var cp_timeoutDelay = 2000; 	// milliseconds, change this if you like, set to 0 for the calendar to never auto disappear
var cp_timeoutId = false;	// used by timeout auto hide functions
var cp_location = 1;		// 0 = At the side of the button. 1 = At the bottom of the input field.
var g_startDay = 0;		// 0=sunday, 1=monday

var g_Calendar;  		// global to hold the calendar reference, set by constructor

// constructor for calendar class
function Calendar() {
	g_Calendar = this;

	// some constants needed throughout the program
	this.daysOfWeek = "Sun Mon Tue Wed Thu Fri Sat".split(" ");
	this.months = "January February March April May June July August September October November December".split(" ");
	this.daysInMonth = new Array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31); 
	this.containerLayer = null;
	this.dayMask = [1,1,1,1,1,1,1];
	this.Holidays = null;
	this.showHolidays = true;
}

Calendar.prototype.show = function(e, target, dateFormat, dateFrom, dateTo, menuYearFrom, menuYearTo){
	if(!document.getElementById) {
		alert("This browser is not suppored for a calendar popup.");
		return;
	}
	
	if (!document.getElementById(target)) {
		alert("Error: input field \"" + target + "\" does not exist.");
		return;
	}

	this.containerLayer = document.getElementById('calcontainer');
	// if calendar popup container does not exist, create it.
	if(!this.containerLayer) {
		this.containerLayer = document.createElement('div');
		this.containerLayer.id = 'caldiv';
		this.containerLayer.onmouseout=calendarTimeout;
		this.containerLayer.onmouseover=calendarClearTimeout;
		this.containerLayer.onclick=this.handleClick;
		document.body.insertBefore(this.containerLayer,document.body.childNodes[0]);
	}

	// If the container is visible, hide it and return. This is the second click on the button.
	if (this.isVisible()) {
		this.hide();
		return;
	}

	calendarClearTimeout();

	// Get the source element that the user clicked on so that we can calculate the position
	// of the calendar.
	var elSrc;
	if (!e){
		e = window.event;
	}
	if (e.target) {
		elSrc = e.target;
	} else if (e.srcElement) {
		elSrc = e.srcElement;
	}

	// Don't allow the click event to go to any other element.
	e.cancelBubble = true;
	if (e.stopPropagation){
		e.stopPropagation();
	}

	// find the x/y position of the element that the user clicked on or the element that
	// will receive the date..
	var x, y, obj;
	
	x = y = 0;
	if (cp_location == 1) {
		// Use the element that will receive the date.
		obj = document.getElementById(target);
	} else {
		// Use the element that the user clicked on.
		obj = elSrc;
	}

	// Find the x/y position of the element.
	if(obj.offsetParent) {
		while (obj) {
			x += obj.offsetLeft;
			y += obj.offsetTop;
			obj = obj.offsetParent;
		}
	} else {
		x = obj.x;
		y = obj.y;
	}
	
	if (cp_location == 1) {
		// Get the scroll offset of the window.
		var yScroll;
		if (self.pageYOffset) // all except Explorer
		{
			yScroll = self.pageYOffset;
		}
		else if (document.documentElement && document.documentElement.scrollTop) // Explorer 6 Strict
		{
			yScroll = document.documentElement.scrollTop;
		}
		else if (document.body) // all other Explorers
		{
			yScroll = document.body.scrollTop;
		}

		this.containerLayer.style.left = x + "px";
		// if the calendar goes below the bottom of the page, pop the calendar up instead of down.
		if ((y+document.getElementById(target).offsetHeight+1+this.containerLayer.offsetHeight) > this.getWindowHeight() + yScroll) {
			this.containerLayer.style.top = ((y-this.containerLayer.offsetHeight)-1) + "px";
		} else {
			this.containerLayer.style.top = (y+document.getElementById(target).offsetHeight+1) + "px";
		}
	} else {
		// Position the calender to the right of the clicked element and aligned with the top of
		// the clicked element.
		this.containerLayer.style.left = (x+elSrc.offsetWidth+1) + "px";
		this.containerLayer.style.top = y + "px";
	}

