// -----------------------------------------------------------------------------------
//
//  ImageFlow 0.9
//  by Steven Pothoven - http://blog.pothoven.net
//  1/22/08
//
//  Derived from:
//
//	ImageFlow 0.8
//
//	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/
//
// -----------------------------------------------------------------------------------


ImageFlow = function() {

    /* 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 = [];
    var new_slider_pos = 0;
    var dragging = false;
    var dragobject = null;
    var dragx = 0;
    var posx = 0;
    var new_posx = 0;
    var xstep = 150;

    var imageflow_div, img_div, scrollbar_div, slider_div, caption_div;
    var images_width, images_top, images_left, max_conf_focus, size, scrollbar_width, max_height;


    function step() {
        if (target < current-1 || target > current+1) { 
            moveTo(current + (target-current)/3);
            window.setTimeout(step, 50);
		    timer = 1;
        } else { 
		  timer = 0;
        }
    }

    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;
                var new_img_w;
                if (new_img_h > max_height) {
                    new_img_h = max_height;
                    new_img_w = image.w * new_img_h / image.h;
                } else {
                    new_img_w = image.pc / z * size;
                }
                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';
                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 */
                if (x < 0) {
                    zIndex++;
                } else {
                    zIndex--;
                }
            
                /* Change zIndex and onclick function of the focussed image */
                if ( image.i === caption_id ) {
                    zIndex++;
                    image.onclick = function() { document.location = this.url; };
                } else {
                    image.onclick = function() { glideTo(this.x_pos, this.i); };
                }
                image.style.zIndex = zIndex;
            }
            x += xstep;
        }
    }

    /* Main function */
    function refresh(onload) {
        /* Cache document objects in global variables */
        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;
		img_div.style.visibility = 'hidden';
		
					caption_id = 0;
				new_caption_id = 0;
				current = 0;
				target = 0;
				mem_target = 0;
				timer = 0;
				array_images = [];
				new_slider_pos = 0;
				dragging = false;
				dragobject = null;
				dragx = 0;
				posx = 0;
				new_posx = 0;
		

        /* 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! */
                if ((image.w + 1) > (image.h / (conf_reflection_p + 1))) {
                    /* Landscape format */
                    image.pc = 118;
                } else {
                    /* Portrait and square format */
                    image.pc = 100;
                }

                /* 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';
    }

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

        /* 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) {
            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;
    }

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

    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;
        }
    };

    return {
        /* Hide loading bar, show content and initialize mouse event listening after loading */
        initialize : function() {
            // set internal global variable
            imageflow_div = document.getElementById(conf_imageflow);
        
            if (imageflow_div) {
                var images = imageflow_div.getElementsByTagName("img");
                var ready = true;
                for (var i = 0; i < images.length; i++) {
                    if (! images[i].complete) {
                        ready = false;
                        break;
                    }
                }
                if (! ready) {
                    setTimeout(ImageFlow.initialize, 500);
                } else {
                    hide(conf_loading);
                    refresh(true);
                    show(conf_images);
                    show(conf_scrollbar);
					show(conf_captions);
                    initMouseWheel();
                    initMouseDrag();
                }
            }
        }   
    };
}();