(function($) {
	$.fn.dsImageView = function(opts) {
		var options = $.extend({
				transition : "fade",                              // Transition
				playSpeed : 5000,                                 // Time (ms) for each image when playing through
				disabledClass : "disabled",                       // CSS class for disabled previous/next elements
				image : $("#ds-image"),                           // [required] image element, will have its src attribute replaced as necessary
				description : $("#ds-description"),               // [required] Description element, its content is replaced by the current image description
				previous : $("#ds-previous"),                     // [required] "previous" element
				imageNumber : $("#ds-image-number"),              // [required] Image number element, its content is replaced by the current image number
				next : $("#ds-next"),                             // [required] "next" element
				totalNumber : $("#ds-total-number"),              // [required] Total number element, its content is replaced by the total number of images
				descriptions : null,                              // [required] Collection of image description elements
				close : $("#ds-close"),                           // [optional] "Close" button
				play : $("#ds-play"),                             // [optional] "play" element
				stop : $("#ds-pause"),                            // [optional] "stop" element
				overlay : null,                                   // [optional] Overlay element, automatically faded in/out and resized as necessary
				container : null,                                 // [optional] Container element, resized as necessary
				activeClass : "active",                           // [optional] CSS class for "active" links
				playable : true,                                  // [optional] Playing enabled
				autoPlay : false,                                 // [optional] Start playing automatically
				callback : null,                                  // [optional] callback to be notified of image changes - function (activatedImageNumber) {...}
                containerTop : 20                                 // [optional] Sets default space for the fullview container from top
			}, opts),
			playable = options.playable && options.play && options.stop,
			autoPlay = options.autoPlay && playable,
			subjects = this,
			disabledClass = options.disabledClass,
			ie6 = ($.browser.msie && $.browser.version < "7"),
			currentImage = null,
			images = [],
			playId = null,
			containerWidth = null,
			containerHeight = null,
			containerTop = null;

		function show () {
			var obj = $(this);
			currentImage = null;

			// Size image view appropriately
			adjustSize();

			// Hide objects that MSIE would show above the overlay
			if (ie6)
			{
				$("embed, object, select").css({ visibility : "hidden" });
			}

			// Show image view
			presentContainer(function () { 
				view(obj);
				initPlaying();
			});

			eventHandlers("bind");
			return false;
		}

		function view (obj) {
			var index = subjects.index(obj);
			stopPlaying();
			go(index);
			return false;
		}

		function go (image) {
			var from = currentImage,
				to = image;
			image = (image + images.length) % images.length;
			to = image;
			
			if (image !== currentImage && image >= 0 && image < images.length)
			{
				currentImage = image;
				loadImage(images[currentImage].src, function () {
					if (currentImage !== null)
					{
						transitionImage(from, to);
					}
				});
				refreshNavigation();
				if (options.callback)
				{
					options.callback(currentImage);
				}
				resetPlayTimeout();
				preloadNeighbours();
			}
		}

		function transitionImage (from, to) {
			var	obj = options.image.parent().parent(),
				fwd = ((from < to) && !(from === 0 && to === images.length - 1)) || (from === images.length - 1 && to === 0),
				src = images[currentImage].src;
			obj.transitionTo(src, from === null ? false : options.transition, fwd);
		}

		function previous () {
			go(currentImage - 1);
			return false;
		}

		function next () {
			go(currentImage === null ? 0 : currentImage + 1);
			return false;
		}

		function initPlaying () {
			options.totalNumber.html(images.length);
			if (images.length <= 1) {
				options.previous.parent().hide();
			}
			else {
				options.previous.parent().show();
			}
			// Hide elements as necessary
			if (playable) {
				options.play.show();
				options.stop.show();

				// Autostart?
				if (autoPlay)
				{
					startPlaying();
				}
			}
			else {
				options.play.hide();
				options.stop.hide();
			}
		}
		
		function playClicked () {
			startPlaying();
			next();
		}
		
		function startPlaying () {
			stopPlaying();
			playId = window.setTimeout(next, options.playSpeed);
			options.play.addClass(options.disabledClass);
			options.stop.removeClass(options.disabledClass);
			return false;
		}

		function stopPlaying () {
			if (playId)
			{
				window.clearTimeout(playId);
				playId = null;
				refreshNavigation();
			}
			options.play.removeClass(options.disabledClass);
			options.stop.addClass(options.disabledClass);
			return false;
		}

		function togglePlaying () {
			if (playId)
			{
				stopPlaying();
			}
			else
			{
				playClicked();
			}		
		}

		function resetPlayTimeout () {
			if (playId)
			{
				window.clearTimeout(playId);
				playId = window.setTimeout(next, options.playSpeed);
			}
		}

		function presentContainer (callback) {
			// Prepare for animation
			var children = options.container.find("> *");
			options.container.css({
				width: 0,
				height: 0,
				minWidth: 0,
				minHeight: 0
			});
			options.image.css("visibility", "hidden");
			children.css("opacity", 0);

			children.fixIEBackground();

