// Copyright 2024 The Flutter Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file or at https://developers.google.com/open-source/licenses/bsd.

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

import 'package:devtools_tool/license_utils.dart';
import 'package:path/path.dart' as p;
import 'package:test/test.dart';

import '../../packages/devtools_shared/test/helpers/helpers.dart';

const licenseText1 = '''// This is some 2015 multiline license
// text that should be removed from the file.
''';

const licenseText2 = '''/* This is other 1999 multiline license
text that should be removed from the file. */
''';

const licenseText3 = '''# This is more 2001 multiline license
# text that should be removed from the file.
''';

const licenseText4 = '''// This is some multiline license text to
// remove that does not contain a stored value.
''';

const extraText = '''

This is just some extra text to fill in the
contents following the license text in the test files.

It really doesn't matter what the text says.''';

late Directory testDirectory;

late File configFile;

late Directory repoRoot;
late File hiddenFile;
late File testFile1;
late File testFile2;
late File testFile3;
late File testFile4;
late File testFile5;
late File testFile6;
late File testFile7;
late File testFile8;
late File testFile9;
late File testFile10;
late File excludeFile1;
late File excludeFile2;

void main() {
  group('config file tests', () {
    setUp(() async {
      await _setupTestDirectoryStructure();
      await _setupTestConfigFile();
    });

    tearDownAll(() async {
      await deleteDirectoryWithRetry(testDirectory);
    });

    test('config can be read from disk without any errors', () {
      expect(() => LicenseConfig.fromYamlFile(configFile), returnsNormally);
    });

    test('remove licenses text is parsed correctly', () {
      final config = LicenseConfig.fromYamlFile(configFile);

      expect(config.removeLicenses.length, equals(4));

      var expectedVal = '''// This is some <value1> multiline license
// text that should be removed from the file.
''';
      expect(config.removeLicenses[0], equals(expectedVal));

      expectedVal = '''/* This is other <value2> multiline license
text that should be removed from the file. */
''';
      expect(config.removeLicenses[1], equals(expectedVal));

      expectedVal = '''# This is more <value3> multiline license
# text that should be removed from the file.
''';
      expect(config.removeLicenses[2], equals(expectedVal));

      expectedVal = '''// This is some multiline license text to
// remove that does not contain a stored value.
''';
      expect(config.removeLicenses[3], equals(expectedVal));
    });

    test('add licenses text is parsed correctly', () {
      final config = LicenseConfig.fromYamlFile(configFile);

      expect(config.addLicenses.length, equals(3));

      var expectedVal = '''// This is some <value1> multiline license
// text that should be added to the file.
''';
      expect(config.addLicenses[0], equals(expectedVal));

      expectedVal = '''# This is other <value3> multiline license
# text that should be added to the file.
''';
      expect(config.addLicenses[1], equals(expectedVal));

      expectedVal = '''// This is some multiline license text to
// add that does not contain a stored value.
''';
      expect(config.addLicenses[2], equals(expectedVal));
    });

    test('file types parsed correctly', () {
      final config = LicenseConfig.fromYamlFile(configFile);

      var removeIndices = config.getRemoveIndicesForExtension('ext1');
      expect(removeIndices.length, equals(2));
      expect(removeIndices[0], equals(0));
      expect(removeIndices[1], equals(1));

      var addIndex = config.getAddIndexForExtension('ext1');
      expect(addIndex, equals(0));

      removeIndices = config.getRemoveIndicesForExtension('ext2');
      expect(removeIndices.length, equals(1));
      expect(removeIndices[0], equals(2));

      addIndex = config.getAddIndexForExtension('ext2');
      expect(addIndex, equals(1));
    });

    test("included files shouldn't be excluded", () {
      final config = LicenseConfig.fromYamlFile(configFile);
      expect(config.shouldExclude(testFile1), false);
      expect(config.shouldExclude(testFile2), false);
      expect(config.shouldExclude(testFile3), false);
      expect(config.shouldExclude(testFile7), false);
      expect(config.shouldExclude(testFile8), false);
      expect(config.shouldExclude(testFile9), false);
      expect(config.shouldExclude(testFile10), false);
    });

    test('excluded files should be excluded', () {
      final config = LicenseConfig.fromYamlFile(configFile);
      expect(config.shouldExclude(excludeFile1), true);
      expect(config.shouldExclude(excludeFile2), true);
    });

