/* Jalali.js  Gregorian to Jalali and inverse date converter
 * Copyright (C) 2001  Roozbeh Pournader <roozbeh@sharif.edu>
 * Copyright (C) 2001  Mohammad Toossi <mohammad@bamdad.org>
 * Copyright (C) 2003,2008  Behdad Esfahbod <js@behdad.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You can receive a copy of GNU Lesser General Public License at the
 * World Wide Web address <http://www.gnu.org/licenses/lgpl.html>.
 *
 * For licensing issues, contact The FarsiWeb Project Group,
 * Computing Center, Sharif University of Technology,
 * PO Box 11365-8515, Tehran, Iran, or contact us the
 * email address <FWPG@sharif.edu>.
 */

/* Changes:
 * 2013-May-25:
 *   Move JalaliConverter to Ext.Date.
 *
 * 2010-Sep-19:
 *   Some minor changes to names of functions for better naming conventions.
 *   Also redundant functions removed to prevent namespace pollution.
 *
 * 2008-Jul-32:
 *   Use a remainder() function to fix conversion of ancient dates
 *   (before 1600 gregorian).  Reported by Shamim Rezaei.
 *
 * 2003-Mar-29:
 *   Ported to javascript by Behdad Esfahbod
 *
 * 2001-Sep-21:
 *   Fixed a bug with "30 Esfand" dates, reported by Mahmoud Ghandi
 *
 * 2001-Sep-20:
 *   First LGPL release, with both sides of conversions
 */

(function () {
    'use strict';

    Ext.define('Ext.ux.Jalali', {
        override: 'Ext.Date',
        JalaliConverter: {
            gregorianDaysInMonth: [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31],
            jalaliDaysInMonth: [31, 31, 31, 31, 31, 31, 30, 30, 30, 30, 30, 29],

            div: function (a, b) {
                return Math.floor(a / b);
            },

            remainder: function (a, b) {
                return a - Math.floor(a / b) * b;
            },

            /**
             * Converts a Gregorian date to Jalali.
             * @param {Array} g An array containing Gregorian year, month and date.
             * @return {Array} An array containing Jalali year, month and date.
             */
            gregorianToJalali: function (g) {
                var gy, gm, gd,
                    jy, jm, jd,
                    g_day_no, j_day_no,
                    j_np, i, div, remainder,
                    g_days_in_month, j_days_in_month;

                gy = g[0] - 1600;
                gm = g[1] - 1;
                gd = g[2] - 1;

                div = Ext.Date.JalaliConverter.div;
                remainder = Ext.Date.JalaliConverter.remainder;
                g_days_in_month = Ext.Date.JalaliConverter.gregorianDaysInMonth;
                j_days_in_month = Ext.Date.JalaliConverter.jalaliDaysInMonth;

                g_day_no = 365 * gy + div((gy + 3), 4) - div((gy + 99), 100) + div((gy + 399), 400);
                for (i = 0; i < gm; i += 1) {
                    g_day_no += g_days_in_month[i];
                }
                if (gm > 1 && ((gy % 4 === 0 && gy % 100 !== 0) || (gy % 400 === 0))) {
                    /* leap and after Feb */
                    g_day_no += 1;
                }
                g_day_no += gd;

                j_day_no = g_day_no - 79;

                j_np = div(j_day_no, 12053);
                j_day_no = remainder(j_day_no, 12053);

                jy = 979 + 33 * j_np + 4 * div(j_day_no, 1461);
                j_day_no = remainder(j_day_no, 1461);

                if (j_day_no >= 366) {
                    jy += div((j_day_no - 1), 365);
                    j_day_no = remainder((j_day_no - 1), 365);
                }

                for (i = 0; i < 11 && j_day_no >= j_days_in_month[i]; i += 1) {
                    j_day_no -= j_days_in_month[i];
                }
                jm = i + 1;
                jd = j_day_no + 1;

                return [jy, jm, jd];
            },

            /**
             * Converts a Jalali date to Gregorian.
             * @param {Array} j An array containing Jalali year, month and date.
             * @return {Array} An array containing Gregorian year, month and date.
             */
            jalaliToGregorian: function (j) {
                var gy, gm, gd,
                    jy, jm, jd,
                    g_day_no, j_day_no,
                    leap, i, div, remainder,
                    g_days_in_month, j_days_in_month;

                jy = j[0] - 979;
                jm = j[1] - 1;
                jd = j[2] - 1;

                div = Ext.Date.JalaliConverter.div;
                remainder = Ext.Date.JalaliConverter.remainder;
                g_days_in_month = Ext.Date.JalaliConverter.gregorianDaysInMonth;
                j_days_in_month = Ext.Date.JalaliConverter.jalaliDaysInMonth;

                j_day_no = 365 * jy + div(jy, 33) * 8 + div((remainder(jy, 33) + 3), 4);
                for (i = 0; i < jm; i += 1) {
                    j_day_no += j_days_in_month[i];
                }

                j_day_no += jd;

                g_day_no = j_day_no + 79;

                gy = 1600 + 400 * div(g_day_no, 146097);
                /* 146097 = 365*400 + 400/4 - 400/100 + 400/400 */
                g_day_no = remainder(g_day_no, 146097);

                leap = 1;
                if (g_day_no >= 36525) { /* 36525 = 365*100 + 100/4 */
                    g_day_no -= 1;
                    gy += 100 * div(g_day_no, 36524);
                    /* 36524 = 365*100 + 100/4 - 100/100 */
                    g_day_no = remainder(g_day_no, 36524);

                    if (g_day_no >= 365) {
                        g_day_no += 1;
                    } else {
                        leap = 0;
                    }
                }

                gy += 4 * div(g_day_no, 1461);
                /* 1461 = 365*4 + 4/4 */
                g_day_no = remainder(g_day_no, 1461);

                if (g_day_no >= 366) {
                    leap = 0;

                    g_day_no -= 1;
                    gy += div(g_day_no, 365);
                    g_day_no = remainder(g_day_no, 365);
                }

                for (i = 0; g_day_no >= g_days_in_month[i] + (i === 1 && leap); i += 1) {
                    g_day_no -= g_days_in_month[i] + (i === 1 && leap);
                }
                gm = i + 1;
                gd = g_day_no + 1;

                return [gy, gm, gd];
            }
        }
    });
}());