/*

    Notes
    
    default: top, left (0,0);
    requires width and height of viewable text area
    
    text area is sized to account for a scrollbar
    
    so -- we have the scrollbar region 
    and the text region -- they always touch
    
    
*/

var _scroller_uniqueID = 0;

document.currentScrollArea = null;

function
ScrollArea(w, h)
{

    this.top = 0;
    this.left = 0;
    this.width = w; 
    this.height = h;
    this.topInset = 0;
    this.leftInset = 2;
    this.rightInset = 2;
    
    this.scrollbarWidth = 23;
    this.scrollUpHeight = 24;
    this.scrollDnHeight = 25;
    this.scrollThumbHeight = 16;
    this.scrollTrackHeight = 1;
    this.scrollUpImage = "";
    this.scrollDnImage = "";
    this.scrollTrackImage = "";
    this.scrollThumbImage = "";
    this.scrollUpImageActive = "";
    this.scrollDnImageActive = "";
    this.doc = null;
    this.container = null;
    this.scrollRgn = null;
   
    this.trackRange = this.height - this.scrollUpHeight - this.scrollDnHeight - this.scrollThumbHeight;
    this.trackStart = this.scrollUpHeight;
    this.documentRange = 0; // offsetHeight - this.height;
    this.trackDirection = 0;
    this.trackOffset = 1;
    this.hitLocation = 0;
    this.hitOffset = 0;
    this.thumbMarker = 0;
    this.util = 0;
    
    this.override = false;
    this.useHeight = 0;
    
    this.actionTimer = null;
    
    this.holderDiv = null;
    
    
    this.changeText = function(srcTxt) { 
                
                this.doc.innerHTML = srcTxt; 
                
                
                this.useHeight = (arguments.length > 1) ? arguments[1] : this.doc.offsetHeight;
                
                
                
                if(/*this.doc.offsetHeight*/ this.useHeight < this.height) 
               // if(this.container.offsetHeight < this.height) 
                    this.disableRgn.style.visibility = "inherit";
                    else
                    this.disableRgn.style.visibility = "hidden";
                    }
    
    
    this.setStyle = function(attr, val) {
               with(this.doc.style)
                {
                   eval(attr + " = '"  + val + "'");
                }
        }
    this.setTopLeft = function(t, l) {
                                        this.container.style.top = t;
                                        this.container.style.left = l;
                                     }
    
    this.setBackgroundColor = function(c) { this.container.style.backgroundColor = c; }
    this.setTextColor = function(c) { this.doc.style.color = c; }
    this.setBorder = function(borderAttr) { this.container.style.border = borderAttr; }
    
    this.handleButtonHit = function(evt) { 
                                                if(evt)
                                                    alert(evt.type + ": " + evt.target.name);
                                                  else
                                                    alert(window.event.type + ": " + window.event.srcElement.name);
                                            }
    
 
 
 //      
 
    this.killAction = function(evt) { 
    
                    var e = document.all ? window.event : evt;
                    var sa = document.all ? e.srcElement.owner : e.target.owner;
                    
                if(sa.actionTimer != null) clearTimeout(sa.actionTimer);
                sa.actionTimer = null;
                
                if(sa.util == 1)  {  
                    sa.scrollUp.style.backgroundImage = "url(" + sa.scrollUpImage + ")";
             
                        }
                if(sa.util == -1) {
                    sa.scrollDn.style.backgroundImage = "url(" + sa.scrollDnImage + ")";
             
                        }
                   
                sa.util = 0;
                
                }
    
    this.upAction = function(evt) {
    
            var e = document.all ? window.event : evt;
            
            var sa = document.all ? e.srcElement.owner : e.target.owner;
            
            var th = sa.scrollThumb;
            
            sa.util = 1;
            sa.scrollUp.style.backgroundImage = "url(" + sa.scrollUpImageActive + ")";
            
            sa.documentRange = sa.useHeight/*doc.offsetHeight*/ - sa.height;
            
            document.currentScrollArea = sa;
            
            sa.trackDirection = -1;
            
            sa.moveAction();
            
            return false;
                
