/*
 *	WuBin-jsScroll V2.1 - simple gallery with jQuery
 *	made by Wubin.chen 2010-09-08
 */

(function ($) {
    $.fn.WBjsScroll = function (o) {
        var settings = {
            //autoArrows:1,//是否显示根据内容自动显示滚动条，1：自动、2：只显示垂直直滚动条、3：只显示水平滚动条。默认为true。
            showArrows:true,//是否显示箭头，默认为true
            wheelSpeed:18,//鼠标滚动速度
            IntervalIime:80//鼠标按定是主显示区及滚动条的移动速度,单位毫秒，默认为80
        };
		
        var self,self_data,set,Scroll_main,Scroll_Outside,Scroll_y,Scroll_y_Drag,Scroll_y_Drag_Bar,Scroll_y_Up,Scroll_y_Down,ArrowDirection;
        var ArrowsInterval,KeyIntervalArr,DragInterval,TextMoveInterval;
		
        //开始初始化
        var set = $.extend({}, settings, o || {});
        init(this);
		
        //初始化函数
        function init(e) {
            self = $(e);
			
            //给主体加强制加入自动换行样式
            self.css({
                "overflow": "auto", 
                "word-wrap": "break-word", 
                "word-break": "keep-all"
            }); 
			
            //主体数据组
            self_data = {
                height:self.height(),
                innerHeight:self.innerHeight(),
                Scroll_main_Height:0,
                Scroll_main_max:0,
                Scroll_y_show:0,
                Scroll_y_Drag_height:0,
                Scroll_y_Bar_height:0,
                Scroll_y_max:0,
                WheelMultiplier:0,
                dragPosition:0,
                mouseInBarposition:0
            };			
			
            self.wrapInner("<div class='Scroll_main'></div>"); 
            Scroll_main = self.find(".Scroll_main");
			
            if (Scroll_main.height() > self_data.height) {
                self.attr('tabindex', 0);
                self.css({
                    "position":"relative",
                    "outline":"none"
                }); 
                Scroll_main.wrap("<div class='Scroll_Outside' style='position:relative; overflow:hidden; width:100%; height:100%'></div>"); 
                Scroll_Outside = self.find(".Scroll_Outside")
                Scroll_main.css({
                    "position":"relative"
                }); 
				
                ShowScroll_y();
                SetScroll_size();
                SetScroll_bind();
				
                self_data.Scroll_y_show = 1;
                self_data.Scroll_main_max = self_data.Scroll_main_Height - self_data.height;//内容显示区最大活动空间
                self_data.Scroll_y_max = self_data.Scroll_y_Drag_height - self_data.Scroll_y_Bar_height;//计算滚动条最大活动空间
                self_data.WheelMultiplier = 2 * set.wheelSpeed * self_data.Scroll_y_max / self_data.Scroll_main_Height;//计算滚动条滚动比例值
            }
        };
		
        function ShowScroll_y() {
            self.append("<div class='Scroll_y' style=' position:absolute; right:10px; top:0px;'></div>");
            Scroll_y = self.find(".Scroll_y");
			
            self.css({
                "width": self.width() - Scroll_y.width() + "px", 
                "padding-right": parseInt(self.css("padding-right").replace("px","")) + Scroll_y.width() + "px", 
                "word-break": "keep-all"
            }); 
			
            if (set.showArrows) Scroll_y.append("<div class='Scroll_y_Up'></div>");
            Scroll_y.append("<div class='Scroll_y_Drag' style='position:relative; overflow:hidden;'><div class='Scroll_y_Drag_Bar' style=' position:relative;'></div></div>");
			
            Scroll_y_Drag = Scroll_y.find(".Scroll_y_Drag");
            Scroll_y_Drag_Bar = Scroll_y.find(".Scroll_y_Drag_Bar");

            Scroll_y_Drag_Bar.append("<div class='Scroll_y_DBT'></div>")
            .append("<div class='Scroll_y_DBM'><div class='Scroll_y_DBMB'></div></div>")
            .append("<div class='Scroll_y_DBB'></div>");

            if (set.showArrows) Scroll_y.append("<div class='Scroll_y_Down'></div>");
			
