enum ScooterConnectionStatus {
  disconnected,
  connecting,
  connected,
  authenticating,
  authenticated,
  ready,
  error,
}

/// Observable snapshot of everything the UI needs.
///
/// Numeric protocol values are kept in their native representation. Units
/// (km vs miles, Ah vs mAh, percent) are NOT asserted here until they have
/// been LIVE VERIFIED against a physical scooter.
class ScooterState {
  final ScooterConnectionStatus connectionStatus;

  final bool authenticated;
  final bool canWrite;

  /// Human-readable description of the last error, if [connectionStatus] is
  /// [ScooterConnectionStatus.error].
  final String? errorMessage;

  /// Which connection step is in progress (0-based index into
  /// [connectionSteps]) while [connectionStatus] is connecting or
  /// authenticated-but-waiting. Null when no multi-step work is running.
  final int? connectionStep;

  /// Steps shown to the rider while a link is being established.
  static const connectionSteps = [
    'Connecting',
    'Setting up services',
    'Checking this is a supported device',
    'Waiting for telemetry',
    'Waiting for scooter confirmation',
  ];

  final double? speed;
  final double? voltage;
  final double? current;
  final double? power;

  final double? tripDistance;
  final double? odometer;

  final int? batteryLevel;
  final int? batteryTemperature;
  final int? batteryCycles;

  final int? motorTemperature;
  final int? controllerTemperature;

  final int? gear;

  final bool? locked;
  final bool? headlight;
  final bool? atmosphereLight;
  final bool? cruiseControl;

  final bool? leftTurnSignal;
  final bool? rightTurnSignal;

  /// Scooter's own unit preference bit (monitor byte 22 bit 5).
  final bool? imperial;

  /// Speed limit for the current gear and the highest configured limit, in
  /// native protocol units. Gear-to-mode mapping is INFERRED.
  final int? speedLimit;
  final int? maxSpeedLimit;

  final String? displayId;
  final String? displayVersion;

  const ScooterState({
    this.connectionStatus = ScooterConnectionStatus.disconnected,
    this.authenticated = false,
    this.canWrite = false,
    this.errorMessage,
    this.connectionStep,
    this.speed,
    this.voltage,
    this.current,
    this.power,
    this.tripDistance,
    this.odometer,
    this.batteryLevel,
    this.batteryTemperature,
    this.batteryCycles,
    this.motorTemperature,
    this.controllerTemperature,
    this.gear,
    this.locked,
    this.headlight,
    this.atmosphereLight,
    this.cruiseControl,
    this.leftTurnSignal,
    this.rightTurnSignal,
    this.imperial,
    this.speedLimit,
    this.maxSpeedLimit,
    this.displayId,
    this.displayVersion,
  });

  /// Sentinel so callers can explicitly clear a nullable field.
  static const Object _unset = Object();

  ScooterState copyWith({
    ScooterConnectionStatus? connectionStatus,
    bool? authenticated,
    bool? canWrite,
    Object? errorMessage = _unset,
    Object? connectionStep = _unset,
    Object? speed = _unset,
    Object? voltage = _unset,
    Object? current = _unset,
    Object? power = _unset,
    Object? tripDistance = _unset,
    Object? odometer = _unset,
    Object? batteryLevel = _unset,
    Object? batteryTemperature = _unset,
    Object? batteryCycles = _unset,
    Object? motorTemperature = _unset,
    Object? controllerTemperature = _unset,
    Object? gear = _unset,
    Object? locked = _unset,
    Object? headlight = _unset,
    Object? atmosphereLight = _unset,
    Object? cruiseControl = _unset,
    Object? leftTurnSignal = _unset,
    Object? rightTurnSignal = _unset,
    Object? imperial = _unset,
    Object? speedLimit = _unset,
    Object? maxSpeedLimit = _unset,
    Object? displayId = _unset,
    Object? displayVersion = _unset,
  }) {
    return ScooterState(
      connectionStatus: connectionStatus ?? this.connectionStatus,
      authenticated: authenticated ?? this.authenticated,
      canWrite: canWrite ?? this.canWrite,
      errorMessage: errorMessage == _unset
          ? this.errorMessage
          : errorMessage as String?,
      connectionStep:
          connectionStep == _unset ? this.connectionStep : connectionStep as int?,
      speed: speed == _unset ? this.speed : speed as double?,
      voltage: voltage == _unset ? this.voltage : voltage as double?,
      current: current == _unset ? this.current : current as double?,
      power: power == _unset ? this.power : power as double?,
      tripDistance:
          tripDistance == _unset ? this.tripDistance : tripDistance as double?,
      odometer: odometer == _unset ? this.odometer : odometer as double?,
      batteryLevel:
          batteryLevel == _unset ? this.batteryLevel : batteryLevel as int?,
      batteryTemperature: batteryTemperature == _unset
          ? this.batteryTemperature
          : batteryTemperature as int?,
      batteryCycles:
          batteryCycles == _unset ? this.batteryCycles : batteryCycles as int?,
      motorTemperature: motorTemperature == _unset
          ? this.motorTemperature
          : motorTemperature as int?,
      controllerTemperature: controllerTemperature == _unset
          ? this.controllerTemperature
          : controllerTemperature as int?,
      gear: gear == _unset ? this.gear : gear as int?,
      locked: locked == _unset ? this.locked : locked as bool?,
      headlight: headlight == _unset ? this.headlight : headlight as bool?,
      atmosphereLight: atmosphereLight == _unset
          ? this.atmosphereLight
          : atmosphereLight as bool?,
      cruiseControl:
          cruiseControl == _unset ? this.cruiseControl : cruiseControl as bool?,
      leftTurnSignal: leftTurnSignal == _unset
          ? this.leftTurnSignal
          : leftTurnSignal as bool?,
      rightTurnSignal: rightTurnSignal == _unset
          ? this.rightTurnSignal
          : rightTurnSignal as bool?,
      imperial: imperial == _unset ? this.imperial : imperial as bool?,
      speedLimit: speedLimit == _unset ? this.speedLimit : speedLimit as int?,
      maxSpeedLimit:
          maxSpeedLimit == _unset ? this.maxSpeedLimit : maxSpeedLimit as int?,
      displayId: displayId == _unset ? this.displayId : displayId as String?,
      displayVersion: displayVersion == _unset
          ? this.displayVersion
          : displayVersion as String?,
    );
  }
}