import 'package:flutter/foundation.dart';

import '../models/venue.dart';
import '../services/kooltap_api_client.dart';
import '../services/remote_sync_service.dart';

enum RegistrationStep {
  initial,
  loadingVenues,
  venuesLoaded,
  error,
  registering,
  registered,
}

class RegistrationViewModel extends ChangeNotifier {
  final KoolTapApiClient apiClient;
  final RemoteSyncService syncService;

  RegistrationViewModel({required this.apiClient, required this.syncService});

  RegistrationStep _step = RegistrationStep.initial;
  RegistrationStep get step => _step;

  List<Venue> _venues = [];
  List<Venue> get venues => _venues;

  Venue? _selectedVenue;
  Venue? get selectedVenue => _selectedVenue;

  /// Server-provided, so shown as-is.
  String? _errorMessage;
  String? get errorMessage => _errorMessage;

  void selectVenue(Venue venue) {
    _selectedVenue = venue;
    _errorMessage = null;
    notifyListeners();
  }

  void deselectVenue() {
    _selectedVenue = null;
    _errorMessage = null;
    notifyListeners();
  }

  Future<void> fetchVenues() async {
    _step = RegistrationStep.loadingVenues;
    _selectedVenue = null;
    _errorMessage = null;
    notifyListeners();

    try {
      _venues = await apiClient.getVenues();
      _step = RegistrationStep.venuesLoaded;
    } on Exception catch (e) {
      debugPrint('RegistrationViewModel: fetchVenues error: $e');
      _errorMessage = e.toString();
      _step = RegistrationStep.error;
    }

    notifyListeners();
  }

  Future<bool> registerDevice({
    required String deviceName,
    required String registrationCode,
  }) async {
    final venue = _selectedVenue;
    if (venue == null) return false;

    _step = RegistrationStep.registering;
    _errorMessage = null;
    notifyListeners();

    try {
      final credentials = await apiClient.registerDevice(
        venueId: venue.id,
        deviceName: deviceName,
        registrationCode: registrationCode,
      );

      await syncService.setCredentials(
        deviceId: credentials.deviceId,
        token: credentials.token,
        venueId: venue.id,
        venueName: venue.name,
      );

      _step = RegistrationStep.registered;
      notifyListeners();
      return true;
    } on ApiException catch (e) {
      _errorMessage = e.message.isEmpty
          ? 'Registration failed (HTTP ${e.statusCode})'
          : e.message;
    } on Exception catch (e) {
      debugPrint('RegistrationViewModel: registerDevice error: $e');
      _errorMessage = e.toString();
    }

    _step = RegistrationStep.venuesLoaded;
    notifyListeners();
    return false;
  }

  Future<void> retry() => fetchVenues();
}