        }
    
   this.moveAction = function()
   {
        var o = document.currentScrollArea;
        var dir = o.trackDirection;
        
        var th = o.scrollThumb;
        
        var newy = th.offsetTop + dir * 12;
        
        if(newy < o.trackStart) 
                newy = o.trackStart;
        if(newy > o.trackStart + o.trackRange)
                newy = o.trackStart + o.trackRange;
        
        th.style.top = newy;
        
        o.doc.style.top = -Math.round(o.documentRange * (newy-o.trackStart)/o.trackRange);
        
        o.actionTimer = setTimeout( "document.currentScrollArea.moveAction()", 50);
        
        
   }
    
    
    this.dnAction = function(evt) {
    
            var e = document.all ? window.event : evt;
            
            var sa = document.all ? e.srcElement.owner : e.target.owner;
            var th = sa.scrollThumb;
            
            
            sa.util = -1;
            sa.scrollDn.style.backgroundImage = "url(" + sa.scrollDnImageActive + ")";
                
             sa.documentRange = sa.useHeight/*doc.offsetHeight*/ - sa.height;
             
            document.currentScrollArea = sa;
            sa.trackDirection = 1;
            
            sa.moveAction();
                
                return false;
            
        }
    
    /*  grab page global coordinates -- calculate offset 
    */
    this.thumbAction = function(evt) {
    
            var e = document.all ? window.event : evt;
            var sa = document.all ? e.srcElement.owner : e.target.owner;
            
            var pt_y = document.all ? e.y : e.layerY;
           
            
            document.currentScrollArea = sa;
            sa.hitLocation = e.clientY; // good for IE5+/NN6+
            sa.hitOffset = pt_y;
            sa.thumbMarker = sa.scrollThumb.offsetTop;
            sa.documentRange = sa.useHeight/*doc.offsetHeight*/ - sa.height;
            
            sa.storeMouseMove = document.onmousemove;
            sa.storeMouseUp = document.onmouseup;
            document.onmousemove = sa.handleDrag;
            document.onmouseup = function() { 
                        document.onmousemove = document.currentScrollArea.storeMouseMove;
                        document.onmouseup = document.currentScrollArea.storeMouseUp;
                        
                        };
            
            //showObj(e);
            return false;
        }
    
    this.handleDrag = function(evt) {
                    var e = document.all ? window.event : evt;
                    var sa = document.currentScrollArea;
                    var th = sa.scrollThumb;
                    
                    var offset = sa.hitLocation - e.clientY;
                    
                    //window.status = sa.thumbMarker - offset;
                    
                    var set = sa.thumbMarker - offset;
                    if(set < sa.trackStart)
                        set = sa.trackStart;
                    if(set > sa.trackRange + sa.trackStart)
                        set = sa.trackRange + sa.trackStart;
                        
                       sa.scrollThumb.style.top = set;
                       sa.doc.style.top = -Math.round(sa.documentRange * (set - sa.trackStart)/sa.trackRange);
                    
                   // window.status = window.defaultStatus = (document.all ? e.clientY : e.clientY) + " : " + (document.all ? e.srcElement.name : e.target.name);
            }
    this.trackAction = function(evt) {
    
            var e = document.all ? window.event : evt;
            
            var tr = document.all ? e.srcElement : e.target;
            var sa = tr.owner;
            var th = sa.scrollThumb;
            var pt_y = document.all ? e.offsetY : e.layerY;
            var pt_x = document.all ? e.offsetX : e.layerX;
            
           document.currentScrollArea = sa;
            sa.documentRange = sa.useHeight/*doc.offsetHeight*/ - sa.height;
            
            sa.trackOffset = Math.ceil(sa.documentRange * 0.1);
            
            sa.hitLocation = pt_y;
            
              if(  pt_y > th.offsetTop - sa.scrollUpHeight  )
               sa.trackDirection = 1;
               if( pt_y < th.offsetTop - sa.scrollUpHeight )
                sa.trackDirection = -1;
                
                sa.moveAction_trk(evt);
            
            return false;
        }
        
   this.moveAction_trk = function(evt)
   {
        var o = document.currentScrollArea;
         var e = document.all ? window.event : evt;
         
        var dir = o.trackDirection;
        
        var th = o.scrollThumb;
        
