// 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 'dart:async';
import 'dart:convert';
import 'dart:io' as io;

import 'package:args/command_runner.dart';
import 'package:file/file.dart';
import 'package:file/memory.dart';
import 'package:flutter_plugin_tools/src/common/core.dart';
import 'package:flutter_plugin_tools/src/common/file_utils.dart';
import 'package:flutter_plugin_tools/src/common/plugin_utils.dart';
import 'package:flutter_plugin_tools/src/common/process_runner.dart';
import 'package:meta/meta.dart';
import 'package:path/path.dart' as p;
import 'package:platform/platform.dart';
import 'package:quiver/collection.dart';

import 'mocks.dart';

/// Returns the exe name that command will use when running Flutter on
/// [platform].
String getFlutterCommand(Platform platform) =>
    platform.isWindows ? 'flutter.bat' : 'flutter';

/// Creates a packages directory in the given location.
///
/// If [parentDir] is set the packages directory will be created there,
/// otherwise [fileSystem] must be provided and it will be created an arbitrary
/// location in that filesystem.
Directory createPackagesDirectory(
    {Directory? parentDir, FileSystem? fileSystem}) {
  assert(parentDir != null || fileSystem != null,
      'One of parentDir or fileSystem must be provided');
  assert(fileSystem == null || fileSystem is MemoryFileSystem,
      'If using a real filesystem, parentDir must be provided');
  final Directory packagesDir =
      (parentDir ?? fileSystem!.currentDirectory).childDirectory('packages');
  packagesDir.createSync();
  return packagesDir;
}

/// Details for platform support in a plugin.
@immutable
class PlatformDetails {
  const PlatformDetails(
    this.type, {
    this.hasNativeCode = true,
    this.hasDartCode = false,
  });

  /// The type of support for the platform.
  final PlatformSupport type;

  /// Whether or not the plugin includes native code.
  ///
  /// Ignored for web, which does not have native code.
  final bool hasNativeCode;

  /// Whether or not the plugin includes Dart code.
  ///
  /// Ignored for web, which always has native code.
  final bool hasDartCode;
}

/// Creates a plugin package with the given [name] in [packagesDirectory].
///
/// [platformSupport] is a map of platform string to the support details for
/// that platform.
///
/// [extraFiles] is an optional list of plugin-relative paths, using Posix
/// separators, of extra files to create in the plugin.
// TODO(stuartmorgan): Convert the return to a RepositoryPackage.
Directory createFakePlugin(
  String name,
  Directory parentDirectory, {
  List<String> examples = const <String>['example'],
  List<String> extraFiles = const <String>[],
  Map<String, PlatformDetails> platformSupport =
      const <String, PlatformDetails>{},
  String? version = '0.0.1',
  String flutterConstraint = '>=2.5.0',
}) {
  final Directory pluginDirectory = createFakePackage(name, parentDirectory,
      isFlutter: true,
      examples: examples,
      extraFiles: extraFiles,
      version: version,
      flutterConstraint: flutterConstraint);

  createFakePubspec(
    pluginDirectory,
    name: name,
    isFlutter: true,
    isPlugin: true,
    platformSupport: platformSupport,
    version: version,
    flutterConstraint: flutterConstraint,
  );

  return pluginDirectory;
}

/// Creates a plugin package with the given [name] in [packagesDirectory].
///
/// [extraFiles] is an optional list of package-relative paths, using unix-style
/// separators, of extra files to create in the package.
// TODO(stuartmorgan): Convert the return to a RepositoryPackage.
Directory createFakePackage(
  String name,
  Directory parentDirectory, {
  List<String> examples = const <String>['example'],
  List<String> extraFiles = const <String>[],
  bool isFlutter = false,
  String? version = '0.0.1',
  String flutterConstraint = '>=2.5.0',
}) {
  final Directory packageDirectory = parentDirectory.childDirectory(name);
  packageDirectory.createSync(recursive: true);

  createFakePubspec(packageDirectory,
      name: name,
      isFlutter: isFlutter,
      version: version,
      flutterConstraint: flutterConstraint);
  createFakeCHANGELOG(packageDirectory, '''
## $version
  * Some changes.
  ''');
  createFakeAuthors(packageDirectory);

