/*
 * World Calendars
 * https://github.com/alexcjohnson/world-calendars
 *
 * Batch-converted from kbwood/calendars
 * Many thanks to Keith Wood and all of the contributors to the original project!
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

/* http://keith-wood.name/calendars.html
   Mayan calendar for jQuery v2.0.2.
   Written by Keith Wood (wood.keith{at}optusnet.com.au) August 2009.
   Available under the MIT (http://keith-wood.name/licence.html) license. 
   Please attribute the author if you use it. */

var main = require('../main');
var assign = require('object-assign');


/** Implementation of the Mayan Long Count calendar.
    See also <a href="http://en.wikipedia.org/wiki/Mayan_calendar">http://en.wikipedia.org/wiki/Mayan_calendar</a>.
    @class MayanCalendar
    @param [language=''] {string} The language code (default English) for localisation. */
function MayanCalendar(language) {
    this.local = this.regionalOptions[language || ''] || this.regionalOptions[''];
}

MayanCalendar.prototype = new main.baseCalendar;

assign(MayanCalendar.prototype, {
    /** The calendar name.
        @memberof MayanCalendar */
    name: 'Mayan',
    /** Julian date of start of Mayan epoch: 11 August 3114 BCE.
        @memberof MayanCalendar */
    jdEpoch: 584282.5,
    /** <code>true</code> if has a year zero, <code>false</code> if not.
        @memberof MayanCalendar */
    hasYearZero: true,
    /** The minimum month number.
        @memberof MayanCalendar */
    minMonth: 0,
    /** The first month in the year.
        @memberof MayanCalendar */
    firstMonth: 0,
    /** The minimum day number.
        @memberof MayanCalendar */
    minDay: 0,

    /** Localisations for the plugin.
        Entries are objects indexed by the language code ('' being the default US/English).
        Each object has the following attributes.
        @memberof MayanCalendar
        @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.
        @property haabMonths {string[]} The names of the Haab months.
        @property tzolkinMonths {string[]} The names of the Tzolkin months. */
    regionalOptions: { // Localisations
        '': {
            name: 'Mayan',
            epochs: ['', ''],
            monthNames: ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
            '10', '11', '12', '13', '14', '15', '16', '17'],
            monthNamesShort: ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
            '10', '11', '12', '13', '14', '15', '16', '17'],
            dayNames: ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
            '10', '11', '12', '13', '14', '15', '16', '17', '18', '19'],
            dayNamesShort: ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
            '10', '11', '12', '13', '14', '15', '16', '17', '18', '19'],
            dayNamesMin: ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
            '10', '11', '12', '13', '14', '15', '16', '17', '18', '19'],
            digits: null,
            dateFormat: 'YYYY.m.d',
            firstDay: 0,
            isRTL: false,
            haabMonths: ['Pop', 'Uo', 'Zip', 'Zotz', 'Tzec', 'Xul', 'Yaxkin', 'Mol', 'Chen', 'Yax',
            'Zac', 'Ceh', 'Mac', 'Kankin', 'Muan', 'Pax', 'Kayab', 'Cumku', 'Uayeb'],
            tzolkinMonths: ['Imix', 'Ik', 'Akbal', 'Kan', 'Chicchan', 'Cimi', 'Manik', 'Lamat', 'Muluc', 'Oc',
            'Chuen', 'Eb', 'Ben', 'Ix', 'Men', 'Cib', 'Caban', 'Etznab', 'Cauac', 'Ahau']
        }
    },

    /** Determine whether this date is in a leap year.
        @memberof MayanCalendar
        @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) {
        this._validate(year, this.minMonth, this.minDay, main.local.invalidYear);
        return false;
    },

    /** Format the year, if not a simple sequential number.
        @memberof MayanCalendar
        @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, main.local.invalidYear);
        year = date.year();
        var baktun = Math.floor(year / 400);
        year = year % 400;
        year += (year < 0 ? 400 : 0);
        var katun = Math.floor(year / 20);
        return baktun + '.' + katun + '.' + (year % 20);
    },

