/***/
function BLOG_LinkList() {
  this._listId = "";

/***/

  this.BACKGROUND_COLOR = [255, 255, 255];
  this.LINK_COLOR = [0, 0, 255];
  this.OLD_LINK_COLOR = [255, 0, 255];

  this.HIDE_TIME = 300;
  this.HIDE_STEPS = 10;
  this.HIDE_DELAY = 0;
  this.HIDE_DISTANCE = 0;

  this.SHOW_TIME = 500;
  this.SHOW_STEPS = 10;
  this.SHOW_DELAY = 0;
  this.SHOW_DISTANCE = 0;
}

/***/
BLOG_LinkList.prototype.getList = function() {
  return document.getElementById(this._listId);
};

/***/
BLOG_LinkList.prototype.getItems = function() {
  return this.getList().getElementsByTagName("div");
};

/***/
BLOG_LinkList.prototype.getLinks = function() {
  return this.getList().getElementsByTagName("a");
};

/***/
BLOG_LinkList.prototype._fixStyle = function(numItems) {
  var list = this.getList();
  var items = this.getItems();

  for (var i = 0; i < numItems; ++i) {
    items[i].style.display = "block";
  }

  var needsClass = true;
  var classes = list.className.split(" ");

  for (var c in classes) {
    if (c == "yesscript") {
      needsClass = false;
      break;
    }
  }
  
  if (needsClass) {
    list.className += " yesscript";
  }
};




/***/
function BLOG_ScrollList(listId) {
  this.SHOW_COUNT = 1;

  this._listId = listId;
  this._replacementList = null;
  this._discardCount = 0;
}

BLOG_ScrollList.prototype = new BLOG_LinkList();

BLOG_ScrollList.prototype.init = function() {
  this._fixStyle(this.SHOW_COUNT + 1);
  this._hideCurrent();
};

BLOG_ScrollList.prototype._showNext = function() {
  if (this._replacementList) {
    this._replaceList();
  }

  var list = this.getList();
  var items = this.getItems();
  var links = this.getLinks();

  if (items.length > this.SHOW_COUNT) {
    var currentItem = items[0];
    var currentLink = links[0];
    var nextItem = items[this.SHOW_COUNT];
    var nextLink = links[this.SHOW_COUNT];

    var animation = new ANIM_Animation(this.SHOW_TIME, this.SHOW_STEPS,
                                       this.SHOW_DELAY);

    animation.addColorChange(currentLink, "color",
                             this.LINK_COLOR, this.OLD_LINK_COLOR);

    animation.addColorChange(nextLink, "color",
                             this.BACKGROUND_COLOR, this.LINK_COLOR);

    animation.setBeginHandler(function() {
      nextItem.style.display = "block";
    });

    var done = function() {
      arguments.callee.obj._hideCurrent();
    };
    done.obj = this;
    animation.setDoneHandler(done);
    
    animation.start();
  }
};

BLOG_ScrollList.prototype._hideCurrent = function() {
  var list = this.getList();
  var items = this.getItems();
  var links = this.getLinks();
  
  if (items.length > this.SHOW_COUNT) {
    var currentItem = items[0];
    var currentLink = links[0];
    var nextItem = items[1];
    var nextLink = links[1];

    var animation = new ANIM_Animation(this.HIDE_TIME, this.HIDE_STEPS,
                                       this.HIDE_DELAY);
    
    animation.addColorChange(currentLink, "color",
                             this.OLD_LINK_COLOR, this.BACKGROUND_COLOR);
    animation.addMovement(currentItem, "top", 0, this.HIDE_DISTANCE + this.SHOW_DISTANCE);
    animation.addMovement(list, "top", 0, -this.SHOW_DISTANCE);

    var done = function() {
      var obj = arguments.callee.obj;

      currentItem.style.top = "";
      currentItem.style.display = "none";
      list.style.top = "";

      window.setTimeout(function() {
        if (obj._discardCount > 0) {
          obj.getList().removeChild(currentItem);
          obj._discardCount--;
        } else {
          obj.getList().appendChild(currentItem);
        }

        obj._showNext();
       }, 0);

