// Requires Prototype Framework
var dateUtils = Class.create();
dateUtils.prototype = {
	initialize: function(){
		this.MONTH_NAMES=new Array('January','February','March','April','May','June','July','August','September','October','November','December','Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec');
		this.DAY_NAMES=new Array('Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday','Sun','Mon','Tue','Wed','Thu','Fri','Sat');
	},
	
	LZ: function(x){
		return (x<0||x>9?"":"0")+x;
	},
	
	isDate: function(val,format){
		var date = this.getDateFromFormat(val,format);	
		return date === 0 ? false : true;
	}, 
	
	compareDates: function(date1,dateformat1,date2,dateformat2){
		var d1 = this.getDateFromFormat(date1,dateformat1);
		var d2 = this.getDateFromFormat(date2,dateformat2);
		if (d1===0 || d2===0)
			return -1;
		else if (d1 > d2)
			return 1;
		else 
			return 0;
	},
	
	 isInteger: function(val) {
		var digits="1234567890";
		for (var i=0; i < val.length; i++) {
			if (digits.indexOf(val.charAt(i))==-1)
				return false; 
		}
		return true;
	},

	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;
	},
	
	getDateFromFormat: function (val,format) {
		val += "";
		format += "";
		var i_val=0;
		var i_format=0;
		var c = "";
		var token="";
		var x = "";
		var y = "";
		var now = new Date();
		var year = now.getYear();
		var month = now.getMonth()+1;
		var date = 1;
		var hh = now.getHours();
		var mm = now.getMinutes();
		var ss = now.getSeconds();
		var ampm = "";
		
		while (i_format < format.length) {
			// Get next this.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 0; }
				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;
				for (var i=0; i<MONTH_NAMES.length; i++) {
					this.month_name=MONTH_NAMES[i];
					if (val.substring(i_val,i_val+this.month_name.length).toLowerCase()==this.month_name.toLowerCase()) {
						if (token=="MMM"||(token=="NNN"&&i>11)) {
							month=i+1;
							if (month>12) { month -= 12; }
							i_val += this.month_name.length;
							break;
							}
						}
					}
				if ((month < 1)||(month>12)){return 0;}
				}
			else if (token=="EE"||token=="E"){
				for (var i=0; i<DAY_NAMES.length; i++) {
					this.day_name=DAY_NAMES[i];
					if (val.substring(i_val,i_val+this.day_name.length).toLowerCase()==this.day_name.toLowerCase()) {
						i_val += this.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 0;}
				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 0;}
				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 0;}
				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 0;}
				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 0;}
				i_val+=hh.length;}
			else if (token=="kk"||token=="k") {
				hh=this.getInt(val,i_val,token.length,2);
				if(hh===null||(hh<1)||(hh>24)){return 0;}
				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 0;}
				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 0;}
				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 0;}
				i_val+=2;}
			else {
				if (val.substring(i_val,i_val+token.length)!=token) {return 0;}
				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 0; }
		// 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 0; }
				}
			else { if (date > 28) { return 0; } }
			}
		if ((month==4)||(month==6)||(month==9)||(month==11)) {
			if (date > 30) { return 0; }
			}
		// Correct hours value
		if (hh<12 && ampm=="PM")
			hh=hh-0+12;
		else if (hh>11 && ampm=="AM")
			hh-=12;
		this.newdate=new Date(year,month-1,date,hh,mm,ss);
		return this.newdate.getTime();
	}
}