/**
 * jQuery Magnifier Plugin
 * 
 * @version 0.2
 * @author Dieter Orens dieter@dio5.com
 * 
 * @option Number lensWidth -  width of the lens 
 * @option Number lensHeight - height of the lens
 * @option Boolean link - makes clicking go to the large image (default:true)
 * @option Number delay - adds a delay to the appearing of the lens (default:0)
 * 
 */
(function($){
	$.extend($.fn,
	{
		magnify:function(options)
		{
			return this.each(function()
			{
				var magnifier = 
				{
					defaults:
					{
						lensWidth: 160,
						lensHeight: 160,
						link: true,
						delay: 0				
					},
					
					a: null,
					$img: null,
					$largeImage: null,
					$lens: null,
					$sensor: null,
					$loader: null,
					timeOut: null,
					largeWidth: 0,
					largeHeight: 0,
					
					init:function(options)
					{
						magnifier.options = $.extend({}, magnifier.defaults, options);
						magnifier.a = this;
						magnifier.$img = $('img', this);
						magnifier.setLargeImage();
						magnifier.setLens();
						magnifier.setSensor();
						magnifier.setLoader();
						magnifier.loadImage();
						magnifier.addHandles();
					},
					
					setLargeImage:function()
					{
						magnifier.$largeImage = $(new Image());
						magnifier.$largeImage.attr('src', magnifier.a.href).css('display', 'none');
					},
					
					setLens:function()
					{
						magnifier.$lens = $("<div id='dio-lens'></div>");
						magnifier.$lens.css({
							width: magnifier.options.lensWidth,
	                		height: magnifier.options.lensHeight,
							visibility: 'hidden',
							overflow: 'hidden',
							position: 'absolute',
							left:0,
							top:0
						}).appendTo('body');
					},
					
					setSensor:function()
					{
						magnifier.$sensor = $("<div id='dio-sensor' style='position:absolute;'></div>");
						$('body').append(magnifier.$sensor);
						
						if (magnifier.options.link)
						{
							magnifier.$sensor.click(function(){ window.location = magnifier.a.href });
						}
					},
					
					setLoader:function()
					{
						magnifier.$loader = $("<div id='dio-loader'>loading</div>").css({width: magnifier.options.lensWidth, height: magnifier.options.lensHeight});
						magnifier.$lens.append(magnifier.$loader);
					},
					
					loadImage:function()
					{
						
						magnifier.$largeImage.load(function(e)
						{
							magnifier.imgLoadCheck(magnifier.$largeImage[0], magnifier.loadCallback, magnifier.errorCallback, e);
						});
					},
					
					imgLoadCheck:function(img, loadCallback, errorCallback)
					{
						if(img!=null)
						{
							function imgWatch()
							{
								if(img.complete)
								{
									clearInterval(loadWatch);
									loadCallback();
								}
							}			
							var loadWatch = setInterval(imgWatch, 100);	
						}
						else
						{
							errorCallback();
						}
					},
					
					loadCallback:function()
					{
						magnifier.$lens.append(magnifier.$largeImage);
						
						function moveWatch()
						{
							if(magnifier.$largeImage.width())
							{
								magnifier.largeWidth = magnifier.$largeImage.width();
								magnifier.largeHeight = magnifier.$largeImage.height();								
							}
							if (magnifier.largeWidth) {
								magnifier.$loader.remove();
								clearInterval(moveID);
							}
						}
						var moveID = setInterval(moveWatch, 100);
					},
					
					errorCallback:function()
					{
						alert("large image could not be loaded");
					},
					
					addHandles:function()
					{
						magnifier.$sensor.css(
						{
							width: magnifier.$img.width() + "px",
							height: magnifier.$img.height() + "px",
							top: magnifier.$img.offset().top + "px",
							left: magnifier.$img.offset().left + "px",
							backgroundColor: "#fff",
							opacity: "0"
						})
						.mousemove(function(e){ magnifier.handleMouseMove(e);})
						.mouseout(function(e){ magnifier.handleMouseOut(e);});	
					},
										
					handleMouseMove:function(e)
					{
						magnifier.$lens.css({
							left: parseInt(e.pageX - (magnifier.options.lensWidth * .5)) + "px",
							top: parseInt(e.pageY - (magnifier.options.lensHeight * .5)) + "px"
						});
						

						if (magnifier.options.delay) 
						{
							if (!magnifier.timeOut) {
								magnifier.timeOut = setTimeout(function(){
									magnifier.$lens.css('visibility', 'visible');
								}, magnifier.options.delay);
							}
						}
						else {
							magnifier.$lens.css('visibility', 'visible');
						}
						
						if(magnifier.largeWidth){ magnifier.positionLargeImage(e);}
						
						magnifier.$lens.css('display', 'block');
					},
					
					positionLargeImage:function(e)
					{				
						var scale = {};
				
						scale.x = magnifier.largeWidth / magnifier.$img.width();
						scale.y = magnifier.largeHeight / magnifier.$img.height();
					
						var left = -scale.x * Math.abs((e.pageX - magnifier.$img.offset().left)) + magnifier.options.lensWidth / 2 + "px";
						var top = -scale.y * Math.abs((e.pageY - magnifier.$img.offset().top)) + magnifier.options.lensHeight / 2 + "px";
										
						magnifier.$largeImage.css(
						{
							position: 'absolute',
							left: left,
							top: top,
							display:'block'
						});
					},
					
					handleMouseOut: function(e)
					{
						if (magnifier.timeOut) {
							clearTimeout(magnifier.timeOut);
							magnifier.timeOut = null;
						}
						magnifier.$lens.css({
							visibility: 'hidden',
							display: 'none'
						});
					}				
				};
				
				magnifier.init.call(this,options);			
			});
		}
	});
})(jQuery);