            Scroll_y_Up = Scroll_y.find(".Scroll_y_Up");
            Scroll_y_Down = Scroll_y.find(".Scroll_y_Down");
        }

        function SetScroll_size(){
            with (Scroll_y){
                var Scroll_y_Drag_height = Scroll_y_Drag.height();
				
                self_data.Scroll_main_Height = Scroll_main.height();
				
                css({
                    "height": self_data.innerHeight
                    });
                Scroll_y_Drag.height(self_data.innerHeight - Scroll_y_Up.outerHeight() - Scroll_y_Down.outerHeight() + "px");
				
                if (Scroll_y_Drag.outerHeight() > Scroll_y_Drag_height){
                    Scroll_y_Drag.height(Scroll_y_Drag_height - (Scroll_y_Drag.outerHeight() - Scroll_y_Drag_height) + "px")
                    };
				
                self_data.Scroll_y_Drag_height = Scroll_y_Drag.height();
				
                var Proportion =  self_data.height / self_data.Scroll_main_Height;
                Scroll_y_Drag_Bar.height(Scroll_y_Drag.height() * Proportion  + "px");
                self_data.Scroll_y_Bar_height = Scroll_y_Drag_Bar.outerHeight();
				
                var Scroll_y_DBT = find(".Scroll_y_DBT");
                var Scroll_y_DBM = find(".Scroll_y_DBM");
                var Scroll_y_DBMB = find(".Scroll_y_DBMB");
                var Scroll_y_DBB = find(".Scroll_y_DBB");
				
                var BarMinHeight = Scroll_y_DBT.height() + Scroll_y_DBM.height() + Scroll_y_DBB.height();
				
                if (BarMinHeight >= Scroll_y_Drag_Bar.height()){
                    Scroll_y_Drag_Bar.height(BarMinHeight + "px");
                    self_data.Scroll_y_Bar_height = Scroll_y_Drag_Bar.outerHeight();
                }
                else{					
                    Scroll_y_DBM.height(Scroll_y_Drag_Bar.height() - Scroll_y_DBT.height() - Scroll_y_DBB.height() + "px");
                    Scroll_y_DBMB.height(Scroll_y_DBM.height() + "px");
                }
                }
        };
		
        function SetScroll_bind(){
            self.bind("keydown",function(e){	
                switch (e.keyCode) {
                    case 38: //up
                        ArrowsUpdate();
                        if (!KeyIntervalArr) KeyIntervalArr = setInterval(Arrowsclick,set.IntervalIime);
                        return false;
                    case 40: //down
                        ArrowsDowndate();	
                        if (!KeyIntervalArr) KeyIntervalArr = setInterval(Arrowsclick,set.IntervalIime);
                        return false;
                    case 33: // page up
                    case 34: // page down
                        // TODO
                        return false;
                    default:
                }
            }).bind('keyup',function(e) {
                if (e.keyCode == 38 || e.keyCode == 40) {
                    resetArrowsClsaa();
                    clearInterval(KeyIntervalArr);
                    return false;
                }
            });
			
            var Scroll_y_Up_On = 0
            Scroll_y_Up.bind("mouseenter",function(){
                if (Scroll_y_Up_On){
                    ArrowsUpdate();
                    ArrowsInterval = setInterval(Arrowsclick,set.IntervalIime);
                }
            }).bind("mouseleave",ArrowsLeave)
            .bind("mousedown", function(){
                Scroll_y_Up_On = 1
                ArrowsUpdate();
                ArrowsMouseDown();
            });	
			
            var Scroll_y_Down_On = 0
            Scroll_y_Down.bind("mouseenter",function(){
                if (Scroll_y_Down_On){
                    ArrowsDowndate();
                    ArrowsInterval = setInterval(Arrowsclick,set.IntervalIime);
                }
            }).bind("mouseleave",ArrowsLeave)
            .bind("mousedown", function(){
                Scroll_y_Down_On = 1
                ArrowsDowndate();
                ArrowsMouseDown();
            });
			
            function ArrowsLeave(){
                if (Scroll_y_Up_On) resetArrowsClsaa();
                if (Scroll_y_Down_On) resetArrowsClsaa();
            };
			
