/*
 * @projectDescription Creates a revolving series of content slides
 * @version: 2.15
 * @optional: jquery.onfontresize.js
 */
(function($){	
	$.fn.revolver = function(opts){
		opts = $.extend(true,{
			duration: 500,
			interval: 7500,
			index: 0,
			selectors: {
				item: 			'.revolverItem',
				prev: 			'.revolverPrev',
				next: 			'.revolverNext',
				pager: 			'.revolverPager',
				select:			'.revolverSelect'
			},
			classes: {
				window:				'revolverWindow',
				belt: 				'revolverBelt',
				pagerItem: 			'pagerItem',
				pagerItemSelected: 	'pagerItemSelected',
				prevDisabled: 		'prevDisabled',
				nextDisabled: 		'nextDisabled',
				selected:			'selected'
			},
			infinite: true,
			mobile: false,
			selected: -1,
			stopOnHover: true,
			movedItems:	1
		}, opts);
		
		return this.each(function(){
			var $this = $(this),
				$window = $this.find('.' + opts.classes.window),
				$belt = $this.find('.' + opts.classes.belt),
				$prev = $this.find(opts.selectors.prev),
				$next = $this.find(opts.selectors.next),
				maxHeight = 0,
				currIndex = opts.index,
				visibleItems = 0,
				busy = false,
				autoPlayTimer = null,
				items = [],
				filteredItems = [],
				selected = opts.selected;

			if(!$window.length){
				$window = $('<div class="' + opts.classes.window + '"/>').prependTo($this).width($this.width());
				$belt = $('<div class="' + opts.classes.belt + '"/>').prependTo($window);
			}
			
			var $pager = null;
			$this.find(opts.selectors.pager).empty();
			if($this.find(opts.selectors.pager)[0].nodeName !== 'UL'){
				$this.find(opts.selectors.pager).append('<ul />');
				$pager = $this.find(opts.selectors.pager + ' ul');
			}
			else{
				$pager = $this.find(opts.selectors.pager);
			}
			
			var $items = $this.find(opts.selectors.item).appendTo($belt),
				itemWidth = $items.outerWidth();
				
			//add aria role attributes
			$this.attr({
				'aria-live':		'polite',	
				'aria-relevant':	'all'
			});
			
			//load images before revolver is called
			var imageTotal = $this.find('img').length,
				imageCount = 0;
				
			if(imageTotal){
	    		$this.find('img').each(function(){
	    			$(this)
	    				.attr('src', $(this).attr('src') + '?' + new Date().getTime())
	    				.load(function(){
			    			if(++imageCount == imageTotal){
			    				loadComplete();
			    			}
			    		});
	    		});
	    	}
			else{
				loadComplete();
			}
			
			/**
			 * Sets relevant css properties and makes calls to other functions.
			 */
			function loadComplete(){
				$items.each(function(i){
					maxHeight = Math.max(maxHeight, $(this).outerHeight());
					
					if((i+1) * itemWidth <= $window.width()){
						visibleItems++;
					}
					if(opts.infinite){
						items.push($(this));
					}
				});
				if (visibleItems === 0){
					visibleItems = 1;
				}
				
				//return if not enough items to warrant revolver
				if($items.length <= visibleItems){
					$this.trigger('onabortrevolver');
					return;
				}
				
				if(opts.infinite){
					filteredItems = items;
					filter();
				}
				
				$window.css({
					position: 'relative',
					height: maxHeight,
					overflow: 'hidden'
				});
				$belt.css({
					position: 'absolute',
					top: 0,
					left: 0,
					width: getBeltWidth(itemWidth)
				});
				
				if(typeof $.onFontResize === 'object'){
					$(document).bind('fontresize', function(){
						$window.height(getMaxHeight());
					});
				}
				
				drawPager();
				bindNavEvents();
				bindCustomEvents();
				