    test('files in an excluded directory should be excluded', () {
      final config = LicenseConfig.fromYamlFile(configFile);
      expect(config.shouldExclude(testFile4), true);
      expect(config.shouldExclude(testFile5), true);
      expect(config.shouldExclude(testFile6), true);
    });

    test('files not in an included directory should be excluded', () {
      final config = LicenseConfig.fromYamlFile(configFile);

      final fileNotInTestDirectory = File('test.txt');
      expect(config.shouldExclude(fileNotInTestDirectory), true);
    });
  });

  group('license update tests', () {
    setUp(() async {
      await _setupTestDirectoryStructure();
    });

    tearDownAll(() async {
      await deleteDirectoryWithRetry(testDirectory);
    });

    test('default to the current year in replacement header', () async {
      const existingLicenseText = '''// This is some multiline license text to
// remove that does not contain a stored value.''';
      const replacementLicenseText =
          '''// This is some <value4> multiline license
// text that should be added to the file.''';

      final replacementInfo = await _getTestReplacementInfo(
        testFile: testFile10,
        existingLicenseText: existingLicenseText,
        replacementLicenseText: replacementLicenseText,
      );

      const expectedExistingHeader =
          '''// This is some multiline license text to
// remove that does not contain a stored value.''';

      // Note: There might be a potential failure case if the test is
      // run right when the year ends and a new year starts.
      final currentYear = DateTime.now().year.toString();
      final expectedReplacementHeader =
          '''// This is some $currentYear multiline license
// text that should be added to the file.''';

      expect(replacementInfo.existingHeader, equals(expectedExistingHeader));

      expect(
        replacementInfo.replacementHeader,
        equals(expectedReplacementHeader),
      );
    });

    test('stored value preserved in replacement header', () async {
      final testFiles = [testFile1, testFile2, testFile3];
      final existingLicenseTexts = [
        '''// This is some <value1> multiline license
// text that should be removed from the file.''',
        '''# This is more <value2> multiline license
# text that should be removed from the file.''',
        '''/* This is other <value3> multiline license
text that should be removed from the file. */''',
      ];
      final replacementLicenseTexts = [
        '''// This is some <value1> multiline license
// text that should be added to the file.''',
        '''# This is more <value2> multiline license
// text that should be added to the file.''',
        '''/* This is other <value3> multiline license
text that should be added to the file. */''',
      ];
      final expectedExistingHeaders = [
        '''// This is some 2015 multiline license
// text that should be removed from the file.''',
        '''# This is more 2001 multiline license
# text that should be removed from the file.''',
        '''/* This is other 1999 multiline license
text that should be removed from the file. */''',
      ];
      final expectedReplacementHeaders = [
        '''// This is some 2015 multiline license
// text that should be added to the file.''',
        '''# This is more 2001 multiline license
// text that should be added to the file.''',
        '''/* This is other 1999 multiline license
text that should be added to the file. */''',
      ];

      for (var i = 0; i < testFiles.length; i++) {
        final replacementInfo = await _getTestReplacementInfo(
          testFile: testFiles[i],
          existingLicenseText: existingLicenseTexts[i],
          replacementLicenseText: replacementLicenseTexts[i],
        );

        expect(
          replacementInfo.existingHeader,
          equals(expectedExistingHeaders[i]),
          reason: 'Failed on iteration $i',
        );

        expect(
          replacementInfo.replacementHeader,
          equals(expectedReplacementHeaders[i]),
          reason: 'Failed on iteration $i',
        );
      }
    });

    test('update skipped if license text not found', () async {
      var errorMessage = '';
      final header = LicenseHeader();
      try {
        await header.getReplacementInfo(
          file: testFile9,
          existingLicenseText: 'test',
          replacementLicenseText: 'test',
          byteCount: 50,
        );
      } on StateError catch (e) {
        errorMessage = e.toString();
      }
      expect(
        errorMessage,
        equals(
          'Bad state: License header expected in ${testFile9.path}, but not found!',
        ),
      );
    });

    test("update skipped if file can't be read", () async {
      var errorMessage = '';
      final header = LicenseHeader();
      try {
        await header.getReplacementInfo(
          file: File('bad.txt'),
          existingLicenseText: 'test',
          replacementLicenseText: 'test',
          byteCount: 50,
        );
      } on StateError catch (e) {
        errorMessage = e.toString();
      }
      expect(
        errorMessage,
        contains(
          'Bad state: License header expected, but error reading file - PathNotFoundException',
        ),
      );
    });

