// Copyright 2016 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 '../application_package.dart';
import '../base/common.dart';
import '../base/file_system.dart';
import '../base/process.dart';
import '../cache.dart';
import '../dart/package_map.dart';
import '../dart/sdk.dart';
import '../device.dart';
import '../globals.dart';
import '../resident_runner.dart';
import 'run.dart';

/// Runs integration (a.k.a. end-to-end) tests.
///
/// An integration test is a program that runs in a separate process from your
/// Flutter application. It connects to the application and acts like a user,
/// performing taps, scrolls, reading out widget properties and verifying their
/// correctness.
///
/// This command takes a target Flutter application that you would like to test
/// as the `--target` option (defaults to `lib/main.dart`). It then looks for a
/// corresponding test file within the `test_driver` directory. The test file is
/// expected to have the same name but contain the `_test.dart` suffix. The
/// `_test.dart` file would generally be a Dart program that uses
/// `package:flutter_driver` and exercises your application. Most commonly it
/// is a test written using `package:test`, but you are free to use something
/// else.
///
/// The app and the test are launched simultaneously. Once the test completes
/// the application is stopped and the command exits. If all these steps are
/// successful the exit code will be `0`. Otherwise, you will see a non-zero
/// exit code.
class DriveCommand extends RunCommandBase {
  DriveCommand() {
    requiresPubspecYaml();

    argParser
      ..addFlag('keep-app-running',
        defaultsTo: null,
        help: 'Will keep the Flutter application running when done testing.\n'
              'By default, "flutter drive" stops the application after tests are finished,\n'
              'and --keep-app-running overrides this. On the other hand, if --use-existing-app\n'
              'is specified, then "flutter drive" instead defaults to leaving the application\n'
              'running, and --no-keep-app-running overrides it.',
      )
      ..addOption('use-existing-app',
        help: 'Connect to an already running instance via the given observatory URL.\n'
              'If this option is given, the application will not be automatically started,\n'
              'and it will only be stopped if --no-keep-app-running is explicitly set.',
        valueHelp: 'url',
      )
      ..addOption('driver',
        help: 'The test file to run on the host (as opposed to the target file to run on\n'
              'the device). By default, this file has the same base name as the target\n'
              'file, but in the "test_driver/" directory instead, and with "_test" inserted\n'
              'just before the extension, so e.g. if the target is "lib/main.dart", the\n'
              'driver will be "test_driver/main_test.dart".',
        valueHelp: 'path',
      )
      ..addFlag('preview-dart-2',
        defaultsTo: true,
        help: 'Preview Dart 2.0 functionality.');
  }

  @override
  final String name = 'drive';

  @override
  final String description = 'Runs Flutter Driver tests for the current project.';

  @override
  final List<String> aliases = <String>['driver'];

  Device _device;
  Device get device => _device;

  /// Subscription to log messages printed on the device or simulator.
  // ignore: cancel_subscriptions
  StreamSubscription<String> _deviceLogSubscription;

  @override
  Future<Null> runCommand() async {
    final String testFile = _getTestFile();
    if (testFile == null)
      throwToolExit(null);

    _device = await targetDeviceFinder();
    if (device == null)
      throwToolExit(null);

    if (await fs.type(testFile) != FileSystemEntityType.FILE)
      throwToolExit('Test file not found: $testFile');

    String observatoryUri;
    if (argResults['use-existing-app'] == null) {
      printStatus('Starting application: $targetFile');

      if (getBuildInfo().isRelease) {
        // This is because we need VM service to be able to drive the app.
        throwToolExit(
          'Flutter Driver does not support running in release mode.\n'
          '\n'
          'Use --profile mode for testing application performance.\n'
          'Use --debug (default) mode for testing correctness (with assertions).'
        );
      }

      final LaunchResult result = await appStarter(this);
      if (result == null)
        throwToolExit('Application failed to start. Will not run test. Quitting.', exitCode: 1);
      observatoryUri = result.observatoryUri.toString();
    } else {
      printStatus('Will connect to already running application instance.');
      observatoryUri = argResults['use-existing-app'];
    }

    Cache.releaseLockEarly();

    try {
      await testRunner(<String>[testFile], observatoryUri, argResults['preview-dart-2']);
    } catch (error, stackTrace) {
      if (error is ToolExit)
        rethrow;
      throwToolExit('CAUGHT EXCEPTION: $error\n$stackTrace');
    } finally {
      if (argResults['keep-app-running'] ?? (argResults['use-existing-app'] != null)) {
        printStatus('Leaving the application running.');
      } else {
        printStatus('Stopping application instance.');
        await appStopper(this);
      }
    }
  }

  String _getTestFile() {
    if (argResults['driver'] != null)
      return argResults['driver'];

    // If the --driver argument wasn't provided, then derive the value from
    // the target file.
    String appFile = fs.path.normalize(targetFile);

    // This command extends `flutter run` and therefore CWD == package dir
    final String packageDir = fs.currentDirectory.path;

    // Make appFile path relative to package directory because we are looking
    // for the corresponding test file relative to it.
    if (!fs.path.isRelative(appFile)) {
      if (!fs.path.isWithin(packageDir, appFile)) {
        printError(
          'Application file $appFile is outside the package directory $packageDir'
        );
        return null;
      }

      appFile = fs.path.relative(appFile, from: packageDir);
    }

    final List<String> parts = fs.path.split(appFile);

    if (parts.length < 2) {
      printError(
        'Application file $appFile must reside in one of the sub-directories '
        'of the package structure, not in the root directory.'
      );
      return null;
    }