        //if(e)
        {
        var newy = th.offsetTop + dir*o.trackOffset; // relative to scrollrgn
        
        var loc = o.hitLocation; // relative to track!
        
        if(dir < 0 && newy < loc + o.trackStart) 
                newy = loc + o.trackStart;
        if(dir > 0 && newy > loc + o.trackStart - o.scrollThumbHeight/*+ o.trackRange*/)
                newy = loc +  o.trackStart - o.scrollThumbHeight/*+ o.trackRange*/;
        
        th.style.top = newy;
        
        o.doc.style.top = -Math.round(o.documentRange * (newy-o.trackStart)/o.trackRange);
        
        }
        
        o.actionTimer = setTimeout( "document.currentScrollArea.moveAction_trk()", 50);
        
        
   }     
      
        
// -------end experimentals -        
        
    this.setScrollImage = function(part, src)
    {
        part = part.toLowerCase();
        
        var the_part = "";
        
            if(part.indexOf("act") != -1 && part.indexOf("u") != -1)
                the_part = "uh";
            else
            if(part.indexOf("act") != -1 && part.indexOf("d") != -1)
                the_part = "dh";
             else
            if(part.indexOf("up") != -1)
                the_part = "up";
             else
            if(part.indexOf("d") != -1)
                the_part = "dn";
             else
            if(part.indexOf("th") != -1)
                the_part = "th";
             else
            if(part.indexOf("tr") != -1)
                the_part = "tr";
             
        switch(the_part)
        {
            case "up" : this.scrollUpImage = src; break;
            case "dn" : this.scrollDnImage = src; break;
            case "th" : this.scrollThumbImage = src; break;
            case "tr" : this.scrollTrackImage = src; break;
            case "uh" : this.scrollUpImageActive  = src; break;
            case "dh" : this.scrollDnImageActive = src; break;
        }
    }
    
    this.destroy = function()
    {
       // alert(this.container.id);
       // showObj(document.getElementById(this.container.id));
       
       if(this.actionTimer != null)
        clearTimeout(this.actionTimer);
        
        if(this.holderDiv != null)
        {
            var theNode = this.holderDiv.removeNode(true);
                theNode = null;
         }
        //var oDiv = document.getElementById(this.container.id).removeNode(false);
       // showObj(oDiv);
    }
    
    this.create = function(parent)
    {
        var ref = this; // callback into ScrollArea
        
        
        this.container = document.createElement("DIV");
        this.container.owner = this;
        this.container.id = "__scrollarea_" + _scroller_uniqueID++;
        
        with(this.container.style)
        {
            position = "absolute";
            top = ref.top;
            left = ref.left;
            width = ref.width;
            height = ref.height;
            visibility = "hidden";
            overflow = "hidden";
            
        }
        
        this.doc = document.createElement("DIV");
        this.doc.owner = this;
        this.doc.id = "doc";
        
        with (this.doc.style)
        {
            position = "absolute";
            top = ref.topInset;
            left = ref.leftInset;
            width = ref.width - ref.leftInset - ref.rightInset - ref.scrollbarWidth;
            height = "auto";
            visibility = "inherit";
            fontSize = "10px";
            fontFamily = "Verdana";
        }
        // god damn internet explorer!!!
        document.onselectstart = this.doc.onselectstart = function() { return false; }
        document.onmousedown = this.doc.onmousedown = function() { return false; }
        document.onfocus = this.doc.onfocus = function() { return false; }
        document.ondblclick = this.doc.ondblclick = function() { return false; }
        document.ondragstart = this.doc.ondragstart = function() {return false; }
        document.onactivate = this.doc.onactivate = function() { return false; }
        
        this.container.appendChild(this.doc);
        
        this.scrollRgn = document.createElement("DIV");
        this.scrollRgn.owner = this;
        
