/******************************************************************************
 DatePickerWidget v0.4 (August 1, 2006) by Bramus! 
 http://www.bram.us/
 
 Based upon the 'JavaScript DHTML datepicker' (version 1.4 - December 20, 2004) 
 originally made by Julian Robichaux - http://www.nsftools.com/tips/DatePickerTest.htm
 
 Version History:
 
 	0.4 (August 1, 2006)
		- added startdate parameter, handy when a user for example already entered 
		  his year of birth somewhere.s
 
 	0.3 (July 28, 2006)
		- added yearswitching buttons (+1, -1)
 
 	0.2 (Late 2005?)
 		- fixed small bug where script would set focus to element, but if it's hidden
 		  IE would pop an error --> try-catch hooked into it.
 		- fixed hover behavior of the cells (in CSS (FX, Safari) and JS (IE))
 		
 	0.1 (June 2005?)
 		- converted the base code to a Widget
 		- Safari Fix (Safari gave back 1970 by default)
 		
 Example Usage:
 	
 	<input type="text" id="txtDate" name="txtDate" />
 	<input type="button" onclick"DatePickerWidget('txtDate', this, startDate);" />
	
	* this denotes that the datepicker should appear underneath the button,
	  one could for example change it to document.getElementById('txtDate')
	  
	* startDate should be in the same format as defined by dtFormat and dtSep
	  (or by defaultDateFormat and defaultDateSeparator if no dtFormat and/or 
	   dtSep are defined, which is the case in this example)
 
 ******************************************************************************/

function DatePickerWidget() {
	DatePickerWidget.prototype.displayDatePicker.apply(this, arguments);
}

DatePickerWidget.prototype = {

	// these variables define the date formatting we're expecting and outputting.
	
	defaultDateSeparator 	: "-",		// common values would be "/" or "."
	defaultDateFormat 		: "ymd",	// valid values are "mdy", "dmy", and "ymd"
	
	// Language Settings

	/*
	// dutch
	dayArrayShort 			: new Array('ZO', 'MA', 'DI', 'WO', 'DO', 'VR', 'ZA'),
	dayArrayMed 			: new Array('Zon', 'Maa', 'Din', 'Woe', 'Don', 'Vri', 'Zat'),
	dayArrayLong 			: new Array('Zondag', 'Maandag', 'Dinsdag', 'Woensdag', 'Donderdag', 'Vrijdag', 'Zaterdag'),
	monthArrayShort 		: new Array('Jan', 'Feb', 'Mar', 'Apr', 'Mei', 'Jun', 'Jul', 'Aug', 'Sep', 'Okt', 'Nov', 'Dec'),
	monthArrayMed 			: new Array('Jan', 'Feb', 'Mar', 'Apr', 'Mei', 'Juni', 'Juli', 'Aug', 'Sept', 'Okt', 'Nov', 'Dec'),
	monthArrayLong 			: new Array('Januari', 'Februari', 'Maart', 'April', 'Mei', 'Juni', 'Juli', 'Augustus', 'September', 'Oktober', 'November', 'December'),
	*/

	// english	
	dayArrayShort 			: new Array('Su', 'Mo', 'Tu', 'We', 'Th', 'Fr', 'Sa'),
	dayArrayMed 			: new Array('Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'),
	dayArrayLong 			: new Array('Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'),
	monthArrayShort 		: new Array('Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'),
	monthArrayMed 			: new Array('Jan', 'Feb', 'Mar', 'Apr', 'May', 'June', 'July', 'Aug', 'Sept', 'Oct', 'Nov', 'Dec'),
	monthArrayLong 			: new Array('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'),
	
	/** Don't touch from here */
	
	datePickerDivID 		: "datepicker",
	iFrameDivID 			: "datepickeriframe",
	
	dateSeparator 			: DatePickerWidget.prototype.defaultDateSeparator,
	dateFormat 				: DatePickerWidget.prototype.defaultDateFormat,
	
	
	
	/**
		This is the main function you'll call from the onClick event of a button.
		Normally, you'll have something like this on your HTML page:
	*/
	displayDatePicker		: function (dateFieldName, displayBelowThisObject, startDate, dtFormat, dtSep) {
	
								var targetDateField = document.getElementsByName(dateFieldName).item(0);
								
