packages/flutter_tools/tool/daemon_client.dart

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

late Process daemon;

// To use, start from the console and enter:
//   version: print version
//   shutdown: terminate the server
//   start: start an app
//   stop: stop a running app
//   devices: list devices
//   emulators: list emulators
//   emulator-launch: launch an emulator, append the word coldBoot to cold boot the emulator.

Future<void> main() async {
  daemon = await Process.start('dart', <String>['bin/flutter_tools.dart', 'daemon']);
  print('daemon process started, pid: ${daemon.pid}');

  daemon.stdout
      .transform<String>(utf8.decoder)
      .transform<String>(const LineSplitter())
      .listen((String line) => print('<== $line'));
  daemon.stderr.listen(stderr.add);

  stdout.write('> ');
  stdin.transform<String>(utf8.decoder).transform<String>(const LineSplitter()).listen((
    String line,
  ) {
    final List<String> words = line.split(' ');

    if (line == 'version' || line == 'v') {
      _send(<String, dynamic>{'method': 'daemon.version'});
    } else if (line == 'shutdown' || line == 'q') {
      _send(<String, dynamic>{'method': 'daemon.shutdown'});
    } else if (words.first == 'start') {
      _send(<String, dynamic>{
        'method': 'app.start',
        'params': <String, dynamic>{
          'deviceId': words[1],
          'projectDirectory': words[2],
          'launchMode': words[3],
        },
      });
    } else if (words.first == 'stop') {
      if (words.length > 1) {
        _send(<String, dynamic>{
          'method': 'app.stop',
          'params': <String, dynamic>{'appId': words[1]},
        });
      } else {
        _send(<String, dynamic>{'method': 'app.stop'});
      }
    } else if (words.first == 'restart') {
      if (words.length > 1) {
        _send(<String, dynamic>{
          'method': 'app.restart',
          'params': <String, dynamic>{'appId': words[1]},
        });
      } else {
        _send(<String, dynamic>{'method': 'app.restart'});
      }
    } else if (line == 'devices') {
      _send(<String, dynamic>{'method': 'device.getDevices'});
    } else if (line == 'emulators') {
      _send(<String, dynamic>{'method': 'emulator.getEmulators'});
    } else if (words.first == 'emulator-launch') {
      _send(<String, dynamic>{
        'method': 'emulator.launch',
        'params': <String, dynamic>{
          'emulatorId': words[1],
          if (words.contains('coldBoot')) 'coldBoot': true,
        },
      });
    } else if (line == 'enable') {
      _send(<String, dynamic>{'method': 'device.enable'});
    } else {
      _send(<String, dynamic>{'method': line.trim()});
    }
    stdout.write('> ');
  });

  // Print in the callback can't fail.
  unawaited(
    daemon.exitCode.then<int>((int code) {
      print('daemon exiting ($code)');
      exit(code);
    }),
  );
}

int _id = 0;

void _send(Map<String, dynamic> map) {
  map['id'] = _id++;
  final str = '[${json.encode(map)}]';
  daemon.stdin.writeln(str);
  print('==> $str');
}