// Copyright 2014 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 'dart:io';

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

import '../check_code_samples.dart';
import '../utils.dart';
import 'common.dart';

void main() {
  late SampleChecker checker;
  late FileSystem fs;
  late Directory examples;
  late Directory packages;
  late Directory dartUIPath;
  late Directory flutterRoot;

  String getRelativePath(File file, [Directory? from]) {
    from ??= flutterRoot;
    return path.relative(file.absolute.path, from: flutterRoot.absolute.path);
  }

  void writeLink({required File source, required File example}) {
    source
      ..createSync(recursive: true)
      ..writeAsStringSync('''
/// Class documentation
///
/// {@tool dartpad}
/// Example description
///
/// ** See code in ${getRelativePath(example)} **
/// {@end-tool}
''');
  }

  void buildTestFiles({bool missingLinks = false, bool missingTests = false}) {
    final Directory examplesLib = examples.childDirectory('lib').childDirectory('layer')..createSync(recursive: true);
    final File fooExample = examplesLib.childFile('foo_example.0.dart')
      ..createSync(recursive: true)
      ..writeAsStringSync('// Example for foo');
    final File barExample = examplesLib.childFile('bar_example.0.dart')
      ..createSync(recursive: true)
      ..writeAsStringSync('// Example for bar');
    final File curvesExample =
        examples.childDirectory('lib').childDirectory('animation').childDirectory('curves').childFile('curve2_d.0.dart')
          ..createSync(recursive: true)
          ..writeAsStringSync('// Missing a test, but OK');
    if (missingLinks) {
      examplesLib.childFile('missing_example.0.dart')
        ..createSync(recursive: true)
        ..writeAsStringSync('// Example that is not linked');
    }
    final Directory examplesTests = examples.childDirectory('test').childDirectory('layer')
      ..createSync(recursive: true);
    examplesTests.childFile('foo_example.0_test.dart')
      ..createSync(recursive: true)
      ..writeAsStringSync('// test for foo example');
    if (!missingTests) {
      examplesTests.childFile('bar_example.0_test.dart')
        ..createSync(recursive: true)
        ..writeAsStringSync('// test for bar example');
    }
    if (missingLinks) {
      examplesTests.childFile('missing_example.0_test.dart')
        ..createSync(recursive: true)
        ..writeAsStringSync('// test for foo example');
    }
    final Directory flutterPackage = packages.childDirectory('flutter').childDirectory('lib').childDirectory('src')
      ..createSync(recursive: true);
    writeLink(source: flutterPackage.childDirectory('layer').childFile('foo.dart'), example: fooExample);
    writeLink(source: flutterPackage.childDirectory('layer').childFile('bar.dart'), example: barExample);
    writeLink(source: flutterPackage.childDirectory('animation').childFile('curves.dart'), example: curvesExample);
  }

  setUp(() {
    fs = MemoryFileSystem(style: Platform.isWindows ? FileSystemStyle.windows : FileSystemStyle.posix);
    // Get the root prefix of the current directory so that on Windows we get a
    // correct root prefix.
    flutterRoot = fs.directory(path.join(path.rootPrefix(fs.currentDirectory.absolute.path), 'flutter sdk'))..createSync(recursive: true);
    fs.currentDirectory = flutterRoot;
    examples = flutterRoot.childDirectory('examples').childDirectory('api')..createSync(recursive: true);
    packages = flutterRoot.childDirectory('packages')..createSync(recursive: true);
    dartUIPath = flutterRoot
        .childDirectory('bin')
        .childDirectory('cache')
        .childDirectory('pkg')
        .childDirectory('sky_engine')
        .childDirectory('lib')
      ..createSync(recursive: true);
    checker = SampleChecker(
      examples: examples,
      packages: packages,
      dartUIPath: dartUIPath,
      flutterRoot: flutterRoot,
      filesystem: fs,
    );
  });

  test('check_code_samples.dart - checkCodeSamples catches missing links', () async {
    buildTestFiles(missingLinks: true);
    bool? success;
    final String result = await capture(
      () async {
        success = checker.checkCodeSamples();
      },
      shouldHaveErrors: true,
    );
    final String lines = <String>[
      '╔═╡ERROR╞═══════════════════════════════════════════════════════════════════════',
      '║ The following examples are not linked from any source file API doc comments:',
      '║   examples/api/lib/layer/missing_example.0.dart',
      '║ Either link them to a source file API doc comment, or remove them.',
      '╚═══════════════════════════════════════════════════════════════════════════════',
    ].map((String line) {
      return line.replaceAll('/', Platform.isWindows ? r'\' : '/');
    }).join('\n');
    expect(result, equals('$lines\n'));
    expect(success, equals(false));
  });

  test('check_code_samples.dart - checkCodeSamples catches missing tests', () async {
    buildTestFiles(missingTests: true);
    bool? success;
    final String result = await capture(
      () async {
        success = checker.checkCodeSamples();
      },
      shouldHaveErrors: true,
    );
    final String lines = <String>[
      '╔═╡ERROR╞═══════════════════════════════════════════════════════════════════════',
      '║ The following example test files are missing:',
      '║   examples/api/test/layer/bar_example.0_test.dart',
      '╚═══════════════════════════════════════════════════════════════════════════════',
    ].map((String line) {
      return line.replaceAll('/', Platform.isWindows ? r'\' : '/');
    }).join('\n');
    expect(result, equals('$lines\n'));
    expect(success, equals(false));
  });

  test('check_code_samples.dart - checkCodeSamples succeeds', () async {
    buildTestFiles();
    bool? success;
    final String result = await capture(
      () async {
        success = checker.checkCodeSamples();
      },
    );
    expect(result, isEmpty);
    expect(success, equals(true));
  });
}

typedef AsyncVoidCallback = Future<void> Function();

Future<String> capture(AsyncVoidCallback callback, {bool shouldHaveErrors = false}) async {
  final StringBuffer buffer = StringBuffer();
  final PrintCallback oldPrint = print;
  try {
    print = (Object? line) {
      buffer.writeln(line);
    };
    await callback();
    expect(
      hasError,
      shouldHaveErrors,
      reason: buffer.isEmpty
          ? '(No output to report.)'
          : hasError
              ? 'Unexpected errors:\n$buffer'
              : 'Unexpected success:\n$buffer',
    );
  } finally {
    print = oldPrint;
    resetErrorStatus();
  }
  if (stdout.supportsAnsiEscapes) {
    // Remove ANSI escapes when this test is running on a terminal.
    return buffer.toString().replaceAll(RegExp(r'(\x9B|\x1B\[)[0-?]{1,3}[ -/]*[@-~]'), '');
  } else {
    return buffer.toString();
  }
}