								// if we weren't told what node to display the datepicker beneath, just display it
								// beneath the date field we're updating
								if (!displayBelowThisObject)
									displayBelowThisObject = targetDateField;
								
								// if a date separator character was given, update the dateSeparator variable
								if (dtSep)
									DatePickerWidget.prototype.dateSeparator = dtSep;
								else
									DatePickerWidget.prototype.dateSeparator = DatePickerWidget.prototype.defaultDateSeparator;
								
								// if a date format was given, update the dateFormat variable
								if (dtFormat)
									DatePickerWidget.prototype.dateFormat = dtFormat;
								else
									DatePickerWidget.prototype.dateFormat = DatePickerWidget.prototype.defaultDateFormat;
									
								var x = displayBelowThisObject.offsetLeft;
								var y = displayBelowThisObject.offsetTop + displayBelowThisObject.offsetHeight;
								
								// deal with elements inside tables and such
								var parent = displayBelowThisObject;
								while (parent.offsetParent) {
									parent = parent.offsetParent;
									x += parent.offsetLeft;
									y += parent.offsetTop;
								}
								
								DatePickerWidget.prototype.drawDatePicker(targetDateField, x, y, startDate);
								  
	},
	
	
	
	/**
		Draw the datepicker object (which is just a table with calendar elements) at the
		specified x and y coordinates, using the targetDateField object as the input tag
		that will ultimately be populated with a date.
		
		This function will normally be called by the displayDatePicker function.
	*/
	
	drawDatePicker			: function (targetDateField, x, y, startDate) {
								if (targetDateField.value == "") {
									var dt = DatePickerWidget.prototype.getFieldDate(startDate)
								} else {
									var dt = DatePickerWidget.prototype.getFieldDate(targetDateField.value);
								}
								
								// the datepicker table will be drawn inside of a <div> with an ID defined by the
								// global datePickerDivID variable. If such a div doesn't yet exist on the HTML
								// document we're working with, add one.
								if (!document.getElementById(DatePickerWidget.prototype.datePickerDivID)) {
									// don't use innerHTML to update the body, because it can cause global variables
									// that are currently pointing to objects on the page to have bad references
									//document.body.innerHTML += "<div id='" + datePickerDivID + "' class='dpDiv'></div>";
									var newNode = document.createElement("div");
									newNode.setAttribute("id", DatePickerWidget.prototype.datePickerDivID);
									newNode.setAttribute("class", "dpDiv");
									newNode.setAttribute("style", "visibility: hidden;");
									document.body.appendChild(newNode);
								}
								
								// move the datepicker div to the proper x,y coordinate and toggle the visiblity
								var pickerDiv = document.getElementById(DatePickerWidget.prototype.datePickerDivID);
								pickerDiv.style.position = "absolute";
								pickerDiv.style.left = x + "px";
								pickerDiv.style.top = y + "px";
								pickerDiv.style.visibility = (pickerDiv.style.visibility == "visible" ? "hidden" : "visible");
								pickerDiv.style.zIndex = 10000;
								
								// draw the datepicker table
								DatePickerWidget.prototype.refreshDatePicker(targetDateField.name, dt.getFullYear(), dt.getMonth(), dt.getDate());
	},
	
	
	
	
	
	
	
	/**
		This is the function that actually draws the datepicker calendar.
	*/
	refreshDatePicker			: function (dateFieldName, year, month, day) {
	
									// if no arguments are passed, use today's date; otherwise, month and year
									// are required (if a day is passed, it will be highlighted later)
									var thisDay = new Date();
									
									if ((month == '') || isNaN(month))
										month = 0;
									if ((year == '') || isNaN(year))
										year = 0;
									
									if ((month >= 0) && (year > 0)) {
										thisDay = new Date(year, month, 1);
									} else {
										day = thisDay.getDate();
										year = thisDay.getFullYear();
										thisDay.setDate(1);
										thisDay.setFullYear(year);
									}
									