	// calendar can restrict choices between 2 dates, if however no restrictions
	// are made, let them choose any date between 1900 and 3000
	this.dateFrom = dateFrom || new Date(1900,0,1);
	this.dateFromDay = this.padZero(this.dateFrom.getDate());
	this.dateFromMonth = this.padZero(this.dateFrom.getMonth());
	this.dateFromYear = this.dateFrom.getFullYear();
	this.dateTo = dateTo || new Date(3000,0,1);
	this.dateToDay = this.padZero(this.dateTo.getDate());
	this.dateToMonth = this.padZero(this.dateTo.getMonth());
	this.dateToYear = this.dateTo.getFullYear();

	this.dateToday = new Date();
	this.tYear = this.dateToday.getFullYear();
	this.tMonth = this.dateToday.getMonth();
	this.tDay = this.dateToday.getDate();

	// Is dateFormat provided?
	if (dateFormat){
		this.dateFormat = dateFormat;
	} else if (dp_dateFormat) {
		// if dp_dateFormat has been defined, use its format.
		this.dateFormat = dp_dateFormat;
	} else if (!this.dateFormat) {	// Has it been set previously?
		// If not, default date to US format.
		this.dateFormat = 'm/d/yyyy';
	}

	dp_dateFormat = this.dateFormat;	// Set the date parser format the same.

	// Get the date delimiter.
	if(this.dateFormat.indexOf('-') != -1) {
		this.dateDelim = '-';
	} else if(this.dateFormat.indexOf('/') != -1) {
		this.dateDelim = '/';
	} else if(this.dateFormat.indexOf('.') != -1) {
		this.dateDelim = '.';
	} else if(this.dateFormat.indexOf(' ') != -1) {
		this.dateDelim = ' ';
	} else {
		this.dateDelim = '/';
	}

	this.target = target;
	var tmp = document.getElementById(this.target);
	tmp.className=tmp.className.replace("error", "").replace("  ", " ");
	if (tmp && tmp.value && tmp.value.split(this.dateDelim).length==3){
		// There is a date in the target input field. Split the elements of the date into
		// an array.
		var atmp = tmp.value.split(this.dateDelim);
		var delim = eval('/\\' + this.dateDelim + '/g');
		switch (this.dateFormat.replace(delim,"")){
		case 'ddmmmyyyy':
		case 'dmmmyyyy':
			this.day = 1;
			this.year = this.oYear = parseInt(atmp[2],10);
			for (var i=0;i<this.months.length;i++){
				if (atmp[1].toLowerCase()==this.months[i].substr(0,3).toLowerCase()){
					this.month = this.oMonth = i;
					break;
				}
			}
			this.day = parseInt(atmp[0],10);
			break;

		case 'ddmmyyyy':
		case 'dmmyyyy':
		case 'dmyyyy':
			this.day = 1;
			this.year = this.oYear = parseInt(atmp[2],10);
			this.month = this.oMonth = parseInt(atmp[1]-1,10); 
			this.day = parseInt(atmp[0],10);
			break;

		case 'mmddyyyy':
		case 'mddyyyy':
		case 'mdyyyy':
			this.day = 1;
			this.year = this.oYear = parseInt(atmp[2],10);
			this.month = this.oMonth = parseInt(atmp[0]-1,10);
			this.day = parseInt(atmp[1],10);
			break;

		case 'yyyymmdd':
			this.day = 1;
			this.year = this.oYear = parseInt(atmp[0],10);
			this.month = this.oMonth = parseInt(atmp[1]-1,10);
			this.day = parseInt(atmp[2],10);
			break;
		}
	} else { // no date set, default to today
		var theDate = new Date();
		this.year = this.oYear = theDate.getFullYear();
		this.month = this.oMonth = theDate.getMonth();
		this.day = this.oDay = theDate.getDate();
	}
	
