// Copyright 2013 The Flutter 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 'package:file/file.dart';

import 'common/core.dart';
import 'common/output_utils.dart';
import 'common/package_looping_command.dart';
import 'common/plugin_utils.dart';
import 'common/pub_utils.dart';
import 'common/repository_package.dart';

const int _exitUnknownTestPlatform = 3;

enum _TestPlatform {
  // Must run in the command-line VM.
  vm,
  // Must run in a browser.
  browser,
}

/// A command to run Dart unit tests for packages.
class DartTestCommand extends PackageLoopingCommand {
  /// Creates an instance of the test command.
  DartTestCommand(
    super.packagesDir, {
    super.processRunner,
    super.platform,
  }) {
    argParser.addOption(
      kEnableExperiment,
      defaultsTo: '',
      help:
          'Runs Dart unit tests in Dart VM with the given experiments enabled. '
          'See https://github.com/dart-lang/sdk/blob/main/docs/process/experimental-flags.md '
          'for details.',
    );
    argParser.addOption(
      _platformFlag,
      help: 'Runs tests on the given platform instead of the default platform '
          '("vm" in most cases, "chrome" for web plugin implementations).',
    );
  }

  static const String _platformFlag = 'platform';

  @override
  final String name = 'dart-test';

  // TODO(stuartmorgan): Eventually remove 'test', which is a legacy name from
  // before there were other test commands that made it ambiguous. For now it's
  // an alias to avoid breaking people's workflows.
  @override
  List<String> get aliases => <String>['test', 'test-dart'];

  @override
  final String description = 'Runs the Dart tests for all packages.\n\n'
      'This command requires "flutter" to be in your path.';

  @override
  PackageLoopingType get packageLoopingType =>
      PackageLoopingType.includeAllSubpackages;

  @override
  Future<PackageResult> runForPackage(RepositoryPackage package) async {
    if (!package.testDirectory.existsSync()) {
      return PackageResult.skip('No test/ directory.');
    }

    String? platform = getNullableStringArg(_platformFlag);

    // Skip running plugin tests for non-web-supporting plugins (or non-web
    // federated plugin implementations) on web, since there's no reason to
    // expect them to work.
    final bool webPlatform = platform != null && platform != 'vm';
    final bool explicitVMPlatform = platform == 'vm';
    final bool isWebOnlyPluginImplementation = pluginSupportsPlatform(
            platformWeb, package,
            requiredMode: PlatformSupport.inline) &&
        package.directory.basename.endsWith('_web');
    if (webPlatform) {
      if (isFlutterPlugin(package) &&
          !pluginSupportsPlatform(platformWeb, package)) {
        return PackageResult.skip(
            "Non-web plugin tests don't need web testing.");
      }
      if (_testOnTarget(package) == _TestPlatform.vm) {
        // This explict skip is necessary because trying to run tests in a mode
        // that the package has opted out of returns a non-zero exit code.
        return PackageResult.skip('Package has opted out of non-vm testing.');
      }
    } else if (explicitVMPlatform) {
      if (isWebOnlyPluginImplementation) {
        return PackageResult.skip("Web plugin tests don't need vm testing.");
      }
      final _TestPlatform? target = _testOnTarget(package);
      if (target != null && _testOnTarget(package) != _TestPlatform.vm) {
        // This explict skip is necessary because trying to run tests in a mode
        // that the package has opted out of returns a non-zero exit code.
        return PackageResult.skip('Package has opted out of vm testing.');
      }
    } else if (platform == null && isWebOnlyPluginImplementation) {
      // If no explicit mode is requested, run web plugin implementations in
      // Chrome since their tests are not expected to work in vm mode. This
      // allows easily running all unit tests locally, without having to run
      // both modes.
      platform = 'chrome';
    }

    // All the web tests assume the html renderer currently.
    final String? webRenderer = (platform == 'chrome') ? 'html' : null;
    bool passed;
    if (package.requiresFlutter()) {
      passed = await _runFlutterTests(package,
          platform: platform, webRenderer: webRenderer);
    } else {
      passed = await _runDartTests(package, platform: platform);
    }
    return passed ? PackageResult.success() : PackageResult.fail();
  }

  /// Runs the Dart tests for a Flutter package, returning true on success.
  Future<bool> _runFlutterTests(RepositoryPackage package,
      {String? platform, String? webRenderer}) async {
    final String experiment = getStringArg(kEnableExperiment);

    final int exitCode = await processRunner.runAndStream(
      flutterCommand,
      <String>[
        'test',
        '--color',
        if (experiment.isNotEmpty) '--enable-experiment=$experiment',
        // Flutter defaults to VM mode (under a different name) and explicitly
        // setting it is deprecated, so pass nothing in that case.
        if (platform != null && platform != 'vm') '--platform=$platform',
        if (webRenderer != null) '--web-renderer=$webRenderer',
      ],
      workingDir: package.directory,
    );
    return exitCode == 0;
  }

  /// Runs the Dart tests for a non-Flutter package, returning true on success.
  Future<bool> _runDartTests(RepositoryPackage package,
      {String? platform}) async {
    // Unlike `flutter test`, `dart run test` does not automatically get
    // packages
    if (!await runPubGet(package, processRunner, super.platform)) {
      printError('Unable to fetch dependencies.');
      return false;
    }

    final String experiment = getStringArg(kEnableExperiment);

    final int exitCode = await processRunner.runAndStream(
      'dart',
      <String>[
        'run',
        if (experiment.isNotEmpty) '--enable-experiment=$experiment',
        'test',
        if (platform != null) '--platform=$platform',
      ],
      workingDir: package.directory,
    );

    return exitCode == 0;
  }

  /// Returns the required test environment, or null if none is specified.
  ///
  /// Throws if the target is not recognized.
  _TestPlatform? _testOnTarget(RepositoryPackage package) {
    final File testConfig = package.directory.childFile('dart_test.yaml');
    if (!testConfig.existsSync()) {
      return null;
    }
    final RegExp testOnRegex = RegExp(r'^test_on:\s*([a-z].*[a-z])\s*$');
    for (final String line in testConfig.readAsLinesSync()) {
      final RegExpMatch? match = testOnRegex.firstMatch(line);
      if (match != null) {
        final String targetFilter = match.group(1)!;
        // test_on lines can be very complex, but in pratice the packages in
        // this repo currently only need the ability to require vm or not, so a
        // simple one-target directive is all that's supported currently.
        // Making it deliberately strict avoids the possibility of accidentally
        // skipping vm coverage due to a complex expression that's not handled
        // correctly.
        switch (targetFilter) {
          case 'vm':
            return _TestPlatform.vm;
          case 'browser':
            return _TestPlatform.browser;
          default:
            printError('Unknown "test_on" value: "$targetFilter"\n'
                "If this value needs to be supported for this package's tests, "
                'please update the repository tooling to support more test_on '
                'modes.');
            throw ToolExit(_exitUnknownTestPlatform);
        }
      }
    }
    return null;
  }
}