//
// Configuration
//

// If you would like to use a custom loading image or close button reference them in the next two lines.
var loadingImage = 'image/imageviewer/loading.gif';		
var closeButton = 'image/imageviewer/close.gif';

//
// getPageScroll()
// Returns array with x,y page scroll values.
// Core code from - quirksmode.org
//
function getPageScroll(){

	var yScroll;

	if (self.pageYOffset) {
		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;
	}

	arrayPageScroll = new Array('',yScroll) 
	return arrayPageScroll;
}



//
// getPageSize()
// Returns array with page width, height and window width, height
// Core code from - quirksmode.org
// Edit for Firefox by pHaez
//
function getPageSize(){
	
	var xScroll, yScroll;
	
	if (window.innerHeight && window.scrollMaxY) {	
		xScroll = document.body.scrollWidth;
		yScroll = window.innerHeight + window.scrollMaxY;
	} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
		xScroll = document.body.scrollWidth;
		yScroll = document.body.scrollHeight;
	} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
		xScroll = document.body.offsetWidth;
		yScroll = document.body.offsetHeight;
	}
	
	var windowWidth, windowHeight;
	if (self.innerHeight) {	// all except Explorer
		windowWidth = self.innerWidth;
		windowHeight = self.innerHeight;
	} else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
		windowWidth = document.documentElement.clientWidth;
		windowHeight = document.documentElement.clientHeight;
	} else if (document.body) { // other Explorers
		windowWidth = document.body.clientWidth;
		windowHeight = document.body.clientHeight;
	}	
	
	// for small pages with total height less then height of the viewport
	if(yScroll < windowHeight){
		pageHeight = windowHeight;
	} else { 
		pageHeight = yScroll;
	}

	// for small pages with total width less then width of the viewport
	if(xScroll < windowWidth){	
		pageWidth = windowWidth;
	} else {
		pageWidth = xScroll;
	}


	arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight) 
	return arrayPageSize;
}


//
// pause(numberMillis)
// Pauses code execution for specified time. Uses busy code, not good.
// Code from http://www.faqts.com/knowledge_base/view.phtml/aid/1602
//
function pause(numberMillis) {
	var now = new Date();
	var exitTime = now.getTime() + numberMillis;
	while (true) {
		now = new Date();
		if (now.getTime() > exitTime)
			return;
	}
}

//
// getKey(key)
// Gets keycode. If 'x' is pressed then it hides the menuviewer.
//

function getKey(e){
	if (e == null) { // ie
		keycode = event.keyCode;
	} else { // mozilla
		keycode = e.which;
	}
	key = String.fromCharCode(keycode).toLowerCase();
	
	if(key == 'x'){ hideMenuViewer(); }
}


//
// listenKey()
//
function listenKey () {	document.onkeypress = getKey; }
	

//
// showMenuViewer()
// Preloads images. Pleaces new image in menuviewer then centers and displays.
//
function showMenuViewer(objLink)
{
	// prep objects
	var objOverlay = document.getElementById('overlay');
	var objMenuViewer = document.getElementById('menuviewer');
	var objMenuViewerContent = document.getElementById('menuviewerContent');

	var arrayPageSize = getPageSize();
	var arrayPageScroll = getPageScroll();

	// center objMenuViewer if it exists
	if (objMenuViewer) 
	{
		objMenuViewer.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 35 - 648) / 2) + 'px');
		objMenuViewer.style.left = (((arrayPageSize[0] - 20 - 620) / 2) + 'px');
		objMenuViewer.style.display = 'block';
	}
	
	if (objMenuViewerContent)
	{
	  include(objLink.href, objMenuViewerContent, loadingImage);
	  objMenuViewerContent.style.display = 'block';
	}

	// set height of Overlay to take up whole page and show
	objOverlay.style.height = (arrayPageSize[1] + 'px');
	objOverlay.style.display = 'block';


	// Hide select boxes as they will 'peek' through the image in IE
	selects = document.getElementsByTagName("select");
        for (i = 0; i != selects.length; i++) 
        {
                selects[i].style.visibility = "hidden";
        }

	
	// update the overlay height
	arrayPageSize = getPageSize();
	objOverlay.style.height = (arrayPageSize[1] + 'px');