									// the calendar will be drawn as a table
									// you can customize the table elements with a global CSS style sheet,
									// or by hardcoding style and formatting elements below
									var crlf = "\r\n";
									var TABLE = "<table cols=7 class='dpTable'>" + crlf;
									var xTABLE = "</table>" + crlf;
									var TR = "<tr class='dpTR'>";
									var TR_title = "<tr class='dpTitleTR'>";
									var TR_days = "<tr class='dpDayTR'>";
									var TR_todaybutton = "<tr class='dpTodayButtonTR'>";
									var xTR = "</tr>" + crlf;
									var TD = "<td class='dpTD'";	// leave this tag open, because we'll be adding an onClick event
									var TD_title = "<td colspan=5 class='dpTitleTD'>";
									var TD_buttons = "<td class='dpButtonTD'>";
									var TD_todaybutton = "<td colspan=7 class='dpTodayButtonTD'>";
									var TD_days = "<td class='dpDayTD'>";
									var TD_selected = "<td class='dpDayHighlightTD'";	// leave this tag open, because we'll be adding an onClick event
									var xTD = "</td>" + crlf;
									var DIV_title = "<div class='dpTitleText'>";
									var DIV_selected = "<div class='dpDayHighlight'>";
									var xDIV = "</div>";
									
									// start generating the code for the calendar table
									var html = TABLE;
									
									// this is the title bar, which displays the month and the buttons to
									// go back to a previous month or forward to the next month
									html += TR_title;
									html += TD_buttons + DatePickerWidget.prototype.getButtonCodeYear(dateFieldName, thisDay, -1, "&lt;&lt;") + DatePickerWidget.prototype.getButtonCode(dateFieldName, thisDay, -1, "&lt;") + xTD;
									html += TD_title + DIV_title + DatePickerWidget.prototype.monthArrayLong[thisDay.getMonth()] + " " + thisDay.getFullYear() + xDIV + xTD;
									html += TD_buttons + DatePickerWidget.prototype.getButtonCode(dateFieldName, thisDay, 1, "&gt;") + DatePickerWidget.prototype.getButtonCodeYear(dateFieldName, thisDay, 1, "&gt;&gt;") + xTD;
									html += xTR;
									
									// this is the row that indicates which day of the week we're on
									html += TR_days;
									for(i = 0; i < DatePickerWidget.prototype.dayArrayShort.length; i++)
										html += TD_days + DatePickerWidget.prototype.dayArrayShort[i] + xTD;
									html += xTR;
									
									// now we'll start populating the table with days of the month
									html += TR;
									
									// first, the leading blanks
									for (i = 0; i < thisDay.getDay(); i++)
										html += TD + "&nbsp;" + xTD;
									
									// now, the days of the month
									do {
										dayNum = thisDay.getDate();
										TD_onclick 		= " onclick=\"DatePickerWidget.prototype.updateDateField('" + dateFieldName + "', '" + DatePickerWidget.prototype.getDateString(thisDay) + "');\"";
										TD_hoverfake 	= " onmouseover=\"this.className='dpTDHover';\"  onmouseout=\"this.className='dpTD';\"";
										TD_end			= ">";
										
										if (dayNum == day)
											html += TD_selected + TD_onclick + (document.all?TD_hoverfake:'') + TD_end + DIV_selected + dayNum + xDIV + xTD;
										else
											html += TD + TD_onclick + (document.all?TD_hoverfake:'') + TD_end + dayNum + xTD;
										
										// if this is a Saturday, start a new row
										if (thisDay.getDay() == 6)
											html += xTR + TR;
										
										// increment the day
										thisDay.setDate(thisDay.getDate() + 1);
									} while (thisDay.getDate() > 1)
									
									// fill in any trailing blanks
									if (thisDay.getDay() > 0) {
										for (i = 6; i > thisDay.getDay(); i--)
											html += TD + "&nbsp;" + xTD;
									}
									html += xTR;
									
									// add a button to allow the user to easily return to today, or close the calendar
									var today = new Date();
									var todayString = "Today is " + DatePickerWidget.prototype.dayArrayMed[today.getDay()] + ", " + DatePickerWidget.prototype.monthArrayMed[today.getMonth()] + " " + today.getDate();
									html += TR_todaybutton + TD_todaybutton;
									html += "<button class='dpTodayButton' onClick='DatePickerWidget.prototype.refreshDatePicker(\"" + dateFieldName + "\");'>Today</button> ";
									html += "<button class='dpTodayButton' onClick='DatePickerWidget.prototype.updateDateField(\"" + dateFieldName + "\");'>Close</button>";
									html += xTD + xTR;
									
