(function(ptm){
	ptm.extend(ptm.easing,{
		easeinsine: function (x, t, b, c, d) {
			return -c * math.cos(t/d * (math.pi/2)) + c + b;
		}
	});

	ptm.fn.xslider=function(settings){
		settings=ptm.extend({},ptm.fn.xslider.sn.defaults,settings);
		this.each(function(){
			var scrollobj=settings.scrollobj ? ptm(this).find(settings.scrollobj) : ptm(this).find("ul"),
			    viewedsize=settings.viewedsize || (settings.dir=="h" ? scrollobj.parent().width() : scrollobj.parent().height()),//length of the wrapper visible;
			    scrollunits=scrollobj.find("li"),//units to move;
			    unitlen=settings.unitlen || (settings.dir=="h" ? scrollunits.eq(0).outerwidth() : scrollunits.eq(0).outerheight()),
			    unitdisplayed=settings.unitdisplayed,//units num displayed;
				numtomove=settings.numtomove > unitdisplayed ? unitdisplayed : settings.numtomove,
			    scrollobjsize=settings.scrollobjsize || scrollunits.length*unitlen,//length of the scrollobj;
			    offset=0,//max width to move;
			    offsetnow=0,//scrollobj now offset;
			    movelength=unitlen*numtomove,
				pos=settings.dir=="h" ? "left" : "top",
			    moving=false,//moving now?;
			    btnright=ptm(this).find("a.aright"),
			    btnleft=ptm(this).find("a.aleft");
			
			btnright.unbind("click");
			btnleft.unbind("click");
					
			settings.dir=="h" ? scrollobj.css("left","0px") : scrollobj.css("top","0px");
							
			if(scrollobjsize>viewedsize){
				if(settings.loop=="cycle"){
					btnleft.removeclass("agrayleft");
					if(scrollunits.length<2*numtomove+unitdisplayed-numtomove){
						scrollobj.find("li").clone().appendto(scrollobj);	
					}
				}else{
					btnleft.addclass("agrayleft");
					offset=scrollobjsize-viewedsize;
				}
				btnright.removeclass("agrayright");
			}else{
				btnleft.addclass("agrayleft");
				btnright.addclass("agrayright");
			}

			btnleft.click(function(){
				if(ptm(this).is("[class*='agrayleft']")){return false;}
				
				if(!moving){
					moving=true;
					
					if(settings.loop=="cycle"){
						scrollobj.find("li:gt("+(scrollunits.length-numtomove-1)+")").prependto(scrollobj);
						scrollobj.css(pos,"-"+movelength+"px");
						ptm.fn.xslider.sn.animate(scrollobj,0,settings.dir,settings.speed,function(){moving=false;});
					}else{
						offsetnow-=movelength;
						if(offsetnow>unitlen*unitdisplayed-viewedsize){
							ptm.fn.xslider.sn.animate(scrollobj,-offsetnow,settings.dir,settings.speed,function(){moving=false;});
						}else{
							ptm.fn.xslider.sn.animate(scrollobj,0,settings.dir,settings.speed,function(){moving=false;});
							offsetnow=0;
							ptm(this).addclass("agrayleft");
						}
						btnright.removeclass("agrayright");
					}
				}

				return false;
			});
			btnright.click(function(){
				if(ptm(this).is("[class*='agrayright']")){return false;}
				
				if(!moving){
					moving=true;
					
					if(settings.loop=="cycle"){
						var callback=function(){
							scrollobj.find("li:lt("+numtomove+")").appendto(scrollobj);
							scrollobj.css(pos,"0px");
							moving=false;
						}
						ptm.fn.xslider.sn.animate(scrollobj,-movelength,settings.dir,settings.speed,callback);
					}else{
						offsetnow+=movelength;
						if(offsetnow<offset-(unitlen*unitdisplayed-viewedsize)){
							ptm.fn.xslider.sn.animate(scrollobj,-offsetnow,settings.dir,settings.speed,function(){moving=false;});
						}else{
							ptm.fn.xslider.sn.animate(scrollobj,-offset,settings.dir,settings.speed,function(){moving=false;});//���������һ��λ��;
							offsetnow=offset;
							ptm(this).addclass("agrayright");
						}
						btnleft.removeclass("agrayleft");
					}
				}
				
				return false;
			});
			
			if(settings.autoscroll){
				ptm.fn.xslider.sn.autoscroll(ptm(this),settings.autoscroll);
			}
		})
	}
	
	ptm.fn.xslider.sn={
		defaults:{
			dir:"h",
			speed:500
		},
		animate:function(obj,w,dir,speed,callback){
			if(dir=="h"){
				obj.animate({
					left:w
				},speed,"easeinsine",callback);
			}else if(dir=="v"){
				obj.animate({
					top:w
				},speed,"easeinsine",callback);	
			}	
		},
		autoscroll:function(obj,time){
			var  vane="right";
			function autoscrolling(){
				if(vane=="right"){
					if(!obj.find("a.agrayright").length){
						obj.find("a.aright").trigger("click");
					}else{
						vane="left";
					}
				}
				if(vane=="left"){
					if(!obj.find("a.agrayleft").length){	
						obj.find("a.aleft").trigger("click");
					}else{
						vane="right";
					}
				}
			}
		}
	}
})(jquery);