/*

 * Copyright (C) 2004 Baron Schwartz <baron at sequent dot 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, version 2.1.

 *

 * 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.

 */

Date.parseFunctions = {count:0};

Date.parseRegexes = [];

Date.formatFunctions = {count:0};

Date.prototype.dateFormat = function(format, ignore_offset) {

    if (Date.formatFunctions[format] == null) {

        Date.createNewFormat(format);

    }

    var func = Date.formatFunctions[format];

    if (ignore_offset || ! this.offset) {

      return this[func]();

    } else {

      return (new Date(this.valueOf() - this.offset))[func]();

    }

};

Date.createNewFormat = function(format) {

    var funcName = "format" + Date.formatFunctions.count++;

    Date.formatFunctions[format] = funcName;

    var code = "Date.prototype." + funcName + " = function(){return ";

    var special = false;

    var ch = '';

    for (var i = 0; i < format.length; ++i) {

        ch = format.charAt(i);

        if (!special && ch == "\\") {

            special = true;

        }

        else if (special) {

            special = false;

            code += "'" + String.escape(ch) + "' + ";

        }

        else {

            code += Date.getFormatCode(ch);

        }

    }

    eval(code.substring(0, code.length - 3) + ";}");

};

Date.getFormatCode = function(character) {

    switch (character) {

    case "d":

        return "String.leftPad(this.getDate(), 2, '0') + ";

    case "D":

        return "Date.dayNames[this.getDay()].substring(0, 3) + ";

    case "j":

        return "this.getDate() + ";

    case "l":

        return "Date.dayNames[this.getDay()] + ";

    case "S":

        return "this.getSuffix() + ";

    case "w":

        return "this.getDay() + ";

    case "z":

        return "this.getDayOfYear() + ";

    case "W":

        return "this.getWeekOfYear() + ";

    case "F":

        return "Date.monthNames[this.getMonth()] + ";

    case "m":

        return "String.leftPad(this.getMonth() + 1, 2, '0') + ";

    case "M":

        return "Date.monthNames[this.getMonth()].substring(0, 3) + ";

    case "n":

        return "(this.getMonth() + 1) + ";

    case "t":

        return "this.getDaysInMonth() + ";

    case "L":

        return "(this.isLeapYear() ? 1 : 0) + ";

    case "Y":

        return "this.getFullYear() + ";

    case "y":

        return "('' + this.getFullYear()).substring(2, 4) + ";

    case "a":

        return "(this.getHours() < 12 ? 'am' : 'pm') + ";

    case "A":

        return "(this.getHours() < 12 ? 'AM' : 'PM') + ";

    case "g":

        return "((this.getHours() %12) ? this.getHours() % 12 : 12) + ";

    case "G":

        return "this.getHours() + ";

    case "h":

        return "String.leftPad((this.getHours() %12) ? this.getHours() % 12 : 12, 2, '0') + ";

    case "H":

        return "String.leftPad(this.getHours(), 2, '0') + ";

    case "i":

        return "String.leftPad(this.getMinutes(), 2, '0') + ";

    case "s":

        return "String.leftPad(this.getSeconds(), 2, '0') + ";

    case "O":

        return "this.getGMTOffset() + ";

    case "T":

        return "this.getTimezone() + ";

    case "Z":

        return "(this.getTimezoneOffset() * -60) + ";

    default:

        return "'" + String.escape(character) + "' + ";

    }

};

Date.parseDate = function(input, format) {

    if (Date.parseFunctions[format] == null) {

        Date.createParser(format);

    }

    var func = Date.parseFunctions[format];

    return Date[func](input);

};

Date.createParser = function(format) {

    var funcName = "parse" + Date.parseFunctions.count++;

    var regexNum = Date.parseRegexes.length;

    var currentGroup = 1;

    Date.parseFunctions[format] = funcName;

    var code = "Date." + funcName + " = function(input){\n"

        + "var y = -1, m = -1, d = -1, h = -1, i = -1, s = -1, z = 0;\n"

        + "var d = new Date();\n"

