/*
jQ向上滚动带上下翻页按钮
*/
(function($){
$.fn.extend({
        Scroll:function(opt,callback){
                //参数初始化
                if(!opt) var opt={};
                var _wrap = $("#" + opt.wrap);
                var _btnUp = $("#"+ opt.up);//Shawphy:向上按钮
                var _btnDown = $("#"+ opt.down);//Shawphy:向下按钮
                var timerID;
                var _this=this.eq(0).find("ul:first");
                var     lineH=_wrap.find('ul').height() / _wrap.find('li').length, //获取行高
                        line=opt.line?parseInt(opt.line,10):parseInt(this.height()/lineH,10), //每次滚动的行数，默认为一屏，即父容器高度
                        speed=opt.speed?parseInt(opt.speed,10):500; //卷动速度，数值越大，速度越慢（毫秒）
                        timer=opt.timer //?parseInt(opt.timer,10):3000; //滚动的时间间隔（毫秒）
                if(line==0) line=1;
                var upHeight=0-line*lineH;
                var counter = 0;
                var itemLength = _wrap.find('li').length;
                var defaultLength = (_wrap.height() / lineH).toFixed(0);
                console.log(_wrap);
                console.log(defaultLength, 333);
                console.log(itemLength,333);
                var lens = itemLength - defaultLength;
                //滚动函数
                var scrollUp = function () {
                        if (itemLength <= defaultLength) return;
                        counter++;
                        if (counter > lens) counter = lens;
                        _btnUp.unbind("click",scrollUp); //Shawphy:取消向上按钮的函数绑定
                        _this.animate({
                                marginTop:upHeight * counter
                        },speed,function(){
                                // for(i=1;i<=line;i++){
                                //         _this.find("li:first").appendTo(_this);
                                // }
                                // _this.css({marginTop:0});
                                _btnUp.bind("click",scrollUp); //Shawphy:绑定向上按钮的点击事件
                        });
                }
                //Shawphy:向下翻页函数
                var scrollDown = function () {
                        if (itemLength <= defaultLength) return;
                        counter--;
                        if (counter < 0) counter = 0;
                        _btnDown.unbind("click",scrollDown);
                        // for(i=1;i<=line;i++){
                        //         _this.find("li:last").show().prependTo(_this);
                        // }
                        // _this.css({marginTop:upHeight});
                        _this.animate({
                                marginTop: upHeight * counter
                        },speed,function(){
                                _btnDown.bind("click",scrollDown);
                        });
                }
               //Shawphy:自动播放
                var autoPlay = function(){
                        if(timer)timerID = window.setInterval(scrollUp,timer);
                };
                var autoStop = function(){
                        if(timer)window.clearInterval(timerID);
                };
                 //鼠标事件绑定
                _this.hover(autoStop,autoPlay).mouseout();
                _btnUp.css("cursor","pointer").click( scrollUp ).hover(autoStop,autoPlay);//Shawphy:向上向下鼠标事件绑定
                _btnDown.css("cursor","pointer").click( scrollDown ).hover(autoStop,autoPlay);

        }       
})
})(jQuery);