// Lightbox v2.04 by Lokesh Dhakar (www.lokeshdhakar.com/projects/lightbox2/), last modified 02/09/08
// modified by James Pardey 23/04/10 and again on 02/09/10 
//
// Licensed under the Creative Commons Attribution 2.5 License (http://creativecommons.org/licenses/by/2.5/)
// - Free for use in both personal and commercial projects
// - Attribution requires leaving author name, author link, and the license info intact.

// Table of Contents:
//
// configuration
// lightbox class declaration
// - initialize()
// - updateImageList()
// - start()
// - changeImage()
// - resizeImageContainer()
// - showImage()
// - updateDetails()
// - updateNav()
// - enableKeyboardNav()
// - disableKeyboardNav()
// - keyboardAction()
// - preloadNeighborImages()
// - end()
// function calls
// - document.observe()

// lightbox configuration
LightboxOptions = Object.extend({
    fileLoadingImage:        'thumbnails/loading.gif',     
    fileBottomNavCloseImage: 'thumbnails/close.gif',
    fileBottomNavCloseOver:  'thumbnails/close_hover.gif',
    overlayOpacity: 0.7,     // controls transparency of shadow overlay
    animate: true,           // turns resizing animation on or off
    resizeSpeed: 9,          // resizing animation speed (1=slowest and 10=fastest)
    borderSize: 1,           // update this variable if you adjust the padding in the CSS
    labelImage: "image",     // label for 'image # of #' 
    labelOf: "of"            // label for 'image # of #' 
}, window.LightboxOptions || {});

var Lightbox = Class.create();

Lightbox.prototype = {
    imageArray: [],
    activeImage: undefined,
    
    // constructor runs on completion of the DOM loading
    // calls updateImageList() and then the function inserts html at the bottom of the page which is used to display the shadow overlay and the image container
    initialize: function() {    
        this.updateImageList();
        this.keyboardAction = this.keyboardAction.bindAsEventListener(this);
        if (LightboxOptions.resizeSpeed > 10) LightboxOptions.resizeSpeed = 10;
        if (LightboxOptions.resizeSpeed < 1)  LightboxOptions.resizeSpeed = 1;
	this.resizeDuration = LightboxOptions.animate ? ((11 - LightboxOptions.resizeSpeed) * 0.15) : 0;
        // shadow fade in/out duration
	this.overlayDuration = LightboxOptions.animate ? 0.2 : 0;  
        // lightbox first opens as a 250 x 250 px box and then resizes to the current image (this is hidden if animations are turned off to prevent flicker)
        var size = (LightboxOptions.animate ? 250 : 1) + 'px';
        // the code below inserts html at the bottom of the page that looks similar to this:
        //  <div id="overlay"></div>
        //  <div id="lightbox">
        //    <div id="outerImageContainer">
        //      <div id="imageContainer">
        //        <img id="lightboxImage">
        //        <div style="" id="hoverNav">
        //          <a href="#" id="prevLink"></a>
        //          <a href="#" id="nextLink"></a>
        //        </div>
        //        <div id="loading">
        //          <a href="#" id="loadingLink"><img src="thumbnails/loading.gif"></a>
        //        </div>
        //      </div>
        //    </div>
        //    <div id="imageDataContainer">
        //      <div id="imageData">
        //        <div id="imageDetails">
        //          <span id="caption"></span>
        //          <span id="numberDisplay"></span>
        //        </div>
        //        <div id="bottomNav">
        //          <a href="#" id="bottomNavClose"><img src="thumbnails/close.gif"></a>
        //        </div>
        //      </div>
        //    </div>
        //  </div>
        var objBody = $$('body')[0];
	objBody.appendChild(Builder.node('div',{id:'overlay'}));
        objBody.appendChild(Builder.node('div',{id:'lightbox'}, [
            Builder.node('div',{id:'outerImageContainer'}, 
                Builder.node('div',{id:'imageContainer'}, [
                    Builder.node('img',{id:'lightboxImage'}), 
                    Builder.node('div',{id:'hoverNav'}, [
                        Builder.node('a',{id:'prevLink', href: '#' }),
                        Builder.node('a',{id:'nextLink', href: '#' })
                    ]),
                    Builder.node('div',{id:'loading'}, 
                        Builder.node('a',{id:'loadingLink', href: '#' }, 
                            Builder.node('img', {src: LightboxOptions.fileLoadingImage})
                        )
                    )
                ])
            ),
            Builder.node('div', {id:'imageDataContainer'},
                Builder.node('div',{id:'imageData'}, [
                    Builder.node('div',{id:'imageDetails'}, [
                        Builder.node('span',{id:'caption'}),
                        Builder.node('span',{id:'numberDisplay'})
                    ]),
                    Builder.node('div',{id:'bottomNav'},
                        Builder.node('a',{id:'bottomNavClose', href: '#' },
                            Builder.node('img', { id:'bottomNavCloseImage', src: LightboxOptions.fileBottomNavCloseImage })
                        )
                    )
                ])
            )
        ]));

