/// A Bluetooth Classic device already paired with the tablet.
///
/// [deviceClass] is Android's class-of-device value. CarDash uses it to keep
/// phones, headsets and other non-SPP devices out of the default OBD-II
/// adapter list. Devices with no class information stay visible; hiding a real
/// adapter would be worse than showing an extra device.
class BluetoothDeviceInfo {
  const BluetoothDeviceInfo({
    required this.name,
    required this.address,
    this.deviceClass,
    this.uuids = const [],
  });

  static const _sppUuid = '00001101-0000-1000-8000-00805f9b34fb';

  /// Names commonly used by ELM327 and compatible OBD-II adapters.
  static const _obdNameHints = <String>[
    'obd',
    'elm',
    'vlink',
    'v-link',
    'vgate',
    'v-gate',
    'veepeak',
    'bafx',
    'obdlink',
    'scantool',
    'konnwei',
    'autel',
    'car scanner',
  ];

  /// Android major device classes that can plausibly carry an SPP ELM327.
  static const _likelyMajorClasses = <int>{
    0x0000, // Miscellaneous
    0x0100, // Computer
    0x0300, // Networking / LAN access
    0x1F00, // Uncategorized
  };

  final String name;
  final String address;
  final int? deviceClass;

  /// Cached SDP UUIDs, when Android already has them.
  final List<String> uuids;

  factory BluetoothDeviceInfo.fromMap(Map<dynamic, dynamic> map) {
    final rawUuids = map['uuids'];
    return BluetoothDeviceInfo(
      name: (map['name'] as String?)?.trim() ?? 'Unknown device',
      address: (map['address'] as String?) ?? '',
      deviceClass: (map['deviceClass'] as num?)?.toInt(),
      uuids: rawUuids is List
          ? rawUuids
                .whereType<String>()
                .map((uuid) => uuid.toLowerCase())
                .toList(growable: false)
          : const [],
    );
  }

  int? get majorClass => deviceClass == null ? null : deviceClass! & 0x1F00;

  bool get hasSppService => uuids.contains(_sppUuid);

  bool get hasObdName {
    final normalized = name.toLowerCase();
    return _obdNameHints.any(normalized.contains);
  }

  /// Whether the adapter is likely to be a Bluetooth Classic OBD-II device.
  ///
  /// A recognised name or the SPP service UUID always wins. Otherwise the
  /// Android major class decides; unknown class information is treated as
  /// possibly usable so a real adapter is never hidden.
  bool get isLikelyObd {
    if (hasObdName || hasSppService) return true;
    final major = majorClass;
    if (major == null) return true;
    return _likelyMajorClasses.contains(major);
  }

  String get label => name.isEmpty ? address : '$name · $address';
}