//=========================================================
// custom scroller developed for 2027.org by aaron boodman
//
// some sections based on ypSimpleScroll.js.
//
// www.youngpup.net
// 3/28/2001 (3 hours before site launch!)
//
// updated 
// - 8/29/02 : fixed performance issues related to using
//   background images
//=========================================================
// code is art!
//=========================================================

var Scroller = {
     speed               : 15,
     aniLen               : 1000,
     clipH               : 283,
     thumbMax          : 247,
     thumbH               : 20,
     scrollbarH          : 262,
     scrollTop          : 0,
     scrollLeft          : 0,
     minRes               : 10,
     ie4                    : navigator.appName == "Microsoft Internet Explorer" && !document.getElementById,
     ns4                    : document.layers ? 1 : 0,
     dom                    : document.getElementById ? 1 : 0,
     mac                    : navigator.platform == "MacPPC",
     mo5                    : navigator.userAgent.indexOf("Gecko") != -1,

     imgElevBack1     : ypImage("imgs/scroll/elevator1.gif"),
     imgElevBack2     : ypImage("imgs/scroll/elevator2.gif"),
     imgElevBack3     : ypImage("imgs/scroll/elevator3.gif"),

     imgThumb1          : ypImage("imgs/scroll/thumb1.gif"),
     imgThumb2          : ypImage("imgs/scroll/thumb2.gif"),

     imgUp1               : ypImage("imgs/scroll/scrollUp1.gif"),
     imgUp2               : ypImage("imgs/scroll/scrollUp2.gif"),
     imgUp3               : ypImage("imgs/scroll/scrollUp3.gif"),
     imgDn1               : ypImage("imgs/scroll/scrollDn1.gif"),
     imgDn2               : ypImage("imgs/scroll/scrollDn2.gif"),
     imgDn3               : ypImage("imgs/scroll/scrollDn3.gif"),

     dir:0,lastTime:0,aniTimer:0,dragActive:0,dragLastY:0,dragStartOffset:0,
     startPos:0,startTime:0,accel:0,endPos:0,dist:0
}

Scroller.init = function() {
     with (this) {
          // gather pieces
          this.lyrFrame               = getLyr("scroller", document)
          this.lyrScrollbar          = getLyr("scrollbar", lyrFrame)
          this.lyrThumb               = getLyr("thumb", lyrScrollbar)
          this.lyrMarker               = getLyr("marker", lyrScrollbar)
          this.lyrElevUp               = getLyr("elevUp", lyrScrollbar)
          this.lyrElevDn               = getLyr("elevDn", lyrScrollbar)
          this.lyrScrollUp          = getLyr("scrollUp", lyrFrame)
          this.lyrScrollDn          = getLyr("scrollDn", lyrFrame)
          this.lyrThumbArrowUp     = getLyr("thumbArrowUp", lyrScrollbar)
          this.lyrThumbArrowDn     = getLyr("thumbArrowDn", lyrScrollbar)
          this.lyrContainer          = getLyr("container", lyrFrame)
          this.lyrContent               = getLyr("content", lyrContainer)

          // calculate some values
          this.docH                    = Math.max(ns4 ? lyrContent.document.height : lyrContent.offsetHeight, clipH)
          this.scrollH               = docH - clipH

          if (this.docH > clipH) {
               // hook events
               lyrElevUp.onmousedown   = slideTo
               lyrElevDn.onmousedown     = slideTo
               lyrThumb.onmousedown    = startDrag
               lyrThumb.onmouseover    = function() { Scroller.toggleThumb(true) }
               lyrThumb.onmouseout     = function() { Scroller.toggleThumb(false) }
               lyrThumb.ondragstart     = function() { return false; }
               lyrElevUp.onmouseover   = function() { Scroller.toggleElev(Scroller.lyrElevUp, 2) }
               lyrElevUp.onmouseout    = function() { Scroller.toggleElev(Scroller.lyrElevUp, 1) }
               lyrElevDn.onmouseover     = function() { Scroller.toggleElev(Scroller.lyrElevDn, 2) }
               lyrElevDn.onmouseout     = function() { Scroller.toggleElev(Scroller.lyrElevDn, 1) }
               lyrScrollDn.onmouseover = function() { Scroller.toggleButton("Dn", 2); Scroller.startScroll('+'); }
               lyrScrollDn.onmousedown = function() { Scroller.toggleButton("Dn", 3); Scroller.speed = 350; return false }
               lyrScrollDn.onmouseup   = function() { Scroller.toggleButton("Dn", 2); Scroller.speed = 100 }
               lyrScrollDn.onmouseout  = function() { Scroller.toggleButton("Dn", 1); Scroller.endScroll() }
               lyrScrollUp.onmouseover = function() { Scroller.toggleButton("Up", 2); Scroller.startScroll('-') }
               lyrScrollUp.onmousedown = function() { Scroller.toggleButton("Up", 3); Scroller.speed = 350; return false }
               lyrScrollUp.onmouseup   = function() { Scroller.toggleButton("Up", 2); Scroller.speed = 100 }
               lyrScrollUp.onmouseout  = function() { Scroller.toggleButton("Up", 1); Scroller.endScroll() }

