// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

/**
 * @fileoverview
 * Class to communicate with the Host components via Native Messaging.
 */

'use strict';

/** @suppress {duplicate} */
var remoting = remoting || {};

/**
 * @constructor
 */
remoting.HostNativeMessaging = function() {
  /**
   * @type {number}
   * @private
   */
  this.nextId_ = 0;

  /**
   * @type {Object.<number, remoting.HostNativeMessaging.PendingReply>}
   * @private
   */
  this.pendingReplies_ = {};

  /** @type {?chrome.extension.Port} @private */
  this.port_ = null;

  /** @type {string} @private */
  this.version_ = '';

  /** @type {Array.<remoting.HostController.Feature>} @private */
  this.supportedFeatures_ = [];
};

/**
 * Type used for entries of |pendingReplies_| list.
 *
 * @param {string} type Type of the originating request.
 * @param {?function(...):void} onDone The callback, if any, to be triggered
 *     on response. The actual parameters depend on the original request type.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @constructor
 */
remoting.HostNativeMessaging.PendingReply = function(type, onDone, onError) {
  this.type = type;
  this.onDone = onDone;
  this.onError = onError;
};

/**
 * Sets up connection to the Native Messaging host process and exchanges
 * 'hello' messages. If Native Messaging is not available or the host
 * process is not installed, this returns false to the callback.
 *
 * @param {function(): void} onDone Called after successful initialization.
 * @param {function(remoting.Error): void} onError Called if initialization
 *     failed.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.initialize = function(onDone, onError) {
  if (!chrome.runtime.connectNative) {
    console.log('Native Messaging API not available');
    onError(remoting.Error.UNEXPECTED);
    return;
  }

  // NativeMessaging API exists on Chrome 26.xxx but fails to notify
  // onDisconnect in the case where the Host components are not installed. Need
  // to blacklist these versions of Chrome.
  var majorVersion = navigator.appVersion.match('Chrome/(\\d+)\.')[1];
  if (!majorVersion || majorVersion <= 26) {
    console.log('Native Messaging not supported on this version of Chrome');
    onError(remoting.Error.UNEXPECTED);
    return;
  }

  try {
    this.port_ = chrome.runtime.connectNative(
        'com.google.chrome.remote_desktop');
    this.port_.onMessage.addListener(this.onIncomingMessage_.bind(this));
    this.port_.onDisconnect.addListener(this.onDisconnect_.bind(this));
    this.postMessage_({type: 'hello'}, onDone,
                      onError.bind(null, remoting.Error.UNEXPECTED));
  } catch (err) {
    console.log('Native Messaging initialization failed: ',
                /** @type {*} */ (err));
    onError(remoting.Error.UNEXPECTED);
    return;
  }
};

/**
 * Verifies that |object| is of type |type|, logging an error if not.
 *
 * @param {string} name Name of the object, to be included in the error log.
 * @param {*} object Object to test.
 * @param {string} type Expected type of the object.
 * @return {boolean} Result of test.
 */
function checkType_(name, object, type) {
  if (typeof(object) !== type) {
    console.error('NativeMessaging: "' + name + '" expected to be of type "' +
                  type + '", got: ' + object);
    return false;
  }
  return true;
}

/**
 * Returns |result| as an AsyncResult. If |result| is not valid, returns null
 * and logs an error.
 *
 * @param {*} result
 * @return {remoting.HostController.AsyncResult?} Converted result.
 */
function asAsyncResult_(result) {
  if (!checkType_('result', result, 'string')) {
    return null;
  }
  if (!remoting.HostController.AsyncResult.hasOwnProperty(result)) {
    console.error('NativeMessaging: unexpected result code: ', result);
    return null;
  }
  return remoting.HostController.AsyncResult[result];
}

