/**
* Copyright (c)2005-2009 Matt Kruse (javascripttoolbox.com)
* 
* Dual licensed under the MIT and GPL licenses. 
* This basically means you can use this code however you want for
* free, but don't claim to have written it yourself!
* Donations always accepted: http://www.JavascriptToolbox.com/donate/
* 
* Please do not link to the .js files on javascripttoolbox.com from
* your site. Copy the files locally to your server instead.
* 
*/
/*
Date functions

These functions are used to parse, format, and manipulate Date objects.
See documentation and examples at http://www.JavascriptToolbox.com/lib/date/

*/
Date.$VERSION = 1.02;

// Utility function to append a 0 to single-digit numbers
Date.LZ = function(x) { return (x < 0 || x > 9 ? "" : "0") + x };
// Full month names. Change this for local month names
Date.monthNames = new Array('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December');
// Month abbreviations. Change this for local month names
Date.monthAbbreviations = new Array('Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec');
// Full day names. Change this for local month names
Date.dayNames = new Array('Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday');
// Day abbreviations. Change this for local month names
Date.dayAbbreviations = new Array('Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat');
// Used for parsing ambiguous dates like 1/2/2000 - default to preferring 'American' format meaning Jan 2.
// Set to false to prefer 'European' format meaning Feb 1
Date.preferAmericanFormat = true;

// If the getFullYear() method is not defined, create it
if (!Date.prototype.getFullYear) {
    Date.prototype.getFullYear = function() { var yy = this.getYear(); return (yy < 1900 ? yy + 1900 : yy); };
}

// Parse a string and convert it to a Date object.
// If no format is passed, try a list of common formats.
// If string cannot be parsed, return null.
// Avoids regular expressions to be more portable.
Date.parseString = function(val, format) {
    // If no format is specified, try a few common formats
    if (typeof (format) == "undefined" || format == null || format == "") {
        var generalFormats = new Array('y-M-d', 'MMM d, y', 'MMM d,y', 'y-MMM-d', 'd-MMM-y', 'MMM d', 'MMM-d', 'd-MMM');
        var monthFirst = new Array('M/d/y', 'M-d-y', 'M.d.y', 'M/d', 'M-d');
        var dateFirst = new Array('d/M/y', 'd-M-y', 'd.M.y', 'd/M', 'd-M');
        var checkList = new Array(generalFormats, Date.preferAmericanFormat ? monthFirst : dateFirst, Date.preferAmericanFormat ? dateFirst : monthFirst);
        for (var i = 0; i < checkList.length; i++) {
            var l = checkList[i];
            for (var j = 0; j < l.length; j++) {
                var d = Date.parseString(val, l[j]);
                if (d != null) {
                    return d;
                }
            }
        }
        return null;
    };