	// When to start the year menu.
	this.menuYearFrom = menuYearFrom || this.year - 3;
	// When to end the year menu.
	this.menuYearTo = menuYearTo || this.year + 3;
	var tmpCurYear = (new Date()).getFullYear();
	if(this.menuYearTo < tmpCurYear)
		this.menuYearTo = tmpCurYear;
	// Really is up to not to, so increment by one.
	this.menuYearTo++;
	
	this.writeString(this.buildString());

	this.containerLayer.style.visibility='visible';
};

Calendar.prototype.buildString = function(){
	var tmpStr = '';
	
	// See if there are holidays for this month. Save the holidays to a temporary array
	// so that you only have to look at holidays for this month when building the calendar.
	// This is to improve performance.
	var aHolidays = new Array();
	if(this.Holidays) {
		for(var h = 0; h < this.Holidays.length; h++) {
			if(this.Holidays[h].date.getFullYear() == this.year && this.Holidays[h].date.getMonth() == this.month) {
				aHolidays[aHolidays.length] = this.Holidays[h];
			}
		}
	}
	
	if (document.all&&document.getElementById && !window.Opera){
		// Add a shim to hide select items for drop down menus.
		if (navigator.appVersion.substr(22,3)!="5.0"){
			tmpStr = '<iframe src="about:blank" scrolling="no" frameborder="0" style="width: ' + this.containerLayer.offsetWidth + 'px; height: ' + this.containerLayer.offsetHeight + 'px; z-index: -1; position: absolute; filter: progid:DXImageTransform.Microsoft.Alpha(style=0,opacity=0);"></iframe>';
		}
	}
	tmpStr += '<table cellspacing="0">';
	tmpStr += '<thead><tr><td colspan="7"><ul>\n'+
			'<li id="cp_prevMonth"><a href="javascript:g_Calendar.changeMonth(-1)" title="Go to previous month"><span>&lt;</span></a></li>\n'+
			'<li id="cp_monthMenu"><a href="javascript:g_Calendar.openMenuMonths()" title="Open months menu">' + this.months[this.month] + '</a>\n' +
			'<ul id="cp_months"><li><a href="javascript:g_Calendar.clickMonth(0)">January</a></li><li><a href="javascript:g_Calendar.clickMonth(1)">February</a></li><li><a href="javascript:g_Calendar.clickMonth(2)">March</a></li><li><a href="javascript:g_Calendar.clickMonth(3)">April</a></li><li><a href="javascript:g_Calendar.clickMonth(4)">May</a></li><li><a href="javascript:g_Calendar.clickMonth(5)">June</a></li><li><a href="javascript:g_Calendar.clickMonth(6)">July</a></li><li><a href="javascript:g_Calendar.clickMonth(7)">August</a></li><li><a href="javascript:g_Calendar.clickMonth(8)">September</a></li><li><a href="javascript:g_Calendar.clickMonth(9)">October</a></li><li><a href="javascript:g_Calendar.clickMonth(10)">November</a></li><li><a href="javascript:g_Calendar.clickMonth(11)">December</a></li></ul></li>\n' +
			'<li id="cp_nextMonth"><a href="javascript:g_Calendar.changeMonth(1)" title="Go to next month"><span>&gt;</span></a></li>\n' +
			'<li id="cp_prevYear"><a href="javascript:g_Calendar.changeYear(-1)" title="Go to previous year"><span>&lt;</span></a></li>\n' +
			'<li id="cp_yearMenu"><a href="javascript:g_Calendar.openMenuYears();" title="Open years menu">' + this.year + '</a>\n';

	if(this.menuYearTo - this.menuYearFrom > 7){
		// I hate to do this with an inline style. I just couldn't get it to work with a class.
		tmpStr += '<ul id="cp_years" style="overflow: auto; overflow-x: hidden; overflow-y: auto;">';
	}else{
		tmpStr += '<ul id="cp_years">';
	}

	// Make sure that the year menu goes to at least the currently selected year.
	var menuYearTo = this.menuYearTo;
	if(menuYearTo <= this.year)
		menuYearTo = this.year + 1;