/**
 * Returns |result| as a HostController.State. If |result| is not valid,
 * returns null and logs an error.
 *
 * @param {*} result
 * @return {remoting.HostController.State?} Converted result.
 */
function asHostState_(result) {
  if (!checkType_('result', result, 'string')) {
    return null;
  }
  if (!remoting.HostController.State.hasOwnProperty(result)) {
    console.error('NativeMessaging: unexpected result code: ', result);
    return null;
  }
  return remoting.HostController.State[result];
}

/**
 * @param {remoting.HostController.Feature} feature The feature to test for.
 * @return {boolean} True if the implementation supports the named feature.
 */
remoting.HostNativeMessaging.prototype.hasFeature = function(feature) {
  return this.supportedFeatures_.indexOf(feature) >= 0;
};

/**
 * Attaches a new ID to the supplied message, and posts it to the Native
 * Messaging port, adding |onDone| to the list of pending replies.
 * |message| should have its 'type' field set, and any other fields set
 * depending on the message type.
 *
 * @param {{type: string}} message The message to post.
 * @param {?function(...):void} onDone The callback, if any, to be triggered
 *     on response.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 * @private
 */
remoting.HostNativeMessaging.prototype.postMessage_ =
    function(message, onDone, onError) {
  var id = this.nextId_++;
  message['id'] = id;
  this.pendingReplies_[id] = new remoting.HostNativeMessaging.PendingReply(
    message.type + 'Response', onDone, onError);
  this.port_.postMessage(message);
};

/**
 * Handler for incoming Native Messages.
 *
 * @param {Object} message The received message.
 * @return {void} Nothing.
 * @private
 */
remoting.HostNativeMessaging.prototype.onIncomingMessage_ = function(message) {
  /** @type {number} */
  var id = message['id'];
  if (typeof(id) != 'number') {
    console.error('NativeMessaging: missing or non-numeric id');
    return;
  }
  var reply = this.pendingReplies_[id];
  if (!reply) {
    console.error('NativeMessaging: unexpected id: ', id);
    return;
  }
  delete this.pendingReplies_[id];

  var onDone = reply.onDone;
  var onError = reply.onError;

  /** @type {string} */
  var type = message['type'];
  if (!checkType_('type', type, 'string')) {
    onError(remoting.Error.UNEXPECTED);
    return;
  }
  if (type != reply.type) {
    console.error('NativeMessaging: expected reply type: ', reply.type,
                  ', got: ', type);
    onError(remoting.Error.UNEXPECTED);
    return;
  }

  switch (type) {
    case 'helloResponse':
      /** @type {string} */
      var version = message['version'];
      if (checkType_('version', version, 'string')) {
        this.version_ = version;
        if (message['supportedFeatures'] instanceof Array) {
          this.supportedFeatures_ = message['supportedFeatures'];
        } else {
          // Old versions of the native messaging host do not return this list.
          // Those versions don't support any new feature.
          this.supportedFeatures_ = [];
        }
        onDone();
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'getHostNameResponse':
      /** @type {*} */
      var hostname = message['hostname'];
      if (checkType_('hostname', hostname, 'string')) {
        onDone(hostname);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'getPinHashResponse':
      /** @type {*} */
      var hash = message['hash'];
      if (checkType_('hash', hash, 'string')) {
        onDone(hash);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'generateKeyPairResponse':
      /** @type {*} */
      var privateKey = message['privateKey'];
      /** @type {*} */
      var publicKey = message['publicKey'];
      if (checkType_('privateKey', privateKey, 'string') &&
          checkType_('publicKey', publicKey, 'string')) {
        onDone(privateKey, publicKey);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'updateDaemonConfigResponse':
      var result = asAsyncResult_(message['result']);
      if (result != null) {
        onDone(result);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'getDaemonConfigResponse':
      /** @type {*} */
      var config = message['config'];
      if (checkType_('config', config, 'object')) {
        onDone(config);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'getUsageStatsConsentResponse':
      /** @type {*} */
      var supported = message['supported'];
      /** @type {*} */
      var allowed = message['allowed'];
      /** @type {*} */
      var setByPolicy = message['setByPolicy'];
      if (checkType_('supported', supported, 'boolean') &&
          checkType_('allowed', allowed, 'boolean') &&
          checkType_('setByPolicy', setByPolicy, 'boolean')) {
        onDone(supported, allowed, setByPolicy);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'startDaemonResponse':
    case 'stopDaemonResponse':
      var result = asAsyncResult_(message['result']);
      if (result != null) {
        onDone(result);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'getDaemonStateResponse':
      var state = asHostState_(message['state']);
      if (state != null) {
        onDone(state);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'getPairedClientsResponse':
      var pairedClients = remoting.PairedClient.convertToPairedClientArray(
          message['pairedClients']);
      if (pairedClients != null) {
        onDone(pairedClients);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'clearPairedClientsResponse':
    case 'deletePairedClientResponse':
      /** @type {boolean} */
      var success = message['result'];
      if (checkType_('success', success, 'boolean')) {
        onDone(success);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'getHostClientIdResponse':
      /** @type {string} */
      var clientId = message['clientId'];
      if (checkType_('clientId', clientId, 'string')) {
        onDone(clientId);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    case 'getCredentialsFromAuthCodeResponse':
      /** @type {string} */
      var userEmail = message['userEmail'];
      /** @type {string} */
      var refreshToken = message['refreshToken'];
      if (checkType_('userEmail', userEmail, 'string') && userEmail &&
          checkType_('refreshToken', refreshToken, 'string') && refreshToken) {
        onDone(userEmail, refreshToken);
      } else {
        onError(remoting.Error.UNEXPECTED);
      }
      break;

