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

function Each(list, fun){
	for (var i = 0, len = list.length; i < len; i++) { fun(list[i], i); }
};

//设置不透明度
function setOpacity(obj,opacity)
{
	if(opacity >=1 ) opacity = opacity / 100;				
	try{obj.style.opacity = opacity; }catch(e){}			
	try{if(obj.filters) obj.filters("alpha").opacity = opacity * 100;}catch(e){}
}

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 = $FUN(container), oSlider = $FUN(slider), oThis = this;

    this.isChange = false;
    this.preIndex = 0;//前一索引
    this.curIndex = 0;//当前索引
	this.o=60;
	this.opacity=100;
	this.doAlpha = null;
	
    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;
    this.Opac = this.options.Opac;
    
    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:            true,//是否向上(否则向左)
        Step:        5,//滑动变化率
        Time:        10,//滑动延时
        Auto:        true,//是否自动转换
        Pause:        5000,//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
        Opac:  true
    };
    Object.extend(this.options, options || {});
  },
  //开始切换设置
  Start: function() 
  {
    if(this.curIndex < 0){
        this.curIndex = this._count - 1;
    } else if (this.curIndex >= this._count){ this.curIndex = 0; }
    
    this._target = -1 * this._parameter * this.curIndex;
    this.onStart();

    if (!this.Opac)
    	this.Move();
    else
    {
    	var oThis = this;
    	this.doAlpha=setInterval(function(){ oThis.Fade(); }, 25);
    }
  },
  //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.curIndex++; 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";
  },
  //淡入淡出
  Fade: function()
  {
	  var oThis = this;
	  if (this.preIndex == this.curIndex)
	  {//如果点击同一点则不处理
		  clearInterval(this.doAlpha);
		  if (this.Auto) { this._timer = setTimeout(function(){ oThis.curIndex++; oThis.Start(); }, this.Pause); }
		  return;
	  }
	  
	  //对前一个作淡出处理
	  if ($FUN("img"+this.preIndex).filters("alpha").opacity > 60)
	  {
		  $FUN("img"+this.preIndex).filters("alpha").opacity -= 5;
		  return;
	  }
	  
	  //切换到下一个图片
	  if (!this.isChange)
	  {//如果未作淡入，先置为60，淡入到100
		  this._slider.style["left"] = this._target + "px";
		  $FUN("img"+this.curIndex).filters("alpha").opacity = 60;
		  this.isChange = true;
		  return;
	  }
	  
	  //对后一个作淡入处理
	  if ($FUN("img"+this.curIndex).filters("alpha").opacity < 100)
	  {
		  $FUN("img"+this.curIndex).filters("alpha").opacity += 5;
		  return;
	  }
	  
	  //淡入淡出结束则置pre=cur,等待下一个切换
	  this.preIndex = this.curIndex;
	  this.isChange = false;
	  clearInterval(this.doAlpha);
	  this.onFinish();
	  if (this.Auto) { this._timer = setTimeout(function(){ oThis.curIndex++; oThis.Start(); }, this.Pause); }
  }
};