/**
 *	ImageFlow 0.9
 *
 *	This code is based on Michael L. Perrys Cover flow in Javascript.
 *	For he wrote that "You can take this code and use it as your own" [1]
 *	this is my attempt to improve some things. Feel free to use it! If
 *	you have any questions on it leave me a message in my shoutbox [2].
 *
 *	The reflection is generated server-sided by a slightly hacked  
 *	version of Richard Daveys easyreflections [3] written in PHP.
 *	
 *	The mouse wheel support is an implementation of Adomas Paltanavicius
 *	JavaScript mouse wheel code [4].
 *
 *	Thanks to Stephan Droste ImageFlow is now compatible with Safari 1.x.
 *
 *
 *	[1] http://www.adventuresinsoftware.com/blog/?p=104#comment-1981
 *	[2] http://shoutbox.finnrudolph.de/
 *	[3] http://reflection.corephp.co.uk/v2.php
 *	[4] http://adomas.org/javascript-mouse-wheel/
 */


/* Configuration variables */
var conf_reflection_p = 0.5;         // Sets the height of the reflection in % of the source image 
var conf_focus = 4;                  // Sets the numbers of images on each side of the focussed one
var conf_slider_width = 14;          // Sets the px width of the slider div
var conf_images_cursor = 'pointer';  // Sets the cursor type for all images default is 'default'
var conf_slider_cursor = 'default';  // Sets the slider cursor type: try "e-resize" default is 'default'

/* Id names used in the HTML */
var conf_imageflow = 'imageflow';    // Default is 'imageflow'
var conf_loading = 'loading';        // Default is 'loading'
var conf_images = 'images';          // Default is 'images'
var conf_captions = 'captions';      // Default is 'captions'
var conf_scrollbar = 'scrollbar';    // Default is 'scrollbar'
var conf_slider = 'slider';          // Default is 'slider'

/* Define global variables */
var caption_id = 0;
var new_caption_id = 0;
var current = 0;
var target = 0;
var mem_target = 0;
var timer = 0;
var array_images = new Array();
var new_slider_pos = 0;
var dragging = false;
var dragobject = null;
var dragx = 0;
var posx = 0;
var new_posx = 0;
var xstep = 120;

function step()
{
	switch (target < current-1 || target > current+1) 
	{
		case true:
			moveTo(current + (target-current)/3);
			window.setTimeout(step, 50);
			timer = 1;
			break;
		default:
			timer = 0;
			break;
	}
}

function glideTo(x, new_caption_id)
{	
	/* Animate gliding to new x position */
	target = x;
	mem_target = x;
	if (timer == 0)
	{
		window.setTimeout(step, 50);
		timer = 1;
	}
	timer = 1
	/* Display new caption */
	caption_id = new_caption_id;
	caption = img_div.childNodes.item(array_images[caption_id]).getAttribute('alt');
	if (caption == '') caption = '&nbsp;';
	caption_div.innerHTML = caption;
	/* Set scrollbar slider to new position */
	if (false == dragging)
	{
		new_slider_pos = (scrollbar_width * (-(x*100/((max-1)*xstep))) / 100) - new_posx
		slider_div.setStyle({ marginLeft: (new_slider_pos - conf_slider_width) + 'px' })
	}
}

