//滑动条程序
var Slider = Class.create();
Slider.prototype = {
  //容器对象，滑块
  initialize: function(container, bar, options) {
    this.Bar = $(bar);
    this.Container = $(container);
    this._timer = null;//自动滑移的定时器
    this._ondrag = false;//解决ie的click问题
    //是否最小值、最大值、中间值
    this._IsMin = this._IsMax = this._IsMid = false;
    //实例化一个拖放对象，并限定范围
    this._drag = new Drag(this.Bar, { Limit: true, mxContainer: this.Container,
        onStart: Bind(this, this.DragStart), onStop: Bind(this, this.DragStop), onMove: Bind(this, this.Move)
    });
    
    this.SetOptions(options);
    
    this.WheelSpeed = Math.max(0, this.options.WheelSpeed);
    this.KeySpeed = Math.max(0, this.options.KeySpeed);
    
    this.MinValue = this.options.MinValue;
    this.MaxValue = this.options.MaxValue;
    
    this.RunTime = Math.max(1, this.options.RunTime);
    this.RunStep = Math.max(1, this.options.RunStep);
    
    this.Ease = !!this.options.Ease;
    this.EaseStep = Math.max(1, this.options.EaseStep);
    
    this.onMin = this.options.onMin;
    this.onMax = this.options.onMax;
    this.onMid = this.options.onMid;
    
    this.onDragStart = this.options.onDragStart;
    this.onDragStop = this.options.onDragStop;
    
    this.onMove = this.options.onMove;
    
    this._horizontal = !!this.options.Horizontal;//一般不允许修改
    
    //锁定拖放方向
    this._drag[this._horizontal ? "LockY" : "LockX"] = true;
    
    //点击控制
    addEventHandler(this.Container, "click", BindAsEventListener(this, function(e){ this._ondrag || this.ClickCtrl(e);}));
    //取消冒泡，防止跟Container的click冲突
    addEventHandler(this.Bar, "click", BindAsEventListener(this, function(e){ e.stopPropagation(); }));
    
    //设置鼠标滚轮控制
    this.WheelBind(this.Container);
    //设置方向键控制
    this.KeyBind(this.Container);
    //修正获取焦点
    var oFocus = isIE ? (this.KeyBind(this.Bar), this.Bar) : this.Container;
    addEventHandler(this.Bar, "mousedown", function(){ oFocus.focus(); });
    //ie鼠标捕获和ff的取消默认动作都不能获得焦点，所以要手动获取
    //如果ie把focus设置到Container，那么在出现滚动条时ie的focus可能会导致自动滚屏
  },
  //设置默认属性
  SetOptions: function(options) {
    this.options = {//默认值
        MinValue:    0,//最小值
        MaxValue:    100,//最大值
        WheelSpeed: 5,//鼠标滚轮速度,越大越快(0则取消鼠标滚轮控制)
        KeySpeed:     50,//方向键滚动速度,越大越慢(0则取消方向键控制)
        Horizontal:    true,//是否水平滑动
        RunTime:    20,//自动滑移的延时时间,越大越慢
        RunStep:    2,//自动滑移每次滑动的百分比
        Ease:        false,//是否缓动
        EaseStep:    5,//缓动等级,越大越慢
        onMin:        function(){},//最小值时执行
        onMax:        function(){},//最大值时执行
        onMid:        function(){},//中间值时执行
        onDragStart:function(){},//拖动开始时执行
        onDragStop:    function(){},//拖动结束时执行
        onMove:        function(){}//滑动时执行
    };
    Extend(this.options, options || {});
  },
  //开始拖放滑动
  DragStart: function() {
      this.onDragStart();
    this._ondrag = true;
  },
  //结束拖放滑动
  DragStop: function() {
      this.onDragStop();
    setTimeout(Bind(this, function(){ this._ondrag = false; }), 10);
  },
  //滑动中
  Move: function() {
      this.onMove();
    
