import 'package:dio/dio.dart';
import 'package:flutter_test/flutter_test.dart';
import 'package:marianum_mobile/api/demo/demo_mode.dart';
import 'package:marianum_mobile/api/marianumconnect/queries/auth_guardian/auth_guardian_request.dart';
import 'package:marianum_mobile/api/marianumconnect/queries/auth_guardian/auth_guardian_verify.dart';
import 'package:marianum_mobile/api/marianumconnect/queries/auth_guardian/guardian_login_exception.dart';
import 'package:marianum_mobile/api/marianumconnect/queries/auth_login/auth_login_response.dart';
import 'package:marianum_mobile/auth_link/device_binding.dart';
import 'package:marianum_mobile/auth_link/guardian_login_link.dart';
import 'package:marianum_mobile/auth_link/pending_guardian_request.dart';
import 'package:marianum_mobile/session/session.dart';
import 'package:marianum_mobile/view/login/guardian_login_controller.dart';

final _now = DateTime.utc(2026, 9, 19, 12);

class _FakeStore implements PendingGuardianRequestStore {
  PendingGuardianRequest? stored;

  @override
  Future<PendingGuardianRequest?> read() async => stored;

  @override
  Future<void> write(PendingGuardianRequest request) async => stored = request;

  @override
  Future<void> clear() async => stored = null;
}

class _FakeRequest implements AuthGuardianRequest {
  String? lastChallenge;
  int calls = 0;

  @override
  Future<AuthGuardianRequestResponse> run({
    required String email,
    required String deviceChallenge,
    required String tokenName,
  }) async {
    calls++;
    lastChallenge = deviceChallenge;
    return AuthGuardianRequestResponse(
      requestId: 'req-$calls',
      expiresAt: _now.add(const Duration(minutes: 15)),
      resendAvailableAt: _now.add(const Duration(seconds: 60)),
      codeLength: 6,
    );
  }

  @override
  dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
}

class _FakeVerify implements AuthGuardianVerify {
  Object? failWith;
  Map<String, String?>? lastCall;

  @override
  Future<AuthLoginResponse> run({
    required String requestId,
    required String deviceVerifier,
    required String tokenName,
    String? code,
    String? linkToken,
  }) async {
    lastCall = {
      'requestId': requestId,
      'deviceVerifier': deviceVerifier,
      'code': code,
      'linkToken': linkToken,
    };
    final failure = failWith;
    if (failure != null) throw failure;
    return AuthLoginResponse(
      token: 't',
      tokenId: 'id',
      expiresAt: null,
      user: AuthLoginUser(
        id: 'u',
        username: 'e@x.de',
        firstName: '',
        lastName: '',
        userType: 'PARENT',
        className: null,
      ),
    );
  }

  @override
  dynamic noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
}

GuardianLoginException _error(GuardianLoginError error) =>
    GuardianLoginException(error, userMessage: error.name);

void main() {
  late _FakeStore store;
  late _FakeRequest request;
  late _FakeVerify verify;
  late List<Session> signedIn;
  late DateTime now;

  GuardianLoginController controller() => GuardianLoginController(
    request: request,
    verify: verify,
    store: store,
    signIn: (s) async => signedIn.add(s),
    tokenName: () async => 'test',
    now: () => now,
  );

  setUp(() {
    store = _FakeStore();
    request = _FakeRequest();
    verify = _FakeVerify();
    signedIn = [];
    now = _now;
  });

  test(
    'requesting a code persists the request and moves to the code step',
    () async {
      final c = controller();
      expect(await c.requestCode('  E@X.de '), isFalse);
      expect(c.step, GuardianLoginStep.enterCode);
      expect(store.stored?.email, 'e@x.de');
      expect(
        request.lastChallenge,
        DeviceBinding.challengeFor(store.stored!.deviceSecret),
      );
    },
  );

  test(
    'a valid code signs in with the device secret and clears the request',
    () async {
      final c = controller();
      await c.requestCode('e@x.de');
      final secret = store.stored!.deviceSecret;
      expect(await c.submitCode('123 456'), isTrue);
      expect(verify.lastCall?['code'], '123456');
      expect(verify.lastCall?['deviceVerifier'], secret);
      expect(store.stored, isNull);
      expect(signedIn.single, isA<GuardianSession>());
      expect((signedIn.single as GuardianSession).isDemo, isFalse);
    },
  );

  test('a wrong code keeps the request for another try', () async {
    final c = controller();
    await c.requestCode('e@x.de');
    verify.failWith = _error(GuardianLoginError.invalidCode);
    expect(await c.submitCode('000000'), isFalse);
    expect(c.step, GuardianLoginStep.enterCode);
    expect(c.errorMessage, isNotNull);
    expect(store.stored, isNotNull);
  });

