// getAncestorId.js
(function() {
	/*global adventurejs A*/ 
  "use strict";
  var p = adventurejs.Tangible.prototype;	
  /**
   * Get the ID of this asset's topmost parent, excluding {@link adventurejs.Room|Room}.
   * @memberOf adventurejs.Tangible
	 * @method adventurejs.Tangible#getAncestorId
   * @returns {String}
   */
  p.getAncestorId = function Tangible_getAncestorId() 
  {
    var child = this;
    var parent_asset = this.getPlaceAsset();

    // child has no parent, so it's not accessible
    if( !parent_asset ) 
    {
      return "";
    }

    // child parent is room
    if( parent_asset instanceof adventurejs.Room ) 
    {
      return "";
    }

    while ( parent_asset ) 
    {
      child = parent_asset;
      if( !parent_asset.getPlaceAsset() ) 
      {
        return "";
      }
      parent_asset = parent_asset.getPlaceAsset();
      if( parent_asset instanceof adventurejs.Room ) 
      {
        return child.id;
      }
    }
    return "";
  }
}());