	$('overlay').hide().observe('click', (function() { this.end(); }).bind(this));
	$('lightbox').hide().observe('click', (function(event) { if (event.element().id == 'lightbox') this.end(); }).bind(this));
	$('outerImageContainer').setStyle({ width: size, height: size });
	$('prevLink').observe('click', (function(event) { event.stop(); this.changeImage(this.activeImage - 1); }).bindAsEventListener(this));
	$('nextLink').observe('click', (function(event) { event.stop(); this.changeImage(this.activeImage + 1); }).bindAsEventListener(this));
	$('loadingLink').observe('click', (function(event) { event.stop(); this.end(); }).bind(this));
	$('bottomNavClose').observe('click', (function(event) { event.stop(); this.end(); }).bind(this));
        $('bottomNavClose').observe('mouseover', (function() { $('bottomNavCloseImage').setAttribute('src', LightboxOptions.fileBottomNavCloseOver); }).bind(this));
        $('bottomNavClose').observe('mouseout', (function() { $('bottomNavCloseImage').setAttribute('src', LightboxOptions.fileBottomNavCloseImage); }).bind(this));

        var th = this;
        (function(){
            var ids = 
                'overlay lightbox outerImageContainer imageContainer lightboxImage hoverNav prevLink nextLink loading loadingLink ' + 
                'imageDataContainer imageData imageDetails caption numberDisplay bottomNav bottomNavClose';   
            $w(ids).each(function(id){ th[id] = $(id); });
        }).defer();
    },

    // loop through <A> tags looking for 'lightbox' attributes and apply OnClick events to appropriate links
    updateImageList: function() {   
        this.updateImageList = Prototype.emptyFunction;
        document.observe('click', (function(event){
            var target = event.findElement('a[rel^=lightbox]') || event.findElement('area[rel^=lightbox]');
            if (target) {
                event.stop();
                this.start(target);
            }
        }).bind(this));
    },
    
    // display overlay and lightbox and, if image is part of a set, add siblings to imageArray
    start: function(imageLink) {    
        $$('select', 'object', 'embed').each(function(node){ node.style.visibility = 'hidden' });
        // stretch overlay to fill page and fade in
        var arrayPageSize = this.getPageSize();
        $('overlay').setStyle({ width: arrayPageSize[0] + 'px', height: arrayPageSize[1] + 'px' });
        new Effect.Appear(this.overlay, { duration: this.overlayDuration, from: 0.0, to: LightboxOptions.overlayOpacity });
        this.imageArray = [];
        var imageNum = 0;
        imageLink.rel = imageLink.getAttribute('rel');
        if ((imageLink.rel == 'lightbox')){
            // if the image is not part of a set
            this.imageArray.push([imageLink.href, imageLink.title]);         
        } else {
            // if image is part of a set
            this.imageArray = 
                $$(imageLink.tagName + '[href][rel="' + imageLink.rel + '"]').
                collect(function(anchor){ return [anchor.href, anchor.title]; }).
                uniq();
            // count the number of images in the set
            while (this.imageArray[imageNum][0] != imageLink.href) { imageNum++; }
        }
        // calculate top and left offset for the lightbox 
        var arrayPageScroll = document.viewport.getScrollOffsets();
//	var lightboxTop = arrayPageScroll[1] + (document.viewport.getHeight() / 10);
        var lightboxTop = arrayPageScroll[1];
        var lightboxLeft = arrayPageScroll[0];
        this.lightbox.setStyle({ top: lightboxTop + 'px', left: lightboxLeft + 'px' }).show();
        this.changeImage(imageNum);
    },

