var $ = function (id) {
    return "string" == typeof id ? document.getElementById(id) : id;
};

var Class = {
  create: function() {
    return function() {
      this.initialize.apply(this, arguments);
    }
  }
}

Object.extend = function(destination, source) {
	for (var property in source) {
		destination[property] = source[property];
	}
	return destination;
}

function addEventHandler(oTarget, sEventType, fnHandler) {
	if (oTarget.addEventListener) {
		oTarget.addEventListener(sEventType, fnHandler, false);
	} else if (oTarget.attachEvent) {
		oTarget.attachEvent("on" + sEventType, fnHandler);
	} else {
		oTarget["on" + sEventType] = fnHandler;
	}
};


var Scroller = Class.create();
Scroller.prototype = {
  initialize: function(idScroller, idScrollMid, options) {
    var oScroll = this, oScroller = $(idScroller), oScrollMid = $(idScrollMid);
	
	this.SetOptions(options);
	this.scroller = oScroller;			//对象
	this.timer = null;					//时间
	this.Side = [];						//方向
	this.side = 0;						//参数
	
	//方向设置
	switch (this.options.Side.toLowerCase()) {
		case "right-down" :
			this.Side = ["right", "down"];
			break;
		case "right-up" :
			this.Side = ["right", "up"];
			break;
		case "left-down" :
			this.Side = ["left", "down"];
			break;
		case "left-up" :
			this.Side = ["left", "up"];
			break;
		case "right" :
			this.Side = ["right"];
			break;
		case "left" :
			this.Side = ["left"];
			break;
		case "down" :
			this.Side = ["down"];
			break;
		case "up" :
		default :
			this.Side = ["up"];
	}
	
	//用于上下滚动
	this.heightScroller = parseInt(oScroller.style.height) || oScroller.offsetHeight;
	this.heightList = oScrollMid.offsetHeight;
	
	//用于左右滚动
	this.widthScroller = parseInt(oScroller.style.width) || oScroller.offsetWidth;
	this.widthList = oScrollMid.offsetWidth;
	
	//js取不到css设置的height和width
	
	oScroller.style.overflow = "hidden";
	oScrollMid.appendChild(oScrollMid.cloneNode(true));
	oScrollMid.appendChild(oScrollMid.cloneNode(true));
	
	addEventHandler(oScroller, "mouseover", function() { oScroll.Stop(); });
	addEventHandler(oScroller, "mouseout", function() { oScroll.Start(); });
	
	this.Start();
  },
  //设置默认属性
  SetOptions: function(options) {
    this.options = {//默认值
	  Step:			1,//每次变化的px量
	  Speed:		20,//速度(越大越慢)
	  Side:			"up"//滚动方向:"up"是上，"down"是下，"left"是左，"right"是右
    };
    Object.extend(this.options, options || {});
  }, 
  //上下滚动
  ScrollUpDown: function() {
	this.scroller.scrollTop = this.GetScroll(this.scroller.scrollTop, this.heightScroller, this.heightList);
	
	var oThis = this;
	this.timer = window.setTimeout(function(){ oThis.Start(); }, this.options.Speed);
  },
  //左右滚动
  ScrollLeftRight: function() {
	//注意:scrollLeft超过1400会自动变回1400 注意长度
	this.scroller.scrollLeft = this.GetScroll(this.scroller.scrollLeft, this.widthScroller, this.widthList);
	
	var oThis = this;
	this.timer = window.setTimeout(function(){ oThis.Start(); }, this.options.Speed);
  },
  //获取设置滚动数据
  GetScroll: function(iScroll, iScroller, iList) {
	if(this.side > 0){
		if(iScroll >= (iList * 2 - iScroller)){ iScroll -= iList; }
	} else {
		if(iScroll <= 0){ iScroll += iList; }
	}
	
	return (iScroll + this.options.Step * this.side);
  },
  //开始
  Start: function() {
	
	this.Side.push(this.Side.shift().toLowerCase());
	
	//document.getElementById("test").innerHTML+=s+",";
	
	//方向设置
	switch (this.Side[0].toLowerCase()) {
		case "right" :
			if(this.widthList < this.widthScroller) return;
			this.side = -1;
			this.ScrollLeftRight();
			break;
		case "left" :
			if(this.widthList < this.widthScroller) return;
			this.side = 1;
			this.ScrollLeftRight();
			break;
		case "down" :
			if(this.heightList < this.heightScroller) return;
			this.side = -1;
			this.ScrollUpDown();
			break;
		case "up" :
		default :
			if(this.heightList < this.heightScroller) return;
			this.side = 1;
			this.ScrollUpDown();
	}
  },
  //停止
  Stop: function() {
	clearTimeout(this.timer);
  }
};