/*
  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/
  (basically, do anything you want, just leave my name and link)
  
  Table of Contents
  -----------------
  Configuration
  
  Functions
  - getPageScroll()
  - getPageSize()
  - pause()
  - getKey()
  - listenKey()
  - showLightbox()
  - hideLightbox()
  - initLightbox()
  - addLoadEvent()
  
  Function Calls
  - addLoadEvent(initLightbox)

*/



//
// Configuration
//

// If you would like to use a custom loading image or close button reference them in the next two lines.
var loadingImage = '/images/loading.gif';    
var closeButton = '/images/close.gif';    





//
// 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)
{
  // 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
    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(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;
  
}





//
// hideLightbox()
//
function hideLightbox()
{
  // get objects
  objOverlay = document.getElementById('overlay');
  objLightbox = document.getElementById('lightbox');

  // hide lightbox and overlay
  objOverlay.style.display = 'none';
  objLightbox.style.display = 'none';

  // 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 = '';
}




//
// 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()
{
  
  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;}
    }
  }

  // the rest of this code inserts html at the top of the page that looks like this:
  //
  // <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 id="keyboardMsg"></div>
  //    </div>
  // </div>
  
  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 on the image to close this popup');
  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 keyboard message
  var objKeyboardMsg = document.createElement("div");
  objKeyboardMsg.setAttribute('id','keyboardMsg');
  objKeyboardMsg.innerHTML = 'press <a href="#" onclick="hideLightbox(); return false;"><kbd>x</kbd></a> to close';
  objLightboxDetails.appendChild(objKeyboardMsg);


}




//
// addLoadEvent()
// Adds event to window.onload without overwriting currently assigned onload functions.
// Function found at Simon Willison's weblog - http://simon.incutio.com/
//
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