/**
 *	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 mouse wheel support is an implementation of Adomas Paltanavicius
 *	JavaScript mouse wheel code [3].
 *
 *	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://adomas.org/javascript-mouse-wheel/
 */


/* Configuration variables */
var conf_reflection_p = 0;         	 // 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 = 48;          // 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 = 750;
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 setOpacity(image, value) {
	if (image.filters && image.filters[0]) {
		image.filters[0].opacity = value * 100;
	} else {
		image.style.opacity = value;
	}
}

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 firstId = new_caption_id - 2;
	var secondId = new_caption_id - 1 ;
	var fourthId = new_caption_id + 1;
	var fifthId = new_caption_id + 2;
	var sHTML = "";
	if(array_images[firstId]) {
		var firstImage = img_div.childNodes.item(array_images[firstId]);
		sHTML += "<span style='font-size: small;color: gray; margin-right: 49px' onclick='glideTo(" + firstImage.x_pos + ", " + firstImage.i + "); '> " + firstImage.getAttribute('alt') + " </span>";
	}
	if(array_images[secondId]) {
		var secondImage = img_div.childNodes.item(array_images[secondId]);
		sHTML += "<span style='font-size: small;color: gray; margin-right: 49px' onclick='glideTo(" + secondImage.x_pos + ", " + secondImage.i + "); '> " + secondImage.getAttribute('alt') + " </span>"; 
	}
	if (img_div.childNodes.item(array_images[caption_id])) {
		var centerImage = img_div.childNodes.item(array_images[caption_id]);
		window.address = centerImage.url.replace('ajaxGet', 'window.top.ajaxGet');
		sHTML += "<span onclick=\"document.location=window.address;\"> " + centerImage.getAttribute('alt') + " </span>"; 
	}
	if(array_images[fourthId]) {
		var fourthImage = img_div.childNodes.item(array_images[fourthId]);
		sHTML += "<span style='font-size: small;color: gray; margin-left: 49px' onclick='glideTo(" + fourthImage.x_pos + ", " + fourthImage.i + "); '> " + fourthImage.getAttribute('alt') + " </span>" ;
	}
	if(array_images[fifthId]) {
		var fifthImage = img_div.childNodes.item(array_images[fifthId]);
		sHTML += "<span style='font-size: small;color: gray; margin-left: 49px' onclick='glideTo(" + fifthImage.x_pos + ", " + fifthImage.i + "); '> " + fifthImage.getAttribute('alt') + " </span>";
	}
	
	caption_div.innerHTML =  sHTML;
													
	/* Set scrollbar slider to new position */
	if (dragging == false) {
		new_slider_pos = (scrollbar_width * (-(x*100/((max-1)*xstep))) / 100) - new_posx;
		/*
		* defauld: slider_div.style.marginLeft = (new_slider_pos - conf_slider_width) + 'px';
		* add: slider_div.offsetWidth /2
		*/
		slider_div.style.marginLeft = (new_slider_pos - conf_slider_width - slider_div.offsetWidth / 2 ) + '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 ((x < -(xstep*5.5)) || (x > (xstep*5.5))) {
			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) * 0.5 + 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';
			}
			
			/* Set the image opacity */
			if ((x < -(xstep*4.5)) || (x > (xstep*4.5))) {
				if (x > 0) setOpacity(image, (xstep*5.5-x)/xstep);
				else setOpacity(image, (xstep*5.5+x)/xstep);
			} else {
				setOpacity(image, 1);
			}

			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() {
						var url = this.url.replace("ajaxGet", "window.top.ajaxGet");
						document.location = 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 * 0.72;
	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 */
	//value default: 0.338
	img_div.style.height = images_width * 0.32 + '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 */
	//default: 0.02
	scrollbar_div.style.marginTop = images_width * 0.012 + 'px';
	//default: 0.2
	scrollbar_div.style.marginLeft = images_width * 0.12 + 'px';
	scrollbar_div.style.width = scrollbar_width + 'px';
	
	/* Set slider attributes */
	slider_div.onmousedown = function () { dragstart(this); };
	slider_div.onkeydown = 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.getAttribute('w');
				image.h = image.getAttribute('h');
			}

			/* 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.href = 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';
}
function init() {
	
	var image = document.getElementById(conf_images);
	var imgs = null;

	if (image) imgs = image.getElementsByTagName("img");
	if (imgs && imgs.length) {
		
		refresh(true);
		initMouseWheel();
		initMouseDrag();
		glideTo(0, 0);
	}
}

/* Hide loading bar, show content and initialize mouse event listening after loading */
window.onload = function() {init()};

/* Refresh ImageFlow on window resize */
window.onresize = function() {
	var image = document.getElementById(conf_images);
	var imgs = null;
	if (image) imgs = image.getElementsByTagName("img");
	if (imgs && imgs.length) refresh();
}

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

/* 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;
	}
}

init();

