import 'package:flutter_test/flutter_test.dart';

import 'package:emergency/models/country.dart';
import 'package:emergency/models/emergency_number.dart';
import 'package:emergency/models/emergency_type.dart';
import 'package:emergency/providers/emergency_provider.dart';
import 'package:emergency/providers/emergency_status.dart';
import 'package:emergency/repositories/emergency_number_repository.dart';
import 'package:emergency/services/country_code_sources/country_code_source.dart';
import 'package:emergency/services/location_service.dart';

/// Einfache manuelle Fakes statt Mocking-Package (siehe AP4-Vorgabe: kein
/// neues Mocking-Package einführen). Beide Basisklassen sind nicht `final`/
/// `sealed`, daher genügt es, `load`/`lookup` bzw. `resolveCountryCode` zu
/// überschreiben, statt ein eigenes Interface einzuführen.
class _FakeRepository extends EmergencyNumberRepository {
  _FakeRepository({this.loadError, this.countryToReturn});

  Object? loadError;
  Country? countryToReturn;
  int loadCallCount = 0;

  @override
  Future<void> load() async {
    loadCallCount++;
    final error = loadError;
    if (error != null) throw error;
  }

  @override
  Country? lookup(String isoCode) => countryToReturn;
}

/// Nur zur Erfüllung des `super()`-Konstruktors von [LocationService] nötig
/// (wird nie aufgerufen, da [_FakeLocationService.resolveCountryCode]
/// überschrieben ist). Ohne einen expliziten `gpsSource` würde
/// `LocationService()` intern ein echtes `GpsCountryCodeSource` (und damit
/// `Geocoding()`) konstruieren, was außerhalb eines registrierten
/// Platform-Interface (siehe `gps_country_code_source_test.dart`) sofort wirft.
class _NoopSource implements CountryCodeSource {
  const _NoopSource();

  @override
  Future<String?> resolve() async => null;
}

class _FakeLocationService extends LocationService {
  _FakeLocationService(this.isoCode)
      : super(simSource: const _NoopSource(), gpsSource: const _NoopSource());

  /// Simuliert das Ergebnis der automatischen Kette (SIM → GPS → Cache).
  String? isoCode;

  /// Simuliert die manuelle Auswahl (AP6): hat, analog zur echten
  /// Priorisierung in `LocationService`, Vorrang vor [isoCode].
  String? manualIsoCode;

  int resolveCallCount = 0;
  int setManualCallCount = 0;
  String? lastManualCode;

  @override
  Future<String?> resolveCountryCode() async {
    resolveCallCount++;
    return manualIsoCode ?? isoCode;
  }

  @override
  Future<void> setManualCountryCode(String? code) async {
    setManualCallCount++;
    lastManualCode = code;
    manualIsoCode = code;
  }
}

const _germany = Country(
  isoCode: 'DE',
  nameDe: 'Deutschland',
  nameEn: 'Germany',
  flag: '🇩🇪',
  numbers: [
    EmergencyNumber(type: EmergencyType.general, number: '112', labelDe: 'Notruf', labelEn: 'Emergency'),
  ],
);

const _france = Country(
  isoCode: 'FR',
  nameDe: 'Frankreich',
  nameEn: 'France',
  flag: '🇫🇷',
  numbers: [
    EmergencyNumber(type: EmergencyType.general, number: '112', labelDe: 'Notruf', labelEn: 'Emergency'),
  ],
);

void main() {
  group('EmergencyProvider.init()', () {
    test('erfolgreicher Durchlauf -> status ready mit Land', () async {
      final provider = EmergencyProvider(
        repository: _FakeRepository(countryToReturn: _germany),
        locationService: _FakeLocationService('DE'),
      );

      await provider.init();

      expect(provider.status, EmergencyStatus.ready);
      expect(provider.country, _germany);
      expect(provider.errorMessage, isNull);
    });

    test('Ländercode nicht ermittelbar -> status countryUnknown', () async {
      final provider = EmergencyProvider(
        repository: _FakeRepository(countryToReturn: _germany),
        locationService: _FakeLocationService(null),
      );

      await provider.init();

      expect(provider.status, EmergencyStatus.countryUnknown);
      expect(provider.country, isNull);
    });

