import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:uuid/uuid.dart';

class CryptoService {
  static const String _deviceIdPref = 'device_uuid';
  static const _storage = FlutterSecureStorage();

  /// Get or create a persistent device UUID for server-side session tracking.
  static Future<String> getDeviceId() async {
    final existing = await _storage.read(key: _deviceIdPref);
    if (existing != null) return existing;

    final newId = const Uuid().v4();
    await _storage.write(key: _deviceIdPref, value: newId);
    return newId;
  }
}