// Lightbox JS: Fullsize Image Overlays 
// by Lokesh Dhakar - http://www.huddletogether.com

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

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

//
// showLightbox()
// Preloads images. Pleaces new image in lightbox then centers and displays.
//
function showLightbox(objLink, marginTop) {
	// prep objects
	var objOverlay = document.getElementById('cmf-lightboxOverlay');
	var objLightbox = document.getElementById('cmf-lightbox');
	var objImage = document.getElementById('cmf-lightboxImage');
	var objLoading = document.getElementById('cmf-lightboxLoading');
	var objLegend = document.getElementById('cmf-lightboxLegend');
	var objContainer = document.getElementById('cmf-lightboxContainer');
    var objPicContainer = document.getElementById('cmf-lightboxPicContainer');
	var arrayPageSize = getPageSize();
	var arrayPageScroll = getPageScroll();
	// centers loadingDiv if it exists. we set the width in CSS, and negative margin half of it
	if (objLoading) {
		objLoading.style.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 35 ) / 2) + 'px');
		objLoading.style.left = (((arrayPageSize[0] - 20) / 2) + 'px');
		objLoading.style.display = 'block';
	}    
	// set height of Overlay to take up whole page and show
	objOverlay.style.height = (arrayPageSize[1] + 'px');
	objOverlay.style.display = 'block';
    // retrieve the legend if there is one
    var re = /cmflightbox(\d+)/
    var id = re.exec(objLink.id);
    var legend = document.getElementById('cmflightboxlegend'+id[1]);
    if (legend) objLegend.innerHTML = legend.innerHTML;
	// preload image
	imgPreload = new Image();
	imgPreload.onload=function(){
		objImage.src = objLink.href;
		// 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 - imgPreload.height) / 2);
		var lightboxLeft = ((arrayPageSize[0] - 20 - imgPreload.width) / 2);
        // CMF hack to attempt to leave a top space for Flash headers
        if (lightboxTop < marginTop) {
            lightboxTop = marginTop;
        }    
		objLightbox.style.top = (lightboxTop < 0) ? "0px" : lightboxTop + "px";
		objLightbox.style.left = (lightboxLeft < 0) ? "0px" : lightboxLeft + "px";
		// 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 (objLoading) {	objLoading.style.display = 'none'; }
		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');
		// Check for 'x' keypress
		listenKey();
		return false;
	}
	imgPreload.src = objLink.href;
}

// hideLightbox()
function hideLightbox() {
	objOverlay = document.getElementById('cmf-lightboxOverlay');
	objLightbox = document.getElementById('cmf-lightbox');
	objImage = document.getElementById('cmf-lightboxImage');
	objOverlay.style.display = 'none';
	objLightbox.style.display = 'none';
    objImage.src = null;
	document.onkeypress = '';
}

// initLightbox()
// Function runs on window load, going through link tags looking for rel="lightbox".
// These links receive onclick events that enable the lightbox 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 initLightbox(loadingMsg, marginTop){
	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") == "cmf-lightbox")){
			anchor.onclick = function () {showLightbox(this, marginTop); 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','cmf-lightboxOverlay');
	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();
    // create feeback message when loading the picture
    if (loadingMsg.length > 0) {
        var objLoading = document.createElement("div");
        objLoading.setAttribute('id','cmf-lightboxLoading');
        objLoading.innerHTML = loadingMsg;
        objLoading.style.position = 'absolute';
        objLoading.style.zIndex = '150';
        objOverlay.appendChild(objLoading);
    }
	// create lightbox div, same note about styles as above
	var objLightbox = document.createElement("div");
	objLightbox.setAttribute('id','cmf-lightbox');
	objLightbox.style.display = 'none';
	objLightbox.style.position = 'absolute';
	objLightbox.style.zIndex = '100';	
	objBody.insertBefore(objLightbox, objOverlay.nextSibling);
	// create container
	var objContainer = document.createElement("div");
	objContainer.setAttribute('id','cmf-lightboxContainer');
	objLightbox.appendChild(objContainer);
	// create picture container
	var objPicContainer = document.createElement("span");
	objPicContainer.setAttribute('id','cmf-lightboxPicContainer');
	objContainer.appendChild(objPicContainer);
	// create link
	var objLink = document.createElement("a");
	objLink.setAttribute('href','#');
	objLink.setAttribute('title','Click to close');
	objLink.onclick = function () {hideLightbox(); return false;}
	objPicContainer.appendChild(objLink);
    // create image
	var objImage = document.createElement("img");
	objImage.setAttribute('id','cmf-lightboxImage');
	objLink.appendChild(objImage);
    // create legend
	var objLegend = document.createElement("div");
	objLegend.setAttribute('id','cmf-lightboxLegend');
    objContainer.insertBefore(objLegend, objLink.nextSibling); 
}