import 'package:flutter_bloc/flutter_bloc.dart';

/// Explizite Zustandsfolge Plan -> Connect -> Upload -> Fly
/// (Architektur-Doku 2.2).
enum AppMode { plan, connect, upload, fly }

class AppModeState {
  const AppModeState({
    this.mode = AppMode.plan,
    this.missionUploaded = false,
    this.missionVerified = false,
    this.droneArmed = false,
  });

  final AppMode mode;
  final bool missionUploaded;
  final bool missionVerified;
  final bool droneArmed;

  /// Ready-to-Fly-Gate (Doku 2.2 / 4.5): Upload + verifiziert + disarmed.
  /// Muss technisch erzwungen werden, nicht nur als UI-Konvention gelten.
  bool get readyToFly => missionUploaded && missionVerified && !droneArmed;

  AppModeState copyWith({
    AppMode? mode,
    bool? missionUploaded,
    bool? missionVerified,
    bool? droneArmed,
  }) {
    return AppModeState(
      mode: mode ?? this.mode,
      missionUploaded: missionUploaded ?? this.missionUploaded,
      missionVerified: missionVerified ?? this.missionVerified,
      droneArmed: droneArmed ?? this.droneArmed,
    );
  }
}

class AppModeCubit extends Cubit<AppModeState> {
  AppModeCubit() : super(const AppModeState());

  void toConnect() => emit(state.copyWith(mode: AppMode.connect));

  void toUpload() => emit(state.copyWith(mode: AppMode.upload));

  void missionUploadConfirmed() =>
      emit(state.copyWith(missionUploaded: true));

  void missionVerifiedConfirmed() =>
      emit(state.copyWith(missionVerified: true));

  void droneArmedChanged(bool armed) =>
      emit(state.copyWith(droneArmed: armed));

  /// Wirft, wenn das Ready-to-Fly-Gate nicht erfuellt ist (Doku 4.5).
  void toFly() {
    if (!state.readyToFly) {
      throw StateError('Ready-to-Fly-Gate nicht erfuellt.');
    }
    emit(state.copyWith(mode: AppMode.fly));
  }

  /// Verlassen des Fly-Modus setzt den kompletten Handover-Status zurueck.
  void toPlan() => emit(const AppModeState());
}