    default:
      console.error('Unexpected native message: ', message);
      onError(remoting.Error.UNEXPECTED);
  }
};

/**
 * @return {void} Nothing.
 * @private
 */
remoting.HostNativeMessaging.prototype.onDisconnect_ = function() {
  console.error('Native Message port disconnected');

  // Notify the error-handlers of any requests that are still outstanding.
  for (var id in this.pendingReplies_) {
    this.pendingReplies_[/** @type {number} */(id)].onError(
        remoting.Error.UNEXPECTED);
  }
  this.pendingReplies_ = {};
}

/**
 * @param {function(string):void} onDone Callback to be called with the
 *     local hostname.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.getHostName =
    function(onDone, onError) {
  this.postMessage_({type: 'getHostName'}, onDone, onError);
};

/**
 * Calculates PIN hash value to be stored in the config, passing the resulting
 * hash value base64-encoded to the callback.
 *
 * @param {string} hostId The host ID.
 * @param {string} pin The PIN.
 * @param {function(string):void} onDone Callback.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.getPinHash =
    function(hostId, pin, onDone, onError) {
  this.postMessage_({
      type: 'getPinHash',
      hostId: hostId,
      pin: pin
  }, onDone, onError);
};

/**
 * Generates new key pair to use for the host. The specified callback is called
 * when the key is generated. The key is returned in format understood by the
 * host (PublicKeyInfo structure encoded with ASN.1 DER, and then BASE64).
 *
 * @param {function(string, string):void} onDone Callback.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.generateKeyPair =
    function(onDone, onError) {
  this.postMessage_({type: 'generateKeyPair'}, onDone, onError);
};

/**
 * Updates host config with the values specified in |config|. All
 * fields that are not specified in |config| remain
 * unchanged. Following parameters cannot be changed using this
 * function: host_id, xmpp_login. Error is returned if |config|
 * includes these parameters. Changes take effect before the callback
 * is called.
 *
 * @param {Object} config The new config parameters.
 * @param {function(remoting.HostController.AsyncResult):void} onDone
 *     Callback to be called when finished.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.updateDaemonConfig =
    function(config, onDone, onError) {
  this.postMessage_({
      type: 'updateDaemonConfig',
      config: config
  }, onDone, onError);
};

