text: goog.provide('ol.source.CartoDB');
  
  goog.require('ol');
  goog.require('ol.obj');
  goog.require('ol.source.State');
  goog.require('ol.source.XYZ');
  
  
  /**
   * @classdesc
   * Layer source for the CartoDB Maps API.
   *
   * @constructor
   * @extends {ol.source.XYZ}
   * @param {olx.source.CartoDBOptions} options CartoDB options.
   * @api
   */
  ol.source.CartoDB = function(options) {
  
    /**
     * @type {string}
     * @private
     */
    this.account_ = options.account;
  
    /**
     * @type {string}
     * @private
     */
    this.mapId_ = options.map || '';
  
    /**
     * @type {!Object}
     * @private
     */
    this.config_ = options.config || {};
  
    /**
     * @type {!Object.<string, CartoDBLayerInfo>}
     * @private
     */
    this.templateCache_ = {};
  
    ol.source.XYZ.call(this, {
      attributions: options.attributions,
      cacheSize: options.cacheSize,
      crossOrigin: options.crossOrigin,
      logo: options.logo,
      maxZoom: options.maxZoom !== undefined ? options.maxZoom : 18,
      minZoom: options.minZoom,
      projection: options.projection,
      state: ol.source.State.LOADING,
      wrapX: options.wrapX
    });
    this.initializeMap_();
  };
  ol.inherits(ol.source.CartoDB, ol.source.XYZ);
  
  
  /**
   * Returns the current config.
   * @return {!Object} The current configuration.
   * @api
   */
  ol.source.CartoDB.prototype.getConfig = function() {
    return this.config_;
  };
  
  
  /**
   * Updates the carto db config.
   * @param {Object} config a key-value lookup. Values will replace current values
   *     in the config.
   * @api
   */
  ol.source.CartoDB.prototype.updateConfig = function(config) {
    ol.obj.assign(this.config_, config);
    this.initializeMap_();
  };
  
  
  /**
   * Sets the CartoDB config
   * @param {Object} config In the case of anonymous maps, a CartoDB configuration
   *     object.
   * If using named maps, a key-value lookup with the template parameters.
   * @api
   */
  ol.source.CartoDB.prototype.setConfig = function(config) {
    this.config_ = config || {};
    this.initializeMap_();
  };
  
  
  /**
   * Issue a request to initialize the CartoDB map.
   * @private
   */
  ol.source.CartoDB.prototype.initializeMap_ = function() {
    var paramHash = JSON.stringify(this.config_);
    if (this.templateCache_[paramHash]) {
      this.applyTemplate_(this.templateCache_[paramHash]);
      return;
    }
    var mapUrl = 'https://' + this.account_ + '.carto.com/api/v1/map';
  
    if (this.mapId_) {
      mapUrl += '/named/' + this.mapId_;
    }
  
    var client = new XMLHttpRequest();
    client.addEventListener('load', this.handleInitResponse_.bind(this, paramHash));
    client.addEventListener('error', this.handleInitError_.bind(this));
    client.open('POST', mapUrl);
    client.setRequestHeader('Content-type', 'application/json');
    client.send(JSON.stringify(this.config_));
  };
  
  
  /**
   * Handle map initialization response.
   * @param {string} paramHash a hash representing the parameter set that was used
   *     for the request
   * @param {Event} event Event.
   * @private
   */
  ol.source.CartoDB.prototype.handleInitResponse_ = function(paramHash, event) {
    var client = /** @type {XMLHttpRequest} */ (event.target);
    // status will be 0 for file:// urls
    if (!client.status || client.status >= 200 && client.status < 300) {
      var response;
      try {
        response = /** @type {CartoDBLayerInfo} */(JSON.parse(client.responseText));
      } catch (err) {
        this.setState(ol.source.State.ERROR);
        return;
      }
      this.applyTemplate_(response);
      this.templateCache_[paramHash] = response;
      this.setState(ol.source.State.READY);
    } else {
      this.setState(ol.source.State.ERROR);
    }
  };
  
  
  /**
   * @private
   * @param {Event} event Event.
   */
  ol.source.CartoDB.prototype.handleInitError_ = function(event) {
    this.setState(ol.source.State.ERROR);
  };
  
  
  /**
   * Apply the new tile urls returned by carto db
   * @param {CartoDBLayerInfo} data Result of carto db call.
   * @private
   */
  ol.source.CartoDB.prototype.applyTemplate_ = function(data) {
    var tilesUrl = 'https://' + data.cdn_url.https + '/' + this.account_ +
        '/api/v1/map/' + data.layergroupid + '/{z}/{x}/{y}.png';
    this.setUrl(tilesUrl);
  };
  