// JavaScript Document
(function($){
	
	$.fn.InfiniteScroll = function(options){
		
		var element = $(this);
		var triggerFlag = false;
		var triggerScrollPx = -1;
		
		var settings = {
			
			contentSelector:"",
			selectorIndex:0,
			bufferNumber:5,
			bufferPx:40,
			startPage:2,
			dataPara:{},
			dataPath:document.URL,
			dataType:"json",
			getDataHtml:function() {},
			finishHandler:function() {}
			
		};
		
		if(options){
			$.extend(settings, options);	
		}
		
		setNavigation(settings.startPage, true);
		
		function addContentHtml(Html, isBuffer){
			
			var len = $(settings.contentSelector).length;
			
			if(isBuffer){
				if(len > settings.bufferNumber){
					$(settings.contentSelector).eq(-1 * settings.bufferNumber).after(Html);	
				}else{
					$(settings.contentSelector).eq(settings.selectorIndex).after(Html);	
				}
			}else{
				$(settings.contentSelector).eq(settings.selectorIndex).after(Html);		
			}
			
		}
		
		function setNavigation(page, isBuffer){
			
			addContentHtml('<a class="navigation" data-page="'+ page +'"></a>', isBuffer);
			setTriggerScrollPx();
			
		}
		
		function setTriggerScrollPx(){
			
			triggerScrollPx = getNavigation().offset().top;
			
		}
		
		function getNavigation(){
			
			return element.find(".navigation");
			
		}
		
		$(window).scroll(function (e) {
			
			if(triggerFlag){

				 return false;
				 
			}
			
			var scrollNow = parseInt($(this).scrollTop()) + parseInt($(this).height()) + settings.bufferPx;
			
			if (scrollNow >= triggerScrollPx) {
				
				triggerFlag = true;
				
				var _navigation = getNavigation();
				var _page = parseInt(_navigation.attr("data-page"));
				_navigation.remove();

				var data = {};
				data.isAjax = true;
				data.page = _page;
				
				if(settings.dataPara != null){
					$.extend(data, settings.dataPara);
				}
				
				$.post(settings.dataPath, data, function(response){
					
					var HTML = settings.getDataHtml(response.data);
					addContentHtml(HTML);
					
					if(!response.isFinish){
						setNavigation(++_page, true);
						triggerFlag = false;
					}else{
						settings.finishHandler();
					}
					
				}, settings.dataType)
				
			}
			
		});
		
	}
	
})(jQuery)