var $1 = 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;

}



var TransformView = Class.create();

TransformView.prototype = {

  //容器对象,滑动对象,切换参数,切换数量

  initialize: function(container, slider, parameter, count, options) {

	if(parameter <= 0 || count <= 0) return;

	var oContainer = $1(container), oSlider = $1(slider), oThis = this;



	this.Index = 0;//当前索引

	

	this._timer = null;//定时器

	this._slider = oSlider;//滑动对象

	this._parameter = parameter;//切换参数

	this._count = count || 0;//切换数量

	this._target = 0;//目标参数

	

	this.SetOptions(options);

	

	this.Up = !!this.options.Up;

	this.Step = Math.abs(this.options.Step);

	this.Time = Math.abs(this.options.Time);

	this.Auto = !!this.options.Auto;

	this.Pause = Math.abs(this.options.Pause);

	this.onStart = this.options.onStart;

	this.onFinish = this.options.onFinish;

	

	oContainer.style.overflow = "hidden";

	oContainer.style.position = "relative";

	

	oSlider.style.position = "absolute";

	oSlider.style.top = oSlider.style.left = 0;

  },

  //设置默认属性

  SetOptions: function(options) {

	this.options = {//默认值

		Up:		false,//true向上(false向左) 

		Step:		5,//滑动变化率

		Time:		20,//滑动延时

		Auto:		true,//是否自动转换

		Pause:		3000,//停顿时间(Auto为true时有效)

		onStart:	function(){},//开始转换时执行

		onFinish:	function(){}//完成转换时执行

	};

	Object.extend(this.options, options || {});

  },

  //开始切换设置

  Start: function() {

	if(this.Index < 0){

		this.Index = this._count - 1;

	} else if (this.Index >= this._count){ this.Index = 0; }

	

	this._target = -1 * this._parameter * this.Index;

	this.onStart();

	this.Move();

  },

  //移动

  Move: function() {

	clearTimeout(this._timer);

	var oThis = this, style = this.Up ? "top" : "left", iNow = parseInt(this._slider.style[style]) || 0, iStep = this.GetStep(this._target, iNow);

	

	if (iStep != 0) {

		this._slider.style[style] = (iNow + iStep) + "px";

		this._timer = setTimeout(function(){ oThis.Move(); }, this.Time);

	} else {

		this._slider.style[style] = this._target + "px";

		this.onFinish();

		if (this.Auto) { this._timer = setTimeout(function(){ oThis.Index++; oThis.Start(); }, this.Pause); }

	}

  },

  //获取步长

  GetStep: function(iTarget, iNow) {

	var iStep = (iTarget - iNow) / this.Step;

	if (iStep == 0) return 0;

	if (Math.abs(iStep) < 1) return (iStep > 0 ? 1 : -1);

	return iStep;

  },

  //停止

  Stop: function(iTarget, iNow) {

	clearTimeout(this._timer);

	this._slider.style[this.Up ? "top" : "left"] = this._target + "px";

  }

};