// formatDate :
// a PHP date like function, for formatting date strings
// authored by Svend Tofte <www.svendtofte.com>
// the code is in the public domain
//
// see http://www.svendtofte.com/javascript/javascript-date-string-formatting/
// and http://www.php.net/date
//
// thanks to
//  - Daniel Berlin <mail@daniel-berlin.de>,
//    major overhaul and improvements
//  - Matt Bannon,
//    correcting some stupid bugs in my days-in-the-months list!
//  - levon ghazaryan. pointing out an error in z switch.
//  - Andy Pemberton. pointing out error in c switch
//
// input : format string
// time : epoch time (seconds, and optional)
//
// if time is not passed, formatting is based on
// the current "this" date object's set time.
//
// supported switches are
// a, A, B, c, d, D, F, g, G, h, H, i, I (uppercase i), j, l (lowecase L),
// L, m, M, n, N, O, P, r, s, S, t, U, w, W, y, Y, z, Z
//
// unsupported (as compared to date in PHP 5.1.3)
// T, e, o

Date.prototype.formatDate = function (input,time) {

		var daysLong =    ["Sunday", "Monday", "Tuesday", "Wednesday",
											 "Thursday", "Friday", "Saturday"];
		var daysShort =   ["Sun", "Mon", "Tue", "Wed",
											 "Thu", "Fri", "Sat"];
		var monthsShort = ["Jan", "Feb", "Mar", "Apr",
											 "May", "Jun", "Jul", "Aug", "Sep",
											 "Oct", "Nov", "Dec"];
		var monthsLong =  ["January", "February", "March", "April",
											 "May", "June", "July", "August", "September",
											 "October", "November", "December"];

		var switches = { // switches object

				a : function () {
						// Lowercase Ante meridiem and Post meridiem
						return date.getHours() > 11? "pm" : "am";
				},

				A : function () {
						// Uppercase Ante meridiem and Post meridiem
						return (this.a().toUpperCase ());
				},

				B : function (){
						// Swatch internet time. code simply grabbed from ppk,
						// since I was feeling lazy:
						// http://www.xs4all.nl/~ppk/js/beat.html
						var off = (date.getTimezoneOffset() + 60)*60;
						var theSeconds = (date.getHours() * 3600) +
														 (date.getMinutes() * 60) +
															date.getSeconds() + off;
						var beat = Math.floor(theSeconds/86.4);
						if (beat > 1000) beat -= 1000;
						if (beat < 0) beat += 1000;
						if ((String(beat)).length == 1) beat = "00"+beat;
						if ((String(beat)).length == 2) beat = "0"+beat;
						return beat;
				},

				c : function () {
						// ISO 8601 date (e.g.: "2004-02-12T15:19:21+00:00"), as per
						// http://www.cl.cam.ac.uk/~mgk25/iso-time.html
						return (this.Y() + "-" + this.m() + "-" + this.d() + "T" +
										this.H() + ":" + this.i() + ":" + this.s() + this.P());
				},

				d : function () {
						// Day of the month, 2 digits with leading zeros
						var j = String(this.j());
						return (j.length == 1 ? "0"+j : j);
				},

				D : function () {
						// A textual representation of a day, three letters
						return daysShort[date.getDay()];
				},

				F : function () {
						// A full textual representation of a month
						return monthsLong[date.getMonth()];
				},

				g : function () {
					 // 12-hour format of an hour without leading zeros, 1 through 12!
					 if (date.getHours() == 0) {
							 return 12;
					 } else {
							 return date.getHours()>12 ? date.getHours()-12 : date.getHours();
					 }
			 },

				G : function () {
						// 24-hour format of an hour without leading zeros
						return date.getHours();
				},

				h : function () {
						// 12-hour format of an hour with leading zeros
						var g = String(this.g());
						return (g.length == 1 ? "0"+g : g);
				},

				H : function () {
						// 24-hour format of an hour with leading zeros
						var G = String(this.G());
						return (G.length == 1 ? "0"+G : G);
				},

				i : function () {
						// Minutes with leading zeros
						var min = String (date.getMinutes ());
						return (min.length == 1 ? "0" + min : min);
				},

				I : function () {
						// Whether or not the date is in daylight saving time (DST)
						// note that this has no bearing in actual DST mechanics,
						// and is just a pure guess. buyer beware.
						var noDST = new Date ("January 1 " + this.Y() + " 00:00:00");
						return (noDST.getTimezoneOffset () ==
										date.getTimezoneOffset () ? 0 : 1);
				},

				j : function () {
						// Day of the month without leading zeros
						return date.getDate();
				},

				l : function () {
						// A full textual representation of the day of the week
						return daysLong[date.getDay()];
				},

				L : function () {
						// leap year or not. 1 if leap year, 0 if not.
						// the logic should match iso's 8601 standard.
						// http://www.uic.edu/depts/accc/software/isodates/leapyear.html
						var Y = this.Y();
						if (
								(Y % 4 == 0 && Y % 100 != 0) ||
								(Y % 4 == 0 && Y % 100 == 0 && Y % 400 == 0)
								) {
								return 1;
						} else {
								return 0;
						}
				},

				m : function () {
						// Numeric representation of a month, with leading zeros
						var n = String(this.n());
						return (n.length == 1 ? "0"+n : n);
				},

				M : function () {
						// A short textual representation of a month, three letters
						return monthsShort[date.getMonth()];
				},

				n : function () {
						// Numeric representation of a month, without leading zeros
						return date.getMonth()+1;
				},

				N : function () {
						// ISO-8601 numeric representation of the day of the week
						var w = this.w();
						return (w == 0 ? 7 : w);
				},

