// 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.

// @dart = 2.6
import 'dart:async';
import 'dart:io' as io;

import 'package:args/args.dart';
import 'package:args/command_runner.dart';
import 'package:meta/meta.dart';
import 'package:path/path.dart' as path;

import 'environment.dart';
import 'exceptions.dart';

/// Clears the terminal screen and places the cursor at the top left corner.
///
/// This works on Linux and Mac. On Windows, it's a no-op.
void clearTerminalScreen() {
  if (!io.Platform.isWindows) {
    // See: https://en.wikipedia.org/wiki/ANSI_escape_code#CSI_sequences
    print("\x1B[2J\x1B[1;2H");
  }
}

class FilePath {
  FilePath.fromCwd(String relativePath)
      : _absolutePath = path.absolute(relativePath);
  FilePath.fromWebUi(String relativePath)
      : _absolutePath = path.join(environment.webUiRootDir.path, relativePath);

  final String _absolutePath;

  String get absolute => _absolutePath;
  String get relativeToCwd => path.relative(_absolutePath);
  String get relativeToWebUi =>
      path.relative(_absolutePath, from: environment.webUiRootDir.path);

  @override
  bool operator ==(Object other) {
    return other is FilePath && other._absolutePath == _absolutePath;
  }

  @override
  String toString() => _absolutePath;
}

/// Runs [executable] merging its output into the current process' standard out and standard error.
Future<int> runProcess(
  String executable,
  List<String> arguments, {
  String workingDirectory,
  bool mustSucceed: false,
  Map<String, String> environment = const <String, String>{},
}) async {
  final io.Process process = await io.Process.start(
    executable,
    arguments,
    workingDirectory: workingDirectory,
    // Running the process in a system shell for Windows. Otherwise
    // the process is not able to get Dart from path.
    runInShell: io.Platform.isWindows,
    mode: io.ProcessStartMode.inheritStdio,
    environment: environment,
  );
  final int exitCode = await process.exitCode;
  if (mustSucceed && exitCode != 0) {
    throw ProcessException(
      description: 'Sub-process failed.',
      executable: executable,
      arguments: arguments,
      workingDirectory: workingDirectory,
      exitCode: exitCode,
    );
  }
  return exitCode;
}

/// Runs [executable]. Do not follow the exit code or the output.
Future<void> startProcess(
  String executable,
  List<String> arguments, {
  String workingDirectory,
  bool mustSucceed: false,
}) async {
  final io.Process process = await io.Process.start(
    executable,
    arguments,
    workingDirectory: workingDirectory,
    // Running the process in a system shell for Windows. Otherwise
    // the process is not able to get Dart from path.
    runInShell: io.Platform.isWindows,
    mode: io.ProcessStartMode.inheritStdio,
  );
  processesToCleanUp.add(process);
}

/// Runs [executable] and returns its standard output as a string.
///
/// If the process fails, throws a [ProcessException].
Future<String> evalProcess(
  String executable,
  List<String> arguments, {
  String workingDirectory,
}) async {
  final io.ProcessResult result = await io.Process.run(
    executable,
    arguments,
    workingDirectory: workingDirectory,
  );
  if (result.exitCode != 0) {
    throw ProcessException(
      description: result.stderr as String,
      executable: executable,
      arguments: arguments,
      workingDirectory: workingDirectory,
      exitCode: result.exitCode,
    );
  }
  return result.stdout as String;
}

Future<void> runFlutter(
  String workingDirectory,
  List<String> arguments, {
  bool useSystemFlutter = false,
}) async {
  final String executable =
      useSystemFlutter ? 'flutter' : environment.flutterCommand.path;
  arguments.add('--local-engine=host_debug_unopt');
  final int exitCode = await runProcess(
    executable,
    arguments,
    workingDirectory: workingDirectory,
  );

  if (exitCode != 0) {
    throw ToolException('ERROR: Failed to run $executable with '
        'arguments ${arguments.toString()}. Exited with exit code $exitCode');
  }
}

@immutable
class ProcessException implements Exception {
  ProcessException({
    @required this.description,
    @required this.executable,
    @required this.arguments,
    @required this.workingDirectory,
    @required this.exitCode,
  });

  final String description;
  final String executable;
  final List<String> arguments;
  final String workingDirectory;
  final int exitCode;

  @override
  String toString() {
    final StringBuffer message = StringBuffer();
    message
      ..writeln(description)
      ..writeln('Command: $executable ${arguments.join(' ')}')
      ..writeln(
          'Working directory: ${workingDirectory ?? io.Directory.current.path}')
      ..writeln('Exit code: $exitCode');
    return '$message';
  }
}

/// Adds utility methods
mixin ArgUtils<T> on Command<T> {
  /// Extracts a boolean argument from [argResults].
  bool boolArg(String name) => argResults[name] as bool;

  /// Extracts a string argument from [argResults].
  String stringArg(String name) => argResults[name] as String;

  /// Extracts a integer argument from [argResults].
  ///
  /// If the argument value cannot be parsed as [int] throws an [ArgumentError].
  int intArg(String name) {
    final String rawValue = stringArg(name);
    if (rawValue == null) {
      return null;
    }
    final int value = int.tryParse(rawValue);
    if (value == null) {
      throw ArgumentError(
        'Argument $name should be an integer value but was "$rawValue"',
      );
    }
    return value;
  }
}

/// Parses additional options that can be used for all tests.
class GeneralTestsArgumentParser {
  static final GeneralTestsArgumentParser _singletonInstance =
      GeneralTestsArgumentParser._();

  /// The [GeneralTestsArgumentParser] singleton.
  static GeneralTestsArgumentParser get instance => _singletonInstance;

  GeneralTestsArgumentParser._();

  /// If target name is provided integration tests can run that one test
  /// instead of running all the tests.
  bool verbose = false;

  void populateOptions(ArgParser argParser) {
    argParser
      ..addFlag(
        'verbose',
        defaultsTo: false,
        help: 'Flag to indicate extra logs should also be printed.',
      );
  }

  /// Populate results of the arguments passed.
  void parseOptions(ArgResults argResults) {
    verbose = argResults['verbose'] as bool;
  }
}

bool get isVerboseLoggingEnabled => GeneralTestsArgumentParser.instance.verbose;

/// There might be proccesses started during the tests.
///
/// Use this list to store those Processes, for cleaning up before shutdown.
final List<io.Process> processesToCleanUp = <io.Process>[];

/// There might be temporary directories created during the tests.
///
/// Use this list to store those directories and for deleteing them before
/// shutdown.
final List<io.Directory> temporaryDirectories = <io.Directory>[];

typedef AsyncCallback = Future<void> Function();

/// There might be additional cleanup needs to be done after the tools ran.
///
/// Add these operations here to make sure that they will run before felt
/// exit.
final List<AsyncCallback> cleanupCallbacks = <AsyncCallback>[];

/// Cleanup the remaning processes, close open browsers, delete temp files.
void cleanup() async {
  // Cleanup remaining processes if any.
  if (processesToCleanUp.length > 0) {
    for (io.Process process in processesToCleanUp) {
      process.kill();
    }
  }
  // Delete temporary directories.
  if (temporaryDirectories.length > 0) {
    for (io.Directory directory in temporaryDirectories) {
      if (!directory.existsSync()) {
        directory.deleteSync(recursive: true);
      }
    }
  }

  for (final AsyncCallback callback in cleanupCallbacks) {
    await callback();
  }
}