        with(this.scrollRgn.style)
        {
            position = "absolute";
            top = ref.topInset;
            left = ref.width - ref.scrollbarWidth;
            width = ref.scrollbarWidth;
            height = ref.height - 2 * ref.topInset;
            backgroundImage = "url(" + ref.scrollTrackImage + ")";
            
            visibility = "inherit";
        }
        
            // ------------ add scroll components
            
            this.scrollUp = document.createElement("DIV");
            this.scrollUp.name = "upButton";
            this.scrollUp.owner = this;
            
            with(this.scrollUp.style)
            {
                position = "absolute";
                top = 0;
                left = 0;
                width = ref.scrollbarWidth;
                height = ref.scrollUpHeight;
                visibility = "inherit";
                backgroundImage = "url(" + ref.scrollUpImage + ")";
            }
             
               
               this.scrollUp.onmousedown = ref.upAction; //function() { alert("Up button"); }
               this.scrollUp.onmouseup = ref.killAction;
               
               this.scrollRgn.appendChild(this.scrollUp);
             
            this.scrollDn = document.createElement("DIV");
            this.scrollDn.name = "dnButton";
            this.scrollDn.owner = this;
            
            with(this.scrollDn.style)
            {
                position = "absolute";
                top = ref.height - ref.scrollDnHeight;
                left = 0;
                width = ref.scrollbarWidth;
                height = ref.scrollUpHeight;
                visibility = "inherit";
                backgroundImage = "url(" + ref.scrollDnImage + ")";
            }
             
               this.scrollDn.onmousedown = ref.dnAction; //function() { alert("Down button"); }
               this.scrollDn.onmouseup = ref.killAction;
                this.scrollRgn.appendChild(this.scrollDn);
                
            
               
            this.scrollTrack = document.createElement("DIV");
            this.scrollTrack.name = "track";
            this.scrollTrack.owner = this;
            
            with(this.scrollTrack.style)
            {
                position = "absolute";
                top = ref.trackStart;
                left = 0;
                width = ref.scrollbarWidth;
                height = ref.height - ref.scrollUpHeight - ref.scrollDnHeight;
                visibility = "inherit";
                
            }
             
                
               this.scrollTrack.onmousedown = ref.trackAction; //function() { alert("Track"); }
               this.scrollTrack.onmouseup = ref.killAction;
               this.scrollRgn.appendChild(this.scrollTrack);
               
            this.scrollThumb = document.createElement("DIV");
            this.scrollThumb.name = "thumb";
            this.scrollThumb.owner = this;
            
            with(this.scrollThumb.style)
            {
                position = "absolute";
                top = ref.trackStart;
                left = 0;
                width = ref.scrollbarWidth;
                height = ref.scrollThumbHeight;
                visibility = "inherit";
                backgroundImage = "url(" + ref.scrollThumbImage + ")";
            }
             
                
               this.scrollThumb.onmousedown = ref.thumbAction; //function() { alert("Thumb button"); }
               this.scrollThumb.onmouseup = ref.killAction;
               this.scrollRgn.appendChild(this.scrollThumb);
             
             
             
        this.disableRgn = document.createElement("DIV");
        this.disableRgn.owner = this;
        
        with(this.disableRgn.style)
        {
            position = "absolute";
            top = 0;
            left = 1;
            width = ref.scrollbarWidth-2;
            height = ref.height - 2 * ref.topInset;
            backgroundImage = "url(scrollbar/fadeout.gif)";
            border = "1px solid white";
            visibility = "hidden";
        }
        
             this.scrollRgn.appendChild(this.disableRgn);
             
             
               
          // ------------- end add scroll components
               
        this.container.appendChild(this.scrollRgn);
        
        if(parent)
        {
            parent.appendChild(this.container);
         }
        else
        document.body.appendChild(this.container);
    
    }
    
    this.show = function()
    {
    
        this.container.style.visibility = "visible";
    }
    
    this.hide = function()
    {
        this.container.style.visibility = "hidden";
    }
    
    
}