/**

 *	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/

 *

 *   var conf_start_image added by Boris Glumpler

 */





/* Configuration variables */

var conf_reflection_p = 0.7;         // Sets the height of the reflection in % of the source image

var conf_focus = 2;                  // 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 = 'e-resize';  // Sets the slider cursor type: try "e-resize" default is 'default'

var conf_start_image = 3;				// Sets which image the slideshow should start with 



/* Id names used in the HTML */

var conf_imageflow = 'if_imageflow';    // Default is 'imageflow'

var conf_loading = 'if_loading';        // Default is 'loading'

var conf_images = 'if_images';          // Default is 'images'

var conf_captions = 'if_captions';      // Default is 'captions'

var conf_scrollbar = 'if_scrollbar';    // Default is 'scrollbar'

var conf_slider = 'if_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 = 150;





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;

	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 (dragging == false)

	{

		new_slider_pos = (scrollbar_width * (-(x*100/((max-1)*xstep))) / 100) - new_posx;

		slider_div.style.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]);

		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.style.visibility = 'hidden';

			image.style.display = 'none';

		}

		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.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.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);

	scrollbar_div = document.getElementById(conf_scrollbar);

	slider_div = document.getElementById(conf_slider);

	caption_div = document.getElementById(conf_captions);



	/* Cache global variables, that only change on refresh */

	images_width = img_div.offsetWidth;

	images_top = imageflow_div.offsetTop;

	images_left = imageflow_div.offsetLeft;

	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.style.height = max_height + 'px';



	/* Change images div properties */

	img_div.style.height = images_width * 0.338 + 'px';



	/* Change captions div properties */

	caption_div.style.width = images_width + 'px';

	caption_div.style.marginTop = images_width * 0.03 + 'px';



	/* Change scrollbar div properties */

	scrollbar_div.style.marginTop = images_width * 0.02 + 'px';

	scrollbar_div.style.marginLeft = images_width * 0.2 + 'px';

	scrollbar_div.style.width = scrollbar_width + 'px';

	

	/* Set slider attributes */

	slider_div.onmousedown = function () { dragstart(this); };

	slider_div.style.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)

		{

			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; }



			/* 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);

		show(conf_scrollbar);

		initMouseWheel();

		initMouseDrag();

		glideTo(-(conf_start_image-1)*150, conf_start_image-1)

	}

}



/* 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;

}



/* 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.style.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 () 

	{

		if (dragging == true)

		{

			return false;

		}

		else

		{

			return true;

		}

	}

}



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;

	}

}