var loadingImage = 'loading.gif';
var closeButton = 'close.gif';
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;
}

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

if(key == 'x'){ hideLightbox(); }
}
function listenKey () {document.onkeypress = getKey; }
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;
// center lightbox and make sure that the top and left values are not negative
// and the image placed outside the viewport

//ebr the below 2 lines nave - xxx on the end as I wanted them higher and to the left
var lightboxTop = arrayPageScroll[1] + ((arrayPageSize[3] - 35 - imgPreload.height) / 2);
var lightboxLeft = ((arrayPageSize[0] - 20 - imgPreload.width) / 2);

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

if(objLink.getAttribute('title')){
objCaption.style.display = 'block';
//objCaption.style.width = imgPreload.width + 'px';
objCaption.innerHTML = objLink.getAttribute('title');
} 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(500);
} 
if (objLoadingImage) {objLoadingImage.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;

}
function hideLightbox()
{
// get objects
objOverlay = document.getElementById('overlay');
objLightbox = document.getElementById('lightbox');
// hide lightbox and overlay
objOverlay.style.display = 'none';
objLightbox.style.display = 'none';

// disable keypress listener
document.onkeypress = '';
}
function initLightbox()
{

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") == "lightbox")){
anchor.onclick = function () {showLightbox(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 () {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(){};//clear onLoad, as IE will flip out w/animated gifs
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);
//create b&w or color link
var objBWColorLink = document.createElement("div");
objBWColorLink.setAttribute('id','bwcolorLink');
//objBWColorLink.innerHTML = '<a class="bwcolorlink" onclick="ChangeColor();">View in Black and White</a>';
objLightboxDetails.appendChild(objBWColorLink);

// create keyboard message
var objKeyboardMsg = document.createElement("div");
objKeyboardMsg.setAttribute('id','keyboardMsg');
objKeyboardMsg.innerHTML = 'click anywhere or type <kbd>x</kbd> to close';
objLightboxDetails.appendChild(objKeyboardMsg);
//create printer icon
//var objPrint = document.createElement("div"
//TODO: do this later, figure out how to print the picture only
}
function ChangeColor()
{
var objImage = document.getElementById('lightboxImage');
var objLink = document.getElementById('bwcolorLink');
if (objImage.style.filter == 'Gray')
{
objImage.style.filter = '';
objLink.innerHTML = '<a class="bwcolorlink" onclick="ChangeColor();">View in Black and White</a>';
}
else
{
objImage.style.filter = 'Gray';
objLink.innerHTML = '<a class="bwcolorlink" onclick="ChangeColor();">View in Color</a>';
}
}
function addLoadEvent(func)
{
var oldonload = window.onload;
if (typeof window.onload != 'function'){
 window.onload = func;
} else {
window.onload = function(){
oldonload();
func();
}
}
}
addLoadEvent(initLightbox);// run initLightbox onLoad