    // hide most elements and preload image in preparation for resizing the image container
    changeImage: function(imageNum) {   
        this.activeImage = imageNum; 
        // hide elements during transition
        if (LightboxOptions.animate) this.loading.show();
        this.lightboxImage.hide();
        this.hoverNav.hide();
        this.prevLink.hide();
        this.nextLink.hide();
        // hack for Opera 9 which does not currently support scriptaculous opacity and appearance effects
        this.imageDataContainer.setStyle({opacity: .0001});
        this.numberDisplay.hide();      
        var imgPreloader = new Image();
        // once image is preloaded, resize the image container
        imgPreloader.onload = (function(){
            this.lightboxImage.src = this.imageArray[this.activeImage][0];
            this.resizeImageContainer(imgPreloader.width, imgPreloader.height);
        }).bind(this);
        imgPreloader.src = this.imageArray[this.activeImage][0];
    },

    // resize the image container
    resizeImageContainer: function(imgWidth, imgHeight) {
        // get current width and height
        var widthCurrent  = this.outerImageContainer.getWidth();
        var heightCurrent = this.outerImageContainer.getHeight();
        // get new width and height
        var widthNew  = (imgWidth  + LightboxOptions.borderSize * 2);
        var heightNew = (imgHeight + LightboxOptions.borderSize * 2);
        // scalars based on change from old to new
        var xScale = (widthNew  / widthCurrent)  * 100;
        var yScale = (heightNew / heightCurrent) * 100;
        // calculate difference between new and old image sizes and resize if necessary
        var wDiff = widthCurrent - widthNew;
        var hDiff = heightCurrent - heightNew;
        if (hDiff != 0) new Effect.Scale(this.outerImageContainer, yScale, {scaleX: false, duration: this.resizeDuration, queue: 'front'}); 
        if (wDiff != 0) new Effect.Scale(this.outerImageContainer, xScale, {scaleY: false, duration: this.resizeDuration, delay: this.resizeDuration}); 
        // if no resizing is necessary insert a pause to prevent flicker
        var timeout = 0;
        if ((hDiff == 0) && (wDiff == 0)){
            timeout = 100;
            if (Prototype.Browser.IE) timeout = 250;   
        }
        (function(){
            this.prevLink.setStyle({ height: imgHeight + 'px' });
            this.nextLink.setStyle({ height: imgHeight + 'px' });
            this.imageDataContainer.setStyle({ width: widthNew + 'px' });
            this.showImage();
        }).bind(this).delay(timeout / 1000);
    },
    
    // display image and begin preloading neighbours
    showImage: function(){
        this.loading.hide();
        new Effect.Appear(this.lightboxImage, { 
            duration: this.resizeDuration, 
            queue: 'end', 
            afterFinish: (function(){ this.updateDetails(); }).bind(this) 
        });
        this.preloadNeighborImages();
    },

    // display caption, 'image x of x' and navigation
    updateDetails: function() {
        // if caption is not empty
        if (this.imageArray[this.activeImage][1] != ""){
            this.caption.update(this.imageArray[this.activeImage][1]).show();
        }
//      // if image is part of set display 'image x of x' 
//      if (this.imageArray.length > 1){
//          this.numberDisplay.update( LightboxOptions.labelImage + ' ' + (this.activeImage + 1) + ' ' + LightboxOptions.labelOf + ' ' + this.imageArray.length).show();
//      }
        new Effect.Parallel(
            [ 
                new Effect.SlideDown(this.imageDataContainer, { sync: true, duration: this.resizeDuration, from: 0.0, to: 1.0 }), 
                new Effect.Appear(this.imageDataContainer, { sync: true, duration: this.resizeDuration }) 
            ], 
            { 
                duration: this.resizeDuration, 
                afterFinish: (function() {
	                // update overlay size and navigation
	                var arrayPageSize = this.getPageSize();
	                this.overlay.setStyle({ height: arrayPageSize[1] + 'px' });
	                this.updateNav();
                }).bind(this)
            } 
        );
    },

