text: goog.provide('ol.source.TileArcGISRest');
  
  goog.require('ol');
  goog.require('ol.extent');
  goog.require('ol.math');
  goog.require('ol.obj');
  goog.require('ol.size');
  goog.require('ol.source.TileImage');
  goog.require('ol.tilecoord');
  goog.require('ol.uri');
  
  
  /**
   * @classdesc
   * Layer source for tile data from ArcGIS Rest services. Map and Image
   * Services are supported.
   *
   * For cached ArcGIS services, better performance is available using the
   * {@link ol.source.XYZ} data source.
   *
   * @constructor
   * @extends {ol.source.TileImage}
   * @param {olx.source.TileArcGISRestOptions=} opt_options Tile ArcGIS Rest
   *     options.
   * @api
   */
  ol.source.TileArcGISRest = function(opt_options) {
  
    var options = opt_options || {};
  
    ol.source.TileImage.call(this, {
      attributions: options.attributions,
      cacheSize: options.cacheSize,
      crossOrigin: options.crossOrigin,
      logo: options.logo,
      projection: options.projection,
      reprojectionErrorThreshold: options.reprojectionErrorThreshold,
      tileGrid: options.tileGrid,
      tileLoadFunction: options.tileLoadFunction,
      url: options.url,
      urls: options.urls,
      wrapX: options.wrapX !== undefined ? options.wrapX : true,
      transition: options.transition
    });
  
    /**
     * @private
     * @type {!Object}
     */
    this.params_ = options.params || {};
  
    /**
     * @private
     * @type {ol.Extent}
     */
    this.tmpExtent_ = ol.extent.createEmpty();
  
    this.setKey(this.getKeyForParams_());
  };
  ol.inherits(ol.source.TileArcGISRest, ol.source.TileImage);
  
  
  /**
   * @private
   * @return {string} The key for the current params.
   */
  ol.source.TileArcGISRest.prototype.getKeyForParams_ = function() {
    var i = 0;
    var res = [];
    for (var key in this.params_) {
      res[i++] = key + '-' + this.params_[key];
    }
    return res.join('/');
  };
  
  
  /**
   * Get the user-provided params, i.e. those passed to the constructor through
   * the "params" option, and possibly updated using the updateParams method.
   * @return {Object} Params.
   * @api
   */
  ol.source.TileArcGISRest.prototype.getParams = function() {
    return this.params_;
  };
  
  
  /**
   * @param {ol.TileCoord} tileCoord Tile coordinate.
   * @param {ol.Size} tileSize Tile size.
   * @param {ol.Extent} tileExtent Tile extent.
   * @param {number} pixelRatio Pixel ratio.
   * @param {ol.proj.Projection} projection Projection.
   * @param {Object} params Params.
   * @return {string|undefined} Request URL.
   * @private
   */
  ol.source.TileArcGISRest.prototype.getRequestUrl_ = function(tileCoord, tileSize, tileExtent,
      pixelRatio, projection, params) {
  
    var urls = this.urls;
    if (!urls) {
      return undefined;
    }
  
    // ArcGIS Server only wants the numeric portion of the projection ID.
    var srid = projection.getCode().split(':').pop();
  
    params['SIZE'] = tileSize[0] + ',' + tileSize[1];
    params['BBOX'] = tileExtent.join(',');
    params['BBOXSR'] = srid;
    params['IMAGESR'] = srid;
    params['DPI'] = Math.round(
        params['DPI'] ? params['DPI'] * pixelRatio : 90 * pixelRatio
    );
  
    var url;
    if (urls.length == 1) {
      url = urls[0];
    } else {
      var index = ol.math.modulo(ol.tilecoord.hash(tileCoord), urls.length);
      url = urls[index];
    }
  
    var modifiedUrl = url
        .replace(/MapServer\/?$/, 'MapServer/export')
        .replace(/ImageServer\/?$/, 'ImageServer/exportImage');
    return ol.uri.appendParams(modifiedUrl, params);
  };
  
  
  /**
   * @inheritDoc
   */
  ol.source.TileArcGISRest.prototype.getTilePixelRatio = function(pixelRatio) {
    return /** @type {number} */ (pixelRatio);
  };
  
  
  /**
   * @inheritDoc
   */
  ol.source.TileArcGISRest.prototype.fixedTileUrlFunction = function(tileCoord, pixelRatio, projection) {
  
    var tileGrid = this.getTileGrid();
    if (!tileGrid) {
      tileGrid = this.getTileGridForProjection(projection);
    }
  
    if (tileGrid.getResolutions().length <= tileCoord[0]) {
      return undefined;
    }
  
    var tileExtent = tileGrid.getTileCoordExtent(
        tileCoord, this.tmpExtent_);
    var tileSize = ol.size.toSize(
        tileGrid.getTileSize(tileCoord[0]), this.tmpSize);
  
    if (pixelRatio != 1) {
      tileSize = ol.size.scale(tileSize, pixelRatio, this.tmpSize);
    }
  
    // Apply default params and override with user specified values.
    var baseParams = {
      'F': 'image',
      'FORMAT': 'PNG32',
      'TRANSPARENT': true
    };
    ol.obj.assign(baseParams, this.params_);
  
    return this.getRequestUrl_(tileCoord, tileSize, tileExtent,
        pixelRatio, projection, baseParams);
  };
  
  
  /**
   * Update the user-provided params.
   * @param {Object} params Params.
   * @api
   */
  ol.source.TileArcGISRest.prototype.updateParams = function(params) {
    ol.obj.assign(this.params_, params);
    this.setKey(this.getKeyForParams_());
  };
  