        + "y = d.getFullYear();\n"

        + "m = d.getMonth();\n"

        + "d = d.getDate();\n"

        + "var results = input.match(Date.parseRegexes[" + regexNum + "]);\n"

        + "if (results && results.length > 0) {" ;

    var regex = "";

    var special = false;

    var ch = '';

    for (var i = 0; i < format.length; ++i) {

        ch = format.charAt(i);

        if (!special && ch == "\\") {

            special = true;

        }

        else if (special) {

            special = false;

            regex += String.escape(ch);

        }

        else {

            obj = Date.formatCodeToRegex(ch, currentGroup);

            currentGroup += obj.g;

            regex += obj.s;

            if (obj.g && obj.c) {

                code += obj.c;

            }

        }

    }

    code += "if (y > 0 && m >= 0 && d > 0 && h >= 0 && i >= 0 && s >= 0)\n"

        + "{return new Date(y, m, d, h, i, s).applyOffset(z);}\n"

        + "else if (y > 0 && m >= 0 && d > 0 && h >= 0 && i >= 0)\n"

        + "{return new Date(y, m, d, h, i).applyOffset(z);}\n"

        + "else if (y > 0 && m >= 0 && d > 0 && h >= 0)\n"

        + "{return new Date(y, m, d, h).applyOffset(z);}\n"

        + "else if (y > 0 && m >= 0 && d > 0)\n"

        + "{return new Date(y, m, d).applyOffset(z);}\n"

        + "else if (y > 0 && m >= 0)\n"

        + "{return new Date(y, m).applyOffset(z);}\n"

        + "else if (y > 0)\n"

        + "{return new Date(y).applyOffset(z);}\n"

        + "}return null;}";

    Date.parseRegexes[regexNum] = new RegExp("^" + regex + "$");

    eval(code);

};

Date.formatCodeToRegex = function(character, currentGroup) {

    switch (character) {

    case "D":

        return {g:0,

        c:null,

        s:"(?:Sun|Mon|Tue|Wed|Thu|Fri|Sat)"};

    case "j":

    case "d":

        return {g:1,

            c:"d = parseInt(results[" + currentGroup + "], 10);\n",

            s:"(\\d{1,2})"};

    case "l":

        return {g:0,

            c:null,

            s:"(?:" + Date.dayNames.join("|") + ")"};

    case "S":

        return {g:0,

            c:null,

            s:"(?:st|nd|rd|th)"};

    case "w":

        return {g:0,

            c:null,

            s:"\\d"};

    case "z":

        return {g:0,

            c:null,

            s:"(?:\\d{1,3})"};

    case "W":

        return {g:0,

            c:null,

            s:"(?:\\d{2})"};

    case "F":

        return {g:1,

            c:"m = parseInt(Date.monthNumbers[results[" + currentGroup + "].substring(0, 3)], 10);\n",

            s:"(" + Date.monthNames.join("|") + ")"};

    case "M":

        return {g:1,

            c:"m = parseInt(Date.monthNumbers[results[" + currentGroup + "]], 10);\n",

            s:"(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)"};

    case "n":

    case "m":

        return {g:1,

            c:"m = parseInt(results[" + currentGroup + "], 10) - 1;\n",

            s:"(\\d{1,2})"};

    case "t":

        return {g:0,

            c:null,

            s:"\\d{1,2}"};

    case "L":

        return {g:0,

            c:null,

            s:"(?:1|0)"};

    case "Y":

        return {g:1,

            c:"y = parseInt(results[" + currentGroup + "], 10);\n",

            s:"(\\d{4})"};

    case "y":

        return {g:1,

            c:"var ty = parseInt(results[" + currentGroup + "], 10);\n"

                + "y = ty > Date.y2kYear ? 1900 + ty : 2000 + ty;\n",

            s:"(\\d{1,2})"};

    case "a":

        return {g:1,

            c:"if (results[" + currentGroup + "] == 'am') {\n"

                + "if (h == 12) { h = 0; }\n"

