add period(s) to a date.
			@memberof BaseCalendar
			@private
			@param date {CDate} The starting date.
			@param offset {number} The number of periods to adjust by.
			@param period {string} One of 'y' for year, 'm' for month, 'w' for week, 'd' for day.
			@return {CDate} The updated date. */
		_add: function(date, offset, period) {
			this._validateLevel++;
			if (period === 'd' || period === 'w') {
				var jd = date.toJD() + offset * (period === 'w' ? this.daysInWeek() : 1);
				var d = date.calendar().fromJD(jd);
				this._validateLevel--;
				return [d.year(), d.month(), d.day()];
			}
			try {
				var y = date.year() + (period === 'y' ? offset : 0);
				var m = date.monthOfYear() + (period === 'm' ? offset : 0);
				var d = date.day();// + (period === 'd' ? offset : 0) +
					//(period === 'w' ? offset * this.daysInWeek() : 0);
				var resyncYearMonth = function(calendar) {
					while (m < calendar.minMonth) {
						y--;
						m += calendar.monthsInYear(y);
					}
					var yearMonths = calendar.monthsInYear(y);
					while (m > yearMonths - 1 + calendar.minMonth) {
						y++;
						m -= yearMonths;
						yearMonths = calendar.monthsInYear(y);
					}
				};
				if (period === 'y') {
					if (date.month() !== this.fromMonthOfYear(y, m)) { // Hebrew
						m = this.newDate(y, date.month(), this.minDay).monthOfYear();
					}
					m = Math.min(m, this.monthsInYear(y));
					d = Math.min(d, this.daysInMonth(y, this.fromMonthOfYear(y, m)));
				}
				else if (period === 'm') {
					resyncYearMonth(this);
					d = Math.min(d, this.daysInMonth(y, this.fromMonthOfYear(y, m)));
				}
				var ymd = [y, this.fromMonthOfYear(y, m), d];
				this._validateLevel--;
				return ymd;
			}
			catch (e) {
				this._validateLevel--;
				throw e;
			}
		},

		/** Correct a candidate date after adding period(s) to a date.
			Handle no year zero if necessary.
			@memberof BaseCalendar
			@private
			@param date {CDate} The starting date.
			@param ymd {number[]} The added date.
			@param offset {number} The number of periods to adjust by.
			@param period {string} One of 'y' for year, 'm' for month, 'w' for week, 'd' for day.
			@return {CDate} The updated date. */
		_correctAdd: function(date, ymd, offset, period) {
			if (!this.hasYearZero && (period === 'y' || period === 'm')) {
				if (ymd[0] === 0 || // In year zero
						(date.year() > 0) !== (ymd[0] > 0)) { // Crossed year zero
					var adj = {y: [1, 1, 'y'], m: [1, this.monthsInYear(-1), 'm'],
						w: [this.daysInWeek(), this.daysInYear(-1), 'd'],
						d: [1, this.daysInYear(-1), 'd']}[period];
					var dir = (offset < 0 ? -1 : +1);
					ymd = this._add(date, offset * adj[0] + dir * adj[1], adj[2]);
				}
			}
			return date.date(ymd[0], ymd[1], ymd[2]);
		},

		/** Set a portion of the date.
			@memberof BaseCalendar
			@param date {CDate} The starting date.
			@param value {number} The new value for the period.
			@param period {string} One of 'y' for year, 'm' for month, 'd' for day.
			@return {CDate} The updated date.
			@throws Error if an invalid date or a different calendar used. */
		set: function(date, value, period) {
			this._validate(date, this.minMonth, this.minDay,
				$.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate);
			var y = (period === 'y' ? value : date.year());
			var m = (period === 'm' ? value : date.month());
			var d = (period === 'd' ? value : date.day());
			if (period === 'y' || period === 'm') {
				d = Math.min(d, this.daysInMonth(y, m));
			}
			return date.date(y, m, d);
		},

		/** Determine whether a date is valid for this calendar.
			@memberof BaseCalendar
			@param year {number} The year to examine.
			@param month {number} The month to examine.
			@param day {number} The day to examine.
			@return {boolean} <code>true</code> if a valid date, <code>false</code> if not. */
		isValid: function(year, month, day) {
			this._validateLevel++;
			var valid = (this.hasYearZero || year !== 0);
			if (valid) {
				var date = this.newDate(year, month, this.minDay);
				valid = (month >= this.minMonth && month - this.minMonth < this.monthsInYear(date)) &&
					(day >= this.minDay && day - this.minDay < this.daysInMonth(date));
			}
			this._validateLevel--;
			return valid;
		},

		/** Convert the date to a standard (Gregorian) JavaScript Date.
			@memberof BaseCalendar
			@param year {CDate|number} The date to convert or the year to convert.
			@param [month] {number} The month to convert.
			@param [day] {number} The day to convert.
			@return {Date} The equivalent JavaScript date.
			@throws Error if an invalid date or a different calendar used. */
		toJSDate: function(year, month, day) {
			var date = this._validate(year, month, day,
				$.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate);
			return $.calendars.instance().fromJD(this.toJD(date)).toJSDate();
		},

