var gThumbWidth;
if (gThumbWidth == undefined)
	gThumbWidth = 24;
  
var gThumbHeight;
if (gThumbHeight == undefined)
	gThumbHeight = 24;

var gSlideShowInterval;
if (gSlideShowInterval == undefined)
	gSlideShowInterval = 3000; // msecs between images.

var gAutoStartSlideShow;
if (gAutoStartSlideShow == undefined)
	gAutoStartSlideShow = true;

var gBehaviorsArray = [];
var gSlideShowOn = false;
var gSlideShowTimer = null;
var gImageLoader = null;

// Register a callback on the dsPhotos data set so we can turn
// off the slide show before it attempts to load new data.

dsPhotos.addObserver(function(nType, notifier, data) {
	if (nType == "onPreLoad")
		StopSlideShow();
});

// Register a callback on the thumbnails region so we can show the first
// image in the data set after all the thumbnails have loaded.

Spry.Data.Region.addObserver("thumbnails", function(nType, notifier, data) {
	if (nType == "onPostUpdate")
	{
		ShowCurrentImage();
		if (gAutoStartSlideShow)
			StartSlideShow(true);
	}
});

// Trigger the transition animation from the current image
// being displayed to the image at imgPath.

function SetMainImage(imgPath, width, height, tnID)
{
	var img = document.getElementById("mainImage");
	if (!img)
		return;

	CancelBehavior("mainImage");

	Spry.Utils.SelectionManager.clearSelection("thumbnailSelection");

	if (tnID)
		Spry.Utils.SelectionManager.select("thumbnailSelection", document.getElementById(tnID), "selectedThumbnail");

	if (gImageLoader)
	{
		gImageLoader.onload = function() {};
		gImageLoader = null;
	}

	gBehaviorsArray["mainImage"] = new Spry.Effect.Opacity(img, Spry.Effect.getOpacity(img), 0, { duration: 400,
		finish: function()
		{
			gBehaviorsArray["mainImage"] = new Spry.Effect.Size(img.parentNode, Spry.Effect.getDimensions(img.parentNode), { width: width, height: height, units:"px"}, {duration: 400,
				finish: function()
				{
					// Use an image loader to make sure we only fade in the new image after
					// it is completely loaded.
					gImageLoader = new Image();
					gImageLoader.onload = function()
					{
						img.src = gImageLoader.src;
						gImageLoader = null;
						gBehaviorsArray["mainImage"] = new Spry.Effect.Opacity(img, 0, 1, { duration: 400,
							finish: function()
							{
								gBehaviorsArray["mainImage"] = null;
								
								// Our new image is fully visible now. Remove any opacity related
								// style properties on the img to workaround the IE bug that creates
								// white dots/holes in the images. Removing the properties forces
								// IE to re-render the image correctly.

								img.style.opacity = "";
								img.style.filter = "";

								// If the slide show is on, fire off the timer for the next image.

								if (gSlideShowOn)
									SetSlideShowTimer();
							}});
						gBehaviorsArray["mainImage"].start();
					};
					gImageLoader.src = imgPath;
				}
		  });
		  gBehaviorsArray["mainImage"].start();
		}
	});
	gBehaviorsArray["mainImage"].start();
}

// Cancel the animation behavior of the object with the given id.

function CancelBehavior(id)
{
	if (gBehaviorsArray[id])
	{
		gBehaviorsArray[id].cancel();
		gBehaviorsArray[id] = null;
	}
}

function SizeAndPosition(id, toX, toY, toWidth, toHeight, callback)
{
	CancelBehavior(id);
	var effectCluster = new Spry.Effect.Cluster( { finish: callback } );
	var ele = Spry.Effect.getElement(id); 
	var moveEffect = new Spry.Effect.Move(ele, Spry.Effect.getPosition(ele), { x: toX, y: toY, units: "px" }, { duration: 400 });
	var sizeEffect = new Spry.Effect.Size(ele, Spry.Effect.getDimensions(ele), { width: toWidth, height: toHeight, units: "px" }, { duration: 400 });
	
	effectCluster.addParallelEffect(moveEffect);
	effectCluster.addParallelEffect(sizeEffect);
	
	//effectCluster.finish = callback;
	
	gBehaviorsArray[id] = effectCluster;
	gBehaviorsArray[id].start();
}

// Trigger the animation of the thumbnail growing.

function GrowThumbnail(img, width, height)
{
	Spry.Utils.addClassName(img, "inFocus");
	img.style.zIndex = 150;
	
	var id = img.getAttribute("id");
	
	var twidth = Math.floor(width * .75);
	var theight = Math.floor(height * .75);
	var tx = (gThumbWidth - twidth) / 2;
	var ty = (gThumbHeight - theight) / 2;
	
	SizeAndPosition(id, tx, ty, twidth, theight, function(b){gBehaviorsArray[id] = null;});
}

// Trigger the animation of the thumbnail shrinking.

function ShrinkThumbnail(img)
{
	Spry.Utils.addClassName(img, "inFocus");
	img.style.zIndex = 1;
	
	var id = img.getAttribute("id");
	
	SizeAndPosition(id, 0, 0, gThumbWidth, gThumbHeight, function(b){gBehaviorsArray[id] = null; Spry.Utils.removeClassName(img, "inFocus");});
}

// Show the image of the current selected row inside the dsPhotos data set.

function ShowCurrentImage()
{
	var curRow = dsPhotos.getCurrentRow();
	SetMainImage("galleries/" + dsGalleries.getCurrentRow()["@base"] + "images/" + curRow["@path"], curRow["@width"], curRow["@height"], "tn" + curRow["ds_RowID"]);
}

// Utility function to advance (forwards or backwards) the current selected row
// in dsPhotos. This has the side effect of "selecting" the thumbnail and image
// of the new current row.

function AdvanceToNextImage(moveBackwards)
{
	var rows = dsPhotos.getData();
	var curRow = dsPhotos.getCurrentRow();
	
	if (rows.length < 1)
		return;
	
	for (var i = 0; i < rows.length; i++)
	{
		if (rows[i] == curRow)
		{
			if (moveBackwards)
				--i;
			else
				++i;
			break;
		}
	}
	
	if (!moveBackwards && i >= rows.length)
		i = 0;
	else if (moveBackwards && i < 0)
		i = rows.length - 1;
	
	curRow = rows[i];
	dsPhotos.setCurrentRow(curRow["ds_RowID"]);
	ShowCurrentImage();
}

function SetSlideShowTimer()
{
	KillSlideShowTimer();
	gSlideShowTimer = setTimeout(function(){ gSlideShowTimer = null; AdvanceToNextImage(false); }, gSlideShowInterval);
}

function KillSlideShowTimer()
{
	if (gSlideShowTimer)
		clearTimeout(gSlideShowTimer);
	gSlideShowTimer = null;
}

// Start the slide show that runs forwards through all
// the rows in dsPhotos.

function StartSlideShow(skipTimer)
{
	gSlideShowOn = true;
	if (!skipTimer)
		SetSlideShowTimer();
	var playLabel = document.getElementById("playLabel");
	if (playLabel)
		playLabel.firstChild.data = "Pause";
}

// Kill any slide show that is currently running.

function StopSlideShow()
{
	gSlideShowOn = false;
	KillSlideShowTimer();
	var playLabel = document.getElementById("playLabel");
	if (playLabel)
		playLabel.firstChild.data = "Play";
}

function HandleThumbnailClick(id)
{
	StopSlideShow();
	dsPhotos.setCurrentRow(id);
	ShowCurrentImage();
}