<!DOCTYPE html>
<!--
Copyright (c) 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.
-->
<link rel="import" href="/base/base.html">
<script>

'use strict';

/**
 * Contains connection code that inspector's embedding framework calls on
 * tracing, and that tracing can use to talk to inspector.
 */
tr.exportTo('tr.e.about_tracing', function() {
  // Interface used by inspector when it hands data to us from the backend.
  window.DevToolsAPI = {
    setToolbarColors: function() { },
    addExtensions: function() { },
    setInspectedPageId: function() { },

    dispatchMessage: function(payload) {
      throw new Error('Should have been patched by InspectorConnection');
    }
  };
  // Temporary until inspector backend switches to DevToolsAPI.
  window.InspectorFrontendAPI = window.DevToolsAPI;

  /**
   * @constructor
   */
  function InspectorConnection() {
    if (InspectorConnection.instance)
      throw new Error('Singleton');

    this.nextRequestId_ = 1;
    this.pendingRequestResolversId_ = {};

    this.notificationListenersByMethodName_ = {};
    DevToolsAPI.dispatchMessage = this.dispatchMessage_.bind(this);
  }

  InspectorConnection.prototype = {
    req: function(method, params) {
      var id = this.nextRequestId_++;
      var msg = JSON.stringify({
        id: id,
        method: method,
        params: params
      });
      DevToolsHost.sendMessageToBackend(msg);

      return new Promise(function(resolve, reject) {
        this.pendingRequestResolversId_[id] = {
          resolve: resolve,
          reject: reject
        };
      }.bind(this));
    },

    setNotificationListener: function(method, listener) {
      this.notificationListenersByMethodName_[method] = listener;
    },

    dispatchMessage_: function(payload) {
      var isStringPayload = typeof payload === 'string';
      // Special handling for Tracing.dataCollected because it is high
      // bandwidth.
      var isDataCollectedMessage = isStringPayload ?
          payload.indexOf('"method": "Tracing.dataCollected"') !== -1 :
          payload.method === 'Tracing.dataCollected';
      if (isDataCollectedMessage) {
        var listener = this.notificationListenersByMethodName_[
            'Tracing.dataCollected'];
        if (listener) {
          // FIXME(loislo): trace viewer should be able to process
          // raw message object because string based version a few times
          // slower on the browser side.
          // see https://codereview.chromium.org/784513002.
          listener(isStringPayload ? payload : JSON.stringify(payload));
          return;
        }
      }

      var message = isStringPayload ? JSON.parse(payload) : payload;
      if (message.id) {
        var resolver = this.pendingRequestResolversId_[message.id];
        if (resolver === undefined) {
          console.log('Unrecognized ack', message);
          return;
        }
        if (message.error) {
          resolver.reject(message.error);
          return;
        }
        resolver.resolve(message.result);
        return;
      }

      if (message['method']) {
        var listener = this.notificationListenersByMethodName_[message.method];
        if (listener === undefined) {
          console.log('Unhandled ', message.method);
          return;
        }
        listener(message.params);
        return;
      }
      console.log('Unknown dispatchMessage: ', payload);
    }
  };

  if (window.DevToolsHost)
    InspectorConnection.instance = new InspectorConnection();
  else
    InspectorConnection.instance = undefined;

  return {
    InspectorConnection: InspectorConnection
  };
});
</script>