    this.isInteger = function(val) {
        for (var i = 0; i < val.length; i++) {
            if ("1234567890".indexOf(val.charAt(i)) == -1) {
                return false;
            }
        }
        return true;
    };
    this.getInt = function(str, i, minlength, maxlength) {
        for (var x = maxlength; x >= minlength; x--) {
            var token = str.substring(i, i + x);
            if (token.length < minlength) {
                return null;
            }
            if (this.isInteger(token)) {
                return token;
            }
        }
        return null;
    };
    val = val + "";
    format = format + "";
    var i_val = 0;
    var i_format = 0;
    var c = "";
    var token = "";
    var token2 = "";
    var x, y;
    var year = new Date().getFullYear();
    var month = 1;
    var date = 1;
    var hh = 0;
    var mm = 0;
    var ss = 0;
    var ampm = "";
    while (i_format < format.length) {
        // Get next token from format string
        c = format.charAt(i_format);
        token = "";
        while ((format.charAt(i_format) == c) && (i_format < format.length)) {
            token += format.charAt(i_format++);
        }
        // Extract contents of value based on format token
        if (token == "yyyy" || token == "yy" || token == "y") {
            if (token == "yyyy") {
                x = 4; y = 4;
            }
            if (token == "yy") {
                x = 2; y = 2;
            }
            if (token == "y") {
                x = 2; y = 4;
            }
            year = this.getInt(val, i_val, x, y);
            if (year == null) {
                return null;
            }
            i_val += year.length;
            if (year.length == 2) {
                if (year > 70) {
                    year = 1900 + (year - 0);
                }
                else {
                    year = 2000 + (year - 0);
                }
            }
        }
        else if (token == "MMM" || token == "NNN") {
            month = 0;
            var names = (token == "MMM" ? (Date.monthNames.concat(Date.monthAbbreviations)) : Date.monthAbbreviations);
            for (var i = 0; i < names.length; i++) {
                var month_name = names[i];
                if (val.substring(i_val, i_val + month_name.length).toLowerCase() == month_name.toLowerCase()) {
                    month = (i % 12) + 1;
                    i_val += month_name.length;
                    break;
                }
            }
            if ((month < 1) || (month > 12)) {
                return null;
            }
        }
        else if (token == "EE" || token == "E") {
            var names = (token == "EE" ? Date.dayNames : Date.dayAbbreviations);
            for (var i = 0; i < names.length; i++) {
                var day_name = names[i];
                if (val.substring(i_val, i_val + day_name.length).toLowerCase() == day_name.toLowerCase()) {
                    i_val += day_name.length;
                    break;
                }
            }
        }
        else if (token == "MM" || token == "M") {
            month = this.getInt(val, i_val, token.length, 2);
            if (month == null || (month < 1) || (month > 12)) {
                return null;
            }
            i_val += month.length;
        }
        else if (token == "dd" || token == "d") {
            date = this.getInt(val, i_val, token.length, 2);
            if (date == null || (date < 1) || (date > 31)) {
                return null;
            }
            i_val += date.length;
        }
        else if (token == "hh" || token == "h") {
            hh = this.getInt(val, i_val, token.length, 2);
            if (hh == null || (hh < 1) || (hh > 12)) {
                return null;
            }
            i_val += hh.length;
        }
        else if (token == "HH" || token == "H") {
            hh = this.getInt(val, i_val, token.length, 2);
            if (hh == null || (hh < 0) || (hh > 23)) {
                return null;
            }
            i_val += hh.length;
        }
        else if (token == "KK" || token == "K") {
            hh = this.getInt(val, i_val, token.length, 2);
            if (hh == null || (hh < 0) || (hh > 11)) {
                return null;
            }
            i_val += hh.length;
            hh++;
        }
        else if (token == "kk" || token == "k") {
            hh = this.getInt(val, i_val, token.length, 2);
            if (hh == null || (hh < 1) || (hh > 24)) {
                return null;
            }
            i_val += hh.length;
            hh--;
        }
        else if (token == "mm" || token == "m") {
            mm = this.getInt(val, i_val, token.length, 2);
            if (mm == null || (mm < 0) || (mm > 59)) {
                return null;
            }
            i_val += mm.length;
        }
        else if (token == "ss" || token == "s") {
            ss = this.getInt(val, i_val, token.length, 2);
            if (ss == null || (ss < 0) || (ss > 59)) {
                return null;
            }
            i_val += ss.length;
        }
        else if (token == "a") {
            if (val.substring(i_val, i_val + 2).toLowerCase() == "am") {
                ampm = "AM";
            }
            else if (val.substring(i_val, i_val + 2).toLowerCase() == "pm") {
                ampm = "PM";
            }
            else {
                return null;
            }
            i_val += 2;
        }
        else {
            if (val.substring(i_val, i_val + token.length) != token) {
                return null;
            }
            else {
                i_val += token.length;
            }
        }
    }
    // If there are any trailing characters left in the value, it doesn't match
    if (i_val != val.length) {
        return null;
    }
    // Is date valid for month?
    if (month == 2) {
        // Check for leap year
        if (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) { // leap year
            if (date > 29) {
                return null;
            }
        }
        else {
            if (date > 28) {
                return null;
            }
        }
    }
    if ((month == 4) || (month == 6) || (month == 9) || (month == 11)) {
        if (date > 30) {
            return null;
        }
    }
    // Correct hours value
    if (hh < 12 && ampm == "PM") {
        hh = hh - 0 + 12;
    }
    else if (hh > 11 && ampm == "AM") {
        hh -= 12;
    }
    return new Date(year, month - 1, date, hh, mm, ss);
};

// Check if a date string is valid
Date.isValid = function(val, format) {
    return (Date.parseString(val, format) != null);
};

// Check if a date object is before another date object
Date.prototype.isBefore = function(date2) {
    if (date2 == null) {
        return false;
    }
    return (this.getTime() < date2.getTime());
};

// Check if a date object is after another date object
Date.prototype.isAfter = function(date2) {
    if (date2 == null) {
        return false;
    }
    return (this.getTime() > date2.getTime());
};

// Check if two date objects have equal dates and times
Date.prototype.equals = function(date2) {
    if (date2 == null) {
        return false;
    }
    return (this.getTime() == date2.getTime());
};

