(function( $ ){

  /**
   * @class ZoomifyTileSource
   * @classdesc A tilesource implementation for the zoomify format.
   *
   * @memberof OpenSeadragon
   * @extends OpenSeadragon.TileSource
   * @param {Number} width - the pixel width of the image.
   * @param {Number} height
   * @param {Number} tileSize
   * @param {String} tilesUrl
   */
  $.ZoomifyTileSource = function( options ) {

  	options.tileSize = 256;
		
		var currentImageSize = {x:options.width,y:options.height};
		options.imageSizes = [{x:options.width,y:options.height}];
  	options.gridSize = [this._getGridSize(options.width,options.height,options.tileSize)];
		
  	while(parseInt(currentImageSize.x) > options.tileSize || parseInt(currentImageSize.y) > options.tileSize) {
				currentImageSize.x = Math.floor(currentImageSize.x/2);
				currentImageSize.y = Math.floor(currentImageSize.y/2);
				options.imageSizes.push({x:currentImageSize.x,y:currentImageSize.y});
				options.gridSize.push(this._getGridSize(currentImageSize.x,currentImageSize.y,options.tileSize));
			}
		options.imageSizes.reverse();
		options.gridSize.reverse();
		options.minLevel = 0;
		options.maxLevel = options.gridSize.length-1;
		
  	
  	OpenSeadragon.TileSource.apply( this, [ options ] );

  };

  $.extend( $.ZoomifyTileSource.prototype, $.TileSource.prototype, /** @lends OpenSeadragon.ZoomifyTileSource.prototype */{
		
		_getGridSize: function(width,height,tileSize) {
			return {x: Math.ceil(width/tileSize),y:Math.ceil(height/tileSize)};
		},
		
		_calculateAbsoluteTileNumber: function (level, x, y) {
			var num = 0;
			for (var z = 0; z < level; z++) {
				var size = this.gridSize[z];
				num += size.x * size.y;
			}
			var size = this.gridSize[level];
			num += size.x*y+ x
			return num;
		},

    /**
     * Determine if the data and/or url imply the image service is supported by
     * this tile source.
     * @function
     * @param {Object|Array} data
     * @param {String} optional - url
     */
    supports: function( data, url ){
      //console.log('ZoomifyTileSource supports ' + data.type); 
      return ( data.type && "zoomifytileservice" == data.type );
    },

    /**
     *
     * @function
     * @param {Object} data - the raw configuration
     * @param {String} url - the url the data was retreived from if any.
     * @return {Object} options - A dictionary of keyword arguments sufficient
     *      to configure this tile sources constructor.
     */
    configure: function( data, url ){
      //console.log('ZoomifyTileSource configure ' + data.tilesUrl);
      return data;
    },


    /**
     * @function
     * @param {Number} level
     * @param {Number} x
     * @param {Number} y
     */
    getTileUrl: function( level, x, y ){
			//console.log(level);
			var result = 0;
			var num = this._calculateAbsoluteTileNumber(level,x,y);
			result = Math.floor(num/256);
			return  this.tilesUrl + 'TileGroup' + result + '/' + level + '-' + x + '-' + y + '.jpg';
      
    },          
  });
	
}( OpenSeadragon ));