function CursorLayer(parentEl)
{
  this.element = document.createElement("div");
  this.element.className = "cursor-layer";
  parentEl.appendChild(this.element); 
  
  this.cursor = document.createElement("div");
  this.cursor.className = "cursor";
  
  this.isVisible = false;
}

CursorLayer.prototype.setCursor = function(position)
{
  this.position = {
    row: position.row,
    column: position.column
  };
};

CursorLayer.prototype.hideCursor = function() 
{
  this.isVisible = false;
  if (this.cursor.parentNode) {
    this.cursor.parentNode.removeChild(this.cursor);
  }
};

CursorLayer.prototype.showCursor = function()
{
  this.isVisible = true;
  this.element.appendChild(this.cursor);
};

CursorLayer.prototype.getPixelPosition = function() {
  return this.pixelPos || {left: 0, top:0};
}

CursorLayer.prototype.update = function(config)
{
  if (!this.position) return;
  
  var cursorLeft = this.position.column * config.characterWidth;
  var cursorTop = this.position.row * config.lineHeight;
  
  this.pixelPos = {
    left: cursorLeft,
    top: cursorTop
  };
  
  this.cursor.style.left = cursorLeft + "px";
  this.cursor.style.top = (cursorTop - (config.firstRow * config.lineHeight)) + "px";
  this.cursor.style.height = config.lineHeight + "px";

  if (this.isVisible) {
    this.element.appendChild(this.cursor);
  }
};