var mSelectedDay;
var mSelectedMonth
var mSelectedYear;
var mHighlightedDay = 0;
var mCurrentMonth;
var mCurrentYear;
var mOnHideFunction;
var mImgFolder = "_images/";

function setSelectedDates(dateString) {
	var currentSelectedDate = new Date(dateString);
	if (isNaN(currentSelectedDate)) {
		currentSelectedDate = new Date();
	}

	mSelectedDay = currentSelectedDate.getDate();
	mSelectedMonth = currentSelectedDate.getMonth();
	mSelectedYear = currentSelectedDate.getFullYear();
	mCurrentMonth = mSelectedMonth;
	mCurrentYear = mSelectedYear;
}

function generateCalendar(month, year, theDivTag) {
	//-- Arrows and Month
	var headingHTML = "<table class='monthHeadingTable' border='0'>";
	headingHTML += "<tr>";
	headingHTML += "<td class='changeMonthTD'>";
	headingHTML += "<img src='" + mImgFolder + "prev.gif' title='Previous Month' onclick='goPreviousMonth(\"" + theDivTag + "\")'>";
	headingHTML += "</td>";
	headingHTML += "<td class='monthHeadingTD'>" + getMonthShortName(month) + "</td>";
	headingHTML += "<td class='changeMonthTD'>";
	headingHTML += "<input id='txtCalMonth' type='text' size='2' maxlength='4' value='" + year + "' onblur='goYear(\"" + theDivTag + "\")';>";
	headingHTML += "</td>";
	headingHTML += "<td class='changeMonthTD'>";
	headingHTML += "<table cellpadding='0' cellspacing='0'>";
	headingHTML += "<tr>";
	headingHTML += "<td>";
	headingHTML += "<img  src='" + mImgFolder + "icoUp.gif' align='top' title='Next Year' onclick='goNextYear(\"" + theDivTag + "\")'>";
	headingHTML += "</td>";
	headingHTML += "</tr>";
	headingHTML += "<tr>";
	headingHTML += "<td>";
	headingHTML += "<img src='" + mImgFolder + "icoDown.gif' align='baseline' title='Previous Year' onclick='goPreviousYear(\"" + theDivTag + "\")'>";
	headingHTML += "</td>";
	headingHTML += "</tr>";
	headingHTML += "</table>";
	headingHTML += "</td>";
	headingHTML += "<td class='changeMonthTD'>";
	headingHTML += "<img src='" + mImgFolder + "next.gif' title='Next Month' onclick='goNextMonth(\"" + theDivTag + "\")'>";
	headingHTML += "</td>";
	headingHTML += "</tr>";
	headingHTML += "</table>";

	//-- Days
	var tableInnerHTML = "";
	tableInnerHTML = "<tr class='dayHeadTR'>";
	tableInnerHTML += "<td class='dayHeadTD'>S</td>";
	tableInnerHTML += "<td class='dayHeadTD'>M</td>";
	tableInnerHTML += "<td class='dayHeadTD'>T</td>"
	tableInnerHTML += "<td class='dayHeadTD'>W</td>";
	tableInnerHTML += "<td class='dayHeadTD'>T</td>";
	tableInnerHTML += "<td class='dayHeadTD'>F</td>";
	tableInnerHTML += "<td class='dayHeadTD'>S</td>";
	tableInnerHTML += "</tr>"

	var elementIndex = 1;
	var iCellCounter;
	var iStartDayOfMonth = getStartDayOfMonthNumber(month, year);
	var iLastDayOfMonth = getDaysInAMonth(month, year);
	var tableRows = 6;
	for (weekIndex = 1; weekIndex <= tableRows; weekIndex++) {
		tableInnerHTML = tableInnerHTML + "<tr>";
		var dayCounter;

		for (dayCounter = 1; dayCounter <= 7; dayCounter++) {
			if (elementIndex <= iStartDayOfMonth || elementIndex > (iLastDayOfMonth + iStartDayOfMonth)) {
				tableInnerHTML += "<td class='emptyTD' id='dayTD";
				tableInnerHTML += elementIndex;
				tableInnerHTML += "'>&nbsp</td>";
			}
			else {
				tableInnerHTML += "<td class='dayTD' onclick='updateSelectedDate(";
				tableInnerHTML += (elementIndex - iStartDayOfMonth);
				tableInnerHTML += "," + month + ",";
				tableInnerHTML += year + "); ";
				tableInnerHTML += " hideCalendar(\"" + theDivTag + "\"); ";
				tableInnerHTML += "'id='dayTD" + elementIndex + "'>";
				tableInnerHTML += (elementIndex - iStartDayOfMonth);
				tableInnerHTML += "</td>";
			}
			elementIndex++;
		}
		tableInnerHTML = tableInnerHTML + "</tr>";
	}

	var calendarDivObject = getTagById(theDivTag)
	calendarDivObject.innerHTML = headingHTML +
	"<table style='calendarTable' cellspacing='0'>" + tableInnerHTML + "</table>" +
	"<a href='javaScript:cancelCalendar(\"" + theDivTag + "\")' class='cancelHyperlink'>Cancel</a>";

	if (mCurrentMonth == mSelectedMonth && mCurrentYear == mSelectedYear) {
		highlightDay(mSelectedDay, mSelectedMonth, mSelectedYear);
	}
}

function getTagById(tagId) {
	if (document.getElementById) {
		return document.getElementById(tagId);
	}
	if (document.all) {
		return document.all.item(tagId);
	}
	return null;
}

function getStartDayOfMonthNumber(month, year) {
	var newDate = new Date();
	newDate.setMonth(month)
	newDate.setFullYear(year);
	newDate.setDate(1);

	return newDate.getDay();
}

function getDaysInAMonth(month, year) {
	var nowDate;
	month = parseInt(month)
	year = parseInt(year)
	var monthDays = new Array(31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31)