    test('Land nicht in Datenbasis -> status ready mit country == null', () async {
      final provider = EmergencyProvider(
        repository: _FakeRepository(countryToReturn: null),
        locationService: _FakeLocationService('XX'),
      );

      await provider.init();

      expect(provider.status, EmergencyStatus.ready);
      expect(provider.country, isNull);
    });

    test('repository.load() wirft -> status error mit errorMessage', () async {
      final repository = _FakeRepository(loadError: const FormatException('kaputtes Asset'));
      final locationService = _FakeLocationService('DE');
      final provider = EmergencyProvider(repository: repository, locationService: locationService);

      await provider.init();

      expect(provider.status, EmergencyStatus.error);
      expect(provider.errorMessage, isNotNull);
      expect(repository.loadCallCount, 1);
      // Ländererkennung darf nach einem Ladefehler nicht mehr angestoßen werden.
      expect(locationService.resolveCallCount, 0);
    });

    test('durchläuft die Status initializing -> locating -> ready', () async {
      final provider = EmergencyProvider(
        repository: _FakeRepository(countryToReturn: _germany),
        locationService: _FakeLocationService('DE'),
      );

      final observedStatuses = <EmergencyStatus>[];
      provider.addListener(() => observedStatuses.add(provider.status));

      await provider.init();

      expect(observedStatuses, [
        EmergencyStatus.initializing,
        EmergencyStatus.locating,
        EmergencyStatus.ready,
      ]);
    });
  });

  group('EmergencyProvider.retry()', () {
    test('wiederholt init() und kann nach einem Fehler erfolgreich sein', () async {
      final repository = _FakeRepository(
        loadError: const FormatException('kaputtes Asset'),
        countryToReturn: _germany,
      );
      final locationService = _FakeLocationService('DE');
      final provider = EmergencyProvider(repository: repository, locationService: locationService);

      await provider.init();
      expect(provider.status, EmergencyStatus.error);
      expect(repository.loadCallCount, 1);

      repository.loadError = null;
      await provider.retry();

      expect(provider.status, EmergencyStatus.ready);
      expect(provider.country, _germany);
      expect(provider.errorMessage, isNull);
      expect(repository.loadCallCount, 2);
    });
  });

  group('EmergencyProvider.selectCountryManually()', () {
    test('persistiert die Auswahl und stößt init() erneut an', () async {
      final repository = _FakeRepository(countryToReturn: _germany);
      final locationService = _FakeLocationService('DE');
      final provider = EmergencyProvider(repository: repository, locationService: locationService);

      await provider.init();
      expect(provider.country, _germany);

      repository.countryToReturn = _france;
      await provider.selectCountryManually('FR');

      expect(locationService.setManualCallCount, 1);
      expect(locationService.lastManualCode, 'FR');
      // init() wurde ein zweites Mal komplett durchlaufen.
      expect(locationService.resolveCallCount, 2);
      expect(provider.status, EmergencyStatus.ready);
      expect(provider.country, _france);
    });
  });

  group('EmergencyProvider.clearManualSelection()', () {
    test('löscht die manuelle Auswahl und ermittelt danach erneut automatisch', () async {
      // isoCode simuliert das Ergebnis der automatischen Kette (z. B. SIM),
      // manualIsoCode eine bereits zuvor gesetzte manuelle Auswahl.
      final locationService = _FakeLocationService('DE')..manualIsoCode = 'FR';
      final repository = _FakeRepository(countryToReturn: _france);
      final provider = EmergencyProvider(repository: repository, locationService: locationService);

      await provider.init();
      expect(provider.country, _france); // manuelle Auswahl hat Vorrang

      repository.countryToReturn = _germany;
      await provider.clearManualSelection();

      expect(locationService.setManualCallCount, 1);
      expect(locationService.lastManualCode, isNull);
      expect(locationService.manualIsoCode, isNull);
      expect(locationService.resolveCallCount, 2);
      expect(provider.status, EmergencyStatus.ready);
      // Nach dem Löschen greift wieder das automatische Ergebnis (DE).
      expect(provider.country, _germany);
    });
  });

  group('EmergencyProvider.repository', () {
    test('exponiert das intern verwendete Repository', () {
      final repository = _FakeRepository(countryToReturn: _germany);
      final provider = EmergencyProvider(
        repository: repository,
        locationService: _FakeLocationService('DE'),
      );

      expect(provider.repository, same(repository));
    });
  });
}