function moveTo(x)
{
	current = x;
	var zIndex = max;
	/* Main loop */
	for (var index = 0; index < max; ++index)
	{
		var image = img_div.childNodes.item(array_images[index]);
		Element.extend(image)
		var current_image = index * -xstep;
		/* Don't display images that are not conf_focussed */
		if ((current_image+max_conf_focus) < mem_target || (current_image-max_conf_focus) > mem_target)
			image.hide()
		else {
			var z = Math.sqrt(10000 + x * x) + 100;
			var xs = x / z * size + size;
			/* Still hide images until they are processed, but set display style to block */
			image.style.display = 'block';
			/* Process new image height and image width */
			var new_img_h = (image.h / image.w * image.pc) / z * size;
			//switch ( new_img_h > max_height )
			//{
				//case false:
					var new_img_w = image.pc / z * size;
				//	break;
			//	default:
			//		//new_img_h = max_height;
			//		var new_img_w = image.w * new_img_h / image.h;
			//		break;
			//}
			var new_img_top = (images_width * 0.34 - new_img_h) + images_top + ((new_img_h / (conf_reflection_p + 1)) * conf_reflection_p);
			/* Set new image properties */
			image.setStyle({ left: xs - (image.pc / 2) / z * size + images_left + 'px' })
			image.setOpacity(Math.ceil(100 * (conf_focus + 1 - Math.abs(x) / xstep) / (conf_focus + 1)) / 100)
			if(new_img_w && new_img_h)
			{ 
				image.setStyle({ height: new_img_h + 'px', width: new_img_w + 'px', top: new_img_top + 'px' })
			}
			image.setStyle({ visibility: 'visible' })
			/* Set image layer through zIndex */
			switch ( x < 0 ) {
				case true:
					++zIndex
					break
				default:
					--zIndex
					break
			}	
			/* Change zIndex and onclick function of the focussed image */
			switch ( image.i == caption_id )
			{
				case false:
					image.onmouseover = function() { glideTo(this.x_pos, this.i); }
					break;
				default:
					zIndex = zIndex + 1;
					image.onclick = function() { /*document.location = this.url;*/ window.open(this.url,'test'); }
					break;
			}
			image.setStyle({ zIndex: zIndex})
		}
		x += xstep;
	}
}

/* Main function */
function refresh(onload)
{
	/* Cache document objects in global variables */
	imageflow_div = $(conf_imageflow);
	img_div = $(conf_images);
	scrollbar_div = $(conf_scrollbar);
	slider_div = $(conf_slider);
	caption_div = $(conf_captions);

	/* Cache global variables, that only change on refresh */
	images_width = img_div.offsetWidth;
	//images_top = imageflow_div.offsetTop - 50;
	//images_left = imageflow_div.offsetLeft;
	images_top = -50;
	images_left = 0;
	max_conf_focus = conf_focus * xstep;
	size = images_width * 0.5;
	scrollbar_width = images_width * 0.6;
	conf_slider_width = conf_slider_width * 0.5;
	max_height = images_width * 0.51;

	/* Change imageflow div properties */
	imageflow_div.setStyle({ height: max_height + 'px' })

	/* Change images div properties */
	img_div.setStyle({ height: images_width * 0.338 + 'px' })

	/* Change captions div properties */
	caption_div.setStyle({width: images_width + 'px', marginTop: images_width * 0.03 + 'px' })

	/* Change scrollbar div properties */
	scrollbar_div.setStyle({ width: scrollbar_width + 'px', marginTop: images_width * 0.02 + 'px', marginLeft: images_width * 0.2 + 'px' })
	
	/* Set slider attributes */
	slider_div.onmousedown = function () { dragstart(this); }
	slider_div.setStyle({ cursor: conf_slider_cursor })

	/* Cache EVERYTHING! */
	max = img_div.childNodes.length;
	var i = 0;
	for (var index = 0; index < max; index++)
	{
		var image = img_div.childNodes.item(index);
		if (image.nodeType == 1)
		{
			Element.extend(image)
			array_images[i] = index;
			/* Set image onclick by adding i and x_pos as attributes! */
			image.onclick = function() { glideTo(this.x_pos, this.i); }
			image.x_pos = (-i * xstep);
			image.i = i;
			/* Add width and height as attributes ONLY once onload */
			if(onload == true)
			{
				image.w = image.width;
				image.h = image.height;
			}
			/* Check source image format. Get image height minus reflection height! */
			switch ((image.w + 1) > (image.h / (conf_reflection_p + 1))) 
			{
				/* Landscape format */
				case true:
					image.pc = 118;
					break;