  test('an expired request falls back to the e-mail step', () async {
    final c = controller();
    await c.requestCode('e@x.de');
    verify.failWith = _error(GuardianLoginError.requestExpired);
    await c.submitCode('123456');
    expect(c.step, GuardianLoginStep.enterEmail);
    expect(store.stored, isNull);
  });

  test(
    'a link for another request is rejected without a server call',
    () async {
      final c = controller();
      await c.requestCode('e@x.de');
      final ok = await c.submitLink(
        const GuardianLoginLink(requestId: 'other', linkToken: 'lt'),
      );
      expect(ok, isFalse);
      expect(verify.lastCall, isNull);
      expect(c.errorMessage, contains('anderen Gerät'));
    },
  );

  test('a matching link signs in', () async {
    final c = controller();
    await c.requestCode('e@x.de');
    final ok = await c.submitLink(
      GuardianLoginLink(requestId: store.stored!.requestId, linkToken: 'lt'),
    );
    expect(ok, isTrue);
    expect(verify.lastCall?['linkToken'], 'lt');
  });

  test('restore resumes an open request and drops an expired one', () async {
    await controller().requestCode('e@x.de');
    final resumed = controller();
    await resumed.restore();
    expect(resumed.step, GuardianLoginStep.enterCode);

    now = _now.add(const Duration(hours: 1));
    final late = controller();
    await late.restore();
    expect(late.step, GuardianLoginStep.enterEmail);
    expect(store.stored, isNull);
  });

  test('resend is only possible after the cooldown', () async {
    final c = controller();
    await c.requestCode('e@x.de');
    expect(c.canResend(), isFalse);
    await c.resend();
    expect(request.calls, 1);
    now = _now.add(const Duration(seconds: 61));
    expect(c.canResend(), isTrue);
    await c.resend();
    expect(request.calls, 2);
  });

  test('the demo address signs in locally', () async {
    final c = controller();
    expect(await c.requestCode(DemoMode.guardianEmail), isTrue);
    expect(request.calls, 0);
    expect(signedIn.single.isDemo, isTrue);
  });

  group('GuardianLoginException.fromDio', () {
    DioException failure(int status, Object? body) => DioException(
      requestOptions: RequestOptions(),
      type: DioExceptionType.badResponse,
      response: Response(
        requestOptions: RequestOptions(),
        statusCode: status,
        data: body,
      ),
    );

    test('reads the JSON error body', () {
      final e =
          GuardianLoginException.fromDio(
                failure(401, {'error': 'invalid_code', 'attemptsLeft': 2}),
              )
              as GuardianLoginException;
      expect(e.error, GuardianLoginError.invalidCode);
      expect(e.attemptsLeft, 2);
      expect(e.userMessage, contains('Noch 2 Versuche'));
    });

    test('reads the plain-text error of the generic server handler', () {
      final e =
          GuardianLoginException.fromDio(
                failure(403, 'Fehler: device_mismatch'),
              )
              as GuardianLoginException;
      expect(e.error, GuardianLoginError.deviceMismatch);
    });

    test('falls back to the status code', () {
      final e =
          GuardianLoginException.fromDio(failure(429, null))
              as GuardianLoginException;
      expect(e.error, GuardianLoginError.rateLimited);
    });

    test('names an address the school has no guardian access for', () {
      final e =
          GuardianLoginException.fromDio(
                failure(404, {'error': 'email_not_registered'}),
              )
              as GuardianLoginException;
      expect(e.error, GuardianLoginError.emailNotRegistered);
      expect(e.userMessage, contains('Sekretariat'));
    });

    test('a bare 404 means the server lacks guardian login, not an '
        'unknown address', () {
      for (final body in <Object?>[null, 'Not Found', 'Endpoint not found']) {
        final e =
            GuardianLoginException.fromDio(failure(404, body))
                as GuardianLoginException;
        expect(e.error, GuardianLoginError.unsupportedServer, reason: '$body');
      }
      final methodMissing =
          GuardianLoginException.fromDio(failure(405, null))
              as GuardianLoginException;
      expect(methodMissing.error, GuardianLoginError.unsupportedServer);
    });

    test('names a disabled guardian account', () {
      final e =
          GuardianLoginException.fromDio(
                failure(403, {'error': 'account_disabled'}),
              )
              as GuardianLoginException;
      expect(e.error, GuardianLoginError.accountDisabled);
    });

    test('server errors keep the generic mapping', () {
      expect(
        GuardianLoginException.fromDio(failure(500, 'boom')),
        isNot(isA<GuardianLoginException>()),
      );
    });
  });
}