// Check if two date objects have equal dates, disregarding times
Date.prototype.equalsIgnoreTime = function(date2) {
    if (date2 == null) {
        return false;
    }
    var d1 = new Date(this.getTime()).clearTime();
    var d2 = new Date(date2.getTime()).clearTime();
    return (d1.getTime() == d2.getTime());
};

// Format a date into a string using a given format string
Date.prototype.format = function(format) {
    format = format + "";
    var result = "";
    var i_format = 0;
    var c = "";
    var token = "";
    var y = this.getYear() + "";
    var M = this.getMonth() + 1;
    var d = this.getDate();
    var E = this.getDay();
    var H = this.getHours();
    var m = this.getMinutes();
    var s = this.getSeconds();
    var yyyy, yy, MMM, MM, dd, hh, h, mm, ss, ampm, HH, H, KK, K, kk, k;
    // Convert real date parts into formatted versions
    var value = new Object();
    if (y.length < 4) {
        y = "" + (+y + 1900);
    }
    value["y"] = "" + y;
    value["yyyy"] = y;
    value["yy"] = y.substring(2, 4);
    value["M"] = M;
    value["MM"] = Date.LZ(M);
    value["MMM"] = Date.monthNames[M - 1];
    value["NNN"] = Date.monthAbbreviations[M - 1];
    value["d"] = d;
    value["dd"] = Date.LZ(d);
    value["E"] = Date.dayAbbreviations[E];
    value["EE"] = Date.dayNames[E];
    value["H"] = H;
    value["HH"] = Date.LZ(H);
    if (H == 0) {
        value["h"] = 12;
    }
    else if (H > 12) {
        value["h"] = H - 12;
    }
    else {
        value["h"] = H;
    }
    value["hh"] = Date.LZ(value["h"]);
    value["K"] = value["h"] - 1;
    value["k"] = value["H"] + 1;
    value["KK"] = Date.LZ(value["K"]);
    value["kk"] = Date.LZ(value["k"]);
    if (H > 11) {
        value["a"] = "PM";
    }
    else {
        value["a"] = "AM";
    }
    value["m"] = m;
    value["mm"] = Date.LZ(m);
    value["s"] = s;
    value["ss"] = Date.LZ(s);
    while (i_format < format.length) {
        c = format.charAt(i_format);
        token = "";
        while ((format.charAt(i_format) == c) && (i_format < format.length)) {
            token += format.charAt(i_format++);
        }
        if (typeof (value[token]) != "undefined") {
            result = result + value[token];
        }
        else {
            result = result + token;
        }
    }
    return result;
};

// Get the full name of the day for a date
Date.prototype.getDayName = function() {
    return Date.dayNames[this.getDay()];
};

// Get the abbreviation of the day for a date
Date.prototype.getDayAbbreviation = function() {
    return Date.dayAbbreviations[this.getDay()];
};

// Get the full name of the month for a date
Date.prototype.getMonthName = function() {
    return Date.monthNames[this.getMonth()];
};

// Get the abbreviation of the month for a date
Date.prototype.getMonthAbbreviation = function() {
    return Date.monthAbbreviations[this.getMonth()];
};

// Clear all time information in a date object
Date.prototype.clearTime = function() {
    this.setHours(0);
    this.setMinutes(0);
    this.setSeconds(0);
    this.setMilliseconds(0);
    return this;
};

// Add an amount of time to a date. Negative numbers can be passed to subtract time.
Date.prototype.add = function(interval, number) {
    if (typeof (interval) == "undefined" || interval == null || typeof (number) == "undefined" || number == null) {
        return this;
    }
    number = +number;
    if (interval == 'y') { // year
        this.setFullYear(this.getFullYear() + number);
    }
    else if (interval == 'M') { // Month
        this.setMonth(this.getMonth() + number);
    }
    else if (interval == 'd') { // Day
        this.setDate(this.getDate() + number);
    }
    else if (interval == 'w') { // Weekday
        var step = (number > 0) ? 1 : -1;
        while (number != 0) {
            this.add('d', step);
            while (this.getDay() == 0 || this.getDay() == 6) {
                this.add('d', step);
            }
            number -= step;
        }
    }
    else if (interval == 'h') { // Hour
        this.setHours(this.getHours() + number);
    }
    else if (interval == 'm') { // Minute
        this.setMinutes(this.getMinutes() + number);
    }
    else if (interval == 's') { // Second
        this.setSeconds(this.getSeconds() + number);
    }
    return this;
};