            function ArrowsMouseDown(){
                ignoreNativeDrag();
                ArrowsInterval = setInterval(Arrowsclick,set.IntervalIime);
                ArrowsToDocumentMouseup();
            };
			
            function ArrowsToDocumentMouseup(){
                $(document).bind("mouseup",function(){					
                    Scroll_y_Up_On = 0;
                    Scroll_y_Down_On = 0;
                    resetArrowsClsaa();
                    $(document).unbind("mouseup");
                    ResumeNativeDrag();
                })
            };
			
            var Scroll_y_Drag_Down_On = 0;
            Scroll_y_Drag.bind("mouseenter",function(e){
                if (Scroll_y_Drag_Down_On){
                    DraglickDirection(e);
                    DragInterval = setInterval(Draglick,set.IntervalIime);
                }
            }).bind("mouseleave",Dragmouseleave)
            .bind("mouseup", function(e){
                Scroll_y_Drag_Down_On = 0;
                Scroll_y_Drag_Bar.removeClass("Scroll_y_Drag_Bar_D");
                clearInterval(DragInterval);
            }).bind("mousedown",Scroll_y_Drag_mousedown);	
			
            var Scroll_y_Bar_Down_On = 0;
            Scroll_y_Drag_Bar.bind("mousedown", function(e){
                Scroll_y_Drag.unbind("mousedown").unbind("mouseleave");
                Scroll_y_Drag_Bar.addClass("Scroll_y_Drag_Bar_D");
                Scroll_y_Bar_Down_On = 1;
                self_data.mouseInBarposition = getPos(e,"Y") - Scroll_y_Drag.offset().top - Scroll_y_Drag_Bar.position().top;
                ignoreNativeDrag();
				
                $(document).bind("mouseup",function(){					
                    Scroll_y_Bar_Down_On = 0;
                    Scroll_y_Drag_Bar.removeClass("Scroll_y_Drag_Bar_D");
                    Scroll_y_Drag.bind("mousedown",Scroll_y_Drag_mousedown).bind("mouseleave",Dragmouseleave);	
                    $(document).unbind("mouseup").unbind("mousemove")
                    ResumeNativeDrag();
                })
                .bind("mousemove", function(e){
                    if (Scroll_y_Bar_Down_On) Barclick(e);
                });
				
            }).bind("mousemove", function(e){
                if (Scroll_y_Bar_Down_On) Barclick(e);
            });	
			
            self.bind('mousewheel',mousewheel).bind('DOMMouseScroll',mousewheel);
			
            var selectDirection = 0;
            var moveIncrease = 1;
            Scroll_Outside.bind("mousedown",function(){
                var maxIntervalTime = 100;
                var minIntervalTime = 1;
				
                $(document).bind("mouseup",function(){	
                    clearInterval(TextMoveInterval);
                    $(this).unbind("mouseup").unbind("mousemove");	
                })
                .bind("mousemove", function(e){
                    var mouseposition = getPos(e,"Y") - Scroll_Outside.offset().top;
                    selectDirection = mouseposition < 0  ? -1 : (mouseposition > Scroll_Outside.height()) ? 1 : 0;
                    if (selectDirection){
                        var marginLong = mouseposition < 0 ? -mouseposition : mouseposition - Scroll_Outside.height();
                        moveIncrease = marginLong / 10;
                        clearInterval(TextMoveInterval);
                        TextMove();
                        TextMoveInterval = setInterval(TextMove,50);
                    }
                });				
            });

            function Dragmouseleave(){
                clearInterval(DragInterval)
                $(document).bind("mouseup",function(){
                    Scroll_y_Drag_Down_On = 0;
                    Scroll_y_Drag_Bar.removeClass("Scroll_y_Drag_Bar_D");
                    clearInterval(DragInterval);
                    ResumeNativeDrag();
                })
            };
			
            function Scroll_y_Drag_mousedown(e){
                Scroll_y_Drag_Bar.addClass("Scroll_y_Drag_Bar_D");
                ignoreNativeDrag();
                Scroll_y_Drag_Down_On = 1;
                DraglickDirection(e);
                DragInterval = setInterval(Draglick,set.IntervalIime);
                Scroll_y_Drag_Bar.bind("mousemove", function(e){
                    moveY = getPos(e,"Y")
                    });
            };
			
