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

SliderGallery.ORAN_GALLERY_SETTING = {
    height: SliderGallery.$gal("SliderGallery_idSlider").getElementsByTagName("img")[0].width, // image width
    count: SliderGallery.$gal("SliderGallery_idNum").getElementsByTagName("li").length // image quantity
}

SliderGallery.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;
}

SliderGallery.TransformView = SliderGallery.Class.create();
SliderGallery.TransformView.prototype = {
    initialize: function(SliderGallery_container, slider, parameter, count, options) {
        if (parameter <= 0 || count <= 0) return;
        var oContainer = SliderGallery.$gal(SliderGallery_container), oSlider = SliderGallery.$gal(slider), oThis = this;

        this.Index = 0; //current index

        this._timer = null; //timer
        this._slider = oSlider; //slider object
        this._parameter = parameter; 
        this._count = count || 0; //gallery quantity
        this._target = 0; //target parameter

        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;
    },
    //set prperties
    SetOptions: function(options) {
        this.options = {//default parameter
            Up: true, //is up(or left)
            Step: 5, //slide speed
            Time: 10, //delay time
            Auto: true, //auto. trun
            Pause: 8000, //pause time(It's available wher Auto=true)
            onStart: function() { }, //be executed when transform started
            onFinish: function() { } //be executed when transform finished
        };
        Object.extend(this.options, options || {});
    },
    //transform
    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();
    },
    //move
    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); }
        }
    },
    //get length of step
    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;
    },
    //stop
    Stop: function(iTarget, iNow) {
        clearTimeout(this._timer);
        this._slider.style[this.Up ? "top" : "left"] = this._target + "px";
    }
};

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

SliderGallery.objs = SliderGallery.$gal("SliderGallery_idNum").getElementsByTagName("li");

SliderGallery.tv = new SliderGallery.TransformView("idTransformView", "SliderGallery_idSlider", SliderGallery.ORAN_GALLERY_SETTING.height, SliderGallery.ORAN_GALLERY_SETTING.count, {
    onStart: function() { SliderGallery.Each(SliderGallery.objs, function(o, i) { o.className = SliderGallery.tv.Index == i ? "on" : ""; }) }, //按钮样式
    Up: false
});

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