				if(opts.selected != -1){
					$(opts.selectors.select).live('click', function(){
						$this = $(this);
						selected = $this.closest(opts.selectors.item).attr('data-index');
						$(opts.selectors.item).removeClass(opts.classes.selected);
						$this.closest(opts.selectors.item).addClass(opts.classes.selected);
					});
				}
				$this.trigger('onloadcompleterevolver');
			}
			/**
			 * Gets the width of the belt
			 */
			function getBeltWidth(width){
				return width * $items.length;
			}
			/**
			 * Displays prev and next buttons and binds click events to them.
			 * Sets autoplay if opts.interval > 0.
			 */
			function bindNavEvents(){
				$prev
					.css({
						display: 'block',
						cursor: 'pointer'
					})
					.click(function(e){
						e.preventDefault();
						if(!$(this).hasClass(opts.classes.prevDisabled)){
							change(currIndex-opts.movedItems, false, true, true);
						}
					});
				$next
					.css({
						display: 'block',
						cursor: 'pointer'
					})
					.click(function(e){
						e.preventDefault();
						if(!$(this).hasClass(opts.classes.nextDisabled)){
							change(currIndex+opts.movedItems, false, true, true);
						}
					});
					
				if(opts.interval > 0){
					setTimer(currIndex+opts.movedItems);
					if(!opts.mobile && opts.stopOnHover){
						$this.hover(function(){
							clearInterval(autoPlayTimer);
						}, function(){
							setTimer(currIndex+opts.movedItems);
						});
					}
				}
			}
			/**
			 * Binds custom events to $this.
			 */
			function bindCustomEvents(){
				$this
					.bind('changerevolver', function(e, index){
						change(index, false, true);
					})
					.bind('stoprevolver', function(){
						clearInterval(autoPlayTimer);
					})
					.bind('startrevolver', function(){
						setTimer(currIndex+1);
					})
					.bind('changeselectedrevolver', function(e, index){
						selected = index;
						$(opts.selectors.item).removeClass(opts.classes.selected);
						filteredItems[index].addClass(opts.classes.selected);
					})
					.bind('filterbyclassrevolver', function(e, className, exclude){
						filterByClass(className, exclude);
					})
					.bind('changeitemsrevolver', function(e, elements, selected){
						filteredItems = elements;
						
						currIndex = 0;
						filter();
						drawPager();
						change(currIndex, true, true);
					})
					.bind('resizerevolver', function(e, width, height){
						$window.css({
							width: width,
							height: height
						});
						$items.width(width);
						$belt.width(getBeltWidth(width));
						itemWidth = width;
					});
			}
			/**
			 * Draws the pager items and attaches pager events
			 */
			function drawPager(){
				$pager.empty().show();
				for(var i=0; i<filteredItems.length; i++){
					var className = (i === filteredItems.length-1) ? 'last' : '',
						$pagerItem = $(
							'<li><a href="#" class="' + opts.classes.pagerItem + ' ' + className + '">' +
								'Carousel item ' + (i+1) +
							'</a></li>'
						);
					$pager.append($pagerItem);
				}
				$pager.find('.' + opts.classes.pagerItem).each(function(i){
					$(this)
						.css('text-indent', '-9999px')
						.click(function(e){
							e.preventDefault();
							change(i, false, true, true);
						});
				});
				updatePager(currIndex);
				if($pager.find('.' + opts.classes.pagerItem).length-1 < visibleItems){
					$pager.hide();
				}
			}
			/**
			 * Appends filtered items to the belt
			 */
			function filter(){
				for(var i=0; i<filteredItems.length; i++){
					filteredItems[i]
						.hide()
						.attr({
							'data-index': i,
							'aria-hidden': 'true'
						});
				}
				
