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

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 = $bs(container), oSlider = $bs(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: 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: 4000, //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";
    }
};

/**
* 初始化滚动图片效果
* 参数格式：
containerID: 整个滚动图片的容器ID ,
sliderId: 图片容器所在的ID ,
numId: 数字所在容器ID ,
imgHeight: 图片切换的高度 int
imgCount：图片个数, int
isUp:是否向上,bool
pauseTime:切换时间
* 
*/
function initTransformView(containerID, sliderId, numId, imgHeight, imgCount, isUp, pauseTime) {

    var objs = $bs(numId).getElementsByTagName("li");
    if (typeof (pauseTime) == "undefined")
        pauseTime = 4000;

    if (typeof (isUp) == "undefined")
        isUp = true;

    var tv = new TransformView(containerID, sliderId, imgHeight, imgCount, {
        Up: isUp, Pause: pauseTime,
        onStart: function () { __Each(objs, function (o, i) { o.className = tv.Index == i ? "on" : ""; }) } //按钮样式 
    });

    tv.Start();

    __Each(objs, function (o, i) {
        o.onmouseover = function () {
            o.className = "on";
            tv.Auto = false;
            tv.Index = i;
            tv.Start();
        }
        o.onmouseout = function () {
            o.className = "";
            tv.Auto = true;
            tv.Start();
        }
    })
}