				O : function () {
						// Difference to Greenwich time (GMT) in hours
						var os = Math.abs(date.getTimezoneOffset());
						var h = String(Math.floor(os/60));
						var m = String(os%60);
						h.length == 1? h = "0"+h:1;
						m.length == 1? m = "0"+m:1;
						return date.getTimezoneOffset() < 0 ? "+"+h+m : "-"+h+m;
				},

				P : function () {
						// Difference to GMT, with colon between hours and minutes
						var O = this.O();
						return (O.substr(0, 3) + ":" + O.substr(3, 2));
				},

				r : function () {
						// RFC 822 formatted date
						var r; // result
						//  Thu         ,     21               Dec              2000
						r = this.D() + ", " + this.d() + " " + this.M() + " " + this.Y() +
						//    16          :    01          :    07               0200
						" " + this.H() + ":" + this.i() + ":" + this.s() + " " + this.O();
						return r;
				},

				s : function () {
						// Seconds, with leading zeros
						var sec = String (date.getSeconds ());
						return (sec.length == 1 ? "0" + sec : sec);
				},

				S : function () {
						// English ordinal suffix for the day of the month, 2 characters
						switch (date.getDate ()) {
								case  1: return ("st");
								case  2: return ("nd");
								case  3: return ("rd");
								case 21: return ("st");
								case 22: return ("nd");
								case 23: return ("rd");
								case 31: return ("st");
								default: return ("th");
						}
				},

				t : function () {
						// thanks to Matt Bannon for some much needed code-fixes here!
						var daysinmonths = [null,31,28,31,30,31,30,31,31,30,31,30,31];
						if (this.L()==1 && this.n()==2) return 29; // ~leap day
						return daysinmonths[this.n()];
				},

				U : function () {
						// Seconds since the Unix Epoch (January 1 1970 00:00:00 GMT)
						return Math.round(date.getTime()/1000);
				},

				w : function () {
						// Numeric representation of the day of the week
						return date.getDay();
				},

				W : function () {
						// Weeknumber, as per ISO specification:
						// http://www.cl.cam.ac.uk/~mgk25/iso-time.html

						var DoW = this.N ();
						var DoY = this.z ();

						// If the day is 3 days before New Year's Eve and is Thursday or earlier,
						// it's week 1 of next year.
						var daysToNY = 364 + this.L () - DoY;
						if (daysToNY <= 2 && DoW <= (3 - daysToNY)) {
								return 1;
						}

						// If the day is within 3 days after New Year's Eve and is Friday or later,
						// it belongs to the old year.
						if (DoY <= 2 && DoW >= 5) {
								return new Date (this.Y () - 1, 11, 31).formatDate ("W");
						}

						var nyDoW = new Date (this.Y (), 0, 1).getDay ();
						nyDoW = nyDoW != 0 ? nyDoW - 1 : 6;

						if (nyDoW <= 3) { // First day of the year is a Thursday or earlier
								return (1 + Math.floor ((DoY + nyDoW) / 7));
						} else {  // First day of the year is a Friday or later
								return (1 + Math.floor ((DoY - (7 - nyDoW)) / 7));
						}
				},

				y : function () {
						// A two-digit representation of a year
						var y = String(this.Y());
						return y.substring(y.length-2,y.length);
				},

				Y : function () {
						// A full numeric representation of a year, 4 digits

						// we first check, if getFullYear is supported. if it
						// is, we just use that. ppks code is nice, but wont
						// work with dates outside 1900-2038, or something like that
						if (date.getFullYear) {
								var newDate = new Date("January 1 2001 00:00:00 +0000");
								var x = newDate .getFullYear();
								if (x == 2001) {
										// i trust the method now
										return date.getFullYear();
								}
						}
						// else, do this:
						// codes thanks to ppk:
						// http://www.xs4all.nl/~ppk/js/introdate.html
						var x = date.getYear();
						var y = x % 100;
						y += (y < 38) ? 2000 : 1900;
						return y;
				},


				z : function () {
						// The day of the year, zero indexed! 0 through 366
						var s = "January 1 " + this.Y() + " 00:00:00 GMT" + this.O();
						var t = new Date(s);
						var diff = date.getTime() - t.getTime();
						return Math.floor(diff/1000/60/60/24);
				},

				Z : function () {
						// Timezone offset in seconds
						return (date.getTimezoneOffset () * -60);
				}

		}

		function getSwitch(str) {
				if (switches[str] != undefined) {
						return switches[str]();
				} else {
						return str;
				}
		}

		var date;
		if (time) {
				var date = new Date (time);
		} else {
				var date = this;
		}

		var formatString = input.split("");
		var i = 0;
		while (i < formatString.length) {
				if (formatString[i] == "%") {
						// this is our way of allowing users to escape stuff
						formatString.splice(i,1);
				} else {
						formatString[i] = getSwitch(formatString[i]);
				}
				i++;
		}

		return formatString.join("");
}


// Some (not all) predefined format strings from PHP 5.1.1, which
// offer standard date representations.
// See: http://www.php.net/manual/en/ref.datetime.php#datetime.constants
//

// Atom      "2005-08-15T15:52:01+00:00"
Date.DATE_ATOM    = "Y-m-d%TH:i:sP";
// ISO-8601  "2005-08-15T15:52:01+0000"
Date.DATE_ISO8601 = "Y-m-d%TH:i:sO";
// RFC 2822  "Mon, 15 Aug 2005 15:52:01 +0000"
Date.DATE_RFC2822 = "D, d M Y H:i:s O";
// W3C       "2005-08-15 15:52:01+00:00"
Date.DATE_W3C     = "Y-m-d%TH:i:sP";