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

function getPageScroll(){
 var yScroll;
 if(self.pageYOffset){
	yScroll=self.pageYOffset;
 }else if(document.documentElement&&document.documentElement.scrollTop){
	yScroll=document.documentElement.scrollTop;
 }else if(document.body){
	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){keycode=event.keyCode;}
 else{keycode=e.which;}
 key=String.fromCharCode(keycode).toLowerCase();
 if(key=='x'){hideLightbox();}
}

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

function showLightbox(objLink){
 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();

 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';
 }

 objOverlay.style.height=(arrayPageSize[1]+'px');
	objOverlay.style.display='block';
	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);
		
		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.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'; }

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

		return false;
	}

	imgPreload.src = objLink.href;
}

function hideLightbox(){
 objOverlay=document.getElementById('overlay');
 objLightbox=document.getElementById('lightbox');
 objOverlay.style.display='none';
 objLightbox.style.display='none';
 selects=document.getElementsByTagName("select");
 for(i=0;i!=selects.length;i++){
	selects[i].style.visibility="visible";
 }
 document.onkeypress = '';
}

function initLightbox(){
 if(!document.getElementsByTagName){return;}
 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;}
	}
 }
 var objBody=document.getElementsByTagName("body").item(0);
 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();
 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','Закрыть');
	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);

}

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

addLoadEvent(initLightbox);