/*
	Standalone (no jQuery) lightweight Lightbox implementation with minimal CSS3 animations
	Based on and mostly compatible with Slimbox2 <http://www.digitalia.be/software/slimbox2>
	(c) 2012+ Vitaliy Filippov <http://yourcmc.ru/wiki>
	MIT-style license.
	Version 2015-05-01
*/

window.addListener = (function() {
	return window.addEventListener
		? function(el, type, fn) { el.addEventListener(type, fn, false); }
		: function(el, type, fn) { el.attachEvent('on'+type, fn); };
})();

window.removeListener = (function() {
	return window.removeEventListener
		? function(el, type, fn) { el.removeEventListener(type, fn, false); }
		: function(el, type, fn) { el.detachEvent('on'+type, fn); };
})();

addListener(window, 'load', function() {

	// Global variables, accessible to Slimbox only
	var options, images, activeImage = -1, activeURL, prevImage, nextImage, noFixed, middle, centerWidth, centerHeight,
		ie6 = !window.XMLHttpRequest, hiddenElements = [], els = {}, css, keyActions,
		// Preload images
		preload = {}, preloadPrev = new Image(), preloadNext = new Image();

	// Initialization

	// Append the Slimbox HTML code at the bottom of the document
	var d = document.createElement('div');
	d.innerHTML = '<div id="lbOverlay" style="display: none"></div>'+
		'<div id="lbCenter" style="display:none">'+
		'<div id="lbWindow"><div id="lbImage"><div id="lbSizer" style="position: relative;">'+
		'<a id="lbPrevLink" href="#"></a><a id="lbNextLink" href="#"></a></div></div></div>'+
		'<div><div id="lbBottom">'+
		'<a id="lbCloseLink" href="#"></a><div id="lbCaption"></div><div id="lbNumber"></div><div style="clear: both;" />'+
		'</div></div></div>';
	while (d.childNodes.length) {
		document.body.appendChild(d.childNodes[0]);
	}
	var l = 'overlay center window image sizer prevLink nextLink bottom closeLink caption number'.split(' ');
	for (var i = 0; i < l.length; i++) {
		els[l[i]] = document.getElementById('lb'+l[i].substr(0, 1).toUpperCase()+l[i].substr(1));
	}
	els.prevLink.onclick = previous;
	els.nextLink.onclick = next;
	els.closeLink.onclick = close;

	// Utils

	function apply(a, b) {
		for (var i in b) {
			a[i] = b[i];
		}
	}
	function foreach(a, f) {
		for (var i in a) {
			f(i, a[i]);
		}
	}
	function curStyle(e) {
		return window.getComputedStyle ? getComputedStyle(e) : e.currentStyle;
	}

	// API

	// Open Slimbox with the specified parameters
	window.slimbox = function(_images, startImage, _options) {
		options = {
			loop: false,				// Allows to navigate between first and last images
			overlayOpacity: 0.8,			// 1 is opaque, 0 is completely transparent (change the color in the CSS file)
			overlayFadeDuration: 400,		// Duration of the overlay fade-in and fade-out animations (in milliseconds)
			initialWidth: 250,			// Initial width of the box (in pixels)
			initialHeight: 250,			// Initial height of the box (in pixels)
			imageFadeDuration: 400,			// Duration of the image fade-in animation (in milliseconds)
			counterText: "Image {x} of {y}",	// Translate or change as you wish, or set it to false to disable counter text for image groups
			closeKeys: [27, 88, 67],		// Array of keycodes to close Slimbox, default: Esc (27), 'x' (88), 'c' (67)
			previousKeys: [37, 80],			// Array of keycodes to navigate to the previous image, default: Left arrow (37), 'p' (80)
			nextKeys: [39, 78]			// Array of keycodes to navigate to the next image, default: Right arrow (39), 'n' (78)
		};
		if (_options) {
			apply(options, _options);
		}
		css = document.createElement('style');
		var D1 = options.overlayFadeDuration+'ms ease';
		var D2 = options.imageFadeDuration+'ms ease';
		var t1 = 'transition: opacity '+D1+';';
		var t3 = 'transition: all '+D2+';';
		css.type = 'text/css';
		css.innerHTML =
'#lbOverlay { opacity: 0; '+t1+' -moz-'+t1+' -o-'+t1+' -webkit-'+t1+' }\n\
#lbOverlay.lbvisible { opacity: '+options.overlayOpacity+'; '+t1+' -moz-'+t1+' -o-'+t1+' -webkit-'+t1+' }\n\
#lbImage { opacity: 0; }\n\
#lbImage.lbvisible { opacity: 1; '+t1+' -moz-'+t1+' -o-'+t1+' -webkit-'+t1+' }\n\
#lbWindow, #lbCenter { '+t3+' -moz-'+t3+' -o-'+t3+' -webkit-'+t3+' }';
		document.head.appendChild(css);

		keyActions = {};
		for (var i in options.closeKeys) {
			keyActions[options.closeKeys[i]] = close;
		}
		for (var i in options.previousKeys) {
			keyActions[options.previousKeys[i]] = previous;
		}
		for (var i in options.nextKeys) {
			keyActions[options.nextKeys[i]] = next;
		}

