/*
 * All script logic for product comparison.
 *
 * The code relies on the jQuery JS library to be also loaded.
 *
 * The logic extends the JS namespace app.*
 */

(function(app){
	if (app) {
   		var products = [null, null, null, null, null, null];
   		var count = 0;
		var emptyImgSrc = '';
		var emptyImgAlt = '';
		var baseButtonLabel = '';
		var confirmationMessage = '';
		var openUrl = '';
		var addUrl = '';
		var removeUrl = '';
		var suppressRefresh = false;

		var refresh = function() {
			if (suppressRefresh) {
				return;
			}
			
	   		var buttonLabel = baseButtonLabel;
	   		if (count > 0) {
	   			buttonLabel += ' (' + count + ')';
	   		}
	
	   		var compareItemsButton = jQuery('#compareItemsButton');
	   		compareItemsButton.html(buttonLabel);
	   		compareItemsButton.each(function() {
	   			jQuery(this).attr('disabled',(count < 2));
	   		});

	   		$('#clearComparedItemsButton').each(function() {
	   			jQuery(this).attr('disabled',(count < 1));
	   		});
	   		
   			$('DIV.compare .compareBtn').removeClass('enabled').attr('disabled', true);
	   		if (count > 1) {
	   			$('DIV.compare input[type=checkbox]:checked').siblings('button').attr('disabled', false).addClass('enabled');
	   		}
	   		
	   		if (count > 0) {
	   			jQuery('#compareItems').show();
	   		} 
	   		else {
	   			jQuery('#compareItems').hide();
	   		}
	   		
	   		/**
	   		 * Gray out all unchecked compare check boxes if the maximum number of 
	   		 * comparable products is reached.
	   		 */
	  		if (count >= 4) {
	  			$('.compare input[type="checkbox"]').each(function (i) {
	  				if ( !this.checked ){
	  					this.disabled=true;
	  					$(this).siblings('button').attr('disabled', true);
	  				}
	  			});
	  		} else {
	  			$('.compare input[type="checkbox"]').each(function (i) {
	  				if ( !this.checked ){
	  					this.disabled=false;
	  					$(this).siblings('button').attr('disabled', false);
	  				}
	  			});
	  		}
	   		
	   	};
	
		var reset = function(options) {
			products = [null, null, null, null, null, null];
			count = 0;
			emptyImgSrc = options.emptyImgSrc;
			emptyImgAlt = options.emptyImgAlt;
			baseButtonLabel = options.baseButtonLabel;
			confirmationMessage = options.confirmation;
			openUrl = options.openUrl;
			addUrl = options.addUrl;
			removeUrl = options.removeUrl;

			refresh();
		};

		var addProduct = function(options) {
	   		var addIndex = count;
			products[addIndex] = {id:options.id, category:options.category};
	   		count++;
	   		return addIndex;
		};
		
		var setProductImage = function(options) {
			jQuery('#compareItemsProduct' + options.index).each(function() {
		   		var productImage = jQuery(this)[0];
				productImage.src = options.src;
				productImage.alt = options.alt;
			});

	   		jQuery('#compareItemsClear' + options.index).show();
		}
		
		app.compare = {
			initialize: function(options) {
				reset(options);

				// Buttons to remove compared products individually	
				for (var i = 0; i < 6; i++) {
					// new Function() syntax ensures loop index is used correctly
					jQuery('#compareItemsClear' + i).click(new Function('app.compare.removeProduct({index: ' + i + '})'));
				}
	
				// Button to go to compare page
				jQuery('#compareItemsButton').click(function() {
					if (count>1) {
						window.location.href = options.openUrl;
					}
				});

				// Button to go to compare page
				$('.compareBtn').click(function() {
					if ($(this).hasClass('enabled') && count>1) {
						window.location.href = options.openUrl;
					}
				});