    var percent = this.GetPercent();
    //最小值判断
    if(percent > 0){
        this._IsMin = false;
    }else{
        if(!this._IsMin){ this.onMin(); this._IsMin = true; }
    }
    //最大值判断
    if(percent < 1){
        this._IsMax = false;
    }else{
        if(!this._IsMax){ this.onMax(); this._IsMax = true; }
    }
    //中间值判断
    if(percent > 0 && percent < 1){
        if(!this._IsMid){ this.onMid(); this._IsMid = true; }
    }else{
        this._IsMid = false;
    }
  },
  //鼠标点击控制
  ClickCtrl: function(e) {
    var o = this.Container, iLeft = o.offsetLeft, iTop = o.offsetTop;
    while (o.offsetParent) { o = o.offsetParent; iLeft += o.offsetLeft; iTop += o.offsetTop; }
    //考虑有滚动条，要用pageX和pageY
    this.EasePos(e.pageX - iLeft - this.Bar.offsetWidth / 2, e.pageY - iTop - this.Bar.offsetHeight / 2);
  },
  //鼠标滚轮控制
  WheelCtrl: function(e) {
    var i = this.WheelSpeed * e.detail;
    this.SetPos(this.Bar.offsetLeft + i, this.Bar.offsetTop + i);
    //防止触发其他滚动条
    e.preventDefault();
  },
  //绑定鼠标滚轮
  WheelBind: function(o) {
      //鼠标滚轮控制
    addEventHandler(o, isIE ? "mousewheel" : "DOMMouseScroll", BindAsEventListener(this, this.WheelCtrl));
  },
  //方向键控制
  KeyCtrl: function(e) {
    if(this.KeySpeed){
        var iLeft = this.Bar.offsetLeft, iWidth = (this.Container.clientWidth - this.Bar.offsetWidth) / this.KeySpeed
            , iTop = this.Bar.offsetTop, iHeight = (this.Container.clientHeight - this.Bar.offsetHeight) / this.KeySpeed;
        //根据按键设置值
        switch (e.keyCode) {
            case 37 ://左
                iLeft -= iWidth; break;
            case 38 ://上
                iTop -= iHeight; break;
            case 39 ://右
                iLeft += iWidth; break;
            case 40 ://下
                iTop += iHeight; break;
            default :
                return;//不是方向按键返回
        }
        this.SetPos(iLeft, iTop);
        //防止触发其他滚动条
        e.preventDefault();
    }
  },
  //绑定方向键
  KeyBind: function(o) {
    addEventHandler(o, "keydown", BindAsEventListener(this, this.KeyCtrl));
    //设置tabIndex使设置对象能支持focus
    o.tabIndex = -1;
    //取消focus时出现的虚线框
    isIE || (o.style.outline = "none");
  },
  //获取当前值
  GetValue: function() {
    //根据最大最小值和滑动百分比取值
    return this.MinValue + this.GetPercent() * (this.MaxValue - this.MinValue);
  },
  //设置值位置
  SetValue: function(value) {
    //根据最大最小值和参数值设置滑块位置
    this.SetPercent((value- this.MinValue)/(this.MaxValue - this.MinValue));
  },
  //获取百分比
  GetPercent: function() {
    //根据滑动条滑块取百分比
    return this._horizontal ? this.Bar.offsetLeft / (this.Container.clientWidth - this.Bar.offsetWidth)
        : this.Bar.offsetTop / (this.Container.clientHeight - this.Bar.offsetHeight)
  },
  //设置百分比位置
  SetPercent: function(value) {
    //根据百分比设置滑块位置
    this.EasePos((this.Container.clientWidth - this.Bar.offsetWidth) * value, (this.Container.clientHeight - this.Bar.offsetHeight) * value);
  },
  //自动滑移(是否递增)
  Run: function(bIncrease) {
    this.Stop();
    //修正一下bIncrease
    bIncrease = !!bIncrease;
    //根据是否递增来设置值
    var percent = this.GetPercent() + (bIncrease ? 1 : -1) * this.RunStep / 100;
    this.SetPos((this.Container.clientWidth - this.Bar.offsetWidth) * percent, (this.Container.clientHeight - this.Bar.offsetHeight) * percent);
    //如果没有到极限值就继续滑移
    if(!(bIncrease ? this._IsMax : this._IsMin)){
        this._timer = setTimeout(Bind(this, this.Run, bIncrease), this.RunTime);
    }
  },
  //停止滑移
  Stop: function() {
    clearTimeout(this._timer);
  },
  //缓动滑移
  EasePos: function(iLeftT, iTopT) {
    this.Stop();
    //如果没有设置缓动
    if(!this.Ease){ this.SetPos(iLeftT, iTopT); return; }
    //获取缓动参数
    var iLeftN = this.Bar.offsetLeft, iLeftS = this.GetStep(iLeftT, iLeftN)
    , iTopN = this.Bar.offsetTop, iTopS = this.GetStep(iTopT, iTopN);
    //如果参数有值
    if(this._horizontal ? iLeftS : iTopS){
        //设置位置
        this.SetPos(iLeftN + iLeftS, iTopN + iTopS);
        //如果没有到极限值则继续缓动
        if(this._IsMid){ this._timer = setTimeout(Bind(this, this.EasePos, iLeftT, iTopT), this.RunTime); }
    }
  },
  //获取步长
  GetStep: function(iTarget, iNow) {
    var iStep = (iTarget - iNow) / this.EaseStep;
    if (iStep == 0) return 0;
    if (Math.abs(iStep) < 1) return (iStep > 0 ? 1 : -1);
    return iStep;
  },
  //设置滑块位置
  SetPos: function(iLeft, iTop) {
    this.Stop();
    this._drag.SetPos(iLeft, iTop);
  }
};