				for(var i=0; i<visibleItems; i++){
					filteredItems[currIndex+i]
						.show()
						.attr('aria-hidden', 'false');
				}
			}
			/**
			 * Filters the items by class.
			 * @param: className {string} - class to filter by
			 * @param: exclude {boolean} - exclude the filter items
			 */
			function filterByClass(className, exclude){
				if(busy){
					setTimeout(function(){filterByClass(className, exclude)}, opts.duration);
					return;
				}
				else{
					filteredItems = [];
					var filteredIndex = 0;
					$.each(items, function(index){
						$this = $(this);
						if(exclude){
							if(!$this.hasClass(className)){
								filteredItems[filteredIndex] = items[index];
								filteredItems[filteredIndex]
									.show()
									.attr({
										'data-index': filteredIndex,
										'aria-hidden': 'false'
									});
								filteredIndex++;
							}
						}
						else{
							if($this.hasClass(className)){
								filteredItems[filteredIndex] = items[index];
								filteredItems[filteredIndex]
									.show()
									.attr({
										'data-index': filteredIndex,
										'aria-hidden': 'false'
									});
								filteredIndex++;
							}
						}
					});
					
					currIndex = 0;
					$belt.empty();
					for(var i=0; i<filteredItems.length; i++){
						$belt.append(filteredItems[i]);
					}
					drawPager();
					change(currIndex, true, true, true);
					
					//return if not enough items to warrant revolver
					if(filteredIndex <= visibleItems){
						$prev.hide();
						$next.hide();
						if(opts.interval > 0){
							clearInterval(autoPlayTimer);
						}
					}
					else{
						$prev.show();
						$next.show();
						if(opts.interval > 0){
							setTimer(currIndex + opts.movedItems);
						}
					}
				}
			}
			/**
			 * Gets the maximum height of all items
			 * @returns maximum height
			 */
			function getMaxHeight(){
				var height = 0;
				$items.each(function(){
					height = Math.max(height, $(this).outerHeight());
				});
				return height;
			}
			/**
			 * Sets the timer to run the autoplay functionality
			 * @param: index {int} - index to start autoplay at
			 */
			function setTimer(index){
				var timeIndex = index;
				clearInterval(autoPlayTimer);
				autoPlayTimer = setInterval(function(){
					change(timeIndex, false);
					if(opts.infinite && timeIndex >= filteredItems.length) {
						timeIndex = (timeIndex - filteredItems.length) + opts.movedItems;
					} 	
					else if(!opts.infinite && timeIndex >= $items.length - visibleItems) {
						timeIndex = 0;
					}
					else{
						timeIndex += opts.movedItems;
					}
				}, opts.interval);
			}
			/**
			 * Changes the visible panels.
			 * @param: index {int} - index to change to
			 * @param: snap {boolean} - whether to snap or animate
			 * @param: resetTimer {boolean} - whether to reset the timer or not
			 * @param: userDriven {boolean} - whether the user has made the revolver change or not
			 */	
			function change(index, snap, resetTimer, userDriven){
				var duration = snap ? 0 : opts.duration;
				
				if(!opts.infinite){
					if(index > filteredItems.length - visibleItems){
						index = filteredItems.length - visibleItems;
					}
				}
				if(opts.interval > 0 && resetTimer){
					clearInterval(autoPlayTimer);
				}
				if(!busy){
					busy = true;
					
					if(opts.infinite){ 
						var left = 0,
							forward = true,
							count = 0,
							limit = index+visibleItems;
						
						//calculate closest direction					
						var forwardDist = 0, 
							backDist = 0;
						if(currIndex < index){
							forwardDist = index - currIndex;
							backDist = filteredItems.length - forwardDist;
						}
						else if(currIndex > index){
							backDist = currIndex - index;
							forwardDist = filteredItems.length - backDist;
						}
						
						if(forwardDist < backDist){
							forward = true;	
						}
						else if(forwardDist === backDist){
							if(index > currIndex){
								forward = true;
							}
							else{
								forward = false;
							}
						}
						else{
							forward = false;	
						}
											