	// Check for 'x' keypress
	listenKey();

	return false;
	
}


//
// hideMenuViewer()
//
function hideMenuViewer()
{
	// get objects
	objOverlay = document.getElementById('overlay');
	objMenuViewer = document.getElementById('menuviewer');

	// hide menuviewer and overlay
	objOverlay.style.display = 'none';
	objMenuViewer.style.display = 'none';

	// make select boxes visible
	selects = document.getElementsByTagName("select");
    for (i = 0; i != selects.length; i++) {
		selects[i].style.visibility = "visible";
	}

	// disable keypress listener
	document.onkeypress = '';
}




//
// initMenuViewer()
// Function runs on window load, going through link tags looking for rel="menuviewer".
// These links receive onclick events that enable the menuviewer display for their targets.
// The function also inserts html markup at the top of the page which will be used as a
// container for the overlay pattern and the inline image.
//
function initMenuViewer()
{
	
	if (!document.getElementsByTagName){ return; }
	var anchors = document.getElementsByTagName("a");

	// loop through all anchor tags
	for (var i=0; i<anchors.length; i++){
		var anchor = anchors[i];

		if (anchor.getAttribute("href") && (anchor.getAttribute("rel") == "menuviewer"))
		{
		   anchor.onclick = function () {showMenuViewer(this); return false;}
		}
	}
	
	var objBody = document.getElementsByTagName("body").item(0);
	
	// create overlay div and hardcode some functional styles (aesthetic styles are in CSS file)
	var objOverlay = document.createElement("div");
	objOverlay.setAttribute('id','overlay');
	objOverlay.onclick = function () {hideMenuViewer(); return false;}
	objOverlay.style.display = 'none';
	objOverlay.style.position = 'absolute';
	objOverlay.style.top = '0';
	objOverlay.style.left = '0';
	objOverlay.style.zIndex = '90';
 	objOverlay.style.width = '100%';
	objBody.insertBefore(objOverlay, objBody.firstChild);
	
	var arrayPageSize = getPageSize();
	var arrayPageScroll = getPageScroll();

	// create menuviewer div, same note about styles as above
	var objMenuViewer = document.createElement("div");
	objMenuViewer.setAttribute('id','menuviewer');
	objMenuViewer.style.display = 'none';
	objMenuViewer.style.position = 'absolute';
	objMenuViewer.style.zIndex = '100';	
	objBody.insertBefore(objMenuViewer, objOverlay.nextSibling);
	
	// create menuviewercontent div
	var objMenuViewerContent = document.createElement("div");
	objMenuViewerContent.setAttribute('id','menuviewerContent');
	objMenuViewerContent.style.display = 'none';
	objMenuViewerContent.style.position = 'absolute';
	objMenuViewerContent.style.zIndex = '150';	
	objMenuViewer.appendChild(objMenuViewerContent);
	
	
	
	// create link
	var objLink = document.createElement("a");
	objLink.setAttribute('href','#');
	objLink.setAttribute('title','Klik om te sluiten');
	objLink.onclick = function () {hideMenuViewer(); return false;}
	objMenuViewer.appendChild(objLink);
	
	// preload and create close button image
	var imgPreloadCloseButton = new Image();

	// if close button image found, 
	imgPreloadCloseButton.onload=function()
	{
		var objCloseButton = document.createElement("img");
		objCloseButton.src = closeButton;
		objCloseButton.setAttribute('id','menuviewercloseButton');
		objCloseButton.style.position = 'absolute';
		objCloseButton.style.zIndex = '200';
		objLink.appendChild(objCloseButton);

		return false;
	}
	
	imgPreloadCloseButton.src = closeButton;
	
	// create image
	var objImage = document.createElement("img");
	objImage.setAttribute('id','menuviewerImage');
	objLink.appendChild(objImage);
	


}




//
// addLoadEvent()
// Adds event to window.onload without overwriting currently assigned onload functions.
// Function found at Simon Willison's weblog - http://simon.incutio.com/
//
function addLoadEvent(func)
{	
	var oldonload = window.onload;
	if (typeof window.onload != 'function'){
    	window.onload = func;
	} else {
		window.onload = function(){
		oldonload();
		func();
		}
	}

}



addLoadEvent(initMenuViewer);	// run initMenuViewer onLoad