/*
**	Anderson Ferminiano
**	contato@andersonferminiano.com -- feel free to contact me for bugs or new implementations.
**	jQuery ScrollPagination
**	28th/March/2011
**	http://andersonferminiano.com/jqueryscrollpagination/
**	You may use this script for free, but keep my credits.
**	Thank you.
*/

(function( $ ){
	 
		 
 $.fn.scrollPagination = function(options) {
  	
		var opts = $.extend($.fn.scrollPagination.defaults, options);  
		var target = opts.scrollTarget;
		if (target == null){
			target = obj; 
	 	}
		opts.scrollTarget = target;
	 
		return this.each(function() {
		  $.fn.scrollPagination.init($(this), opts);
		});

  };
  
  $.fn.stopScrollPagination = function(){
	  return this.each(function() {
	 	$(this).attr('scrollPagination', 'disabled');
	  });
	  
  };
  
  $.fn.scrollPagination.loadContent = function(obj, opts){
	 var target = opts.scrollTarget;

     var nDivHight = $(target).height();
	 var nScrollHight = $(target)[0].scrollHeight;
	 var nScrollTop = $(target)[0].scrollTop;

     var mayLoadContent=nScrollTop + nDivHight>= nScrollHight-opts.heightOffset;
	 //var mayLoadContent = $(target).scrollTop()+opts.heightOffset >= $(document).height() - $(target).height();
	 if (mayLoadContent){
		 if (opts.beforeLoad != null){
			opts.beforeLoad(); 
		 }
		 $(obj).children().attr('rel', 'loaded');
		 $.ajax({
			  type: 'POST',
			  url: opts.contentPage+"&pageindex="+opts.pageindex,
			  data: opts.contentData,
			  success: function(data){
				$(obj).append(data); 
				var objectsRendered = $(obj).children('[rel!=loaded]');
				opts.pageindex=opts.pageindex+1;
				
				if(opts.pageindex>opts.totalpage){
				   $(obj).stopScrollPagination();
				}   
				   
				if (opts.afterLoad != null){
					opts.afterLoad(objectsRendered);	
				}
			  },
			  dataType: 'html'
		 });
	 }
	 
  };
  
  $.fn.scrollPagination.init = function(obj, opts){
	 var target = opts.scrollTarget;
	 $(obj).attr('scrollPagination', 'enabled');
	
	 $(target).scroll(function(event){
		if ($(obj).attr('scrollPagination') == 'enabled'){
	 		$.fn.scrollPagination.loadContent(obj, opts);		
		}
		else {
			event.stopPropagation();	
		}
	 });
	 
	 $.fn.scrollPagination.loadContent(obj, opts);
	 
 };
	
 $.fn.scrollPagination.defaults = {
      	 'contentPage' : null,
     	 'contentData' : {},
		 'beforeLoad': null,
		 'afterLoad': null	,
		 'scrollTarget': null,
		 'heightOffset': 0,
		 'totalpage':0,  //总页数
		 'pageindex':0   //起始页
 };	
})( jQuery );