    test('license header can be rewritten on disk', () async {
      final header = LicenseHeader();
      const existingHeader = '''// This is some 2015 multiline license
// text that should be removed from the file.''';
      const replacementHeader = '''// This is some 2015 multiline license
// text that should be added to the file.''';
      final rewrittenFile = header.rewriteLicenseHeader(
        file: testFile1,
        existingHeader: existingHeader,
        replacementHeader: replacementHeader,
      );

      expect(rewrittenFile.lengthSync(), greaterThan(0));

      final existingContents = testFile1.readAsStringSync();
      expect(
        existingContents.substring(0, existingHeader.length),
        equals(existingHeader),
      );

      final rewrittenContents = rewrittenFile.readAsStringSync();
      expect(
        rewrittenContents.substring(0, replacementHeader.length),
        equals(replacementHeader),
      );

      expect(
        existingContents.substring(existingHeader.length + 1),
        equals(rewrittenContents.substring(replacementHeader.length + 1)),
      );
    });

    test('license headers can be updated in bulk', () async {
      await _setupTestConfigFile();
      final config = LicenseConfig.fromYamlFile(configFile);
      final header = LicenseHeader();

      final contentsBeforeUpdate = testFile1.readAsStringSync();
      final results = await header.bulkUpdate(
        directory: testDirectory,
        config: config,
      );
      final contentsAfterUpdate = testFile1.readAsStringSync();

      final includedPaths = results.includedPaths;
      expect(includedPaths, isNotNull);
      expect(includedPaths.length, equals(7));
      // Order is not guaranteed
      expect(includedPaths.contains(testFile1.path), true);
      expect(contentsBeforeUpdate, isNot(equals(contentsAfterUpdate)));
      expect(includedPaths.contains(testFile2.path), true);
      expect(includedPaths.contains(testFile3.path), true);
      expect(includedPaths.contains(testFile7.path), true);
      expect(includedPaths.contains(testFile8.path), true);
      expect(includedPaths.contains(testFile9.path), true);
      expect(includedPaths.contains(testFile10.path), true);

      final updatedPaths = results.updatedPaths;
      expect(updatedPaths, isNotNull);
      // testFile9 and testFile10 are intentionally misconfigured and so they
      // won't be updated even though they are on the include list.
      expect(updatedPaths.length, equals(5));
      // Order is not guaranteed
      expect(updatedPaths.contains(testFile1.path), true);
      expect(updatedPaths.contains(testFile2.path), true);
      expect(updatedPaths.contains(testFile3.path), true);
      expect(updatedPaths.contains(testFile7.path), true);
      expect(updatedPaths.contains(testFile8.path), true);
    });

    test('license headers bulk update can be dry run', () async {
      await _setupTestConfigFile();
      final config = LicenseConfig.fromYamlFile(configFile);
      final header = LicenseHeader();

      final contentsBeforeUpdate = testFile1.readAsStringSync();
      final results = await header.bulkUpdate(
        directory: testDirectory,
        config: config,
        dryRun: true,
      );
      final contentsAfterUpdate = testFile1.readAsStringSync();

      final updatedPaths = results.updatedPaths;
      expect(updatedPaths, isNotNull);
      expect(updatedPaths.length, equals(5));
      expect(updatedPaths.contains(testFile1.path), true);
      expect(contentsBeforeUpdate, equals(contentsAfterUpdate));
    });
  });

  test('repo wide check', () async {
    // This test is currently skipped because not all existing files
    // have had their license headers updated to the correct license text.
    // So this test will always fail. Set skip to false to run locally, but
    // don't commit the change to the repository.

