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

// For more information on this script, visit:
// http://huddletogether.com/projects/lightbox/

// Licensed under the Creative Commons Attribution 2.5 License 
// http://creativecommons.org/licenses/by/2.5/
// Modified by Mike Piontek for Tense Log

var loadingImage = '/library/enlarge/loading.gif';
var closeButton = '/library/enlarge/close.png';
var lightboxReady = false;
var waitTimer = null;
var storedObject = null;
var imgPreload = null;
var lightboxTop = 0;
var objOverlay = null;
var objLightbox = null;
var objLightboxDetails = null;

function getPageScroll () {

	// Returns array with x,y page scroll values.
	// Core code from - quirksmode.org

	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 () {

	// Returns array with page width, height and window width, height
	// Core code from - quirksmode.org
	// Edit for Firefox by pHaez

	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) {

	// Pauses code execution for specified time. Uses busy code, not good.
	// Code from http://www.faqts.com/knowledge_base/view.phtml/aid/1602

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

function getKey (e) {

	// Gets keycode. If 'x' is pressed then it hides the lightbox.

	if (e == null) { // ie
		keycode = event.keyCode;
	} else keycode = e.which; // mozilla

	key = String.fromCharCode(keycode).toLowerCase();
	
	if (key == 'x') { hideLightbox(); }
}

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

	// Preloads images. Pleaces new image in lightbox then centers and displays.

	if (waitTimer != null) clearTimeout(waitTimer);

	if (lightboxReady == false) {
		storedObject = objLink;
		waitTimer = setTimeout("showLightbox(false)",1000);
	} else {

		if (objLink == false) objLink = storedObject;

		// prep objects
		var objCaption = document.getElementById('lightboxcaption');
		var objImage = document.getElementById('lightboxImage');
		var objLoadingImage = document.getElementById('loadingImage');
		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 the Overlay to take up the whole page and show
		objOverlay.style.width = '100%';
		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";
		}
	
		// preload image
		imgPreload = new Image();
	
		imgPreload.onload=function() {
			objImage.src = objLink.href;
			centerImage();
		
			if (objLink.getAttribute('title')) {
				objCaption.style.display = 'block';
				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(250);
	
			if (objLoadingImage) objLoadingImage.style.display = 'none';
			objLightbox.style.display = 'block';
			adjustOverlay(true);
			listenKey();
	
			return false;
		}
	
		imgPreload.src = objLink.href;

	}
	return false;

}

function hideLightbox () {

	// hide lightbox and overlay
	objOverlay.style.display = 'none';
	objLightbox.style.display = 'none';
	objOverlay.style.width = '1px';
	objOverlay.style.height = '1px';

	imgPreload = null;
	lightboxTop = 0;

	// 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 = '';
}

function centerImage () {

	// center lightbox and make sure that the top and left values are not negative
	// and the image placed outside the viewport
	lightboxTop = arrayPageScroll[1] + ((arrayPageSize[3] - 35 - imgPreload.height) / 2);
	var lightboxLeft = ((arrayPageSize[0] - 20 - imgPreload.width) / 2);
	
	objLightbox.style.top = (lightboxTop < 0) ? "0" : lightboxTop + "px";
	objLightbox.style.left = (lightboxLeft < 0) ? "0" : lightboxLeft + "px";

	objLightboxDetails.style.width = imgPreload.width + 'px';

}

function adjustOverlay (skipCenter) {

	// After image is loaded, update the overlay size as the new image might have
	// increased the overall page width or height.

	if (imgPreload) {

		var arrayPageSize = getPageSize();
		
		centerImage();

		var maxWidth = arrayPageSize[0];
		if ((imgPreload.width + 22) > arrayPageSize[0]) {
			objOverlay.style.width = ((imgPreload.width + 22) + 'px');
		} else objOverlay.style.width = '100%';
	
		var maxHeight = arrayPageSize[1];
		var topOffset = 0;
		if (lightboxTop > 0) topOffset = lightboxTop;
		if ((topOffset + imgPreload.height + 22) > maxHeight) 
			maxHeight = topOffset + imgPreload.height + 22;
		if (objLightbox.offsetHeight && (topOffset + objLightbox.offsetHeight) > maxHeight) 
			maxHeight = topOffset + objLightbox.offsetHeight;
		objOverlay.style.height = (maxHeight + 'px');

	}

}

function initLightbox () {

	// Inserts html markup at the top of the page which will be used as a
	// container for the overlay pattern and the inline image.

	// <div id="overlay">
	//		<a href="#" onclick="hideLightbox(); return false;"><img id="loadingImage" /></a>
	//	</div>
	// <div id="lightbox">
	//		<a href="#" onclick="hideLightbox(); return false;" title="Click anywhere to close image">
	//			<img id="closebutton" />		
	//			<img id="lightboxImage" />
	//		</a>
	//		<div id="lightboxdetails">
	//			<div id="lightboxcaption"></div>
	//		</div>
	// </div>
	
	var objBody = document.getElementsByTagName("body").item(0);
	
	// create overlay div and hardcode some functional styles (aesthetic styles are in CSS file)
	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
	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 here or press x 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
	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);

	window.onresize = adjustOverlay;

	lightboxReady = true;

}