import 'dart:io';

import 'package:flutter/services.dart';
import 'package:path_provider/path_provider.dart';

final class SingBoxRuntime {
  static const String _linuxAssetPath = 'assets/sing-box/linux-amd64/sing-box';

  String? _cachedBinaryPath;

  Future<String> ensureBinary() async {
    if (_cachedBinaryPath != null) {
      final cachedFile = File(_cachedBinaryPath!);
      if (await cachedFile.exists()) {
        return _cachedBinaryPath!;
      }
    }

    if (!Platform.isLinux) {
      throw UnsupportedError('Sing-box runtime currently supports Linux only');
    }

    final appDir = await getApplicationSupportDirectory();
    final runtimeDir = Directory(
      '${appDir.path}${Platform.pathSeparator}sing-box-runtime',
    );
    if (!await runtimeDir.exists()) {
      await runtimeDir.create(recursive: true);
    }

    final binaryPath =
        '${runtimeDir.path}${Platform.pathSeparator}sing-box';
    final binaryFile = File(binaryPath);

    final ByteData byteData = await rootBundle.load(_linuxAssetPath);
    await binaryFile.writeAsBytes(
      byteData.buffer.asUint8List(),
      flush: true,
    );

    await Process.run('chmod', <String>['755', binaryPath]);
    _cachedBinaryPath = binaryPath;
    return binaryPath;
  }

  Future<String> configPath() async {
    final appDir = await getApplicationSupportDirectory();
    final runtimeDir = Directory(
      '${appDir.path}${Platform.pathSeparator}sing-box-runtime',
    );
    if (!await runtimeDir.exists()) {
      await runtimeDir.create(recursive: true);
    }

    return '${runtimeDir.path}${Platform.pathSeparator}config.json';
  }
}