    // TODO(mossmana): This test should stop being skipped only when it is safe to check just new files going forward.
    final rootPathMatcher = RegExp(r'(.*[/|\\]devtools[/|\\]).*');
    // TODO(mossmana): make this work on Google3
    expect(rootPathMatcher.hasMatch(Directory.current.path), true);
    final match = rootPathMatcher.firstMatch(Directory.current.path);
    final rootPath = match?.group(1);
    expect(rootPath, isNotNull);

    final failedPaths = <String>[];
    final subDirectories = ['packages', 'tool'];

    for (final subDirectory in subDirectories) {
      final checkedDirectory = Directory('$rootPath$subDirectory');
      expect(
        checkedDirectory.existsSync(),
        true,
        reason: '$checkedDirectory does not exist.',
      );
      final files =
          checkedDirectory.listSync(recursive: true).whereType<File>().toList();
      final header = LicenseHeader();
      const goodReplacementLicenseText =
          '''// Copyright <copyright_date> The Flutter Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file or at https://developers.google.com/open-source/licenses/bsd.''';
      for (final file in files) {
        final extension = p.extension(file.path);
        // Only check dart source files and exclude any files that are
        // downloaded as part of the flutter-sdk package dependencies.
        if (extension != '.dart' || file.path.contains('flutter-sdk')) {
          continue;
        }
        try {
          final replacementInfo = await header.getReplacementInfo(
            file: file,
            existingLicenseText: goodReplacementLicenseText,
            replacementLicenseText: '',
            byteCount: goodReplacementLicenseText.length,
          );
          if (replacementInfo.existingHeader.isEmpty ||
              replacementInfo.replacementHeader.isEmpty) {
            failedPaths.add(file.path);
          }
        } on StateError {
          failedPaths.add(file.path);
        }
      }
    }
    expect(
      failedPaths.isEmpty,
      true,
      reason:
          'License headers are incorrect for ${failedPaths.length} files: $failedPaths',
    );
  }, skip: true);
}

Future<({String existingHeader, String replacementHeader})>
_getTestReplacementInfo({
  required File testFile,
  required String existingLicenseText,
  required String replacementLicenseText,
}) async {
  final header = LicenseHeader();
  final bytes = utf8.encode(existingLicenseText);
  return await header.getReplacementInfo(
    file: testFile,
    existingLicenseText: existingLicenseText,
    replacementLicenseText: replacementLicenseText,
    byteCount: bytes.length + 1,
  );
}

/// Sets up the config file
Future<void> _setupTestConfigFile() async {
  configFile = File(p.join(testDirectory.path, 'test_config.yaml'))
    ..createSync(recursive: true);

  final contents = '''---
# sequence of license text strings that should be matched against at the top of a file and removed. <value>, which normally represents a date, will be stored.
remove_licenses:
  - |
    // This is some <value1> multiline license
    // text that should be removed from the file.
  - |
    /* This is other <value2> multiline license
    text that should be removed from the file. */
  - |
    # This is more <value3> multiline license
    # text that should be removed from the file.
  - |
    // This is some multiline license text to
    // remove that does not contain a stored value.
# sequence of license text strings that should be added to the top of a file. {value} will be replaced.
add_licenses: 
  - |
    // This is some <value1> multiline license
    // text that should be added to the file.
  - |
    # This is other <value3> multiline license
    # text that should be added to the file.
  - |
    // This is some multiline license text to
    // add that does not contain a stored value.
# defines which files should have license text added or updated.
update_paths:
  # path(s) to recursively check for files to remove/add license
  include:
      - ${testDirectory.path}/repo_root
  # path(s) to recursively check for files to ignore
  exclude:
    # exclude everything in the /repo_root/sub_dir1 directory
    - ${testDirectory.path}/repo_root/sub_dir1/
    # exclude the given files
    - ${testDirectory.path}/repo_root/sub_dir2/exclude1.ext1
    - ${testDirectory.path}/repo_root/sub_dir2/sub_dir3/exclude2.ext2
  file_types:
    # extension
    ext1:
      # one or more indices of remove_licenses to remove
      remove:
        - 0
        - 1
      # index of add_licenses to add
      add: 0
    ext2:
      remove:
        - 2
      add: 1''';

  configFile.writeAsStringSync(contents, flush: true);
}

/// Sets up the directory structure for the tests
/// repo_root/
///    test1.ext1
///    test2.ext2
///    .hidden/
///       test3.ext1
///    sub_dir1/
///       test4.ext1
///       sub_dir1a/
///          test5.ext2
///          sub_dir1b/
///             test6.ext1
///    sub_dir2/
///       exclude1.ext1
///       test7.ext2
///       sub_dir3/
///          test8.ext1
///          exclude2.ext2
///       sub_dir4/
///          test9.ext1
///          sub_dir5/
///            test10.ext2
///
Future<void> _setupTestDirectoryStructure() async {
  testDirectory = Directory.systemTemp.createTempSync();

