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

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

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

Logger log;
bool isDiagnostics = false;

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

  Project _project;

  @override
  final bool hidden;

  DartdevCommand(this._name, this._description, {this.hidden = false});

  @override
  String get name => _name;

  @override
  String get description => _description;

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

  /// 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);

  /// Return the list of Dart experiment flags specified by the user.
  List<String> get specifiedExperiments => globalResults[experimentFlagName];
}

/// A utility method to start the given executable as a process, optionally
/// providing a current working directory.
Future<Process> startProcess(
  String executable,
  List<String> arguments, {
  String cwd,
}) {
  log.trace('$executable ${arguments.join(' ')}');
  return Process.start(executable, 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())
      .listen(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 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);
}