    // display previous and next labels and enable keyboard navigation
    updateNav: function() {
        this.hoverNav.show();               
        // display 'previous' label if not first image and/or 'next' label if not last image
        if (this.activeImage != 0) this.prevLink.show();
        if (this.activeImage != (this.imageArray.length - 1)) this.nextLink.show();
        this.enableKeyboardNav();
    },

    // enable keyboard navigation
    enableKeyboardNav: function() {
        document.observe('keydown', this.keyboardAction); 
    },

    // disable keyboard while loading image
    disableKeyboardNav: function() {
        document.stopObserving('keydown', this.keyboardAction); 
    },

    // keyboard action
    keyboardAction: function(event) {
        var keycode = event.keyCode;
        var escapeKey;
        if (event.DOM_VK_ESCAPE) {
            // Mozilla
            escapeKey = event.DOM_VK_ESCAPE;
        } else { 
            // MSIE
            escapeKey = 27;
        }
        var key = String.fromCharCode(keycode).toLowerCase();
        // if 'x', 'o', 'c' or 'esc' key is pressed close the lightbox
        if (key.match(/x|o|c/) || (keycode == escapeKey)){ 
            this.end();
        // if 'p' or left arrow key is pressed display the previous image
        } else if ((key == 'p') || (keycode == 37)){ 
            if (this.activeImage != 0){
                this.disableKeyboardNav();
                this.changeImage(this.activeImage - 1);
            }
        // if 'n' or right arrow key is pressed display the next image
        } else if ((key == 'n') || (keycode == 39)){ 
            if (this.activeImage != (this.imageArray.length - 1)){
                this.disableKeyboardNav();
                this.changeImage(this.activeImage + 1);
            }
        }
    },

    // preload neighbouring images
    preloadNeighborImages: function(){
        var preloadNextImage, preloadPrevImage;
        if (this.imageArray.length > this.activeImage + 1){
            preloadNextImage = new Image();
            preloadNextImage.src = this.imageArray[this.activeImage + 1][0];
        }
        if (this.activeImage > 0){
            preloadPrevImage = new Image();
            preloadPrevImage.src = this.imageArray[this.activeImage - 1][0];
        }
    
    },

    // close the lightbox
    end: function() {
        this.disableKeyboardNav();
        this.lightbox.hide();
        new Effect.Fade(this.overlay, { duration: this.overlayDuration });
        $$('select', 'object', 'embed').each(function(node){ node.style.visibility = 'visible' });
    },

    // get page size
    getPageSize: function() {
	     var xScroll, yScroll;
		if (window.innerHeight && window.scrollMaxY) {	
			xScroll = window.innerWidth + window.scrollMaxX;
			yScroll = window.innerHeight + window.scrollMaxY;
		} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
			xScroll = document.body.scrollWidth;
			yScroll = document.body.scrollHeight;
		} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
			xScroll = document.body.offsetWidth;
			yScroll = document.body.offsetHeight;
		}
		var windowWidth, windowHeight;
		if (self.innerHeight) {	// all except Explorer
			if(document.documentElement.clientWidth){
				windowWidth = document.documentElement.clientWidth; 
			} else {
				windowWidth = self.innerWidth;
			}
			windowHeight = self.innerHeight;
		} else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
			windowWidth = document.documentElement.clientWidth;
			windowHeight = document.documentElement.clientHeight;
		} else if (document.body) { // other Explorers
			windowWidth = document.body.clientWidth;
			windowHeight = document.body.clientHeight;
		}	
		
		// for small pages with total height less then height of the viewport
		if (yScroll < windowHeight){
			pageHeight = windowHeight;
		} else { 
			pageHeight = yScroll;
		}
	
		// for small pages with total width less then width of the viewport
		if (xScroll < windowWidth){	
			pageWidth = xScroll;		
		} else {
			pageWidth = windowWidth;
		}
		return [pageWidth,pageHeight];
	}
}

document.observe('dom:loaded', function () { new Lightbox(); });