						if(index < 0){
							index = filteredItems.length - (index*-1);
						}
						
						if(forward){
							for(var i=0; i<forwardDist; i++){
								var itemNum = currIndex+visibleItems+i;
								if (itemNum >= filteredItems.length){
									itemNum = itemNum - filteredItems.length;	
								}
								var item = filteredItems[itemNum];
								if (opts.selected != -1 && item.attr('data-index') != selected){
									item.removeClass(opts.classes.selected);
								}
								$belt.append(item.show().attr('aria-hidden', 'false'));
								count++;
							}
							left = (itemWidth*forwardDist)*-1;
						}
						else{
							for(var i=0; i<backDist; i++){
								var itemNum = currIndex-i-1;
								if (itemNum < 0){
									itemNum = filteredItems.length+(currIndex-i-1);
								}
								var item = filteredItems[itemNum];
								if (opts.selected != -1 && item.attr('data-index') != selected){
									item.removeClass(opts.classes.selected);
								}
								$belt.prepend(item.show().attr('aria-hidden', 'false'));
								count++;
							}
							$belt.css('left', (itemWidth*backDist)*-1);
							left = 0;
						}
												
						if(index > filteredItems.length-1){
							index = index - filteredItems.length;
						}
						
						$this.trigger('onbeforechangerevolver', currIndex);
						$belt.animate({left: left}, duration, function(){
							updatePager(index);
							$belt.children().each(function(i){
								var itemIndex = parseInt($(this).attr('data-index'));
								var inRange = calcWithinRange(itemIndex, index, visibleItems, filteredItems.length);
								if(!inRange){
									$(this).hide().attr('aria-hidden', 'true');
								}
							});
							$belt.css('left', 0);
							busy = false;
							
							if(opts.interval > 0 && resetTimer){
								setTimer(index+1);
							}
							
							if(userDriven){
								//focus on first <a> for accessibility
								$belt.find(opts.selectors.item + ':visible').find('a:eq(0)').focus();
							}
							
							currIndex = index;
							$this.trigger('onchangerevolver', currIndex);
						});
					}
					else{
						$this.trigger('onbeforechangerevolver', currIndex);
						$belt.animate({left: (index * itemWidth) * -1}, duration, function(){
							updateNavigation(index);
							updatePager(index);
							busy = false;
							
							if(opts.interval > 0 && resetTimer){
								setTimer(index+1);
							}
							
							if(userDriven){
								//focus on first <a> for accessibility
								$belt.find(opts.selectors.item + ':visible').eq(0).find('a').focus();
							}
							
							currIndex = index;
							$this.trigger('onchangerevolver', currIndex);
						});
					}
				}
			}
			/**
			 * Updates the navigation
			 * @param: index {int} - current index of visible panels
			 */
			function updateNavigation(index){
				if(index == 0){
					$prev.addClass(opts.classes.prevDisabled);
				}
				else{
					$prev.removeClass(opts.classes.prevDisabled);
				}
				
				if(index == $items.length - visibleItems){
					$next.addClass(opts.classes.nextDisabled);
				}
				else{
					$next.removeClass(opts.classes.nextDisabled);
				}
			}
			/**
			 * Updates the pager
			 * @param: index {int} - current index of visible panels
			 */
			function updatePager(index){ 
				$pager.find('.' + opts.classes.pagerItem).each(function(i){
					if((i >= index && i < index+visibleItems) || (opts.infinite && (i <= index + (visibleItems-1)-filteredItems.length))){
						$(this)
							.attr('title', 'Current carousel item')
							.addClass(opts.classes.pagerItemSelected);
					}
					else{
						$(this)
							.attr('title', '')
							.removeClass(opts.classes.pagerItemSelected);
					}
				});
			}
			/**
			 * Calculates if the current index item is within the range of visible elements
			 * @param: itemIndex: The index position of the specified element
			 * @param: index: The index of the first visible item on the page
			 * @param: visibleItems: The number of visible items within the set
			 * @param: setSize: size of the set of items
			 * @returns: Boolean (true if in range else false) 
			*/
			function calcWithinRange(itemIndex, index, visibleItems, setSize){
				//calculate range of values
				
				var tempIndex = index;
				var valueRange = new Array(visibleItems);
				
				for(var i = 0; i < visibleItems; i++){
					if(tempIndex > setSize-1){
						tempIndex = 0;	
					}
					valueRange[i] = tempIndex;
					tempIndex++;
				}
				//check if value is in the calculated range
				if($.inArray(itemIndex, valueRange) != -1){
					return true;	
				}
				else{
					return false;	
				}
			}
		});
	}
})(jQuery);