// Copyright (c) 2019, 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.
@OnPlatform({
  'windows': Skip('Directories cant be deleted while processes are still open'),
})
library;

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

import 'package:build_daemon/constants.dart';
import 'package:build_daemon/daemon.dart';
import 'package:build_daemon/src/fakes/fake_builder.dart';
import 'package:build_daemon/src/fakes/fake_change_provider.dart';
import 'package:test/test.dart';
import 'package:test_descriptor/test_descriptor.dart' as d;

import 'uuid.dart';

final defaultIdleTimeoutSec = defaultIdleTimeout.inSeconds;
void main() {
  final testDaemons = <Process>[];
  final testWorkspaces = <String>[];
  group('Daemon', () {
    setUp(() {
      testDaemons.clear();
      testWorkspaces.clear();
    });
    tearDown(() async {
      for (final testDaemon in testDaemons) {
        testDaemon.kill(ProcessSignal.sigkill);
      }
      for (final testWorkspace in testWorkspaces) {
        final workspace = Directory(daemonWorkspace(testWorkspace));
        if (workspace.existsSync()) {
          workspace.deleteSync(recursive: true);
        }
      }
    });
    test('can be stopped', () async {
      final workspace = randomWorkspace();
      testWorkspaces.add(workspace);
      final daemon = Daemon(workspace);
      await daemon.start(<String>{}, FakeDaemonBuilder(), FakeChangeProvider());
      expect(daemon.onDone, completes);
      await daemon.stop();
    });
    test('can run if no other daemon is running', () async {
      final workspace = randomWorkspace();
      final daemon = await _runDaemon(workspace);
      testDaemons.add(daemon);
      expect(await _statusOf(daemon), 'RUNNING');
    });
    test('shuts down if no client connects', () async {
      final workspace = randomWorkspace();
      final daemon = await _runDaemon(workspace, timeout: 1);
      testDaemons.add(daemon);
      expect(await daemon.exitCode, isNotNull);
    });
    test(
      'can not run if another daemon is running in the same workspace',
      () async {
        final workspace = randomWorkspace();
        testWorkspaces.add(workspace);
        final daemonOne = await _runDaemon(
          workspace,
          timeout: defaultIdleTimeoutSec * 2,
        );
        expect(await _statusOf(daemonOne, logPrefix: 'one'), 'RUNNING');
        final daemonTwo = await _runDaemon(workspace);
        testDaemons.addAll([daemonOne, daemonTwo]);
        expect(await _statusOf(daemonTwo, logPrefix: 'two'), 'ALREADY RUNNING');
      },
      timeout: const Timeout.factor(2),
    );
    test(
      'can run if another daemon is running in a different workspace',
      () async {
        final workspace1 = randomWorkspace();
        final workspace2 = randomWorkspace();
        testWorkspaces.addAll([workspace1, workspace2]);
        final daemonOne = await _runDaemon(workspace1);
        expect(await _statusOf(daemonOne), 'RUNNING');
        final daemonTwo = await _runDaemon(workspace2);
        testDaemons.addAll([daemonOne, daemonTwo]);
        expect(await _statusOf(daemonTwo), 'RUNNING');
      },
      timeout: const Timeout.factor(2),
    );
    test('can start two daemons at the same time', () async {
      final workspace = randomWorkspace();
      testWorkspaces.add(workspace);
      final daemonOne = await _runDaemon(workspace);
      expect(await _statusOf(daemonOne), 'RUNNING');
      final daemonTwo = await _runDaemon(workspace);
      expect(await _statusOf(daemonTwo), 'ALREADY RUNNING');
      testDaemons.addAll([daemonOne, daemonTwo]);
    }, timeout: const Timeout.factor(2));
    test('logs the version when running', () async {
      final workspace = randomWorkspace();
      testWorkspaces.add(workspace);
      final daemon = await _runDaemon(workspace);
      testDaemons.add(daemon);
      expect(await _statusOf(daemon), 'RUNNING');
      expect(await Daemon(workspace).runningVersion(), currentVersion);
    });
    test('does not set the current version if not running', () async {
      final workspace = randomWorkspace();
      testWorkspaces.add(workspace);
      expect(await Daemon(workspace).runningVersion(), null);
    });
    test('logs the options when running', () async {
      final workspace = randomWorkspace();
      testWorkspaces.add(workspace);
      final daemon = await _runDaemon(workspace);
      testDaemons.add(daemon);
      expect(await _statusOf(daemon), 'RUNNING');
      expect(
        (await Daemon(workspace).currentOptions()).contains('foo'),
        isTrue,
      );
    });
    test('does not log the options if not running', () async {
      final workspace = randomWorkspace();
      testWorkspaces.add(workspace);
      expect((await Daemon(workspace).currentOptions()).isEmpty, isTrue);
    });
    test('cleans up after itself', () async {
      final workspace = randomWorkspace();
      testWorkspaces.add(workspace);
      final daemon = await _runDaemon(workspace);
      // Wait for the daemon to be running before checking the workspace exits.
      expect(await _statusOf(daemon), 'RUNNING');
      expect(Directory(daemonWorkspace(workspace)).existsSync(), isTrue);
      // Sending an interrupt signal will let the daemon gracefully exit.
      daemon.kill(ProcessSignal.sigint);
      await daemon.exitCode;
      expect(Directory(daemonWorkspace(workspace)).existsSync(), isFalse);
    });
    test('daemon stops after file changes stream has error', () async {
      final workspace = randomWorkspace();
      testWorkspaces.add(workspace);
      final daemon = await _runDaemon(
        workspace,
        errorChangeProviderAfterNSeconds: 1,
      );
      expect(await _statusOf(daemon), 'RUNNING');
      await daemon.exitCode;
      expect(Directory(daemonWorkspace(workspace)).existsSync(), isFalse);
    });
    test('daemon stops after file changes stream is closed', () async {
      final workspace = randomWorkspace();
      testWorkspaces.add(workspace);
      final daemon = await _runDaemon(
        workspace,
        closeChangeProviderAfterNSeconds: 1,
      );
      expect(await _statusOf(daemon), 'RUNNING');
      await daemon.exitCode;
      expect(Directory(daemonWorkspace(workspace)).existsSync(), isFalse);
    });
  });
}