/**
 * Loads daemon config. The config is passed as a JSON formatted string to the
 * callback.
 *
 * @param {function(Object):void} onDone Callback.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.getDaemonConfig =
    function(onDone, onError) {
  this.postMessage_({type: 'getDaemonConfig'}, onDone, onError);
};

/**
 * Retrieves daemon version. The version is returned as a dotted decimal string
 * of the form major.minor.build.patch.
 * @return {string} The daemon version, or the empty string if not available.
 */
remoting.HostNativeMessaging.prototype.getDaemonVersion = function() {
  // Return the cached version from the 'hello' exchange.
  return this.version_;
};

/**
 * Get the user's consent to crash reporting. The consent flags are passed to
 * the callback as booleans: supported, allowed, set-by-policy.
 *
 * @param {function(boolean, boolean, boolean):void} onDone Callback.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.getUsageStatsConsent =
    function(onDone, onError) {
  this.postMessage_({type: 'getUsageStatsConsent'}, onDone, onError);
};

/**
 * Starts the daemon process with the specified configuration.
 *
 * @param {Object} config Host configuration.
 * @param {boolean} consent Consent to report crash dumps.
 * @param {function(remoting.HostController.AsyncResult):void} onDone
 *     Callback.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.startDaemon =
    function(config, consent, onDone, onError) {
  this.postMessage_({
      type: 'startDaemon',
      config: config,
      consent: consent
  }, onDone, onError);
};

/**
 * Stops the daemon process.
 *
 * @param {function(remoting.HostController.AsyncResult):void} onDone
 *     Callback.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.stopDaemon =
    function(onDone, onError) {
  this.postMessage_({type: 'stopDaemon'}, onDone, onError);
};

/**
 * Gets the installed/running state of the Host process.
 *
 * @param {function(remoting.HostController.State):void} onDone Callback.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.getDaemonState =
    function(onDone, onError) {
  this.postMessage_({type: 'getDaemonState'}, onDone, onError);
}

/**
 * Retrieves the list of paired clients.
 *
 * @param {function(Array.<remoting.PairedClient>):void} onDone Callback to be
 *     called with the result.
 * @param {function(remoting.Error):void} onError Callback to be triggered
 *     on error.
 */
remoting.HostNativeMessaging.prototype.getPairedClients =
    function(onDone, onError) {
  this.postMessage_({type: 'getPairedClients'}, onDone, onError);
}

/**
 * Clears all paired clients from the registry.
 *
 * @param {function(boolean):void} onDone Callback to be called when finished.
 * @param {function(remoting.Error):void} onError Callback to be triggered
 *     on error.
 */
remoting.HostNativeMessaging.prototype.clearPairedClients =
    function(onDone, onError) {
  this.postMessage_({type: 'clearPairedClients'}, onDone, onError);
}

/**
 * Deletes a paired client referenced by client id.
 *
 * @param {string} client Client to delete.
 * @param {function(boolean):void} onDone Callback to be called when finished.
 * @param {function(remoting.Error):void} onError Callback to be triggered
 *     on error.
 */
remoting.HostNativeMessaging.prototype.deletePairedClient =
    function(client, onDone, onError) {
  this.postMessage_({
    type: 'deletePairedClient',
    clientId: client
  }, onDone, onError);
}

/**
 * Gets the API keys to obtain/use service account credentials.
 *
 * @param {function(string):void} onDone Callback.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.getHostClientId =
    function(onDone, onError) {
  this.postMessage_({type: 'getHostClientId'}, onDone, onError);
};

/**
 *
 * @param {string} authorizationCode OAuth authorization code.
 * @param {function(string, string):void} onDone Callback.
 * @param {function(remoting.Error):void} onError The callback to be triggered
 *     on error.
 * @return {void} Nothing.
 */
remoting.HostNativeMessaging.prototype.getCredentialsFromAuthCode =
    function(authorizationCode, onDone, onError) {
  this.postMessage_({
    type: 'getCredentialsFromAuthCode',
    authorizationCode: authorizationCode
  }, onDone, onError);
};