/* Configuration variables */
var conf_reflection_p = 1;         // 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 = 50;
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)
{    
    unregisterHighlightListener(caption_id);
    registerHighlightListener(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)-155;
            /* Set new image properties */
            image.style.left = xs - (image.pc / 2) / z * size + 'px';
            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:
                    // console.info('propably focused: ', index);
                    zIndex = zIndex + 1;
                    if(image.target != ""  && image.target != null) {
                        image.onclick = function() { window.open(this.url, "IdMediaLondon"); return false;}
                    } else {
                        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 = 0;
    images_left = imageflow_div.offsetLeft;
    max_conf_focus = conf_focus * xstep;
    size = images_width * 0.71;
    scrollbar_width = images_width * 0.6;
    conf_slider_width = conf_slider_width * 0.5;
    max_height = images_width * 0.72;
    /* 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 = 100;
                    break;
                /* Portrait and square format */
                default:
                    image.pc = 100;
                    break;
            }
            /* Set ondblclick event */
            image.target = image.getAttribute('linktarget');
            image.url = image.getAttribute('longdesc');
            if(image.target != "" && image.target != null) {
                image.ondblclick = function() { window.open(this.url, "IdMediaLondon"); }
            } else {
                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(-150,3);
        //window.setTimeout("glideTo(-50,1)", 100);
        //window.setTimeout("glideTo(-100,2)", 1800);
        window.setTimeout("glideTo(-150,3)", 600);
        //window.setTimeout("glideTo(-200,4)", 3400);
        //window.setTimeout("glideTo(-250,5)", 4200);
        //window.setTimeout("glideTo(-300,6)", 5000);
        //window.setTimeout("glideTo(-150,3)", 5800);
    }
}
/* Refresh ImageFlow on window resize */
window.onresize = function()
{
    if(document.getElementById(conf_imageflow)) refresh();
}
/* 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;
}
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;
    }
}
function registerHighlightListener(imageId) {
    // console.debug('registering listener for image ', imageId, 'which is', getImage(imageId));
    
    var currentImage = getImage(imageId);
    
    
    // console.info('highlighted src:', currentImage.getAttribute(title));    
    
    currentImage.onmouseover = function() {
        
        
        // console.info('normal src:', this.getAttribute('normalSrc'));
        // console.info('highlighted src:', this.getAttribute('title'));
        
        
        if (this.getAttribute('normalSrc') == null || this.getAttribute('normalSrc') == false) {
            // console.info('saving normal src ', this.src);
            this.setAttribute('normalSrc', this.src);
        }
        this.src = this.getAttribute('title');
        currentImage.onmouseout = function() {
            this.src = this.getAttribute('normalSrc');
        }
    }
}
function unregisterHighlightListener(imageId) {
    // console.debug('remoing listener from image ', imageId, 'which is', getImage(imageId));
    var currentImage = getImage(imageId);
    
    currentImage.onmouseover = function() {};
    currentImage.onmouseout = function() {};
    
    if (currentImage.getAttribute('normalSrc') !== null) {
        currentImage.src = currentImage.getAttribute('normalSrc');
    }
    
}
function getImage(imageId) {
    return img_div.childNodes.item(array_images[imageId]);
}