		// The function is called for a single image, with URL and Title as first two arguments
		if (typeof _images == "string") {
			_images = [ { url: _images, title: startImage } ];
			startImage = 0;
		}

		middle = ((window.innerHeight || document.documentElement.offsetHeight) / 2);
		centerWidth = options.initialWidth;
		centerHeight = options.initialHeight;
		apply(els.center.style, {
			top: Math.max(0, middle - (centerHeight / 2))+'px',
			marginLeft: (-centerWidth/2)+'px',
			display: ''
		});
		// Animate padding instead of width so all edges move synchronously
		apply(els.window.style, {
			paddingLeft: (centerWidth/2)+'px',
			paddingRight: (centerWidth/2)+'px',
			paddingTop: (centerHeight/2)+'px',
			paddingBottom: (centerHeight/2)+'px'
		});
		var cs = curStyle(els.overlay);
		noFixed = ie6 || cs && cs.position != "fixed";
		if (noFixed) els.overlay.style.position = "absolute";

		els.overlay.style.display = '';
		setTimeout(function() {
			els.overlay.className = 'lbvisible';
		}, 15);

		position();
		setup(1);

		images = _images;
		options.loop = options.loop && (images.length > 1);
		return changeImage(startImage);
	};

	// images = [ { element: clickOnWhatElement, url: imgUrl, title: titleHTML } ];
	window.setSlimbox = function(images, options) {
		foreach (images, function(i, img) {
			if (!img.element) {
				return;
			}
			if (img.element.nodeName == 'A') {
				img.element.target = '';
			}
			addListener(img.element, 'click', function(ev) {
				ev = ev || window.event;
				ev.preventDefault();
				window.slimbox(images, parseInt(''+i), options);
				return false;
			});
		});
	};

	// Internal functions

	function position() {
		var l = document.documentElement.scrollLeft, w = document.documentElement.offsetWidth;
		if (noFixed) {
			apply(els.overlay.style, {
				left: l+'px',
				top: '0px',
				width: w+'px',
				height: document.documentElement.offsetHeight+'px'
			});
		}
	}

	function hide(nodes) {
		for (var i = 0; i < nodes.length; i++) {
			hiddenElements.push([nodes[i], nodes[i].style.visibility]);
			nodes[i].style.visibility = "hidden";
		}
	}

	function setup(open) {
		if (open) {
			hide(document.getElementsByTagName('object'));
			hide(document.getElementsByTagName(ie6 ? 'select' : 'embed'));
		} else {
			for (var i in hiddenElements) {
				hiddenElements[i][0].style.visibility = hiddenElements[i][1];
			}
			hiddenElements = [];
		}
		var f = (open ? addListener : removeListener);
		f(window, 'scroll', position);
		f(window, 'resize', position);
		f(document, 'keydown', keyDown);
	}

	function keyDown(event) {
		event = event || window.event;
		var code = event.keyCode;
		// Prevent default keyboard action (like navigating inside the page)
		return keyActions[code] ? keyActions[code]() : false;
	}

	function previous() {
		return changeImage(prevImage);
	}

	function next() {
		return changeImage(nextImage);
	}

	function changeImage(imageIndex) {
		if (imageIndex >= 0) {
			activeImage = imageIndex;
			activeURL = images[activeImage].url;
			prevImage = (activeImage || (options.loop ? images.length : 0)) - 1;
			nextImage = ((activeImage + 1) % images.length) || (options.loop ? 0 : -1);

			els.center.className = "lbLoading";
			els.image.className = '';

			preload = new Image();
			preload.onload = animateBox;
			preload.src = activeURL;
		}

		return false;
	}

	function animateBox() {
		els.center.className = "";
		els.image.style.backgroundImage = "url(" + activeURL + ")";
		els.image.style.marginLeft = (-preload.width/2)+'px';
		els.image.style.marginTop = (-preload.height/2)+'px';
		els.image.style.width = preload.width+'px';
		els.image.style.height = preload.height+'px';
		els.prevLink.style.height = preload.height+'px';
		els.nextLink.style.height = preload.height+'px';
		els.caption.innerHTML = images[activeImage]['title'] || "";
		els.number.innerHTML = (((images.length > 1) && options.counterText) || "").replace(/{x}/, activeImage + 1).replace(/{y}/, images.length);

		if (prevImage >= 0) preloadPrev.src = images[prevImage]['url'];
		if (nextImage >= 0) preloadNext.src = images[nextImage]['url'];

		centerWidth = preload.width;
		centerHeight = preload.height;
		if (els.window.clientHeight != centerHeight) {
			var top = Math.max(0, middle - (centerHeight / 2));
			els.window.style.paddingTop = els.window.style.paddingBottom = (centerHeight/2)+'px';
			els.center.style.top = top+'px';
		}
		if (els.window.clientWidth != centerWidth) {
			els.window.style.paddingLeft = els.window.style.paddingRight = (centerWidth/2)+'px';
			els.center.style.marginLeft = (-centerWidth/2)+'px';
		}
		els.image.className = 'lbvisible';
		if (prevImage >= 0) els.prevLink.style.display = '';
		if (nextImage >= 0) els.nextLink.style.display = '';
	}

	function stop() {
		preload.onload = null;
		preload.src = preloadPrev.src = preloadNext.src = activeURL;
		els.prevLink.style.display = 'none';
		els.nextLink.style.display = 'none';
		setup(0);
	}

	function close() {
		if (activeImage >= 0) {
			stop();
			activeImage = prevImage = nextImage = -1;
			els.center.style.display = 'none';
			els.image.style.width = els.image.style.height = '1px';
			els.overlay.className = '';
			setTimeout(function() {
				els.overlay.style.display = 'none';
				document.head.removeChild(css);
			}, options.overlayFadeDuration);
		}
		return false;
	}

});