            function mousewheel(event,delta){
                delta = delta || (event.wheelDelta ? event.wheelDelta / 120 : (event.detail) ? -event.detail/3 : 0);
				
                var d = self_data.dragPosition;
                positionDrag(self_data.dragPosition - delta * self_data.WheelMultiplier);
                var dragOccured = d != self_data.dragPosition;
                return !dragOccured;
            };
			
            var TextMove = function(){				
                var Scroll_main_position = Scroll_main.position().top - selectDirection * moveIncrease;
                Scroll_main_position = Scroll_main_position < -self_data.Scroll_main_max ? -self_data.Scroll_main_max : Scroll_main_position > 0 ? 0 : Scroll_main_position;
                self_data.dragPosition = self_data.Scroll_y_max * (-Scroll_main_position / self_data.Scroll_main_max);
				
                Scroll_main.css({
                    'top':Scroll_main_position+'px'
                    });
                Scroll_y_Drag_Bar.css({
                    'top':self_data.dragPosition+'px'
                    });
            }
        };
		
        var ignoreNativeDrag = function() {
            $('html').bind('dragstart',function(){
                return false;
            }).bind('selectstart',function(){
                return false;
            });
        };
        var ResumeNativeDrag = function() {
            $('html').unbind('dragstart').unbind('selectstart');
        };
		
        function resetArrowsClsaa(){
            clearInterval(ArrowsInterval);
            if (set.showArrows){
                Scroll_y_Up.removeClass("Scroll_y_Up_D");
                Scroll_y_Down.removeClass("Scroll_y_Down_D");
            }
        };
		
        var ArrowsUpdate = function(){
            if (set.showArrows) Scroll_y_Up.addClass("Scroll_y_Up_D");
            ArrowDirection = -1;
            Arrowsclick();
        };

        var ArrowsDowndate = function(){
            if (set.showArrows) Scroll_y_Down.addClass("Scroll_y_Down_D");
            ArrowDirection = 1;
            Arrowsclick();
        };
		
        var moveY = 0;
        var DraglickDirection = function(e){
            moveY = getPos(e,"Y")
            Draglick();
        };
		
        var Arrowsclick = function() {
            positionDrag(self_data.dragPosition + ArrowDirection * self_data.WheelMultiplier);
        };
		
        var Draglick = function() {
            var mouseposition = moveY - Scroll_y_Drag.offset().top;
            var BarHalf = Scroll_y_Drag_Bar.position().top + self_data.Scroll_y_Bar_height / 2		;	
            ArrowDirection = (mouseposition < BarHalf - self_data.WheelMultiplier / 2) ? -1 : (mouseposition > BarHalf + self_data.WheelMultiplier / 2) ? 1 : 0;
			
            positionDrag(self_data.dragPosition + ArrowDirection * self_data.WheelMultiplier);
            if (!ArrowDirection || (self_data.dragPosition == 0) || (self_data.dragPosition == self_data.Scroll_y_max)){
                clearInterval(DragInterval);
                return false;
            }
        };
		
        function Barclick(e){
            var mouseposition = getPos(e,"Y") - Scroll_y_Drag.offset().top;
            positionDrag(mouseposition - self_data.mouseInBarposition);	
        }		
		
        var positionDrag = function(destY){	
            destY = destY < 0 ? 0 : (destY > self_data.Scroll_y_max ? self_data.Scroll_y_max : destY);//判断滚动条移动位置是否超出可移动区域
            self_data.dragPosition = destY;	

            Scroll_y_Drag_Bar.css({
                'top':destY+'px'
                });
            var p = destY / self_data.Scroll_y_max;
            Scroll_main.css({
                'top':((self_data.height-self_data.Scroll_main_Height)*p ) + 'px'
                });
        };

        var getPos = function (event, c) {
            var p = c.toUpperCase() == 'X' ? 'Left' : 'Top';
            return event['page' + c] || (event['client' + c] + (document.documentElement['scroll' + p] || document.body['scroll' + p])) || 0;
        };
    };	
})(jQuery);