// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:async';

import 'package:fidl/fidl.dart' show InterfaceRequest;
import 'package:fidl_fidl_test_compatibility/fidl_async.dart';
import 'package:fidl_fuchsia_sys/fidl_async.dart';
import 'package:fuchsia_services/services.dart';

class EchoImpl extends Echo {
  final StartupContext _context;

  final _binding = EchoBinding();
  final _echoEventStreamController = StreamController<Struct>();

  // Saves references to proxies from which we're expecting events.
  Map<String, EchoProxy> proxies = {};

  EchoImpl(this._context);

  void bind(InterfaceRequest<Echo> request) {
    _binding.bind(this, request);
  }

  Future<Echo> proxy(String url) async {
    assert(url.isNotEmpty);
    final incoming = Incoming();
    final launchInfo = LaunchInfo(
        url: url, directoryRequest: incoming.request().passChannel());
    final controller = ComponentControllerProxy();
    final launcher = LauncherProxy();
    _context.incoming.connectToService(launcher);
    await launcher.createComponent(launchInfo, controller.ctrl.request());
    final echo = EchoProxy();
    incoming.connectToService(echo);
    return echo;
  }

  @override
  Future<Struct> echoStruct(Struct value, String forwardToServer) async {
    if (forwardToServer != null && forwardToServer.isNotEmpty) {
      return (await proxy(forwardToServer)).echoStruct(value, '');
    }
    return value;
  }

  void _handleEchoEvent(Struct value, String serverUrl) {
    _echoEventStreamController.add(value);
    // Not technically safe if there's more than one outstanding event on this
    // proxy, but that shouldn't happen in the existing test.
    proxies.remove(serverUrl);
  }

  @override
  Future<void> echoStructNoRetVal(Struct value, String forwardToServer) async {
    if (forwardToServer != null && forwardToServer.isNotEmpty) {
      final echo = await proxy(forwardToServer);
      // Keep echo around until we process the expected event.
      proxies[forwardToServer] = echo;
      echo.echoEvent.listen((Struct val) {
        _handleEchoEvent(val, forwardToServer);
      });
      return echo.echoStructNoRetVal(value, '');
    }
    return _echoEventStreamController.add(value);
  }

  @override
  Stream<Struct> get echoEvent => _echoEventStreamController.stream;

  @override
  Future<ArraysStruct> echoArrays(
      ArraysStruct value, String forwardToServer) async {
    if (forwardToServer != null && forwardToServer.isNotEmpty) {
      return (await proxy(forwardToServer)).echoArrays(value, '');
    }
    return value;
  }

  @override
  Future<VectorsStruct> echoVectors(
      VectorsStruct value, String forwardToServer) async {
    if (forwardToServer != null && forwardToServer.isNotEmpty) {
      return (await proxy(forwardToServer)).echoVectors(value, '');
    }
    return value;
  }

  @override
  Future<AllTypesTable> echoTable(
      AllTypesTable value, String forwardToServer) async {
    if (forwardToServer != null && forwardToServer.isNotEmpty) {
      return (await proxy(forwardToServer)).echoTable(value, '');
    }
    return value;
  }

  @override
  Future<List<AllTypesXunion>> echoXunions(
      List<AllTypesXunion> value, String forwardToServer) async {
    if (forwardToServer != null && forwardToServer.isNotEmpty) {
      return (await proxy(forwardToServer)).echoXunions(value, '');
    }
    return value;
  }
}

void main(List<String> args) {
  final StartupContext context = StartupContext.fromStartupInfo();
  final EchoImpl echoImpl = EchoImpl(context);
  context.outgoing.addPublicService(echoImpl.bind, Echo.$serviceName);
}