									// and finally, close the table
									html += xTABLE;
									
									document.getElementById(DatePickerWidget.prototype.datePickerDivID).innerHTML = html;
									// add an "iFrame shim" to allow the datepicker to display above selection lists
									DatePickerWidget.prototype.adjustiFrame();
	},






	/**
		Convenience function for writing the code for the buttons that bring us back or forward
		a month.
	*/
	getButtonCode				: function (dateFieldName, dateVal, adjust, label) {
	
									var newMonth = (dateVal.getMonth() + adjust) % 12;
									var newYear = dateVal.getFullYear() + parseInt((dateVal.getMonth() + adjust) / 12);
									
									if (newMonth < 0) {
										newMonth += 12;
										newYear += -1;
									}
	
									return "<button class='dpButton' onClick='DatePickerWidget.prototype.refreshDatePicker(\"" + dateFieldName + "\", " + newYear + ", " + newMonth + ");'>" + label + "</button>";
	},	






	/**
		Convenience function for writing the code for the buttons that bring us back or forward
		a month.
	*/
	getButtonCodeYear			: function (dateFieldName, dateVal, adjust, label) {
	
									var newYear = dateVal.getFullYear() + parseInt(adjust);
	
									return "<button class='dpButton' onClick='DatePickerWidget.prototype.refreshDatePicker(\"" + dateFieldName + "\", " + newYear + ", " + dateVal.getMonth() + ");'>" + label + "</button>";
	},	
	
	
	
	
	
	
	

	/**
		Convert a JavaScript Date object to a string, based on the dateFormat and dateSeparator
		variables at the beginning of this script library.
	*/
	getDateString				: function (dateVal) {
	
									var dayString = "00" + dateVal.getDate();
									var monthString = "00" + (dateVal.getMonth()+1);
									dayString = dayString.substring(dayString.length - 2);
									monthString = monthString.substring(monthString.length - 2);
									
									switch (DatePickerWidget.prototype.dateFormat) {
										case "dmy" :
											return dayString + DatePickerWidget.prototype.dateSeparator + monthString + DatePickerWidget.prototype.dateSeparator + dateVal.getFullYear();
										case "ymd" :
											return dateVal.getFullYear() + DatePickerWidget.prototype.dateSeparator + monthString + DatePickerWidget.prototype.dateSeparator + dayString;
										case "mdy" :
										default :
											return monthString + DatePickerWidget.prototype.dateSeparator + dayString + DatePickerWidget.prototype.dateSeparator + dateVal.getFullYear();
									}
	},
	
	
	
	
	
	
	/**
		Convert a string to a JavaScript Date object.
	*/
	getFieldDate				: function (dateString) {
	
									var dateVal;
									var dArray;
									var d, m, y;
									
									try {
										dArray = DatePickerWidget.prototype.splitDateString(dateString);
										if (dArray) {
											switch (DatePickerWidget.prototype.dateFormat) {
												case "dmy" :
													d = parseInt(dArray[0], 10);
													m = parseInt(dArray[1], 10) - 1;
													y = parseInt(dArray[2], 10);
													break;
												case "ymd" :
													d = parseInt(dArray[2], 10);
													m = parseInt(dArray[1], 10) - 1;
													y = parseInt(dArray[0], 10);
													break;
												case "mdy" :
												default :
													d = parseInt(dArray[1], 10);
													m = parseInt(dArray[0], 10) - 1;
													y = parseInt(dArray[2], 10);
													break;
											}
											dateVal = new Date(y, m, d);
										} else {
											dateVal = new Date(); /* WAS: new Date(dateString), but gives back 1970 on Safari and Invalid Date in FireFox */
										}
									} catch(e) {
										dateVal = new Date();
									}
									
									return dateVal;
	},
	
	
	
	
	
	
	/**
		Try to split a date string into an array of elements, using common date separators.
		If the date is split, an array is returned; otherwise, we just return false.
	*/
	splitDateString					: function (dateString) {
	
										var dArray;
										if (dateString.indexOf("/") >= 0)
											dArray = dateString.split("/");
										else if (dateString.indexOf(".") >= 0)
											dArray = dateString.split(".");
										else if (dateString.indexOf("-") >= 0)
											dArray = dateString.split("-");
										else if (dateString.indexOf("\\") >= 0)
											dArray = dateString.split("\\");
										else
											dArray = false;
										
										return dArray;
	},
	
	
	