    // Look for the test file inside `test_driver/` matching the sub-path, e.g.
    // if the application is `lib/foo/bar.dart`, the test file is expected to
    // be `test_driver/foo/bar_test.dart`.
    final String pathWithNoExtension = fs.path.withoutExtension(fs.path.joinAll(
      <String>[packageDir, 'test_driver']..addAll(parts.skip(1))));
    return '${pathWithNoExtension}_test${fs.path.extension(appFile)}';
  }
}

/// Finds a device to test on. May launch a simulator, if necessary.
typedef Future<Device> TargetDeviceFinder();
TargetDeviceFinder targetDeviceFinder = findTargetDevice;
void restoreTargetDeviceFinder() {
  targetDeviceFinder = findTargetDevice;
}

Future<Device> findTargetDevice() async {
  final List<Device> devices = await deviceManager.getDevices().toList();

  if (deviceManager.hasSpecifiedDeviceId) {
    if (devices.isEmpty) {
      printStatus("No devices found with name or id matching '${deviceManager.specifiedDeviceId}'");
      return null;
    }
    if (devices.length > 1) {
      printStatus("Found ${devices.length} devices with name or id matching '${deviceManager.specifiedDeviceId}':");
      await Device.printDevices(devices);
      return null;
    }
    return devices.first;
  }

  if (devices.isEmpty) {
    printError('No devices found.');
    return null;
  } else if (devices.length > 1) {
    printStatus('Found multiple connected devices:');
    printStatus(devices.map((Device d) => '  - ${d.name}\n').join(''));
  }
  printStatus('Using device ${devices.first.name}.');
  return devices.first;
}

/// Starts the application on the device given command configuration.
typedef Future<LaunchResult> AppStarter(DriveCommand command);

AppStarter appStarter = _startApp; // (mutable for testing)
void restoreAppStarter() {
  appStarter = _startApp;
}

Future<LaunchResult> _startApp(DriveCommand command) async {
  final String mainPath = findMainDartFile(command.targetFile);
  if (await fs.type(mainPath) != FileSystemEntityType.FILE) {
    printError('Tried to run $mainPath, but that file does not exist.');
    return null;
  }

  printTrace('Stopping previously running application, if any.');
  await appStopper(command);

  printTrace('Installing application package.');
  final ApplicationPackage package = await command.applicationPackages
      .getPackageForPlatform(await command.device.targetPlatform);
  if (await command.device.isAppInstalled(package))
    await command.device.uninstallApp(package);
  await command.device.installApp(package);

  final Map<String, dynamic> platformArgs = <String, dynamic>{};
  if (command.traceStartup)
    platformArgs['trace-startup'] = command.traceStartup;

  printTrace('Starting application.');

  // Forward device log messages to the terminal window running the "drive" command.
  command._deviceLogSubscription = command
      .device
      .getLogReader(app: package)
      .logLines
      .listen(printStatus);

  final LaunchResult result = await command.device.startApp(
    package,
    mainPath: mainPath,
    route: command.route,
    debuggingOptions: new DebuggingOptions.enabled(
      command.getBuildInfo(),
      startPaused: true,
      observatoryPort: command.observatoryPort,
    ),
    platformArgs: platformArgs,
    usesTerminalUi: false,
  );

  if (!result.started) {
    await command._deviceLogSubscription.cancel();
    return null;
  }

  return result;
}

/// Runs driver tests.
typedef Future<Null> TestRunner(List<String> testArgs, String observatoryUri, bool previewDart2);
TestRunner testRunner = _runTests;
void restoreTestRunner() {
  testRunner = _runTests;
}

Future<Null> _runTests(List<String> testArgs, String observatoryUri, bool previewDart2) async {
  printTrace('Running driver tests.');

  PackageMap.globalPackagesPath = fs.path.normalize(fs.path.absolute(PackageMap.globalPackagesPath));
  final List<String> args = testArgs.toList()
    ..add('--packages=${PackageMap.globalPackagesPath}')
    ..add('-rexpanded');
  if (previewDart2) {
    args.add('--preview-dart-2');
  } else {
    args.add('--no-preview-dart-2');
  }

  final String dartVmPath = fs.path.join(dartSdkPath, 'bin', 'dart');
  final int result = await runCommandAndStreamOutput(
    <String>[dartVmPath]..addAll(dartVmFlags)..addAll(args),
    environment: <String, String>{ 'VM_SERVICE_URL': observatoryUri }
  );
  if (result != 0)
    throwToolExit('Driver tests failed: $result', exitCode: result);
}


/// Stops the application.
typedef Future<bool> AppStopper(DriveCommand command);
AppStopper appStopper = _stopApp;
void restoreAppStopper() {
  appStopper = _stopApp;
}

Future<bool> _stopApp(DriveCommand command) async {
  printTrace('Stopping application.');
  final ApplicationPackage package = await command.applicationPackages.getPackageForPlatform(await command.device.targetPlatform);
  final bool stopped = await command.device.stopApp(package);
  await command._deviceLogSubscription?.cancel();
  return stopped;
}