/*!
jquery.higo_plugins_ad.js(v0.1)
http://www.higosoft.cn
mailto:wdong0472@gmail.com

Copyright (c) 2011 wdong
Dual licensed under the MIT and GPL licenses.
*/

(function($){
	$.fn.lastScrollY= 0;
	$.fn.higo_plugins_ad = function(options){
	    $(this).addClass("higo_plugins_ad");
		var settings = $.extend({
			src:null,                    
			closeSrc:null,               
			href:"#",
			autoHide:true,               
			hideSecond:10,               
			top:20,                      
			layout:"left",               
			width:100,                   
			height:100,                  
			opacity:0.5,
			setPosition:function(left, top){
				return;
			}
		},options || {});
		
		if(settings.src && settings.closeSrc){		
			var imgEl = "<a href='" + settings.href + "' target='_blank'><img border=0 width='" + settings.width + "px' height='" + settings.height + "px' src='" + settings.src + "'/> <br></a>";
			var closeImgEl = "<a href=\"#\"; onclick=\"this.parentElement.style.visibility='hidden'\"><img border=0 src='" + settings.closeSrc +"'/></a>";
			
			$(this).append(imgEl + closeImgEl);
			
			$(this).css("position","absolute");
			$(this).css("top",settings.top + "px");
			$(this).css("opacity",settings.opacity);
			$(this).css("filter","alpha(opacity=" + parseInt(settings.opacity * 100)  + ")");
			
			switch(settings.layout) {
				case "left":
					$(this).css("left","22px");
					break;
				case "right":
					$(this).css("right","22px");
					break;
				case "center":
					var left = (parseInt(window.screen.availWidth) - parseInt(settings.width))/2 + "px";
					$(this).css("left",left);
					break;
				default:
					$(this).css("left","22px");
					break;
			}
		} else {
			return;
		}
		
		if(settings.autoHide) {
			setTimeout("(function(){$('" + $(this).selector +  "').hide();})();",parseInt(settings.hideSecond) * 1000);
		}
		
		window.onscroll = function(){
			var diffY;
			if (document.documentElement && document.documentElement.scrollTop)
				diffY = document.documentElement.scrollTop;
			else if (document.body)
				diffY = document.body.scrollTop
			else {
				/*Netscape stuff*/
			}
			
			percent= 1 * (diffY - $.fn.lastScrollY);
			if(percent>0)
				percent=Math.ceil(percent);
			else 
				percent=Math.floor(percent);
			
			var top = $('.higo_plugins_ad').css("top");
			
			$('.higo_plugins_ad').css("top", parseInt(top) + percent + "px");
			$.fn.lastScrollY += percent;
		}
	}
})(jQuery);