	
	
	/**
		Update the field with the given dateFieldName with the dateString that has been passed,
		and hide the datepicker. If no dateString is passed, just close the datepicker without
		changing the field value.
	*/
	updateDateField					: function (dateFieldName, dateString) {
	
										var targetDateField = document.getElementsByName(dateFieldName).item(0);
										
										if (dateString)
											targetDateField.value = dateString;
										document.getElementById(DatePickerWidget.prototype.datePickerDivID).style.visibility = "hidden";
										DatePickerWidget.prototype.adjustiFrame();
										try {
											targetDateField.focus();
										} catch (e) { }
										
										// after the datepicker has closed, optionally run a user-defined function called
										// datePickerClosed, passing the field that was just updated as a parameter
										// (note that this will only run if the user actually selected a date from the datepicker)
										if ((dateString) && (typeof(DatePickerWidget.prototype.datePickerClosed) == "function"))
											DatePickerWidget.prototype.datePickerClosed(dateFieldName);
	},
	
	
	
	
	
	
	/**
		Use an "iFrame shim" to deal with problems where the datepicker shows up behind
		selection list elements, if they're below the datepicker. The problem and solution are
		described at:
	
		http://dotnetjunkies.com/WebLog/jking/archive/2003/07/21/488.aspx
		http://dotnetjunkies.com/WebLog/jking/archive/2003/10/30/2975.aspx
	*/
	adjustiFrame					: function (pickerDiv, iFrameDiv) {
	
										if (!document.getElementById(DatePickerWidget.prototype.iFrameDivID)) {
											// don't use innerHTML to update the body, because it can cause global variables
											// that are currently pointing to objects on the page to have bad references
											//document.body.innerHTML += "<iframe id='" + iFrameDivID + "' src='javascript:false;' scrolling='no' frameborder='0'>";
											var newNode = document.createElement("iFrame");
											newNode.setAttribute("id", DatePickerWidget.prototype.iFrameDivID);
											newNode.setAttribute("src", "javascript:false;");
											newNode.setAttribute("scrolling", "no");
											newNode.setAttribute("frameborder", "0");
											document.body.appendChild(newNode);
										}

										if (!pickerDiv)
											pickerDiv = document.getElementById(DatePickerWidget.prototype.datePickerDivID);
										if (!iFrameDiv)
											iFrameDiv = document.getElementById(DatePickerWidget.prototype.iFrameDivID);
										
										try {
											iFrameDiv.style.position = "absolute";
											iFrameDiv.style.width = pickerDiv.offsetWidth;
											iFrameDiv.style.height = pickerDiv.offsetHeight;
											iFrameDiv.style.top = pickerDiv.style.top;
											iFrameDiv.style.left = pickerDiv.style.left;
											iFrameDiv.style.zIndex = pickerDiv.style.zIndex - 1;
											iFrameDiv.style.visibility = pickerDiv.style.visibility;
										} catch(e) {
										}
	},
	
	
	
	
	
	/**
		If the page developer has defined a function called datePickerClosed anywhere on
		the page or in an imported library, we will attempt to run that function with the updated
		field as a parameter. This can be used for such things as date validation, setting default
		values for related fields, etc. 
	*/	
	datePickerClosed				: function (dateFieldName) {
	
										document.getElementById("lbl_" + dateFieldName).innerHTML = document.getElementById(dateFieldName).value;
	
										/** For example, you might have a function like this to validate a start date field: */
										/**
											var dateObj = getFieldDate(dateField.value);
											var today = new Date();
											today = new Date(today.getFullYear(), today.getMonth(), today.getDate());
											
											if (dateField.name == "StartDate") {
												if (dateObj < today) {
													// if the date is before today, alert the user and display the datepicker again
													alert("Please enter a date that is today or later");
													dateField.value = "";
													document.getElementById(DatePickerWidget.prototype.datePickerDivID).style.visibility = "visible";
													DatePickerWidget.prototype.adjustiFrame();
												} else {
													// if the date is okay, set the EndDate field to 7 days after the StartDate
													dateObj.setTime(dateObj.getTime() + (7 * 24 * 60 * 60 * 1000));
													var endDateField = document.getElementsByName("EndDate").item(0);
													endDateField.value = getDateString(dateObj);
												}
											}
										*/
	}

}