// Copyright 2019 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.

import 'dart:async';
import 'dart:convert';
import 'dart:io';

import 'package:path/path.dart' as path;

import '../framework/framework.dart';
import '../framework/utils.dart';

final Directory _editedFlutterGalleryDir = dir(path.join(Directory.systemTemp.path, 'edited_flutter_gallery'));
final Directory flutterGalleryDir = dir(path.join(flutterDirectory.path, 'examples/flutter_gallery'));

TaskFunction createWebDevModeTest() {
  return () async {
    final List<String> options = <String>[
      '--hot', '-d', 'web', '--verbose', '--resident', '--target=lib/main.dart',
    ];
    setLocalEngineOptionIfNecessary(options);
    int hotRestartCount = 0;
    await inDirectory<void>(flutterDirectory, () async {
      rmTree(_editedFlutterGalleryDir);
      mkdirs(_editedFlutterGalleryDir);
      recursiveCopy(flutterGalleryDir, _editedFlutterGalleryDir);
      await inDirectory<void>(_editedFlutterGalleryDir, () async {
        {
          final Process packagesGet = await startProcess(
              path.join(flutterDirectory.path, 'bin', 'flutter'),
              <String>['packages', 'get'],
              environment: <String, String>{
                'FLUTTER_WEB': 'true',
              },
          );
          await packagesGet.exitCode;
          final Process process = await startProcess(
              path.join(flutterDirectory.path, 'bin', 'flutter'),
              <String>['run']..addAll(options),
              environment: <String, String>{
                'FLUTTER_WEB': 'true',
              },
          );

          final Completer<void> stdoutDone = Completer<void>();
          final Completer<void> stderrDone = Completer<void>();
          process.stdout
              .transform<String>(utf8.decoder)
              .transform<String>(const LineSplitter())
              .listen((String line) {
            if (line.contains('To hot restart')) {
              process.stdin.write('R');
            }
            if (line.contains('Restarted')) {
              if (hotRestartCount == 0) {
                // Update the file and reload again.
                final File appDartSource = file(path.join(
                    _editedFlutterGalleryDir.path, 'lib/gallery/app.dart',
                ));
                appDartSource.writeAsStringSync(
                    appDartSource.readAsStringSync().replaceFirst(
                        "'Flutter Gallery'", "'Updated Flutter Gallery'",
                    )
                );
                process.stdin.writeln('R');
                ++hotRestartCount;
              } else {
                // Quit after second hot restart.
                process.stdin.writeln('q');
              }
            }
            print('stdout: $line');
          }, onDone: () {
            stdoutDone.complete();
          });
          process.stderr
              .transform<String>(utf8.decoder)
              .transform<String>(const LineSplitter())
              .listen((String line) {
            print('stderr: $line');
          }, onDone: () {
            stderrDone.complete();
          });

          await Future.wait<void>(<Future<void>>[
            stdoutDone.future,
            stderrDone.future,
          ]);
          await process.exitCode;

        }

        // Start `flutter run` again to make sure it loads from the previous
        // state. dev compilers loads up from previously compiled JavaScript.
        {
          final Process process = await startProcess(
              path.join(flutterDirectory.path, 'bin', 'flutter'),
              <String>['run']..addAll(options),
              environment: <String, String>{
                'FLUTTER_WEB': 'true',
              },
          );
          final Completer<void> stdoutDone = Completer<void>();
          final Completer<void> stderrDone = Completer<void>();
          process.stdout
              .transform<String>(utf8.decoder)
              .transform<String>(const LineSplitter())
              .listen((String line) {
            if (line.contains('To hot restart')) {
              process.stdin.write('R');
            }
            if (line.contains('Restarted')) {
              process.stdin.writeln('q');
            }
            print('stdout: $line');
          }, onDone: () {
            stdoutDone.complete();
          });
          process.stderr
              .transform<String>(utf8.decoder)
              .transform<String>(const LineSplitter())
              .listen((String line) {
            print('stderr: $line');
          }, onDone: () {
            stderrDone.complete();
          });

          await Future.wait<void>(<Future<void>>[
            stdoutDone.future,
            stderrDone.future,
          ]);
          await process.exitCode;
        }
      });
    });
    if (hotRestartCount != 1) {
      return TaskResult.failure(null);
    }
    return TaskResult.success(null);
  };
}