				// Button to clear all compared items
				jQuery('#clearComparedItemsButton').click(function() {
					suppressRefresh = true;

					jQuery('#compareItems').hide();
					
					for (var i = count - 1; i >= 0; i--) {
						app.compare.removeProduct({index: i});
					}

					suppressRefresh = false;

					refresh();
				});
	
				// Check checkboxes for compared products on the current page 
				for (var i = 0; i < options.products.length; i++) {
					var product = options.products[i];
					var addIndex = addProduct({id:product.id, category:product.category});
					setProductImage({index:addIndex, src:product.imgSrc, alt:product.imgAlt});
	
					jQuery('#compareCheck' + product.id).each(function() {
						jQuery(this)[0].checked = true;
						jQuery(this).addClass("compared");
					});
				}
	
				refresh();
			},
	
			addProduct: function(options){
		  		if (count >= 4) {
		  			if (!confirm(confirmationMessage)) {
		  				jQuery('#compareCheck' + options.id).each(function() {
		  					jQuery(this)[0].checked = false;
		  				});
		  				return;
		  			}
		  			app.compare.removeProduct({index: 0});
		  		} 
		
		  		var complete = function() {
		  			var addIndex = addProduct(options);
		
		  			jQuery('#productThumbnail' + options.id).each(function() {
						var thumbnail = jQuery(this)[0];
						setProductImage({index:addIndex, src:thumbnail.src, alt:thumbnail.alt});
		  			});
	
			   		refresh();
		  		};
		
				var uncheck = function() {
	  				jQuery('#compareCheck' + options.id).each(function() {
	  					jQuery(this)[0].checked = false;
	  					jQuery(this).removeClass("compared");
	  				});
				};
	
		   		jQuery.ajax({
					type: 'POST',
					url: addUrl,
					data: {'pid':options.id, 'category':options.category},
					dataType: 'json',
					success: function(data){
						if (data.success === true) {
							complete();
						}
						else {
							uncheck();
						}
					},
					failure: function(data) {
						uncheck();
					}
				});
			},
	
			removeProduct: function(options) {
				var index = null;
				if (options.index != null) {
					index = options.index;
				}
				else {
			   		for (var i = 0; i < count; i++) {
			   			if (products[i].id === options.id) {
			   				index = i;
			   			}
			   		}
				}
	
				var clearedProduct = products[index];
	
				var complete = function() {
			   		for (var i = index; i < count - 1; i++) {
			   			products[i] = products[i + 1];
	
		  				jQuery('#productThumbnail' + products[i].id).each(function() {
							var thumbnail = jQuery(this)[0];
	
			  				jQuery('#compareItemsProduct' + i).each(function() {
						   		var productImage = jQuery(this)[0];
								productImage.src = thumbnail.src;
								productImage.alt = thumbnail.alt;
			  				});
		  				});
			   		}
	
					var clearedIndex = count - 1;
			   		products[clearedIndex] = null;
			   		count--;
			
	  				jQuery('#compareCheck' + clearedProduct.id).each(function() {
	  					jQuery(this)[0].checked = false;
	  					jQuery(this).removeClass("compared");
	  				});
			
	  				jQuery('#compareItemsProduct' + clearedIndex).each(function() {
	  					var productImage = jQuery(this)[0];
				   		productImage.src = emptyImgSrc;
				   		productImage.alt = emptyImgAlt;
	  				});
	
			   		jQuery('#compareItemsClear' + clearedIndex).hide();
			
			   		refresh();
				};
	
				var check = function() {
	  				jQuery('#compareCheck' + clearedProduct.id).each(function() {
	  					jQuery(this)[0].checked = true;
	  				});
				};
	
		   		jQuery.ajax({
					type: 'POST',
					url: removeUrl,
					data: {'pid':clearedProduct.id, 'category':clearedProduct.category},
					dataType: 'json',
					success: function(data){
						if (data.success === true) {
							complete();
						} else {
							check();
						}
					},
					failure: function(data) {
						check();
					}
				});
			}
		}
	} else {
		// namespace has not been defined yet
		alert("app namespace is not loaded yet!");
	}
})(app);