               // initialize some settings
               lyrThumb.s.top = 0

               // ns4 bullshit.
               if (document.layers) { 
                    lyrThumb.captureEvents(Event.MOUSEDOWN)
                    lyrElevDn.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE)
                    lyrElevUp.captureEvents(Event.MOUSEDOWN | Event.MOUSEMOVE)
                    lyrScrollUp.captureEvents(Event.MOUSEDOWN | Event.MOUSEUP)
                    lyrScrollDn.captureEvents(Event.MOUSEDOWN | Event.MOUSEUP)
               }

               // mozilla5 bullshit.
               if (mo5) document.getElementById("scrollerMo5Shim").style.height = docH
          } 
          else 
          {
               this.lyrScrollbar.s.visibility = 
                    this.lyrScrollUp.s.visibility =
                    this.lyrScrollDn.s.visibility = 
                    'hidden';
          }

          // all done!
          this.loaded = true
     }
}

Scroller.startScroll = function(dir) {
     if (this.aniTimer) window.clearTimeout(this.aniTimer)

     this.dir          = dir
     this.lastTime     = (new Date()).getTime() - this.minRes
     this.startPos     = this.scrollTop
     this.aniTimer     = window.setTimeout("Scroller.scroll()", this.minRes)
}

Scroller.scroll = function() {
     this.aniTimer     = window.setTimeout("Scroller.scroll()", this.minRes)
     var now               = (new Date()).getTime()
     var elapsed          = now - this.lastTime
     var ny               = eval(this.scrollTop + this.dir + (elapsed * this.speed / 1000))
     this.lastTime     = now
     if (ny > this.scrollH && this.dir == "+" || ny < 0 && this.dir == "-") {
          this.endScroll()
          this.jumpTo(this.dir == "+" ? this.scrollH : 0)
     }
     else this.jumpTo(ny)
}

Scroller.endScroll = function() {
     if (this.aniTimer) this.aniTimer = window.clearTimeout(this.aniTimer)
}

Scroller.startDrag = function(e) {
     if (!e) e = window.event
     with (Scroller) {
          if (aniTimer) window.clearTimeout(aniTimer)
          var ey = e.pageY ? e.pageY : e.y
          dragLastY = ey
          dragStartOffset = ey - parseInt(lyrThumb.s.top)
          dragActive = true
          if (ns4) window.document.captureEvents(Event.MOUSEMOVE | Event.MOUSEUP)
          window.document.onmousemove = doDrag
          window.document.onmouseup = stopDrag
     }
     // hip add (muestra arrows de thumb si sigo la secuencia:
     //over (thumb), drag, release, drag
     Scroller.toggleThumb(true)
     return false
}

Scroller.doDrag = function(e) {
     if (!e) e = window.event
     var s  = Scroller
     var ey = (e.pageY ? e.pageY : e.y)
     var dy = ey - s.dragLastY
     var ny = parseInt(Scroller.lyrThumb.s.top) + dy

     // constrain
     if (ny >= s.thumbMax) s.dragLastY = s.thumbMax + s.dragStartOffset
     else if (ny < 0) s.dragLastY = s.dragStartOffset
     else s.dragLastY = ey
     ny = Math.min(Math.max(ny, 0), s.thumbMax)

     s.jumpTo(ny * s.scrollH / s.thumbMax)
     return false;
}

Scroller.positionThumbArrows = function(ny) {
     this.lyrThumbArrowUp.s.top = ny - 6
     this.lyrThumbArrowDn.s.top = ny + 15
}

Scroller.stopDrag = function() {
     Scroller.dragActive = false
     Scroller.toggleThumb(false)
     if (Scroller.ns4) window.document.releaseEvents(Event.MOUSEMOVE | Event.MOUSEUP)
     window.document.onmousemove = null
     window.document.onmouseup   = null
}