  if (examples.length == 1) {
    final Directory exampleDir = packageDirectory.childDirectory(examples.first)
      ..createSync();
    createFakePubspec(exampleDir,
        name: '${name}_example',
        isFlutter: isFlutter,
        publishTo: 'none',
        flutterConstraint: flutterConstraint);
  } else if (examples.isNotEmpty) {
    final Directory exampleDir = packageDirectory.childDirectory('example')
      ..createSync();
    for (final String example in examples) {
      final Directory currentExample = exampleDir.childDirectory(example)
        ..createSync();
      createFakePubspec(currentExample,
          name: example,
          isFlutter: isFlutter,
          publishTo: 'none',
          flutterConstraint: flutterConstraint);
    }
  }

  final p.Context posixContext = p.posix;
  for (final String file in extraFiles) {
    childFileWithSubcomponents(packageDirectory, posixContext.split(file))
        .createSync(recursive: true);
  }

  return packageDirectory;
}

void createFakeCHANGELOG(Directory parent, String texts) {
  parent.childFile('CHANGELOG.md').createSync();
  parent.childFile('CHANGELOG.md').writeAsStringSync(texts);
}

/// Creates a `pubspec.yaml` file with a flutter dependency.
///
/// [platformSupport] is a map of platform string to the support details for
/// that platform. If empty, no `plugin` entry will be created unless `isPlugin`
/// is set to `true`.
void createFakePubspec(
  Directory parent, {
  String name = 'fake_package',
  bool isFlutter = true,
  bool isPlugin = false,
  Map<String, PlatformDetails> platformSupport =
      const <String, PlatformDetails>{},
  String publishTo = 'http://no_pub_server.com',
  String? version,
  String dartConstraint = '>=2.0.0 <3.0.0',
  String flutterConstraint = '>=2.5.0',
}) {
  isPlugin |= platformSupport.isNotEmpty;

  String environmentSection = '''
environment:
  sdk: "$dartConstraint"
''';
  String dependenciesSection = '''
dependencies:
''';
  String pluginSection = '';

  // Add Flutter-specific entries if requested.
  if (isFlutter) {
    environmentSection += '''
  flutter: "$flutterConstraint"
''';
    dependenciesSection += '''
  flutter:
    sdk: flutter
''';

    if (isPlugin) {
      pluginSection += '''
flutter:
  plugin:
    platforms:
''';
      for (final MapEntry<String, PlatformDetails> platform
          in platformSupport.entries) {
        pluginSection +=
            _pluginPlatformSection(platform.key, platform.value, name);
      }
    }
  }

  String yaml = '''
name: $name
${(version != null) ? 'version: $version' : ''}

$environmentSection

$dependenciesSection

$pluginSection
''';

  if (publishTo.isNotEmpty) {
    yaml += '''
publish_to: $publishTo # Hardcoded safeguard to prevent this from somehow being published by a broken test.
''';
  }
  parent.childFile('pubspec.yaml').createSync();
  parent.childFile('pubspec.yaml').writeAsStringSync(yaml);
}

void createFakeAuthors(Directory parent) {
  final File authorsFile = parent.childFile('AUTHORS');
  authorsFile.createSync();
  authorsFile.writeAsStringSync('Google Inc.');
}

String _pluginPlatformSection(
    String platform, PlatformDetails support, String packageName) {
  String entry = '';
  // Build the main plugin entry.
  if (support.type == PlatformSupport.federated) {
    entry = '''
      $platform:
        default_package: ${packageName}_$platform
''';
  } else {
    final List<String> lines = <String>[
      '      $platform:',
    ];
    switch (platform) {
      case platformAndroid:
        lines.add('        package: io.flutter.plugins.fake');
        continue nativeByDefault;
      nativeByDefault:
      case platformIOS:
      case platformLinux:
      case platformMacOS:
      case platformWindows:
        if (support.hasNativeCode) {
          final String className =
              platform == platformIOS ? 'FLTFakePlugin' : 'FakePlugin';
          lines.add('        pluginClass: $className');
        }
        if (support.hasDartCode) {
          lines.add('        dartPluginClass: FakeDartPlugin');
        }
        break;
      case platformWeb:
        lines.addAll(<String>[
          '        pluginClass: FakePlugin',
          '        fileName: ${packageName}_web.dart',
        ]);
        break;
      default:
        assert(false, 'Unrecognized platform: $platform');
        break;
    }
    entry = lines.join('\n') + '\n';
  }

  return entry;
}

typedef _ErrorHandler = void Function(Error error);