  // Setup /repo_root directory structure
  repoRoot = Directory(p.joinAll([testDirectory.path, 'repo_root']))
    ..createSync(recursive: true);

  testFile1 = File(p.join(repoRoot.path, 'test1.ext1'))
    ..createSync(recursive: true);
  testFile1.writeAsStringSync(licenseText1 + extraText, flush: true);

  testFile2 = File(p.join(repoRoot.path, 'test2.ext2'))
    ..createSync(recursive: true);
  testFile2.writeAsStringSync(licenseText3 + extraText, flush: true);

  // Setup /repo_root/.hidden directory structure
  Directory(p.join(repoRoot.path, '.hidden')).createSync(recursive: true);

  testFile3 = File(p.join(repoRoot.path, '.hidden', 'test3.ext1'))
    ..createSync(recursive: true);
  testFile3.writeAsStringSync(licenseText2 + extraText, flush: true);

  // Setup /repo_root/sub_dir1/sub_dir1a/sub_dir1b directory structure
  Directory(
    p.join(repoRoot.path, 'sub_dir1', 'sub_dir1a', 'sub_dir1b'),
  ).createSync(recursive: true);

  testFile4 = File(p.join(repoRoot.path, 'sub_dir1', 'test4.ext1'))
    ..createSync(recursive: true);
  testFile4.writeAsStringSync(licenseText1 + extraText, flush: true);
  testFile5 = File(p.join(repoRoot.path, 'sub_dir1', 'sub_dir1a', 'test5.ext2'))
    ..createSync(recursive: true);
  testFile5.writeAsStringSync(licenseText3 + extraText, flush: true);
  testFile6 = File(
    p.join(repoRoot.path, 'sub_dir1', 'sub_dir1a', 'sub_dir1b', 'test6.ext2'),
  )..createSync(recursive: true);
  testFile6.writeAsStringSync(licenseText3 + extraText, flush: true);

  // Setup /repo_root/sub_dir2 directory structure
  Directory(p.join(repoRoot.path, 'sub_dir2')).createSync(recursive: true);

  excludeFile1 = File(p.join(repoRoot.path, 'sub_dir2', 'exclude1.ext1'))
    ..createSync(recursive: true);
  excludeFile1.writeAsStringSync(licenseText2 + extraText, flush: true);
  testFile7 = File(p.join(repoRoot.path, 'sub_dir2', 'test7.ext2'))
    ..createSync(recursive: true);
  testFile7.writeAsStringSync(licenseText3 + extraText, flush: true);

  // Setup /repo_root/sub_dir2/sub_dir3 directory structure
  Directory(
    p.join(repoRoot.path, 'sub_dir2', 'sub_dir3'),
  ).createSync(recursive: true);

  testFile8 = File(p.join(repoRoot.path, 'sub_dir2', 'sub_dir3', 'test8.ext1'))
    ..createSync(recursive: true);
  testFile8.writeAsStringSync(licenseText2 + extraText, flush: true);
  excludeFile2 = File(
    p.join(repoRoot.path, 'sub_dir2', 'sub_dir3', 'exclude2.ext2'),
  )..createSync(recursive: true);
  excludeFile2.writeAsStringSync(licenseText3 + extraText, flush: true);

  // Setup /repo_root/sub_dir2/sub_dir4 directory structure
  Directory(
    p.join(repoRoot.path, 'sub_dir2', 'sub_dir4'),
  ).createSync(recursive: true);

  testFile9 = File(p.join(repoRoot.path, 'sub_dir2', 'sub_dir4', 'test9.ext1'))
    ..createSync(recursive: true);
  testFile9.writeAsStringSync(extraText, flush: true);

  // Setup /repo_root/sub_dir2/sub_dir4/sub_dir5 directory structure
  Directory(
    p.join(repoRoot.path, 'sub_dir2', 'sub_dir4', 'sub_dir5'),
  ).createSync(recursive: true);

  testFile10 = File(
    p.join(repoRoot.path, 'sub_dir2', 'sub_dir4', 'sub_dir5', 'test10.ext2'),
  )..createSync(recursive: true);
  testFile10.writeAsStringSync(licenseText4 + extraText, flush: true);
}