	// Create the year menu.
	for (var y = this.menuYearFrom; y < menuYearTo; y++) {
		tmpStr += '<li><a href="javascript:g_Calendar.clickYear(' + y + ')">' + y + '</a></li>';
	}

	tmpStr += '</ul></li>\n<li id="cp_nextYear"><a href="javascript:g_Calendar.changeYear(1)" title="Go to next year"><span>&gt;</span></a></li>\n</ul></td></tr>';

	var iCount = 1;

	var iFirstDOM = (7+this.getFirstDOM()-g_startDay)%7; // to prevent calling it in a loop

	var iDaysInMonth = this.getDaysInMonth(); // to prevent calling it in a loop

	tmpStr += '<tr>';
	for (var i=0;i<7;i++){
		tmpStr += '<th>' + this.daysOfWeek[(g_startDay+i)%7] + '</th>';
	}

	var dtToday = new Date();

	tmpStr += '</tr></thead><tfoot><tr><td colspan="7">Today is: <a href="javascript:g_Calendar.clickToday()" title="Go to current month">' + (/^d/.test(this.dateFormat)?dtToday.getDate() + ' ' + this.months[dtToday.getMonth()] + ' ':this.months[dtToday.getMonth()] + ' ' + dtToday.getDate() + ', ') + dtToday.getFullYear()+'</a></td></tr></tfoot><tbody>';
	var tmpFrom = parseInt('' + this.dateFromYear + this.dateFromMonth + this.dateFromDay,10);
	var tmpTo = parseInt('' + this.dateToYear + this.dateToMonth + this.dateToDay,10);
	var tmpCompare;
	for (var j=1;j<=6;j++){
		tmpStr += '<tr>';
		for (i=1;i<=7;i++){
			// Variable that determines if the day is clickable.
			var bShowDay = true;
			// If the day is a holiday, set the title to show a description of the holiday.
			var sTitle = '';
			// Look to see if this day is a holiday.
			for(h = 0; h < aHolidays.length; h++) {
				if(aHolidays[h].date.getDate() == iCount) {
					if(!this.showHolidays)
						bShowDay = false;
					sTitle = aHolidays[h].desc;
				}
			}

			tmpStr += '<td ';
			if ( (7*(j-1) + i)>=iFirstDOM+1  && iCount <= iDaysInMonth){
				if (iCount==this.day && this.year==this.oYear && this.month==this.oMonth){
					tmpStr += 'class="calHighlightColor"';
				} else if (i==7-g_startDay || i==((7-g_startDay)%7)+1) {
						tmpStr += 'class="calWeekend"';
				}
				tmpStr += '>';
				
				if(this.dayMask[i-1] == 0) {
					bShowDay = false;
				} else {
					/* could create a date object here and compare that but probably more efficient to convert to a number
					and compare number as numbers are primitives */
					tmpCompare = parseInt('' + this.year + this.padZero(this.month) + this.padZero(iCount),10);
					if (!(tmpCompare >= tmpFrom && tmpCompare <= tmpTo)) {
						bShowDay = false;
					}
				}
				
				if(bShowDay) {
					if (iCount==this.tDay && this.year==this.tYear && this.month==this.tMonth) {
						tmpStr += '<a class="today"' + (sTitle == ''?'':' title="' + sTitle + '"') + ' href="javascript: g_Calendar.clickDay(' + iCount + ');"><strong>' + iCount + '</strong></a>';
					} else {
						tmpStr += '<a' + (sTitle == ''?'':' title="' + sTitle + '"') + ' href="javascript: g_Calendar.clickDay(' + iCount + ');">' + iCount + '</a>';
					}
				} else {
					if (iCount==this.tDay && this.year==this.tYear && this.month==this.tMonth) {
						tmpStr += '<span' + (sTitle == ''?'':' title="' + sTitle + '"') + ' class="disabled today"><strong>' + iCount + '</strong></span>';
					} else {
						tmpStr += '<span' + (sTitle == ''?'':' title="' + sTitle + '"') + ' class="disabled">' + iCount + '</span>';
					}
				}
				iCount++;
			} else {
				if  (i==7-g_startDay || i==((7-g_startDay)%7)+1) {
					tmpStr += 'class="calWeekend"';
				}
				tmpStr += (sTitle == ''?'':' title="' + sTitle + '"') + '>&nbsp;';
			}
			tmpStr += '</td>';
		}
		tmpStr += '</tr>';
	}
	tmpStr += '</tbody>';
	tmpStr += '</table>';

