import 'package:encrypt/encrypt.dart';
import 'package:pointycastle/asymmetric/api.dart';
import 'package:dio/dio.dart';
import '../network/dio_client.dart';

class CryptoService {
  static final CryptoService _instance = CryptoService._internal();
  factory CryptoService() => _instance;
  CryptoService._internal();

  RSAPublicKey? _publicKey;

  Future<void> fetchPublicKey() async {
    try {
      final dio = Dio(BaseOptions(
        baseUrl: DioClient().dio.options.baseUrl,
        connectTimeout: const Duration(seconds: 10),
        receiveTimeout: const Duration(seconds: 10),
      ));
      final response = await dio.get('/auth/public-key');
      final publicKeyBase64 = response.data['publicKey'] as String;
      _publicKey = RSAKeyParser().parse('-----BEGIN PUBLIC KEY-----\n$publicKeyBase64\n-----END PUBLIC KEY-----') as RSAPublicKey;
    } catch (e) {
      throw Exception('Failed to fetch public key: $e');
    }
  }

  String encrypt(String plainText) {
    if (_publicKey == null) {
      throw Exception('Public key not initialized. Call fetchPublicKey() first.');
    }
    final encrypter = Encrypter(RSA(publicKey: _publicKey));
    final encrypted = encrypter.encrypt(plainText);
    return encrypted.base64;
  }

  bool get isInitialized => _publicKey != null;
}