    /** Convert from the formatted year back to a single number.
        @memberof MayanCalendar
        @param years {string} The year as n.n.n.
        @return {number} The sequential year.
        @throws Error if an invalid value is supplied. */
    forYear: function(years) {
        years = years.split('.');
        if (years.length < 3) {
            throw 'Invalid Mayan year';
        }
        var year = 0;
        for (var i = 0; i < years.length; i++) {
            var y = parseInt(years[i], 10);
            if (Math.abs(y) > 19 || (i > 0 && y < 0)) {
                throw 'Invalid Mayan year';
            }
            year = year * 20 + y;
        }
        return year;
    },

    /** Retrieve the number of months in a year.
        @memberof MayanCalendar
        @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, main.local.invalidYear);
        return 18;
    },

    /** Determine the week of the year for a date.
        @memberof MayanCalendar
        @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.
        @throws Error if an invalid date or a different calendar used. */
    weekOfYear: function(year, month, day) {
        this._validate(year, month, day, main.local.invalidDate);
        return 0;
    },

    /** Retrieve the number of days in a year.
        @memberof MayanCalendar
        @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) {
        this._validate(year, this.minMonth, this.minDay, main.local.invalidYear);
        return 360;
    },

    /** Retrieve the number of days in a month.
        @memberof MayanCalendar
        @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) {
        this._validate(year, month, this.minDay, main.local.invalidMonth);
        return 20;
    },

    /** Retrieve the number of days in a week.
        @memberof MayanCalendar
        @return {number} The number of days. */
    daysInWeek: function() {
        return 5; // Just for formatting
    },

    /** Retrieve the day of the week for a date.
        @memberof MayanCalendar
        @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, main.local.invalidDate);
        return date.day();
    },

    /** Determine whether this date is a week day.
        @memberof MayanCalendar
        @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) {
        this._validate(year, month, day, main.local.invalidDate);
        return true;
    },

    /** Retrieve additional information about a date - Haab and Tzolkin equivalents.
        @memberof MayanCalendar
        @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) {
        var date = this._validate(year, month, day, main.local.invalidDate);
        var jd = date.toJD();
        var haab = this._toHaab(jd);
        var tzolkin = this._toTzolkin(jd);
        return {haabMonthName: this.local.haabMonths[haab[0] - 1],
            haabMonth: haab[0], haabDay: haab[1],
            tzolkinDayName: this.local.tzolkinMonths[tzolkin[0] - 1],
            tzolkinDay: tzolkin[0], tzolkinTrecena: tzolkin[1]};
    },

    /** Retrieve Haab date from a Julian date.
        @memberof MayanCalendar
        @private
        @param jd  {number} The Julian date.
        @return {number[]} Corresponding Haab month and day. */
    _toHaab: function(jd) {
        jd -= this.jdEpoch;
        var day = mod(jd + 8 + ((18 - 1) * 20), 365);
        return [Math.floor(day / 20) + 1, mod(day, 20)];
    },

    /** Retrieve Tzolkin date from a Julian date.
        @memberof MayanCalendar
        @private
        @param jd {number} The Julian date.
        @return {number[]} Corresponding Tzolkin day and trecena. */
    _toTzolkin: function(jd) {
        jd -= this.jdEpoch;
        return [amod(jd + 20, 20), amod(jd + 4, 13)];
    },

    /** Retrieve the Julian date equivalent for this date,
        i.e. days since January 1, 4713 BCE Greenwich noon.
        @memberof MayanCalendar
        @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, main.local.invalidDate);
        return date.day() + (date.month() * 20) + (date.year() * 360) + this.jdEpoch;
    },

    /** Create a new date from a Julian date.
        @memberof MayanCalendar
        @param jd {number} The Julian date to convert.
        @return {CDate} The equivalent date. */
    fromJD: function(jd) {
        jd = Math.floor(jd) + 0.5 - this.jdEpoch;
        var year = Math.floor(jd / 360);
        jd = jd % 360;
        jd += (jd < 0 ? 360 : 0);
        var month = Math.floor(jd / 20);
        var day = jd % 20;
        return this.newDate(year, month, day);
    }
});

// Modulus function which works for non-integers.
function mod(a, b) {
    return a - (b * Math.floor(a / b));
}

// Modulus function which returns numerator if modulus is zero.
function amod(a, b) {
    return mod(a - 1, b) + 1;
}

// Mayan calendar implementation
main.calendars.mayan = MayanCalendar;