// debugging
//	document.getElementById("tarea").value = tmpStr;
//	alert(tmpStr);

	return tmpStr;
};

Calendar.prototype.setDateFormat = function(dateFormat){
	// Default date to US format.
	this.dateFormat = dateFormat || 'm/d/yyyy';
	dp_dateFormat = this.dateFormat;
};

Calendar.prototype.setDayMask = function(mask){
	var j = this.dayMask.length > mask.length?mask.length:this.dayMask.length;
	for(var i = 0; i < j; i++)
		this.dayMask[i] = mask[i];
	return this.dayMask;
};

Calendar.prototype.setHolidays = function(obj, bShow){
	this.Holidays = obj;
	this.showHolidays = bShow;

	return obj;
};

Calendar.prototype.getFirstDOM = function() {
	var thedate = new Date();
	
	thedate.setDate(1);
	thedate.setMonth(this.month);
	thedate.setFullYear(this.year);

	return thedate.getDay();
};

Calendar.prototype.getDaysInMonth = function (){
	// If not February return from the daysInMonth array.
	if (this.month!=1){
		return this.daysInMonth[this.month];
	}

	// Is it a leap year?
	if (this.isLeapYear(this.year)){
		return 29;
	}

	return 28;
};

Calendar.prototype.isLeapYear = function(year) {
	if (year%4==0 && ((year%100!=0) || (year%400==0))) {
		return true;
	} else {
		return false;
	}
};

Calendar.prototype.selectChange = function(el) {
	this.month = el.selectedIndex;
	this.writeString(this.buildString());
};

Calendar.prototype.inputChange = function(el) {
	var tmp = el;
	if (tmp.value >=1900 && tmp.value <=2100) {
		this.year = tmp.value;
		this.writeString(this.buildString());
	} else {
		tmp.value = this.year;
	}
};

Calendar.prototype.changeYear = function(incr) {
	if (incr==1){
		this.year++;
	} else {
		this.year--;
	}

	this.writeString(this.buildString());
};

Calendar.prototype.changeMonth = function(incr){ 
	if (this.month==11 && incr==1) {
		this.month = 0;
		this.year++;
	} else if (this.month==0 && incr==-1) {
			this.month = 11;
			this.year--;
	} else if (incr==1) {
		this.month++;
	} else {
		this.month--;
	}

	this.writeString(this.buildString());
};

Calendar.prototype.clickDay = function(day){
	var el = document.getElementById(this.target);

	if(el){
		el.value = this.formatDateAsString(day,this.month,this.year);
		if(magicDate) {
			magicDate(el);
		}
		el.focus();
	}

	this.hide();
};

Calendar.prototype.clickMonth = function(month){
	this.month = month;
	this.writeString(this.buildString());
};

Calendar.prototype.clickYear = function(year){
	this.year = year;
	this.writeString(this.buildString());
};

Calendar.prototype.clickToday = function(){
	var theDate = new Date();
	this.year = theDate.getFullYear();
	this.month = theDate.getMonth();
	this.writeString(this.buildString());
};

