// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
// for details. 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';

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

import 'experiments.dart';
import 'sdk.dart';
import 'utils.dart';

Logger log;
bool isDiagnostics = false;

/// When set, this function is executed from the [DartdevCommand] constructor to
/// contribute additional flags.
void Function(ArgParser argParser, String cmdName) flagContributor;

abstract class DartdevCommand extends Command<int> {
  final String _name;
  final String _description;
  final bool _verbose;

  Project _project;

  @override
  final bool hidden;

  DartdevCommand(this._name, this._description, this._verbose,
      {this.hidden = false}) {
    flagContributor?.call(argParser, _name);
  }

  @override
  String get name => _name;

  @override
  String get description => _description;

  ArgParser _argParser;

  @override
  ArgParser get argParser => _argParser ??= createArgParser();

  @override
  String get invocation {
    String result = super.invocation;
    if (_verbose) {
      var firstSpace = result.indexOf(' ');
      if (firstSpace < 0) firstSpace = result.length;
      result = result.replaceRange(firstSpace, firstSpace, ' [vm-options]');
    }
    return result;
  }

  /// Create the ArgParser instance for this command.
  ///
  /// Subclasses can override this in order to create a customized ArgParser.
  ArgParser createArgParser() =>
      ArgParser(usageLineLength: dartdevUsageLineLength);

  Project get project => _project ??= Project();
}

extension DartDevCommand on Command {
  /// Return whether commands should emit verbose output.
  bool get verbose => globalResults['verbose'];

  /// Return whether the tool should emit diagnostic output.
  bool get diagnosticsEnabled => globalResults['diagnostics'];

  /// Return whether any Dart experiments were specified by the user.
  bool get wereExperimentsSpecified =>
      globalResults?.wasParsed(experimentFlagName) ?? false;

  List<String> get specifiedExperiments => globalResults[experimentFlagName];
}

/// A utility method to start a Dart VM instance with the given arguments and an
/// optional current working directory.
///
/// [arguments] should contain the snapshot path.
Future<Process> startDartProcess(
  Sdk sdk,
  List<String> arguments, {
  String cwd,
}) {
  log.trace('${sdk.dart} ${arguments.join(' ')}');
  return Process.start(sdk.dart, arguments, workingDirectory: cwd);
}

void routeToStdout(
  Process process, {
  bool logToTrace = false,
  void Function(String str) listener,
}) {
  if (isDiagnostics) {
    _streamLineTransform(process.stdout, (String line) {
      logToTrace ? log.trace(line.trimRight()) : log.stdout(line.trimRight());
      if (listener != null) listener(line);
    });
    _streamLineTransform(process.stderr, (String line) {
      log.stderr(line.trimRight());
      if (listener != null) listener(line);
    });
  } else {
    _streamLineTransform(process.stdout, (String line) {
      logToTrace ? log.trace(line.trimRight()) : log.stdout(line.trimRight());
      if (listener != null) listener(line);
    });

    _streamLineTransform(process.stderr, (String line) {
      log.stderr(line.trimRight());
      if (listener != null) listener(line);
    });
  }
}

void _streamLineTransform(
  Stream<List<int>> stream,
  Function(String line) handler,
) {
  stream
      .transform(utf8.decoder)
      .transform(const LineSplitter())
      .forEach(handler);
}

/// A representation of a project on disk.
class Project {
  final Directory dir;

  PackageConfig _packageConfig;

  Project() : dir = Directory.current;

  Project.fromDirectory(this.dir);

  bool get hasPubspecFile =>
      FileSystemEntity.isFileSync(path.join(dir.path, 'pubspec.yaml'));

  bool get hasPackageConfigFile => packageConfig != null;

  PackageConfig get packageConfig {
    if (_packageConfig == null) {
      File file =
          File(path.join(dir.path, '.dart_tool', 'package_config.json'));

      if (file.existsSync()) {
        try {
          dynamic contents = json.decode(file.readAsStringSync());
          _packageConfig = PackageConfig(contents);
        } catch (_) {}
      }
    }

    return _packageConfig;
  }
}

/// A simple representation of a `package_config.json` file.
class PackageConfig {
  final Map<String, dynamic> contents;

  PackageConfig(this.contents);

  List<Map<String, dynamic>> get packages {
    List<dynamic> _packages = contents['packages'];
    return _packages.map<Map<String, dynamic>>(castStringKeyedMap).toList();
  }

  bool hasDependency(String packageName) =>
      packages.any((element) => element['name'] == packageName);
}