	// If Feb then need to check for leap years
	if (month == 1) {
		nowDate = new Date();
		nowDate.setMonth(1);
		nowDate.setYear(year);
		nowDate.setDate(29);
		if (nowDate.getMonth() == 2) {
			monthDays[1] = 28;
		}
	}

	return monthDays[month];
}

function getMonthName(month) {
	var months = new Array("01", "02", "03", "04", "05", "06", "07", "08", "09", "10", "11", "12");
	return months[month];
}
function getMonthShortName(month) {
	var months = new Array("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec");
	return months[month];
}
function getMonthFullName(month) {
	var months = new Array("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December");
	return months[month];
}

function highlightDay(day, month, year) {
	var idOfCellToHighlight = day + getStartDayOfMonthNumber(month, year);
	idOfCellToHighlight = "dayTD" + idOfCellToHighlight;
	getTagById(idOfCellToHighlight).style.backgroundColor = 'lightgrey';
}

function updateSelectedDate(day, month, year) {
	mSelectedDay = day;
	mSelectedMonth = month;
	mSelectedYear = year;
}

function goPreviousMonth(theDivTag) {
	mCurrentMonth--;
	mCurrentYear = getYearText();
	if (mCurrentMonth < 0) {
		mCurrentMonth = 11;
		mCurrentYear--;
	}

	generateCalendar(mCurrentMonth, mCurrentYear, theDivTag);
}

function goNextMonth(theDivTag) {
	mCurrentMonth++;
	mCurrentYear = getYearText();
	if (mCurrentMonth > 11) {
		mCurrentMonth = 0;
		mCurrentYear++;
	}

	generateCalendar(mCurrentMonth, mCurrentYear, theDivTag);
}


function goNextYear(theDivTag) {
	mCurrentYear++;
	setYearText(mCurrentYear);
	generateCalendar(mCurrentMonth, mCurrentYear, theDivTag);
}

function goPreviousYear(theDivTag) {
	mCurrentYear--;
	setYearText(mCurrentYear);
	generateCalendar(mCurrentMonth, mCurrentYear, theDivTag);
}
function goYear(theDivTag) {
	generateCalendar(mCurrentMonth, getYearText(), theDivTag);
}

function cancelCalendar(theDivTag) {
	//-- I can't get the visibility to work so we have to hide it offscreen for now
	var tag = getTagById(theDivTag);
	tag.style.left = "-100px";
	tag.style.top = "-2000px";

	//var vis = (getTagById(theDivTag).style.visibility == 'hidden') ? 'visible'	: 'hidden';
	//alert(vis);
	//getTagById(theDivTag).style.visibility = vis;
}

function hideCalendar(theDivTag) {
	cancelCalendar(theDivTag);
	mOnHideFunction(mSelectedDay, getMonthName(mSelectedMonth), mSelectedYear);
}

function showCalendar(xPos, yPos, theDivTag, onHideFunction) {
	if (document.getElementById || document.all) {
		var tag = getTagById(theDivTag);
		tag.style.left = xPos + "px";
		tag.style.top = yPos + "px";
		mOnHideFunction = onHideFunction;
	}
}

function setYearText(year) {
	var txtYear = getTagById('txtCalMonth');
	if (txtYear == null || txtYear.value == '' || txtYear.value < 1950) {
		return;
	}
	if (isNaN(year)) {
		var newDate = new Date();
		year = newDate.getYear();
	}
	return txtYear.value;
}
function getYearText() {
	var txtYear = getTagById('txtCalMonth');
	if (txtYear == null || txtYear.value == '' || txtYear.value < 1950) {
		var newDate = new Date();
		return newDate.getYear();
	}

	return txtYear.value;
}

//-- The textfield and div tag need to be global
var TextField;
var DivTag;
//-- Err: Null is null or not an object - Add the Div or form tag dummy.
function setDate(day, month, year, textField) {
	var doc = document.forms[0];
	doc.elements[TextField].value = month + "/" + day + "/" + getYearText();
}

function pickDate(event, textField, divTag) {
	//alert();
	if (document.getElementById || document.all) {
		DivTag = divTag;
		TextField = textField
		var doc = document.forms[0];


		if (doc == null) alert("You forgot the form tag dummy!");
		if (getTagById(DivTag) == null) alert("You forgot the div tag dummy!");

		var dateString = doc.elements[TextField].value;

		setSelectedDates(dateString);
		generateCalendar(mCurrentMonth, mCurrentYear, DivTag);
		showCalendar(event.clientX, event.clientY, DivTag, setDate);
	}
}