var loadingImage = 'http://www.tantrajoga.cz/_pic/loading.gif';
// var closeButton = '../_pic/close.gif';
var isIE=(navigator.appName.indexOf("Microsoft")!=-1)?1:0;
var agt=navigator.userAgent.toLowerCase();
var isOpera = (agt.indexOf("opera") != -1);
var isGecko = (agt.indexOf('gecko') != -1);

var isImageDisplayed = false;
var ff_OldscrollTop;
var totalLightBoxHeight;

//
// getPageScroll()
// Returns array with x,y page scroll values
//
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
// 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;
}


//
// 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; }

//
// called from onresize event
//
function myInit (arrayPageSize, bResize) {

  var objLightbox = document.getElementById('lightbox');
  var objImage = document.getElementById('lightboxImage');
  var lightboxTop = parseInt(objLightbox.style.top);
  var sirka = arrayPageSize[4]; //parseInt(objImage.style.width);

  if(isIE) {
    if(totalLightBoxHeight >= arrayPageSize[3] - lightboxTop) { // obrázek je vetší než okno
       objLightbox.style.height = arrayPageSize[3] - lightboxTop + 'px';
       if(bResize == false)
          objLightbox.style.width = sirka + 15 + 'px';
    }
    else
    {
      objLightbox.style.height = totalLightBoxHeight + 'px';
      if(bResize == false)
         objLightbox.style.width = sirka + 'px';
    }
  }
  else if(isOpera) {
    if(totalLightBoxHeight >= arrayPageScroll[1] + arrayPageSize[3] - lightboxTop) { // obrázek je vetší než okno
       objLightbox.style.height = arrayPageSize[3] + 'px';
       objLightbox.style.top = arrayPageScroll[1] + 'px';

       if(bResize == false)
          objLightbox.style.width = sirka + 15 + 'px';
       window.onmousewheel = null;
    }
    else
    {
      objLightbox.style.height = totalLightBoxHeight + 'px';
      if(bResize == false)
         objLightbox.style.width = sirka + 'px';

      window.onmousewheel = function () {return false;};
    }
  }
  else// noMSIE, noOpera
  {
        if(totalLightBoxHeight >= arrayPageSize[3] - lightboxTop) { // obrázek je vetší než okno
             objLightbox.style.height = arrayPageSize[3] - lightboxTop - 20 + 'px'
        }
        else {
          objLightbox.style.height = totalLightBoxHeight + 'px';
        }
  }
}

//
// showLightbox()
// Preloads images. Pleaces new image in lightbox then centers and displays.
//
function showLightbox(objLink)
{
//  if(!isIE) {
  if(isGecko) {
     ff_OldscrollTop = document.body.scrollTop;
//     window.scrollbars.visible = false;
     document.body.style.overflow = "hidden";
  }
  if(isOpera) {
     document.body.style.overflow = "hidden";
  }

  var sirka = parseInt(objLink.getAttribute("sirka"));
  var vyska = parseInt(objLink.getAttribute("vyska"));

  // 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');

  objImage.src = objLink.href;

  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.top = (arrayPageScroll[1] + ((arrayPageSize[3] - 35 - vyska) / 2) + 'px');
    objLoadingImage.style.left = (((arrayPageSize[0] - 20 - sirka) / 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
//    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 arrayPageSize = getPageSize();
    var lightboxTop;
    var lightboxLeft = ((arrayPageSize[0] - 20 - sirka) / 2);

    if(isIE || isOpera) {
      lightboxTop = arrayPageScroll[1] + ((arrayPageSize[3] - 35 - vyska) / 2);
    }
    else
      lightboxTop = ((arrayPageSize[3] - 35 - vyska) / 2);

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

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

    if(objLink.getAttribute('title')){
      objCaption.style.display = 'block';
      objCaption.innerHTML = objLink.getAttribute('title');
    } else {
      objCaption.style.display = 'none';
    }

    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');

    totalLightBoxHeight = vyska + objCaption.clientHeight + 40;

    arrayPageSize[4] = sirka; // opera: set lightbox width, see myInit
//    objImage.style.width = sirka;
    myInit(arrayPageSize, false);
    // Check for 'x' keypress
    listenKey();

    isImageDisplayed = true;

}

//
// hideLightbox()
//
function hideLightbox()
{
  if(isGecko) {
     document.body.scrollTop = ff_OldscrollTop;
//     window.scrollbars.visible = true;
     document.body.style.overflow = "auto";
  }
  if(isOpera) {
     document.body.style.overflow = "auto";
     window.onmousewheel = null;
  }

  var objImage = document.getElementById('lightboxImage');

  objImage.src = loadingImage;
//  objImage.src = "http://www.tantrajoga.cz/_pic/loading.gif";

  isImageDisplayed = false;

  // 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 = '';
}


//
// 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';
  objLightbox.style.height = arrayPageSize[3];
  objLightbox.style.overflow = "auto"
  objLightbox.style.overflowX = "visible"

  objLightbox.style.scrollbarBaseColor  ="#000000";
  objLightbox.style.scrollbarArrowColor ="#000000";
  objLightbox.style.scrollbarFaceColor  ="#FF9900";
  objLightbox.style.scrollbarHighlightColor ="#EEEEEE";
  objLightbox.style.scrollbarShadowColor  ="#EEEEEE";
  objLightbox.style.scrollbarTrackColor  ="#EEEEEE";

/*  objLightbox.style.backgroundImage = "url(http://www.tantrajoga.cz/_pic/loading.gif)"
  objLightbox.style.backgroundRepeat = "no-repeat"
  objLightbox.style.backgroundPosition = "center"*/

  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 keyboard message
//  var objKeyboardMsg = document.createElement("div");
//  objKeyboardMsg.setAttribute('id','keyboardMsg');
//  objKeyboardMsg.innerHTML = 'press <kbd>x</kbd> to close';
//  objLightboxDetails.appendChild(objKeyboardMsg);

}


//
// addLoadEvent()
// Adds event to window.onload without overwriting currently assigned onload functions.
//
function addLoadEvent(func)
{
  var oldonload = window.onload;
  if (typeof window.onload != 'function'){
      window.onload = func;
  } else {
    window.onload = function(){
    oldonload();
    func();
    }
  }

}

function addResizeEvent() {

  window.onresize = function () {

    // set height of Overlay to take up whole page and show
    if(isImageDisplayed){
      var arrayPageSize = getPageSize();
      myInit(arrayPageSize, true);
    }

    return false;
  }
}

/*function handleOnMouseWheel() {
//    var objLightbox = document.getElementById('lightbox');
//    if(objLightbox.scrollHeight >= objLightbox.style.height)
//      return false;
    //alert(document.body.scrollTop);
    alert(event.wheelDelta);
    return false;
}*/

addResizeEvent();
addLoadEvent(initLightbox); // run initLightbox onLoad