		/** Convert the date from a standard (Gregorian) JavaScript Date.
			@memberof BaseCalendar
			@param jsd {Date} The JavaScript date.
			@return {CDate} The equivalent calendar date. */
		fromJSDate: function(jsd) {
			return this.fromJD($.calendars.instance().fromJSDate(jsd).toJD());
		},

		/** Check that a candidate date is from the same calendar and is valid.
			@memberof BaseCalendar
			@private
			@param year {CDate|number} The date to validate or the year to validate.
			@param [month] {number} The month to validate.
			@param [day] {number} The day to validate.
			@param error {string} Rrror message if invalid.
			@throws Error if different calendars used or invalid date. */
		_validate: function(year, month, day, error) {
			if (year.year) {
				if (this._validateLevel === 0 && this.name !== year.calendar().name) {
					throw ($.calendars.local.differentCalendars || $.calendars.regionalOptions[''].differentCalendars).
						replace(/\{0\}/, this.local.name).replace(/\{1\}/, year.calendar().local.name);
				}
				return year;
			}
			try {
				this._validateLevel++;
				if (this._validateLevel === 1 && !this.isValid(year, month, day)) {
					throw error.replace(/\{0\}/, this.local.name);
				}
				var date = this.newDate(year, month, day);
				this._validateLevel--;
				return date;
			}
			catch (e) {
				this._validateLevel--;
				throw e;
			}
		}
	});

	/** Implementation of the Proleptic Gregorian Calendar.
		See <a href=":http://en.wikipedia.org/wiki/Gregorian_calendar">http://en.wikipedia.org/wiki/Gregorian_calendar</a>
		and <a href="http://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar">http://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar</a>.
		@class GregorianCalendar
		@augments BaseCalendar
		@param [language=''] {string} The language code (default English) for localisation. */
	function GregorianCalendar(language) {
		this.local = this.regionalOptions[language] || this.regionalOptions[''];
	}

	GregorianCalendar.prototype = new BaseCalendar;

	$.extend(GregorianCalendar.prototype, {
		/** The calendar name.
			@memberof GregorianCalendar */
		name: 'Gregorian',
		 /** Julian date of start of Gregorian epoch: 1 January 0001 CE.
			@memberof GregorianCalendar */
		jdEpoch: 1721425.5,
		 /** Days per month in a common year.
			@memberof GregorianCalendar */
		daysPerMonth: [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31],
		 /** <code>true</code> if has a year zero, <code>false</code> if not.
			@memberof GregorianCalendar */
		hasYearZero: false,
		/** The minimum month number.
			@memberof GregorianCalendar */
		minMonth: 1,
		/** The first month in the year.
			@memberof GregorianCalendar */
		firstMonth: 1,
		 /** The minimum day number.
			@memberof GregorianCalendar */
		minDay: 1,

		/** Localisations for the plugin.
			Entries are objects indexed by the language code ('' being the default US/English).
			Each object has the following attributes.
			@memberof GregorianCalendar
			@property name {string} The calendar name.
			@property epochs {string[]} The epoch names.
			@property monthNames {string[]} The long names of the months of the year.
			@property monthNamesShort {string[]} The short names of the months of the year.
			@property dayNames {string[]} The long names of the days of the week.
			@property dayNamesShort {string[]} The short names of the days of the week.
			@property dayNamesMin {string[]} The minimal names of the days of the week.
			@property dateFormat {string} The date format for this calendar.
					See the options on <a href="BaseCalendar.html#formatDate"><code>formatDate</code></a> for details.
			@property firstDay {number} The number of the first day of the week, starting at 0.
			@property isRTL {number} <code>true</code> if this localisation reads right-to-left. */
		regionalOptions: { // Localisations
			'': {
				name: 'Gregorian',
				epochs: ['BCE', 'CE'],
				monthNames: ['January', 'February', 'March', 'April', 'May', 'June',
				'July', 'August', 'September', 'October', 'November', 'December'],
				monthNamesShort: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'],
				dayNames: ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'],
				dayNamesShort: ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'],
				dayNamesMin: ['Su', 'Mo', 'Tu', 'We', 'Th', 'Fr', 'Sa'],
				dateFormat: 'dd-mm-yyyy',
				firstDay: 0,
				isRTL: false
			}
		},
		
		/** Determine whether this date is in a leap year.
			@memberof GregorianCalendar
			@param year {CDate|number} The date to examine or the year to examine.
			@return {boolean} <code>true</code> if this is a leap year, <code>false</code> if not.
			@throws Error if an invalid year or a different calendar used. */
		leapYear: function(year) {
			var date = this._validate(year, this.minMonth, this.minDay,
				$.calendars.local.invalidYear || $.calendars.regionalOptions[''].invalidYear);
			var year = date.year() + (date.year() < 0 ? 1 : 0); // No year zero
			return year % 4 === 0 && (year % 100 !== 0 || year % 400 === 0);
		},

