var snowStorm = null;

    function SnowStorm() {

      // PROPERTIES
      // ------------------

      var imagePath = '/forum/images/snow/'; // relative path to snow images (including trailing slash)
      var flakesMax = 200;
      var flakesMaxActive = 100;
      var vMaxX = 8;
      var vMaxY = 4;
      var usePNG = true;
      var flakeBottom = null;        // Integer for fixed bottom, 0 or null for "full-screen" snow effect
      var snowStick = false;
      var snowCollect = false;
      var targetElement = null;      // element which snow will be appended to (document body if undefined)
      var followMouse = true;
      var flakeTypes = 6;
      var flakeWidth = 5;
      var flakeHeight = 5;

      // ------------------

      var zIndex = 0; // CSS stacking order applied to each snowflake
      var flakeLeftOffset = 0; // amount to subtract from edges of container
      var flakeRightOffset = 0; // amount to subtract from edges of container

      // --- End of user section ---

      var addEvent = function(o,evtName,evtHandler) {
        typeof(attachEvent)=='undefined'?o.addEventListener(evtName,evtHandler,false):o.attachEvent('on'+evtName,evtHandler);
      }

      var removeEvent = function(o,evtName,evtHandler) {
        typeof(attachEvent)=='undefined'?o.removeEventListener(evtName,evtHandler,false):o.detachEvent('on'+evtName,evtHandler);
      }

      var classContains = function(o,cStr) {
        return (typeof(o.className)!='undefined'?o.className.indexOf(cStr)+1:false);
      }

      var s = this;
      var storm = this;
      this.timers = [];
      this.flakes = [];
      this.disabled = false;
      this.terrain = [];
      this.active = false;

      var isIE = navigator.userAgent.match(/msie/i);
      var isIE6 = navigator.userAgent.match(/msie 6/i);
      var isOldIE = (isIE && (isIE6 || navigator.userAgent.match(/msie 5/i)));
      var isWin9X = navigator.appVersion.match(/windows 98/i);
      var isiPhone = navigator.userAgent.match(/iphone/i);
      var isBackCompatIE = (isIE && document.compatMode == 'BackCompat');
      var isOpera = navigator.userAgent.match(/opera/i);
      if (isOpera) isIE = false; // Opera (which may be sneaky, pretending to be IE by default)
      var noFixed = (isBackCompatIE || isIE6 || isiPhone);
      var screenX = null;
      var screenX2 = null;
      var screenY = null;
      var scrollY = null;
      var vRndX = null;
      var vRndY = null;
      var windOffset = 1;
      var windMultiplier = 2;
      var pngSupported = (!isIE || (isIE && !isIE6 && !isOldIE)); // IE <7 doesn't do PNG nicely without crap filters
      var docFrag = document.createDocumentFragment();
      this.oControl = null; // toggle element
      if (flakeLeftOffset == null) flakeLeftOffset = 0;
      if (flakeRightOffset == null) flakeRightOffset = 0;

      function rnd(n,min) {
        if (isNaN(min)) min = 0;
        return (Math.random()*n)+min;
      }

      this.randomizeWind = function() {
        vRndX = plusMinus(rnd(vMaxX,0.2));
        vRndY = rnd(vMaxY,0.2);
        if (this.flakes) {
          for (var i=0; i<this.flakes.length; i++) {
            if (this.flakes[i].active) this.flakes[i].setVelocities();
          }
        }
      }

      function plusMinus(n) {
        return (parseInt(rnd(2))==1?n*-1:n);
      }

      this.scrollHandler = function() {
        // "attach" snowflakes to bottom of window if no absolute bottom value was given
        scrollY = (flakeBottom?0:parseInt(window.scrollY||document.documentElement.scrollTop||document.body.scrollTop));
        if (isNaN(scrollY)) scrollY = 0; // Netscape 6 scroll fix
        if (!flakeBottom && s.flakes) {
          for (var i=0; i<s.flakes.length; i++) {
            if (s.flakes[i].active == 0) s.flakes[i].stick();
          }
        }
      }

      this.resizeHandler = function() {
        if (window.innerWidth || window.innerHeight) {
          screenX = window.innerWidth-(!isIE?16:2)-flakeRightOffset;
          screenY = (flakeBottom?flakeBottom:window.innerHeight);
        } else {
          screenX = (document.documentElement.clientWidth||document.body.clientWidth||document.body.scrollWidth)-(!isIE?8:0)-flakeRightOffset;
          screenY = flakeBottom?flakeBottom:(document.documentElement.clientHeight||document.body.clientHeight||document.body.scrollHeight);
        }
        screenX2 = parseInt(screenX/2);
      }

