var slides_steps = 13; //Parametry
var slides_opaque = 86;

var slides_photos = null; //Deklerace proměnných
var slides_objects = null;
var slides_active = 2;
var slides_id = -1;
var slides_ready = false;
var slides_waiting = true;
var slides_loader = new Image();

slides_loader.onerror = function(){setTimeout("slides_getReady()", 30000);};
slides_loader.onload = function(){slides_loaded();};

function slides_setAlpha(obj, val)
{
 obj.style["filter"] = "alpha(opacity=" + val + ")";
 obj.style["opacity"] = val / 100
 obj.style["moz-opacity"] = val / 100;
}

function slides_getReady()
{
 slides_id++;
 if (slides_id >= slides_photos.length)
  slides_id = 0;
 slides_loader.src = "./images/photos/" + slides_photos[slides_id] + ".jpg";
}

function slides_nextId(oKolik)
{
 return (slides_active + oKolik) % 3;
}

function slides_slide(step)
{
 var obj = slides_objects[slides_active];
 var o = slides_objects[slides_nextId(1)];
 var o3 = slides_objects[slides_nextId(2)];
 step++;
 if (step > slides_steps)
 {
  o.style.display = "block";
  var i = obj.zIndex;
  obj.zIndex = o.zIndex;
  o.zIndex = i;
  setTimeout("slides_next()", 12500 + Math.random() % 22500);
 }
 else
 {
  var stav = Math.round(slides_opaque * Math.sin(Math.PI * step / (2 * slides_steps)));
  o.style.left = (slides_opaque - stav) * obj.offsetWidth / slides_opaque + "px";
  o3.style.left = stav * obj.offsetWidth / slides_opaque + "px";
  slides_setAlpha(obj, stav);
  slides_setAlpha(o, slides_opaque - stav);
  setTimeout("slides_slide(" + step + ")", 40);
 }
}

function slides_next()
{
 if (slides_ready)
 {
  slides_active = slides_nextId(1);
  slides_waiting = false;
  slides_ready = false;
  slides_objects[slides_active].src = slides_loader.src;
  slides_getReady();
  slides_slide(0);
 }
 else
  slides_waiting = true;
}

function slides_loaded()
{
 slides_ready = true;
 if (slides_waiting)
  slides_next();
}

function slides_newImage(depth)
{
 var result = document.createElement("img");
 document.body.appendChild(result);

 var styl = result.style;
 styl.position = "absolute";
 styl.zIndex = depth;
 styl.left = "0px";
 styl.top = "14px";
 styl.height = document.body.offsetHeight - parseInt(styl.top) - 8 + "px";

 slides_setAlpha(result, 0);
 return result;
}

function slides_init(idFotek)
{
 if (idFotek.length >= 2)
 {
  slides_photos = idFotek;
  slides_objects = Array(slides_newImage(-1), slides_newImage(-2), slides_newImage(-3));

  slides_objects[0].style.height = "262px";
  slides_objects[1].style.height = "262px";
  slides_objects[2].style.height = "262px";

  slides_objects[1].style.display = "none";
  slides_objects[2].style.display = "none";
  slides_getReady();
 }
}