			// Do the animation
			options.container.animate({
					width : containerWidth,
					height : containerHeight
				}, function () {
					options.container.css({
						minWidth : containerWidth,
						minHeight : containerHeight,
						height : ie6 ? containerHeight : "auto"
					});
					callback();
					options.image.css("visibility", "visible");
					children.animate({opacity: 1});
				});
			if (options.overlay)
			{
				options.overlay.fadeOut(0).css({opacity : 0.7}).fadeIn("normal");
			}
		}

		function hideImage () {
			options.image.stop(true, true).css({opacity: 0});
			options.description.stop(true, true).css({opacity: 0});
		}

		function refreshNavigation () {
			var speed = options.description.html() ? "normal" : 0;
			options.imageNumber.text(currentImage + 1);
			options.description.stop(true, true);
			options.description.fixIEBackground();
			options.description.fadeOut(speed, function () {
				if (currentImage !== null)
				{
					options.description.html(images[currentImage].description);
					options.description.fadeIn(speed);
				}
			});

			subjects.removeClass(options.activeClass);
			subjects.eq(currentImage).addClass(options.activeClass);
		}

		// Preload previous and next images
		function preloadNeighbours () {
			var total = images.length,
				prev = (currentImage + total - 1) % total,
				next = (currentImage + total + 1) % total;
			loadImage(images[prev].src);
			loadImage(images[next].src);
		}

		function loadImage(url, callback) {
			var image = new Image();
			if (callback)
			{
				image.onload = function () {
					// Reset onload or MSIE will misbehave with animated gifs
					image.onload = function () {};
					callback();
				};
			}
			image.src = url;
		}

		function hide () {
			// Disable event handlers
			eventHandlers("unbind");

			// Stop playing
			if (playable)
			{
				stopPlaying();
			}

			// Hide container
			options.image.parent().parent().css("opacity", "");
			$("> *", options.container).animate({opacity: 0});
			options.container.animate({
				width : 0,
				height : 0,
				minWidth : 0,
				minHeight : 0
			}, "normal", function () {
				options.description.html("");
				options.container.hide().width(containerWidth).height(containerHeight);
			});
			options.overlay.fadeOut("normal", function () {
				if (ie6)
				{
					// Show objects that were hidden for MSIE
					$("embed, object, select").css({ visibility : "visible" });
				}
			});
			currentImage = null;
			return false;
		}

		function eventHandlers (action) {
			// Click handlers
			if (options.close)
			{
				options.close[action]("click", hide);
			}
			options.next[action]("click", next);
			options.previous[action]("click", previous);
			if (playable)
			{
				options.play[action]("click", playClicked);
				options.stop[action]("click", stopPlaying);
			}

			// Window event handlers
			if (options.overlay && options.container)
			{
				options.overlay[action]("click", hide);
				$(window)[action]("resize", adjustSize);
				$(window)[action]("scroll", adjustSize);
			}
			options.image.parent()[action]("click", next);

			// Hotkeys
			if (window.hotkeys)
			{
				if (playable)
				{
					$(document)[action]("keydown", "space", togglePlaying);
				}
				if (options.container)
				{
					$(document)[action]("keydown", "esc", hide);
				}
				$(document)[action]("keydown", "left", previous);
				$(document)[action]("keydown", "right", next);
			}
		}

		function adjustSize() {
			var absolute = ie6,
				position = absolute ? "absolute" : "fixed",
				scrollTop = $(window).scrollTop(),
				scrollLeft = $(window).scrollLeft(),
				xOffset = absolute ? scrollLeft : 0,
				yOffset = absolute ? scrollTop : 0,
				currentTop = Math.max(options.container.position().top, containerTop),
				containerXOffset = ($(window).width() - options.container.width()) / 2,
				containerYOffset = ($(window).height() - options.container.height()) / 2;

			// overlay size
			options.overlay.css({
				position : position,
				left : xOffset,
				top : yOffset,
				width : $(window).width(),
				height : $(window).height()
			});

			containerYOffset = containerTop;

			xOffset += Math.max(0, containerXOffset);
			yOffset += Math.max(0, containerYOffset);

			if ($(window).height() < options.container.height())
			{
				position = "absolute";
				xOffset = scrollLeft + containerXOffset;
				if ((options.container.css("position") == "fixed") || (scrollTop + containerYOffset < currentTop))
				{
					// Extra space at the top, move container further up
					yOffset = scrollTop + containerYOffset;
				}
				else if (scrollTop + $(window).height() > options.container.position().top + options.container.height() + containerTop)
				{
					// Extra space at the bottom, move as far down as possible
					yOffset = Math.min(scrollTop + $(window).height() - options.container.height() - containerTop,
						$(document).height() - options.container.height()) - containerTop;
					yOffset = Math.max(0, yOffset);
				}
				else
				{
					yOffset = currentTop;
				}
			}

			options.container.css({
				position : position,
				left : Math.floor(xOffset),
				top : Math.floor(yOffset)
			});
		}

		// Find all images
		this.each(function (index) {
			var obj = $(this);
			images[index] = {
				id : obj.attr("id"),
				src : obj.attr("href"),
				description : (options.descriptions ? options.descriptions.eq(index).html() : subjects.eq(index).find("img").attr("alt"))
			};
		});

		// Measure container
		if (options.container)
		{
			var css = {
					visibility : options.container.css("visibility"),
					display : options.container.css("display")
				};

			options.container.css({
					visibility : "hidden",
					display : "block"
				});
			containerWidth = options.container.width();
			containerHeight = options.container.height();
			containerTop = options.containerTop;
			options.container.css(css);
		}

		// Set appropriate click handlers
		if (options.container)
		{
			this.click(show);
		}
		else
		{
			eventHandlers("bind");
			initPlaying()
			go(0);
			this.click(function () {
				return view($(this));
			});
		}
		return this;
	};
})(jQuery);