    };
    done.obj = this;
    animation.setDoneHandler(done);

    animation.start();
  }
};

BLOG_ScrollList.prototype.updateList = function(newList) {
  this._replacementList = newList;
};

BLOG_ScrollList.prototype._replaceList = function() {
  var list = this.getList();
  var items = this.getItems();
  var newItems = this._replacementList.getElementsByTagName("div");

  while(items.length > this.SHOW_COUNT) {
    list.removeChild(items[this.SHOW_COUNT]);
  }
  
  while(newItems.length > 0) {
    list.appendChild(newItems[0]);
  }

  this._discardCount = this.SHOW_COUNT;
  this._replacementList = null;
};


/***/

function ANIM_Animation(time, steps, delay) {
  this._time = time;
  this._steps = steps;
  this._delay = delay;

  this._animationFunctions = [];
  this._beginHandler = null;
  this._doneHandler = null;

  this._timer = null;
};


/***/
ANIM_Animation.prototype.addColorChange = function(el, attr, start, end) {
  var animationFunction = function(mix) {
    var colorArray = [0, 0, 0];
    
    for (var i = 0; i < 3; ++i) {
      // simple linear interpolation
      colorArray[i] = (1.0 - mix) * start[i] + mix * end[i];
    }
    
    el.style[attr] = ANIM_arrayToColor(colorArray);
  };

  this.addAnimationFunction(animationFunction);
};


/***/
ANIM_Animation.prototype.addMovement = function(el, attr, start, end) {
  var animationFunction = function(mix) {
    el.style[attr] = ANIM_numToPixels((1.0 - mix) * start + mix * end);
  };

  this.addAnimationFunction(animationFunction);
};


/***/
ANIM_Animation.prototype.addAnimationFunction = function(animationFunction) {
  this._animationFunctions[this._animationFunctions.length] =
    animationFunction;
};


/***/
ANIM_Animation.prototype.setBeginHandler = function(beginHandler) {
  this._beginHandler = beginHandler;
};


/***/
ANIM_Animation.prototype.setDoneHandler = function(doneHandler) {
  this._doneHandler = doneHandler;
};



/***/
ANIM_Animation.prototype._callAnimationFunctions = function(mix) {
  for(var i = 0; i < this._animationFunctions.length; ++i) {
    this._animationFunctions[i](mix);
  }
};


/***/
ANIM_Animation.prototype.start = function() {
  var obj = this;

  var nextStep = 0;
  var startTime = 0;

  var animationLoop = function() {
    var currentStep = nextStep;
    ++nextStep;
    
/***/
    var currentMix = currentStep / obj._steps;
    var nextMix = nextStep / obj._steps;
    
    obj._callAnimationFunctions(currentMix);
    
    if (nextStep <= obj._steps) {
/***/

      var curTime = new Date().getTime();
      var nextTime = startTime + Math.floor(obj._time * nextMix);
      var delay = Math.max(0, nextTime - curTime);

      obj._timer = window.setTimeout(animationLoop, delay);
    } else {
      obj._timer = null;

      if (obj._doneHandler) {
        obj._doneHandler();
      }
    }
  };

  var beginAnimation = function() {
    if (obj._beginHandler) {
      obj._beginHandler();
    }

    startTime = new Date().getTime();
    animationLoop();
  };

  this._timer = window.setTimeout(beginAnimation, this._delay);
};


/***/
ANIM_Animation.prototype.stop = function() {
  if (this._timer) {
    window.clearTimeout(this._timer);
  }
};


/***/
function ANIM_arrayToColor(arr) {
  return "rgb(" + Math.floor(arr[0]) +
         ", " + Math.floor(arr[1]) +
	     ", " + Math.floor(arr[2]) + ")";
};


/***/
function ANIM_numToPixels(num) {
  return Math.floor(num) + "px";
};