var Class = {
    create: function() {
      return function() {
        this.initialize.apply(this, arguments);
      }
    }
  }
  
  var fileLoadingImage = "/interface/loading.gif";
  
  var Lightbox = Class.create();
  
  Lightbox.prototype = {

	  initialize: function() {	
      if (!document.getElementsByTagName){ return; }
		  var anchors = document.getElementsByTagName('a');

      for (var i=0; i<anchors.length; i++){
	  	  var anchor = anchors[i];
			  var relAttribute = String(anchor.getAttribute('rel'));	
			  if (anchor.getAttribute('href') && (relAttribute.toLowerCase().match('lightbox'))){
				  anchor.onclick = function () {myLightbox.start(this); return false;}
			  }
		  }
	  
		  //Build Preview Box
		  
		  var objBody = document.getElementsByTagName("body").item(0);
		  var objOverlay = document.createElement("div");
		  objOverlay.setAttribute('id','overlay');
		  objOverlay.style.display = 'none';
		  objOverlay.onclick = function () {myLightbox.close(); return false;}
		  objBody.appendChild(objOverlay);
		  
		  var objLightbox = document.createElement("div");
		  objLightbox.setAttribute('id','lightbox');
		  objOverlay.appendChild(objLightbox);
		  
		  var objImageDataContainer = document.createElement("div");
		  objImageDataContainer.setAttribute('id','imageDataContainer');
		  objLightbox.appendChild(objImageDataContainer);
		  
		  var objLoadingImage = document.createElement("img");
		  objLoadingImage.setAttribute('src', fileLoadingImage);
		  objLoadingImage.setAttribute('id', 'imgloading');
		  objImageDataContainer.appendChild(objLoadingImage);
		  
		  var objLightboxImage = document.createElement("img");
		  objLightboxImage.setAttribute('id','lightboxImage');
		  objImageDataContainer.appendChild(objLightboxImage);
		  
		  var objClose = document.createElement("p");
		  objClose.innerHTML = "Click to Close";
		  objImageDataContainer.appendChild(objClose);
		  
		  //  <div id="overlay">
      //  <div id="jpreview"><div>
      //    <img src="" id="jimage" alt="preview">
      //    <p>Click To Close</p>
      //  </div></div></div>
		  
		},
		
		start: function(imageLink) {			  
		  if (!document.getElementsByTagName){ return; }
    
		  if((imageLink.getAttribute('rel') == 'lightbox')){
		    var arrayPageSize = getPageSize();
		    var overlay = document.getElementById('overlay');
		    overlay.style.height=arrayPageSize[1]+'px';
		    overlay.style.width='100%';
		    overlay.style.display='block';
		    
		    hide('lightboxImage');
		    show('imgloading');
   
			  imgPreloader = new Image();
		
		    imgPreloader.onload=function(){
			    setSource('lightboxImage',imageLink.getAttribute('href'));
			    show('lightboxImage');
			    hide('imgloading');
		    }
		    imgPreloader.src = imageLink.getAttribute('href');
			  
			  myLightbox.position();
		  }
	  },
	  
	  close: function() {
	    hide('overlay');
	  },
	  
	  position: function() {
	    var arrayScroll = getPageScroll();
	    var lightbox = document.getElementById('lightbox');
		  lightbox.style.top=((arrayPageSize[3]/2)-220)+arrayScroll[1]+'px';
	  }
  }
	
	
	//
	//
	//  FUNCTIONS
	//
	//
		
	
  function show(objid) {
    var obj = document.getElementById(objid);
		obj.style.display='block';
  }
  
  function hide(objid) {
    var obj = document.getElementById(objid);
		obj.style.display='none';
  }
  function setSource(objid,src) {
    var obj = document.getElementById(objid);
    obj.src = src;
  }
	
	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 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 addEvent(obj, evType, fn){
    if (obj.addEventListener){
        obj.addEventListener(evType, fn, true);
        return true;
    } else if (obj.attachEvent){
        var r = obj.attachEvent("on"+evType, fn);
        return r;
    } else {
        return false;
    }
  } 
	
	function initLightbox() { myLightbox = new Lightbox(); }
  addEvent(window,'load',initLightbox);
  //addEvent(window,'scroll',myLightbox.position);