// 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 'package:args/args.dart';
import 'package:file/file.dart';
import 'package:file/local.dart';
import 'package:platform/platform.dart';

import 'proto/conductor_state.pb.dart' as pb;

const String gsutilBinary = 'gsutil.py';

const List<String> kReleaseChannels = <String>[
  'stable',
  'beta',
  'dev',
  'master',
];

const String kReleaseDocumentationUrl = 'https://github.com/flutter/flutter/wiki/Flutter-Cherrypick-Process';

const String kLuciPackagingConsoleLink = 'https://ci.chromium.org/p/flutter/g/packaging/console';

final RegExp releaseCandidateBranchRegex = RegExp(
  r'flutter-(\d+)\.(\d+)-candidate\.(\d+)',
);

/// Cast a dynamic to String and trim.
String stdoutToString(dynamic input) {
  final String str = input as String;
  return str.trim();
}

class ConductorException implements Exception {
  ConductorException(this.message);

  final String message;

  @override
  String toString() => 'Exception: $message';
}

Directory? _flutterRoot;
Directory get localFlutterRoot {
  if (_flutterRoot != null) {
    return _flutterRoot!;
  }
  String filePath;
  const FileSystem fileSystem = LocalFileSystem();
  const Platform platform = LocalPlatform();

  filePath = platform.script.toFilePath();
  final String checkoutsDirname = fileSystem.path.normalize(
    fileSystem.path.join(
      fileSystem.path.dirname(filePath),
      '..', // flutter/dev/tools
      '..', // flutter/dev
      '..', // flutter
    ),
  );
  _flutterRoot = fileSystem.directory(checkoutsDirname);
  return _flutterRoot!;
}

bool assertsEnabled() {
  // Verify asserts enabled
  bool assertsEnabled = false;

  assert(() {
    assertsEnabled = true;
    return true;
  }());
  return assertsEnabled;
}

/// Either return the value from [env] or fall back to [argResults].
///
/// If the key does not exist in either the environment or CLI args, throws a
/// [ConductorException].
///
/// The environment is favored over CLI args since the latter can have a default
/// value, which the environment should be able to override.
String? getValueFromEnvOrArgs(
  String name,
  ArgResults argResults,
  Map<String, String> env, {
  bool allowNull = false,
}) {
  final String envName = fromArgToEnvName(name);
  if (env[envName] != null) {
    return env[envName];
  }
  final String? argValue = argResults[name] as String?;
  if (argValue != null) {
    return argValue;
  }

  if (allowNull) {
    return null;
  }
  throw ConductorException(
    'Expected either the CLI arg --$name or the environment variable $envName '
    'to be provided!');
}

/// Return multiple values from the environment or fall back to [argResults].
///
/// Values read from an environment variable are assumed to be comma-delimited.
///
/// If the key does not exist in either the CLI args or environment, throws a
/// [ConductorException].
///
/// The environment is favored over CLI args since the latter can have a default
/// value, which the environment should be able to override.
List<String> getValuesFromEnvOrArgs(
  String name,
  ArgResults argResults,
  Map<String, String> env,
) {
  final String envName = fromArgToEnvName(name);
  if (env[envName] != null && env[envName] != '') {
    return env[envName]!.split(',');
  }
  final List<String> argValues = argResults[name] as List<String>;
  if (argValues != null) {
    return argValues;
  }

  throw ConductorException(
    'Expected either the CLI arg --$name or the environment variable $envName '
    'to be provided!');
}

/// Translate CLI arg names to env variable names.
///
/// For example, 'state-file' -> 'STATE_FILE'.
String fromArgToEnvName(String argName) {
  return argName.toUpperCase().replaceAll(r'-', r'_');
}

/// Return a web link for the user to open a new PR.
///
/// Includes PR title and body via query params.
String getNewPrLink({
  required String userName,
  required String repoName,
  required pb.ConductorState state,
}) {
  assert(state.releaseChannel.isNotEmpty);
  assert(state.releaseVersion.isNotEmpty);
  late final String candidateBranch;
  late final String workingBranch;
  late final String repoLabel;
  switch (repoName) {
    case 'flutter':
      candidateBranch = state.framework.candidateBranch;
      workingBranch = state.framework.workingBranch;
      repoLabel = 'Framework';
      break;
    case 'engine':
      candidateBranch = state.engine.candidateBranch;
      workingBranch = state.engine.workingBranch;
      repoLabel = 'Engine';
      break;
    default:
      throw ConductorException('Expected repoName to be one of flutter or engine but got $repoName.');
  }
  assert(candidateBranch.isNotEmpty);
  assert(workingBranch.isNotEmpty);
  final String title = '[flutter_releases] Flutter ${state.releaseChannel} '
      '${state.releaseVersion} $repoLabel Cherrypicks';
  final StringBuffer body = StringBuffer();
  body.write('''
# Flutter ${state.releaseChannel} ${state.releaseVersion} $repoLabel

## Scheduled Cherrypicks

''');
  if (repoName == 'engine') {
    if (state.engine.dartRevision.isNotEmpty) {
      // shorten hashes to make final link manageable
      // prefix with github org/repo so GitHub will auto-generate a hyperlink
      body.writeln('- Roll dart revision: dart-lang/sdk@${state.engine.dartRevision.substring(0, 9)}');
    }
    for (final pb.Cherrypick cp in state.engine.cherrypicks) {
      // Only list commits that map to a commit that exists upstream.
      if (cp.trunkRevision.isNotEmpty) {
        body.writeln('- commit: flutter/engine@${cp.trunkRevision.substring(0, 9)}');
      }
    }
  } else {
    for (final pb.Cherrypick cp in state.framework.cherrypicks) {
      // Only list commits that map to a commit that exists upstream.
      if (cp.trunkRevision.isNotEmpty) {
        body.writeln('- commit: ${cp.trunkRevision.substring(0, 9)}');
      }
    }
  }
  return 'https://github.com/flutter/$repoName/compare/'
      '$candidateBranch...$userName:$workingBranch?'
      'expand=1'
      '&title=${Uri.encodeQueryComponent(title)}'
      '&body=${Uri.encodeQueryComponent(body.toString())}';
}