/**
 * @license
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */

/**
 * @fileoverview Base OSAPI binding.
 * This file was copied from
 * http://svn.apache.org/repos/asf/shindig/trunk/features/src/main/javascript/features/shindig.container/osapi.js
 * and it's slightly modified for Closure.
 */

goog.provide('goog.osapi');


// Expose osapi from container side.
var osapi = osapi || {};
goog.exportSymbol('osapi', osapi);


/** @type {Function} */
osapi.callback;


/**
 * Dispatch a JSON-RPC batch request to services defined in the osapi namespace
 * @param {Array<Object>} requests an array of rpc requests.
 */
goog.osapi.handleGadgetRpcMethod = function(requests) {
  var responses = new Array(requests.length);
  var callCount = 0;
  var callback = osapi.callback;
  var dummy = function(params, apiCallback) {
    apiCallback({});
  };
  for (var i = 0; i < requests.length; i++) {
    // Don't allow underscores in any part of the method name as a
    // convention for restricted methods
    var current = osapi;
    if (requests[i]['method'].indexOf('_') == -1) {
      var path = requests[i]['method'].split('.');
      for (var j = 0; j < path.length; j++) {
        if (current.hasOwnProperty(path[j])) {
          current = current[path[j]];
        } else {
          // No matching api
          current = dummy;
          break;
        }
      }
    } else {
      current = dummy;
    }

    // Execute the call and latch the rpc callback until all
    // complete
    current(requests[i]['params'], function(i) {
      return function(response) {
        // Put back in json-rpc format
        responses[i] = {'id': requests[i].id, 'data': response};
        callCount++;
        if (callCount == requests.length) {
          callback(responses);
        }
      };
    }(i));
  }
};


/**
 * Initializes container side osapi binding.
 */
goog.osapi.init = function() {
   // Container-side binding for the gadgetsrpctransport used by osapi.
   // Containers add services to the client-side osapi implementation by
   // defining them in the osapi namespace
  if (gadgets && gadgets.rpc) { // Only define if gadgets rpc exists.
    // Register the osapi RPC dispatcher.
    gadgets.rpc.register('osapi._handleGadgetRpcMethod',
        /** @type {!Function} */ (goog.osapi.handleGadgetRpcMethod));
  }
};