// slideTo gets called in the scope of lyrElevUp or lyrElevDn
Scroller.slideTo = function(e) {
     if (!e) e = window.event
     var ey = e.offsetY ? e.offsetY : e.layerY
     if (typeof ey == "undefined") ey = 0
     var ny = (this.id == "elevDn") ? ey-14 : ey
     ny += this.s.top == "" ? 0 : parseInt(this.s.top)
     ny *= Scroller.scrollH / Scroller.thumbMax
     ny = Math.min(ny, Scroller.scrollH)

     with (Scroller) {
          startTime = (new Date()).getTime()
          startPos = scrollTop
          endPos = ny
          dist = endPos - startPos
          accel = dist / 1000 / 1000
          if (aniTimer) aniTimer = window.clearInterval(aniTimer)
          aniTimer = window.setInterval("Scroller.slide()", 10)
     }
}

Scroller.slide = function() {
     with (this) {
          var now = (new Date()).getTime()
          var elapsed = now - startTime
          if (elapsed > 1000) endScroll()
          else {
               var t = 1000 - elapsed
               var ny = endPos - t * t * accel
               jumpTo(ny)
          }
     }
}

Scroller.jumpTo = function(ny) {
     var thumbTop = ny * this.thumbMax / this.scrollH
     this.lyrElevUp[document.layers ? "clip" : "style"].height = thumbTop
     this.lyrElevDn[document.layers ? "clip" : "style"].height = this.scrollbarH - thumbTop
     this.lyrElevDn.s.top = thumbTop
     this.lyrThumb.s.top = thumbTop
     this.lyrContent.s.top = -ny
     this.positionThumbArrows(ny * this.thumbMax / this.scrollH)
     this.scrollTop = ny
}

Scroller.toggleThumb = function(bOn) {
     var img = this.getFirstImage(this.lyrThumb)
     img.src = !bOn && !this.dragActive ? this.imgThumb1.src : this.imgThumb2.src
     if (!bOn && !this.dragActive) this.toggleThumbArrows(false)
     else {
          this.positionThumbArrows(parseInt(this.lyrThumb.s.top))
          this.toggleThumbArrows(true)
     }
}

Scroller.toggleThumbArrows = function(bOn) {
     this.lyrThumbArrowUp.s.visibility = bOn ? "visible" : "hidden"
     this.lyrThumbArrowDn.s.visibility = bOn ? "visible" : "hidden"
}

Scroller.toggleElev = function(lyr, iState) {
     var img = this["imgElevBack" + iState];
     with (this) {
          if (document.layers) lyr.document.images[0].src = img.src;
          else lyr.firstChild.src = img.src;
          lyr.onmousemove = iState == 2 ? moveMarker : null
          if (iState == 1) lyrMarker.s.visibility = "hidden"
     }
}

Scroller.moveMarker = function(e) {
     with (Scroller) {     
          if (!lyrThumb.active) {
               if (!e) e = window.event
               var ey = e.layerY ? e.layerY : e.offsetY
               if (isNaN(ey)) ey = 0
               var ny = Math.round(ey / 2) * 2
               ny += (this.s.top == "" ? 0 : parseInt(this.s.top))
               ny -= 1
               lyrMarker.s.top = ny
               lyrMarker.s.visibility = "visible"
          }
     }
}

Scroller.toggleButton = function(suffix, iState) {
     var lyr = eval("Scroller.lyrScroll" + suffix)
     var img = this.getFirstImage(lyr)
     img.src = "imgs/scroll/scroll"+suffix+iState+".gif"
}

Scroller.getLyr = function(sLyrId, oNestRef) {
     var o
     if (document.all) o = oNestRef.all[sLyrId]
     else if (document.layers) o = oNestRef.layers[sLyrId]
     else o = this.recursiveNs6Get(sLyrId, oNestRef)
     o.s = document.layers ? o : o.style
     return o
}

// this is kinda slow for ns6 -> 
// but best way I could think of w/o totally bloating the code.
Scroller.recursiveNs6Get = function(id, p) {
     if (p.childNodes) {
          for (var i = 0; i < p.childNodes.length; i++) {
               if (p.childNodes[i].id == id) return p.childNodes[i]
               else if (p.childNodes[i].childNodes.length > 0) {
                    var obj = Scroller.recursiveNs6Get(id, p.childNodes[i])
                    if (obj && obj != null) return obj
               }
          }
     }
     return false
}

Scroller.getFirstImage = function(lyr) {
     return document.layers ? lyr.document.images[0] : document.all ? lyr.all.tags("IMG")[0] : lyr.getElementsByTagName("IMG")[0]
}

function ypImage(s) {
     var oImg  = new Image()
     oImg.src = s
     return oImg
}

function dbg(obj) {
     var s = ""
     for (prop in obj) s += prop + ":" + obj[prop] + "\n"
     alert(s)
}