                + "} else { if (h < 12) { h += 12; }}",

            s:"(am|pm)"};

    case "A":

        return {g:1,

            c:"if (results[" + currentGroup + "] == 'AM') {\n"

                + "if (h == 12) { h = 0; }\n"

                + "} else { if (h < 12) { h += 12; }}",

            s:"(AM|PM)"};

    case "g":

    case "G":

    case "h":

    case "H":

        return {g:1,

            c:"h = parseInt(results[" + currentGroup + "], 10);\n",

            s:"(\\d{1,2})"};

    case "i":

        return {g:1,

            c:"i = parseInt(results[" + currentGroup + "], 10);\n",

            s:"(\\d{2})"};

    case "s":

        return {g:1,

            c:"s = parseInt(results[" + currentGroup + "], 10);\n",

            s:"(\\d{2})"};

    case "O":

    case "P":

        return {g:1,

            c:"z = Date.parseOffset(results[" + currentGroup + "], 10);\n",

            s:"(Z|[+-]\\d{2}:?\\d{2})"}; // "Z", "+05:00", "+0500" all acceptable.

    case "T":

        return {g:0,

            c:null,

            s:"[A-Z]{3}"};

    case "Z":

        return {g:1,

            c:"s = parseInt(results[" + currentGroup + "], 10);\n",

            s:"([+-]\\d{1,5})"};

    default:

        return {g:0,

            c:null,

            s:String.escape(character)};

    }

};

Date.parseOffset = function(str) {

  if (str == "Z") { return 0 ; } // UTC, no offset.

  var seconds ;

  seconds = parseInt(str[0] + str[1] + str[2]) * 3600 ; // e.g., "+05" or "-08"

  if (str[3] == ":") {            // "+HH:MM" is preferred iso8601 format ("O")

    seconds += parseInt(str[4] + str[5]) * 60;

  } else {                      // "+HHMM" is frequently used, though. ("P")

    seconds += parseInt(str[3] + str[4]) * 60;

  }

  return seconds ;

};

// convert the parsed date into UTC, but store the offset so we can optionally use it in dateFormat()

Date.prototype.applyOffset = function(offset_seconds) {

  this.offset = offset_seconds * 1000 ;

  this.setTime(this.valueOf() + this.offset);

  return this ;

};

Date.prototype.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").replace(

        /^.*?[0-9]{4} \(([A-Z]{3})\)/, "$1");

};

Date.prototype.getGMTOffset = function() {

    return (this.getTimezoneOffset() > 0 ? "-" : "+")

        + String.leftPad(Math.floor(this.getTimezoneOffset() / 60), 2, "0")

        + String.leftPad(this.getTimezoneOffset() % 60, 2, "0");

};

Date.prototype.getDayOfYear = function() {

    var num = 0;

    Date.daysInMonth[1] = this.isLeapYear() ? 29 : 28;

    for (var i = 0; i < this.getMonth(); ++i) {

        num += Date.daysInMonth[i];

    }

    return num + this.getDate() - 1;

};

Date.prototype.getWeekOfYear = function() {

    // Skip to Thursday of this week

    var now = this.getDayOfYear() + (4 - this.getDay());

    // Find the first Thursday of the year

    var jan1 = new Date(this.getFullYear(), 0, 1);

    var then = (7 - jan1.getDay() + 4);

    document.write(then);

    return String.leftPad(((now - then) / 7) + 1, 2, "0");

};

Date.prototype.isLeapYear = function() {

    var year = this.getFullYear();

    return ((year & 3) == 0 && (year % 100 || (year % 400 == 0 && year)));

};

Date.prototype.getFirstDayOfMonth = function() {

    var day = (this.getDay() - (this.getDate() - 1)) % 7;

    return (day < 0) ? (day + 7) : day;

};

Date.prototype.getLastDayOfMonth = function() {

    var day = (this.getDay() + (Date.daysInMonth[this.getMonth()] - this.getDate())) % 7;

    return (day < 0) ? (day + 7) : day;

};

Date.prototype.getDaysInMonth = function() {

    Date.daysInMonth[1] = this.isLeapYear() ? 29 : 28;