/// Returns the daemon status.
Future<String> _statusOf(Process daemon, {String logPrefix = ''}) async {
  final statusCompleter = Completer<String>();
  daemon.stdout.transform(utf8.decoder).transform(const LineSplitter()).listen((
    line,
  ) {
    print('$logPrefix [STDOUT] $line');
    if (!statusCompleter.isCompleted &&
        (line == 'RUNNING' || line == 'ALREADY RUNNING')) {
      statusCompleter.complete(line);
    }
  });
  daemon.stderr.transform(utf8.decoder).transform(const LineSplitter()).listen((
    line,
  ) {
    print('$logPrefix [STDERR] $line');
  });
  return statusCompleter.future;
}

Future<Process> _runDaemon(
  String workspace, {
  int timeout = -1,
  int errorChangeProviderAfterNSeconds = -1,
  int closeChangeProviderAfterNSeconds = -1,
}) async {
  timeout = timeout > 0 ? timeout : defaultIdleTimeoutSec;
  await d.file('test.dart', '''
    import 'package:build_daemon/daemon.dart';
    import 'package:build_daemon/daemon_builder.dart';
    import 'package:build_daemon/client.dart';
    import 'package:build_daemon/src/fakes/fake_builder.dart';
    import 'package:build_daemon/src/fakes/fake_change_provider.dart';
    main() async {
      var options = ['foo'].toSet();
      var timeout = Duration(seconds: $timeout);
      var daemon = Daemon('$workspace');
      var changeProvider = FakeChangeProvider();
      if(daemon.hasLock) {
        await daemon.start(
          options,
          FakeDaemonBuilder(),
          changeProvider,
          timeout: timeout);
        // Real implementations of the daemon usually have
        // non-trivial set up time.
        await Future.delayed(Duration(seconds: 1));
        print('RUNNING');
        if ($errorChangeProviderAfterNSeconds > 0) {
          Future.delayed(Duration(seconds: $errorChangeProviderAfterNSeconds),
            () {
              changeProvider.changeStreamController.addError('ERROR');
            });
        }
        if ($closeChangeProviderAfterNSeconds > 0) {
          Future.delayed(Duration(seconds: $closeChangeProviderAfterNSeconds),
            () {
              changeProvider.changeStreamController.close();
            });
        }
      }else{
        // Mimic the behavior of actual daemon implementations.
        var version = await daemon.runningVersion();
        if(version != '$currentVersion') throw VersionSkew();
        print('ALREADY RUNNING');
      }
    }
      ''').create();
  final args = [
    ...Platform.executableArguments,
    if (!Platform.executableArguments.any(
      (arg) => arg.startsWith('--packages'),
    ))
      '--packages=${(await Isolate.packageConfig)!.path}',
    'test.dart',
  ];
  final process = await Process.start(
    Platform.resolvedExecutable,
    args,
    workingDirectory: d.sandbox,
  );
  return process;
}