var loadingImage = '/_rxcss/images/lightbox/loading.gif';
var closeButton = '/_rxcss/images/lightbox/close.gif';




function initLightbox() {
	if (!document.getElementsByTagName){ return; }

	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 () {hideLightbox(); 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();

	// preload and create loader image
	var imgPreloader = new Image();

	// if loader image found, create link to hide lightbox and create loadingimage
	imgPreloader.onload=function(){

		var objLoadingImageLink = document.createElement("a");
		objLoadingImageLink.setAttribute('href','#');
		objLoadingImageLink.onclick = function () {hideLightbox(); return false;}
		objOverlay.appendChild(objLoadingImageLink);

		var objLoadingImage = document.createElement("img");
		objLoadingImage.src = loadingImage;
		objLoadingImage.setAttribute('id','loadingImage');
		objLoadingImage.style.position = 'absolute';
		objLoadingImage.style.zIndex = '150';
		objLoadingImageLink.appendChild(objLoadingImage);
		imgPreloader.onload=function(){};
		return false;
	}

	imgPreloader.src = loadingImage;

	// create lightbox div, same note about styles as above
	var objLightbox = document.createElement("div");
	objLightbox.setAttribute('id','lightbox');
	objLightbox.style.display = 'none';
	objLightbox.style.position = 'absolute';
	objLightbox.style.zIndex = '100';	
	objBody.insertBefore(objLightbox, objOverlay.nextSibling);

	// create link
	var objLink = document.createElement("a");
	objLink.setAttribute('href','#');
	objLink.setAttribute('title','Click to close');
	objLink.onclick = function () {hideLightbox(); return false;}
	objLightbox.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','closeButton');
		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','lightboxImage');
	objLink.appendChild(objImage);
	
	// create details div, a container for the caption and keyboard message
	var objLightboxDetails = document.createElement("div");
	objLightboxDetails.setAttribute('id','lightboxDetails');
	objLightbox.appendChild(objLightboxDetails);

	// create caption
	var objCaption = document.createElement("div");
	objCaption.setAttribute('id','lightboxCaption');
	objCaption.style.display = 'none';
	objLightboxDetails.appendChild(objCaption);

	updateLightbox();
}

function updateLightbox() {
	if (!document.getElementsByTagName){ return false; }
	var anchors = document.getElementsByTagName("a");
	for (var i=0; i<anchors.length; i++){
		var anchor = anchors[i];
		if (anchor.getAttribute("href") && (anchor.getAttribute("rel") == "lightbox")) {
			anchor.onclick = function () {showLightbox(this); return false;}
		}
	}
	return true;
}

function showLightbox(objLink) {
	// prep objects
	var objOverlay = document.getElementById('overlay');
	var objLightbox = document.getElementById('lightbox');
	var objCaption = document.getElementById('lightboxCaption');
	var objImage = document.getElementById('lightboxImage');
	var objLoadingImage = document.getElementById('loadingImage');
	var objLightboxDetails = document.getElementById('lightboxDetails');

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

	// center loadingImage if it exists
	if (objLoadingImage) {
		objLoadingImage.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 35 - objLoadingImage.height) / 2) + 'px');
		objLoadingImage.style.left = (((arrayPageSize[0] - 20 - objLoadingImage.width) / 2) + 'px');
		objLoadingImage.style.display = 'block';
	}

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

	// preload image
	imgPreload = new Image();
	imgPreload.onload=function(){
		objImage.src = objLink.href;

		objImage.removeAttribute('width','');
		objImage.removeAttribute('height','');

		// FdB - Fit the image on the screen
		var imgTmp = new Image();
		imgTmp.src = objImage.src;

		var image_width = imgTmp.width;
		var image_height = imgTmp.height;

		if(imgTmp.width && imgTmp.height) {
			var ps = getPageSize();
			var ar_x = ps[2] / imgTmp.width;
			var ar_y = ps[3] / imgTmp.height;
			if( (ar_x < 1.15) || (ar_y < 1.15) ) {
				if(ar_x < ar_y) {
					image_width = parseInt( (imgTmp.width * ar_x) * 0.85);
					image_height = parseInt( (imgTmp.height * ar_x) * 0.85);
					objImage.setAttribute('width', image_width);
				} else {
					image_width = parseInt( (imgTmp.width * ar_y) * 0.85);
					image_height = parseInt( (imgTmp.height * ar_y) * 0.85);
					objImage.setAttribute('height', image_height);
				}
			}
		}

		// center lightbox and make sure that the top and left values are not negative
		// and the image placed outside the viewport
		var lightboxTop = arrayPageScroll[1] + ((arrayPageSize[3] - 35 - image_height) / 2);
		var lightboxLeft = ((arrayPageSize[0] - 20 - image_width) / 2);

		objLightbox.style.top = (lightboxTop < 0) ? "0px" : lightboxTop + "px";
		objLightbox.style.left = (lightboxLeft < 0) ? "0px" : lightboxLeft + "px";

		objLightboxDetails.style.width = image_width + 'px';
		var title = objLink.getAttribute('title') ? objLink.getAttribute('title') : objLink.getAttribute('alt');
		if(title) {
			objCaption.style.display = 'block';
			objCaption.innerHTML = '<b>'+title+'</b>';
			if ( objLink.getAttribute('title') ) {
				if(objLink.getAttribute('alt')) objCaption.innerHTML += '<br />'+objLink.getAttribute('alt');
			}
		} else {
			objCaption.style.display = 'none';
		}

		// A small pause between the image loading and displaying is required with IE,
		// this prevents the previous image displaying for a short burst causing flicker.
		if (navigator.appVersion.indexOf("MSIE")!=-1) pause(250);

		if (objLoadingImage) objLoadingImage.style.display = 'none';

		// 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";

		objLightbox.style.display = 'block';

		// After image is loaded, update the overlay height as the new image might have
		// increased the overall page height.
		arrayPageSize = getPageSize();
		objOverlay.style.height = (arrayPageSize[1] + 'px');

		return false;
	}

	imgPreload.src = objLink.href;
	
}


function hideLightbox() {

	// get objects
	objOverlay = document.getElementById('overlay');
	objLightbox = document.getElementById('lightbox');

	// hide lightbox and overlay
	objOverlay.style.display = 'none';
	objLightbox.style.display = 'none';

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






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;
}

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;
		if(document.body && !self.innerHeight) { // All explorers quirks-mode
			yScroll = document.documentElement.scrollHeight;
		}
	}

	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;
}

function pause(numberMillis) {
	var now = new Date();
	var exitTime = now.getTime() + numberMillis;
	while (true) {
		now = new Date();
		if (now.getTime() > exitTime) return;
	}
}

function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		window.onload = func;
	} else {
		window.onload = function() {oldonload(); func();}
	}
}

addLoadEvent(initLightbox);