/// Run the command [runner] with the given [args] and return
/// what was printed.
/// A custom [errorHandler] can be used to handle the runner error as desired without throwing.
Future<List<String>> runCapturingPrint(
    CommandRunner<void> runner, List<String> args,
    {_ErrorHandler? errorHandler}) async {
  final List<String> prints = <String>[];
  final ZoneSpecification spec = ZoneSpecification(
    print: (_, __, ___, String message) {
      prints.add(message);
    },
  );
  try {
    await Zone.current
        .fork(specification: spec)
        .run<Future<void>>(() => runner.run(args));
  } on Error catch (e) {
    if (errorHandler == null) {
      rethrow;
    }
    errorHandler(e);
  }

  return prints;
}

/// A mock [ProcessRunner] which records process calls.
class RecordingProcessRunner extends ProcessRunner {
  final List<ProcessCall> recordedCalls = <ProcessCall>[];

  /// Maps an executable to a list of processes that should be used for each
  /// successive call to it via [run], [runAndStream], or [start].
  final Map<String, List<io.Process>> mockProcessesForExecutable =
      <String, List<io.Process>>{};

  @override
  Future<int> runAndStream(
    String executable,
    List<String> args, {
    Directory? workingDir,
    bool exitOnError = false,
  }) async {
    recordedCalls.add(ProcessCall(executable, args, workingDir?.path));
    final io.Process? processToReturn = _getProcessToReturn(executable);
    final int exitCode =
        processToReturn == null ? 0 : await processToReturn.exitCode;
    if (exitOnError && (exitCode != 0)) {
      throw io.ProcessException(executable, args);
    }
    return Future<int>.value(exitCode);
  }

  /// Returns [io.ProcessResult] created from [mockProcessesForExecutable].
  @override
  Future<io.ProcessResult> run(
    String executable,
    List<String> args, {
    Directory? workingDir,
    bool exitOnError = false,
    bool logOnError = false,
    Encoding stdoutEncoding = io.systemEncoding,
    Encoding stderrEncoding = io.systemEncoding,
  }) async {
    recordedCalls.add(ProcessCall(executable, args, workingDir?.path));

    final io.Process? process = _getProcessToReturn(executable);
    final List<String>? processStdout =
        await process?.stdout.transform(stdoutEncoding.decoder).toList();
    final String stdout = processStdout?.join('') ?? '';
    final List<String>? processStderr =
        await process?.stderr.transform(stderrEncoding.decoder).toList();
    final String stderr = processStderr?.join('') ?? '';

    final io.ProcessResult result = process == null
        ? io.ProcessResult(1, 0, '', '')
        : io.ProcessResult(process.pid, await process.exitCode, stdout, stderr);

    if (exitOnError && (result.exitCode != 0)) {
      throw io.ProcessException(executable, args);
    }

    return Future<io.ProcessResult>.value(result);
  }

  @override
  Future<io.Process> start(String executable, List<String> args,
      {Directory? workingDirectory}) async {
    recordedCalls.add(ProcessCall(executable, args, workingDirectory?.path));
    return Future<io.Process>.value(
        _getProcessToReturn(executable) ?? MockProcess());
  }

  io.Process? _getProcessToReturn(String executable) {
    final List<io.Process>? processes = mockProcessesForExecutable[executable];
    if (processes != null && processes.isNotEmpty) {
      return processes.removeAt(0);
    }
    return null;
  }
}

/// A recorded process call.
@immutable
class ProcessCall {
  const ProcessCall(this.executable, this.args, this.workingDir);

  /// The executable that was called.
  final String executable;

  /// The arguments passed to [executable] in the call.
  final List<String> args;

  /// The working directory this process was called from.
  final String? workingDir;

  @override
  bool operator ==(dynamic other) {
    return other is ProcessCall &&
        executable == other.executable &&
        listsEqual(args, other.args) &&
        workingDir == other.workingDir;
  }

  @override
  int get hashCode => Object.hash(executable, args, workingDir);

  @override
  String toString() {
    final List<String> command = <String>[executable, ...args];
    return '"${command.join(' ')}" in $workingDir';
  }
}