      this.resizeHandlerAlt = function() {
        screenX = targetElement.offsetLeft+targetElement.offsetWidth-flakeRightOffset;
        screenY = flakeBottom?flakeBottom:targetElement.offsetTop+targetElement.offsetHeight;
        screenX2 = parseInt(screenX/2);
      }

      this.freeze = function() {
        // pause animation
        if (!s.disabled) {
          s.disabled = 1;
        } else {
          return false;
        }
        for (var i=0; i<s.timers.length; i++) {
          clearInterval(s.timers[i]);
        }
      }

      this.resume = function() {
        if (s.disabled) {
           s.disabled = 0;
        } else {
          return false;
        }
        s.timerInit();
      }

      this.toggleSnow = function() {
        if (!s.flakes.length) {
          // first run
          s.start();
          s.setControlActive(true);
        } else {
          s.active = !s.active;
          if (s.active) {
            s.show();
            s.resume();
            s.setControlActive(true);
          } else {
            s.stop();
            s.freeze();
            s.setControlActive(false);
          }
        }
      }

      this.stop = function() {
        this.freeze();
        for (var i=this.flakes.length; i--;) {
          this.flakes[i].o.style.display = 'none';
        }
        removeEvent(window,'scroll',s.scrollHandler);
        removeEvent(window,'resize',s.resizeHandler);
        if (!isIE) {
          removeEvent(window,'blur',s.freeze);
          removeEvent(window,'focus',s.resume);
        }
        // removeEventHandler(window,'resize',this.resizeHandler,false);
      }

      this.show = function() {
        for (var i=this.flakes.length; i--;) {
          this.flakes[i].o.style.display = 'block';
        }
      }

      this.SnowFlake = function(parent,type,x,y) {
        var s = this;
        var storm = parent;
        this.type = type;
        this.x = x||parseInt(rnd(screenX-20));
        this.y = (!isNaN(y)?y:-rnd(screenY)-12);
        this.vX = null;
        this.vY = null;
        this.vAmpTypes = [2.0,1.0,1.25,1.0,1.5,1.75]; // "amplification" for vX/vY (based on flake size/type)
        this.vAmp = this.vAmpTypes[this.type];

        this.active = 1;
        this.o = document.createElement('img');
        this.o.style.position = 'absolute';
        this.o.style.width = flakeWidth+'px';
        this.o.style.height = flakeHeight+'px';
        this.o.style.fontSize = '1px'; // so IE keeps proper size
        this.o.style.zIndex = zIndex;
        this.o.src = imagePath+this.type+(pngSupported && usePNG?'.png':'.gif');
        docFrag.appendChild(this.o);

        this.refresh = function() {
          s.o.style.left = s.x+'px';
          s.o.style.top = s.y+'px';
        }

        this.stick = function() {
          if (noFixed || (targetElement != document.documentElement && targetElement != document.body)) {
       s.o.style.top = (screenY+scrollY-flakeHeight-storm.terrain[Math.floor(s.x)])+'px';
          } else {
            s.o.style.display = 'none';
       s.o.style.top = 'auto';
            s.o.style.bottom = '0px';
       s.o.style.position = 'fixed';
            s.o.style.display = 'block';
          }
        }

        this.vCheck = function() {
          if (s.vX>=0 && s.vX<0.2) {
            s.vX = 0.2;
          } else if (s.vX<0 && s.vX>-0.2) {
            s.vX = -0.2;
          }
          if (s.vY>=0 && s.vY<0.2) {
            s.vY = 0.2;
          }
        }

        this.move = function() {
          var vX = s.vX*windOffset;
          s.x += vX;
          s.y += (s.vY*s.vAmp);
          if (vX >= 0 && (s.x >= screenX || screenX-s.x < (flakeWidth+1))) { // X-axis scroll check
            s.x = 0;
          } else if (vX < 0 && s.x-flakeLeftOffset<0-flakeWidth) {
            s.x = screenX-flakeWidth-1; // flakeWidth;
          }
          s.refresh();
          var yDiff = screenY+scrollY-s.y-storm.terrain[Math.floor(s.x)];
          if (yDiff<flakeHeight) {
            s.active = 0;
            if (snowCollect && snowStick) {
              var height = [0.75,1.5,0.75];
              for (var i=0; i<2; i++) {
                storm.terrain[Math.floor(s.x)+i+2] += height[i];
              }
            }
            s.o.style.left = (s.x/screenX*100)+'%'; // set "relative" left (change with resize)
            if (!flakeBottom) {
         if (snowStick) {
                s.stick();
         } else {
           s.recycle();
         }
            }
          }

