/**
 *	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_focus = 4;                  // Sets the numbers of images on each side of the focussed one
var conf_images_cursor = 'pointer';  // Sets the cursor type for all images 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'

/* 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 posx = 0;
var new_posx = 0;
var xstep = 135;


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;
	}
	
	/* Display new caption */
	caption_id = new_caption_id;
	var IE7_fix_eerst_naar_height_vragen_lost_problemen_op = img_div.childNodes.item(array_images[caption_id]).getAttribute('height');
	caption = img_div.childNodes.item(array_images[caption_id]).getAttribute('alt');
	if (caption == '') caption = '&nbsp;';
	caption_div.innerHTML = caption;
	
	/* Display correct buttons */
	var numul = document.getElementById('numul').innerHTML;
	var ulcounter = 0;
	while(ulcounter < numul) {
		var ulid = 'ab-list-'+ulcounter;
		document.getElementById(ulid).style.display = 'none';
		ulcounter = ulcounter + 1;
	}
	document.getElementById('ab-list-' + new_caption_id).style.display = 'block';
}

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]);
		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/2) > mem_target)
		{
			image.style.visibility = 'hidden';
			image.style.display = 'none';
		}
		else 
		{
			var z = Math.sqrt(10000 + x * x) + 150;
			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_transp = Math.round(new_img_h/max_height*100);
			var new_img_transp = Math.round(100-Math.abs(x/z)*130);
			var new_img_top = (images_width * 0.34 - new_img_h) + images_top ;

			/* Set new image properties */
			image.style.left = xs - (image.pc / 2) / z * size + images_left + 'px';
			if(new_img_w && new_img_h)
			{ 
				image.style.height = new_img_h + 'px'; 
				image.style.width = new_img_w + 'px'; 
				image.style.top = new_img_top + 'px';
			}
			image.style.opacity = new_img_transp/100;
			image.style.filter = 'alpha(opacity='+ new_img_transp + ')';
			image.style.visibility = 'visible';

			/* Set image layer through zIndex */
			switch ( x < 0 )
			{
				case true:
					zIndex++;
					break;

				default:
					zIndex = zIndex - 1;
					break;
			}
			
			/* Change zIndex and onclick function of the focussed image */
			switch ( image.i == caption_id )
			{
				case false:
					image.onclick = function() { glideTo(this.x_pos, this.i); }
					break;

				default:
					zIndex = zIndex + 1;
					image.onclick = function() { document.location = this.url; }
					break;
			}
			image.style.zIndex = zIndex;
		}
		x += xstep;
	}
}

/* Main function */
function refresh(onload)
{
	/* Cache document objects in global variables */
	imageflow_div = document.getElementById(conf_imageflow);
	img_div = document.getElementById(conf_images);
	caption_div = document.getElementById(conf_captions);

	/* Cache global variables, that only change on refresh */
	images_width = img_div.offsetWidth;
	images_top = imageflow_div.offsetTop - 150;
	images_left = imageflow_div.offsetLeft;
	max_conf_focus = conf_focus * xstep;
	size = images_width * 0.5;
	max_height = images_width * 0.19;

	/* Change imageflow div properties */
	imageflow_div.style.height = max_height + 'px';

	/* Change images div properties */
	img_div.style.height = images_width * 0.17 + 'px';

	/* Change captions div properties */
	caption_div.style.width = images_width + 'px';
	caption_div.style.marginTop = '0px';

	/* 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)
		{
			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. */
			switch ((image.w + 1) > (image.h)) 
			{
				/* Landscape format */
				case true:
				//	image.pc = 118;
					image.pc = 100;
					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; }

			/* Set image cursor type */
			image.style.cursor = conf_images_cursor;

			i++;
		}
	}
	max = array_images.length;

	/* Display images in current order */
	moveTo(current);
	glideTo(current, caption_id);
}

/* Show/hide element functions */
function show(id)
{
	var element = document.getElementById(id);
	element.style.visibility = 'visible';
}
function hide(id)
{
	var element = document.getElementById(id);
	element.style.visibility = 'hidden';
	element.style.display = 'none';
}

/* Hide loading bar, show content and initialize mouse event listening after loading */
window.onload = function()
{
	if(document.getElementById(conf_imageflow))
	{
		hide(conf_loading);
		refresh(true);
		show(conf_images);
		initMouseWheel();
	}
}

/* Refresh ImageFlow on window resize */
window.onresize = function()
{
	if(document.getElementById(conf_imageflow)) refresh();
}

/* Fixes the back button issue */
window.onunload = function()
{
  document = null;
}


/* 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;
}

function getKeyCode(event)
{
	event = event || window.event;
	return event.keyCode;
}

document.onkeydown = function(event)
{
	var charCode  = getKeyCode(event);
	switch (charCode)
	{
		/* Right arrow key */
		case 39:
			handle(-1);
			break;
		
		/* Left arrow key */
		case 37:
			handle(1);
			break;
	}
}