		/** Determine the week of the year for a date - ISO 8601.
			@memberof GregorianCalendar
			@param year {CDate|number} The date to examine or the year to examine.
			@param [month] {number} The month to examine.
			@param [day] {number} The day to examine.
			@return {number} The week of the year, starting from 1.
			@throws Error if an invalid date or a different calendar used. */
		weekOfYear: function(year, month, day) {
			// Find Thursday of this week starting on Monday
			var checkDate = this.newDate(year, month, day);
			checkDate.add(4 - (checkDate.dayOfWeek() || 7), 'd');
			return Math.floor((checkDate.dayOfYear() - 1) / 7) + 1;
		},

		/** Retrieve the number of days in a month.
			@memberof GregorianCalendar
			@param year {CDate|number} The date to examine or the year of the month.
			@param [month] {number} The month.
			@return {number} The number of days in this month.
			@throws Error if an invalid month/year or a different calendar used. */
		daysInMonth: function(year, month) {
			var date = this._validate(year, month, this.minDay,
				$.calendars.local.invalidMonth || $.calendars.regionalOptions[''].invalidMonth);
			return this.daysPerMonth[date.month() - 1] +
				(date.month() === 2 && this.leapYear(date.year()) ? 1 : 0);
		},

		/** Determine whether this date is a week day.
			@memberof GregorianCalendar
			@param year {CDate|number} The date to examine or the year to examine.
			@param [month] {number} The month to examine.
			@param [day] {number} The day to examine.
			@return {boolean} <code>true</code> if a week day, <code>false</code> if not.
			@throws Error if an invalid date or a different calendar used. */
		weekDay: function(year, month, day) {
			return (this.dayOfWeek(year, month, day) || 7) < 6;
		},

		/** Retrieve the Julian date equivalent for this date,
			i.e. days since January 1, 4713 BCE Greenwich noon.
			@memberof GregorianCalendar
			@param year {CDate|number} The date to convert or the year to convert.
			@param [month] {number} The month to convert.
			@param [day] {number} The day to convert.
			@return {number} The equivalent Julian date.
			@throws Error if an invalid date or a different calendar used. */
		toJD: function(year, month, day) {
			var date = this._validate(year, month, day,
				$.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate);
			year = date.year();
			month = date.month();
			day = date.day();
			if (year < 0) { year++; } // No year zero
			// Jean Meeus algorithm, "Astronomical Algorithms", 1991
			if (month < 3) {
				month += 12;
				year--;
			}
			var a = Math.floor(year / 100);
			var b = 2 - a + Math.floor(a / 4);
			return Math.floor(365.25 * (year + 4716)) +
				Math.floor(30.6001 * (month + 1)) + day + b - 1524.5;
		},

		/** Create a new date from a Julian date.
			@memberof GregorianCalendar
			@param jd {number} The Julian date to convert.
			@return {CDate} The equivalent date. */
		fromJD: function(jd) {
			// Jean Meeus algorithm, "Astronomical Algorithms", 1991
			var z = Math.floor(jd + 0.5);
			var a = Math.floor((z - 1867216.25) / 36524.25);
			a = z + 1 + a - Math.floor(a / 4);
			var b = a + 1524;
			var c = Math.floor((b - 122.1) / 365.25);
			var d = Math.floor(365.25 * c);
			var e = Math.floor((b - d) / 30.6001);
			var day = b - d - Math.floor(e * 30.6001);
			var month = e - (e > 13.5 ? 13 : 1);
			var year = c - (month > 2.5 ? 4716 : 4715);
			if (year <= 0) { year--; } // No year zero
			return this.newDate(year, month, day);
		},

		/** Convert this date to a standard (Gregorian) JavaScript Date.
			@memberof GregorianCalendar
			@param year {CDate|number} The date to convert or the year to convert.
			@param [month] {number} The month to convert.
			@param [day] {number} The day to convert.
			@return {Date} The equivalent JavaScript date.
			@throws Error if an invalid date or a different calendar used. */
		toJSDate: function(year, month, day) {
			var date = this._validate(year, month, day,
				$.calendars.local.invalidDate || $.calendars.regionalOptions[''].invalidDate);
			var jsd = new Date(date.year(), date.month() - 1, date.day());
			jsd.setHours(0);
			jsd.setMinutes(0);
			jsd.setSeconds(0);
			jsd.setMilliseconds(0);
			// Hours may be non-zero on daylight saving cut-over:
			// > 12 when midnight changeover, but then cannot generate
			// midnight datetime, so jump to 1AM, otherwise reset.
			jsd.setHours(jsd.getHours() > 12 ? jsd.getHours() + 2 : 0);
			return jsd;
		},

		/** Create a new date from a standard (Gregorian) JavaScript Date.
			@memberof GregorianCalendar
			@param jsd {Date} The JavaScript date to convert.
			@return {CDate} The equivalent date. */
		fromJSDate: function(jsd) {
			return this.newDate(jsd.getFullYear(), jsd.getMonth() + 1, jsd.getDate());
		}
	});

	// Singleton manager
	$.calendars = new Calendars();

	// Date template
	$.calendars.cdate = CDate;

	// Base calendar template
	$.calendars.baseCalendar = BaseCalendar;

	// Gregorian calendar implementation
	$.calendars.calendars.gregorian = GregorianCalendar;

})(jQuery);