        }

        this.animate = function() {
          // main animation loop
          // move, check status, die etc.
          s.move();
        }

        this.setVelocities = function() {
          s.vX = vRndX+rnd(vMaxX*0.12,0.1);
          s.vY = vRndY+rnd(vMaxY*0.12,0.1);
        }

        this.recycle = function() {
          s.o.style.display = 'none';
          s.o.style.position = 'absolute';
          s.o.style.bottom = 'auto';
          s.setVelocities();
          s.vCheck();
          s.x = parseInt(rnd(screenX-flakeWidth-20));
          s.y = parseInt(rnd(screenY)*-1)-flakeHeight;
          s.o.style.left = s.x+'px';
          s.o.style.top = s.y+'px';
          s.o.style.display = 'block';
          s.active = 1;
        }

        this.recycle(); // set up x/y coords etc.
        this.refresh();

      }

      this.snow = function() {
        var active = 0;
        var used = 0;
        var waiting = 0;
        for (var i=s.flakes.length; i--;) {
          if (s.flakes[i].active == 1) {
            s.flakes[i].move();
            active++;
          } else if (s.flakes[i].active == 0) {
            used++;
          } else {
            waiting++;
          }
        }
        if (snowCollect && !waiting) { // !active && !waiting
          // create another batch of snow
          s.createSnow(flakesMaxActive,true);
        }
        if (active<flakesMaxActive) {
          with (s.flakes[parseInt(rnd(s.flakes.length))]) {
            if (!snowCollect && active == 0) {
              recycle();
            } else if (active == -1) {
              active = 1;
            }
          }
        }
      }

      this.mouseMove = function(e) {
        if (!followMouse) return true;
        var x = parseInt(e.clientX);
        if (x<screenX2) {
          windOffset = -windMultiplier+(x/screenX2*windMultiplier);
        } else {
          x -= screenX2;
          windOffset = (x/screenX2)*windMultiplier;
        }
      }

      this.createSnow = function(limit,allowInactive) {
        for (var i=0; i<limit; i++) {
          s.flakes[s.flakes.length] = new s.SnowFlake(s,parseInt(rnd(flakeTypes)));
          if (allowInactive || i>flakesMaxActive) s.flakes[s.flakes.length-1].active = -1;
        }
        targetElement.appendChild(docFrag);
      }

      this.timerInit = function() {
        s.timers = (!isWin9X?[setInterval(s.snow,20)]:[setInterval(s.snow,75),setInterval(s.snow,25)]);
      }

      this.init = function() {
        for (var i=0; i<2048; i++) {
          s.terrain[i] = 0;
        }
        s.randomizeWind();
        s.createSnow(snowCollect?flakesMaxActive:flakesMaxActive*2); // create initial batch
        addEvent(window,'resize',s.resizeHandler);
        addEvent(window,'scroll',s.scrollHandler);
        if (!isIE) {
          addEvent(window,'blur',s.freeze);
          addEvent(window,'focus',s.resume);
        }
        s.resizeHandler();
        s.scrollHandler();
        if (followMouse) {
          addEvent(document,'mousemove',s.mouseMove);
        }
        s.timerInit();
      }

      var didInit = false;

      this.start = function(bFromOnLoad) {
       if (!didInit) {
         didInit = true;
       } else if (bFromOnLoad) {
         // already loaded and running
         return true;
       }
        if (typeof targetElement == 'string') {
          targetElement = document.getElementById(targetElement);
          if (!targetElement) throw new Error('Snowstorm: Unable to get targetElement');
        }
       if (!targetElement) {
         targetElement = (!isIE?(document.documentElement?document.documentElement:document.body):document.body);
       }
        if (targetElement != document.documentElement && targetElement != document.body) s.resizeHandler = s.resizeHandlerAlt; // re-map handler to get element instead of screen dimensions
        s.resizeHandler(); // get bounding box elements
        if (screenX && screenY && !s.disabled) {
          s.init();
          s.active = true;
        }
      }

      if (document.addEventListener) {
       // safari 3.0.4 doesn't do DOMContentLoaded, maybe others - use a fallback to be safe.
       document.addEventListener('DOMContentLoaded',function(){s.start(true)},false);
        window.addEventListener('load',function(){s.start(true)},false);
      } else {
        addEvent(window,'load',function(){s.start(true)});
      }

    }



    snowStorm = new SnowStorm();