				/* Portrait and square format */
				default:
					image.pc = 100;
					break;
			}
			/* Set ondblclick event */
			image.url = image.getAttribute('longdesc');
			image.ondblclick = function() { /*document.location = this.url;*/ window.open(this.url,'test');}
			/* Set image cursor type */
			image.setStyle({ cursor: conf_images_cursor })
			++i
		}
	}
	max = array_images.length
	/* Display images in current order */
	moveTo(current)
	glideTo(current, caption_id)
}

/* Handle the wheel angle change (delta) of the mouse wheel */
function handle(delta)
{
	var change = false;
	switch (delta > 0)
	{
		case true:
			if(caption_id >= 1)
			{
				target = target + xstep;
				new_caption_id = caption_id - 1;
				change = true;
			}
			break;

		default:
			if(caption_id < (max-1))
			{
				target = target - xstep;
				new_caption_id = caption_id + 1;
				change = true;
			}
			break;
	}

	/* Glide to next (mouse wheel down) / previous (mouse wheel up) image */
	if (change == true)
	{
		glideTo(target, new_caption_id);
	}
}

/* Event handler for mouse wheel event */
function wheel(event)
{
	var delta = 0;
	if (!event) event = window.event;
	if (event.wheelDelta) {
		delta = event.wheelDelta / 120;
	}
	else if (event.detail) {
		delta = -event.detail / 3;
	}
	if (delta) handle(delta);
	if (event.preventDefault) event.preventDefault();
	event.returnValue = false;
}

/* Initialize mouse wheel event listener */
function initMouseWheel()
{
	if(window.addEventListener) imageflow_div.addEventListener('DOMMouseScroll', wheel, false);
	imageflow_div.onmousewheel = wheel;
}

/* This function is called to drag an object (= slider div) */
function dragstart(element)
{
	dragobject = element;
	dragx = posx - dragobject.offsetLeft + new_slider_pos;
}

/* This function is called to stop dragging an object */
function dragstop()
{
	dragobject = null;
	dragging = false;
}

/* This function is called on mouse movement and moves an object (= slider div) on user action */
function drag(e)
{
	posx = document.all ? window.event.clientX : e.pageX;
	if(dragobject != null)
	{
		dragging = true;
		new_posx = (posx - dragx) + conf_slider_width;

		/* Make sure, that the slider is moved in proper relation to previous movements by the glideTo function */
		if(new_posx < ( - new_slider_pos)) new_posx = - new_slider_pos;
		if(new_posx > (scrollbar_width - new_slider_pos)) new_posx = scrollbar_width - new_slider_pos;
		
		var slider_pos = (new_posx + new_slider_pos);
		var step_width = slider_pos / ((scrollbar_width) / (max-1));
		var image_number = Math.round(step_width);
		var new_target = (image_number) * -xstep;
		var new_caption_id = image_number;

		dragobject.setStyle({ left: new_posx + 'px' })
		glideTo(new_target, new_caption_id);
	}
}

/* Initialize mouse event listener */
function initMouseDrag()
{
	document.onmousemove = drag;
	document.onmouseup = dragstop;
	/* Avoid text and image selection while dragging  */
	document.onselectstart = function () {
			return !dragging
	}
}

function launchEvents() {
	/* Hide loading bar, show content and initialize mouse event listening after loading */
	if($(conf_imageflow)) {
		$(conf_loading).hide()
		refresh(true);
		$(conf_images, conf_scrollbar).invoke('show');
		initMouseWheel();
		initMouseDrag();
		Event.observe(window, 'resize', refresh)
		Event.observe(window, 'keydown', function(e) {
			switch (e.keyCode)
			{
				case Event.KEY_RIGHT:
					handle(-1);
					break;
				case Event.KEY_LEFT:
					handle(1);
					break;
			}			
		})
		/* Fixes the back button issue */
		Event.observe(window, 'unload', function() { document = null })
	}
} // launchEvents

Event.observe(window, 'load', launchEvents)