// Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// @assertion Future<RawSocketEvent> elementAt(int index)
/// Returns the value of the indexth data event of this stream.
/// . .  .
/// If a done event occurs before the value is found, the future completes with
/// a RangeError.
///
/// @description Checks that if a done event occurs before the value is found,
/// the future completes with a RangeError.
/// @author ngl@unipro.ru

import "dart:async";
import "dart:io";
import "../http_utils.dart";
import "../../../Utils/expect.dart";

var localhost = InternetAddress.loopbackIPv4;

Future<dynamic> checkElementAt(int index) async {
  RawDatagramSocket producer = await RawDatagramSocket.bind(localhost, 0);
  RawDatagramSocket receiver = await RawDatagramSocket.bind(localhost, 0);
  List<List<int>> toSend = [[0, 1, 2, 3], [1, 2, 3]];
  List<RawSocketEvent> received = [];
  Completer<dynamic> completer = new Completer<dynamic>();
  Future<dynamic> f = completer.future;
  Duration delay = const Duration(seconds: 2);

  bool wasSent = await sendDatagram(producer, toSend, localhost, receiver.port);
  Expect.isTrue(wasSent, "No datagram was sent");

  Stream bcs = receiver.asBroadcastStream();
  Future fValue = bcs.elementAt(index);

  fValue.then((value) {
    if (!completer.isCompleted) {
      completer.complete(value);
    }
    return f;
  }).catchError((e) {
    if (!completer.isCompleted) {
      completer.complete(e);
    }
  });

  bcs.listen((event) {
    received.add(event);
    receiver.receive();
  });

  new Future.delayed(delay, () {
    if (!completer.isCompleted) {
      receiver.close();
    }
  });

  return f;
}

main() async {
  int attempts = 5;

  check(int index) async {
    for (int i = 0; i < attempts; i++) {
      dynamic value = await checkElementAt(index);
      if (value is RangeError) {
        break;
      }
      if (i == attempts - 1) {
        print('$value element not found. Look like test failed.');
      }
    }
  }

  await check(4);
  await check(50);
  await check(100);
}