Calendar.prototype.formatDateAsString = function(day, month, year){
	var delim = eval('/\\' + this.dateDelim + '/g');
	switch (this.dateFormat.replace(delim,"")){
	case 'ddmmmyyyy':
		return this.padZero(day) + this.dateDelim + this.months[month].substr(0,3) + this.dateDelim + year;
	case 'dmmmyyyy':
		return day + this.dateDelim + this.months[month].substr(0,3) + this.dateDelim + year;
	case 'ddmmyyyy':
		return this.padZero(day) + this.dateDelim + this.padZero(month+1) + this.dateDelim + year;
	case 'dmmyyyy':
		return day + this.dateDelim + this.padZero(month+1) + this.dateDelim + year;
	case 'mmddyyyy':
		return this.padZero((month+1)) + this.dateDelim + this.padZero(day) + this.dateDelim + year;
	case 'mddyyyy':
		return (month+1) + this.dateDelim + this.padZero(day) + this.dateDelim + year;
	case 'mdyyyy':
		return (month+1) + this.dateDelim + day + this.dateDelim + year;
	case 'yyyymmdd':
		return year + this.dateDelim + this.padZero(month+1) + this.dateDelim + this.padZero(day);
	default:
		return (month+1) + this.dateDelim + this.padZero(day) + this.dateDelim + year;
	}
};

Calendar.prototype.writeString = function(str){
	this.containerLayer.innerHTML = str;
};

Calendar.prototype.hide = function(){
	calendarClearTimeout();
	this.containerLayer.style.visibility='hidden';
};

Calendar.prototype.isVisible = function() {
	return this.containerLayer.style.visibility=='visible' ? true : false;
};

Calendar.prototype.isHidden = function() {
	return this.containerLayer.style.visibility=='hidden' ? true : false;
};

Calendar.prototype.padZero = function(num) {
	return ((num <= 9) ? ("0" + num) : num);
};

Calendar.prototype.getWindowHeight = function() {
	var windowHeight=0;

	if (typeof(window.innerHeight)=='number') {
		windowHeight=window.innerHeight;
	} else if (document.documentElement && document.documentElement.clientHeight) {
		windowHeight=document.documentElement.clientHeight;
	} else if (document.body && document.body.clientHeight) {
		windowHeight=document.body.clientHeight;
	}

	return windowHeight;
};

Calendar.prototype.openMenu = function(e) {
	var el = document.getElementById(e);
	if(!el) {
		return;
	}

	if(el.className == "open") {
		el.className = "";
	} else {
		el.className = "open";
	}
};
Calendar.prototype.closeMenu = function(e) {
	var el = document.getElementById(e);
	if(!el) {
		return;
	}

	el.className = "";
};
Calendar.prototype.openMenuMonths = function() {
	this.closeMenu('cp_years');
	this.openMenu('cp_months');
};
Calendar.prototype.openMenuYears = function() {
	this.closeMenu('cp_months');
	this.openMenu('cp_years');
};
Calendar.prototype.closeMenus = function() {
	this.closeMenu('cp_years');
	this.closeMenu('cp_months');
};

Calendar.prototype.handleClick = function(e)
{
	if (!e){
		e = window.event;
	}

	if (e.target){
		elSrc = e.target;
	}else if (e.srcElement){
		elSrc = e.srcElement;
	}

	// Get the x/y position of the mouse.
	if (e.pageX || e.pageY) {
		x = e.pageX;
		y = e.pageY;
	} else if (e.clientX || e.clientY) {
		x = e.clientX + document.body.scrollLeft;
		y = e.clientY + document.body.scrollTop;
	}

	// For some reason this doesn't give me access to the container,
	// so I'm using the global variable instead.
	if(y > parseInt(g_Calendar.containerLayer.style.top,10) + 20) {
		g_Calendar.closeMenus();
	}

	e.cancelBubble = true;
	if (e.stopPropagation){
		e.stopPropagation();
	}
};
// End Calendar Class

// Utility functions
function calendarTimeout() {
	if(cp_timeoutDelay) {
		cp_timeoutId = setTimeout('g_Calendar.hide();',cp_timeoutDelay);
	}
}

function calendarClearTimeout() {
	if (cp_timeoutId) {
		clearTimeout(cp_timeoutId);
	}
}

function cp_handleDocumentClick(e){
	var elSrc, x, y;

	if(!g_Calendar.containerLayer){
		return;
	}

	if(g_Calendar.isHidden()) {
		return;
	}

	g_Calendar.hide();
}

Date.prototype.addDays = function(num){
	return new Date((num*(1000*60*60*24))+this.valueOf());
};

new Calendar(new Date());

window.document.onclick=cp_handleDocumentClick;