/** 
 * Called when the calendar button is clicked on - causes the popup
 * calendar to be displayed.
 */
function popupCalendar(inputfield_id)
{
	// make sure calendar date is synchronized with dropdown date
	updatePopupsFromDropdowns();
	var inputfield = document.getElementById(inputfield_id);
	var calObj = new calendar2(inputfield);
	calObj.callback = updateDropdownsFromPopups;
	calObj.popup(null, "/mindlab/calendar/html/");
}

/**
 * This function updates the dropdown date selection form elements
 * when the user chooses a date via the popup calendar widget.  
 * This function sets the drop-down ("<select>") form elements to the new date value.
 */
function updateDropdownsFromPopups()
{
	var i;
    for (i=0; i<document.calendars.length; i++)
    {
   		var calendarinfo = document.calendars[i];
 		// grab the form elements
    			
 		var yearselect  = document.getElementById(calendarinfo[0]);
		var monthselect = document.getElementById(calendarinfo[1]);
		var dayselect   = document.getElementById(calendarinfo[2]);   			
 		var inputfield  = document.getElementById(calendarinfo[3]);
 		
 		var date = new Date(inputfield.value);
 		
		// update each of them
	    updateSelect(yearselect, date.getFullYear());
	    updateSelect(monthselect, date.getMonth()+1);
	    updateSelect(dayselect, date.getDate());
	}
}


function updatePopupsFromDropdowns()
{
	var i;
	// synchronize the pop-up calendars to the drop-down dates
	for (i=0; i<document.calendars.length; i++)
	{
		var calendarinfo = document.calendars[i];
 		var yearselect  = document.getElementById(calendarinfo[0]);
		var monthselect = document.getElementById(calendarinfo[1]);
		var dayselect   = document.getElementById(calendarinfo[2]);
		var inputfield  = document.getElementById(calendarinfo[3]);
		
		var year = yearselect.options[yearselect.selectedIndex].value;
		var month = monthselect.options[monthselect.selectedIndex].value;
		var day = dayselect.options[dayselect.selectedIndex].value;
		
		// format the selected date like "12/31/2004" and put it into the input
		// field which the pop-up calendar uses
		inputfield.value = month  + '/' + day  + '/' + year;
	}
}

/** 
 * This function sets the given select form element (drop-down list) to a new selection
 * selectObj - the select form element object
 * newSelection - the value to select in the select form element (drop-down list)
 */
function updateSelect(selectObj, newSelection)
{
	for (i=0; i<selectObj.length; i++)
	{
  		if (selectObj.options[i].value == newSelection)
  		{
  			selectObj.selectedIndex = i;
  			return;
  		}
  	}
}

if (document.calendarcounter == undefined) 
{
	document.calendars = new Array();
	document.calendarcounter = 0;
}

function dateselectionwidgetpopup(yearselect_id, monthselect_id, dayselect_id)
{		
	var calendarcounter = document.calendarcounter++;
	
	var inputfield_id = "calendarhiddenfield"+calendarcounter;

	// The image button that the user clicks on to pop up the calendar 
	document.write('<img src="/mindlab/calendar/images/calendar/cal.gif" onClick="popupCalendar(\''+inputfield_id+'\');" alt="" style="cursor: pointer;" title="Popup date selector" />');

	// A hidden input field where the selected date value will be stored. 
	document.write('<input type="hidden" name="'+inputfield_id+'" id="'+inputfield_id+'" />');

	// stuff away variables specific to this particular calendar instance so that updateXXX() can get them   
	document.calendars[calendarcounter] = new Array(yearselect_id, monthselect_id, dayselect_id, inputfield_id);
}