import 'package:riverpod_annotation/riverpod_annotation.dart';
import 'package:shuffle/core/routing/app_routes.dart';
import 'package:shuffle/features/auth/domain/auth_failure.dart';
import 'package:shuffle/features/auth/domain/resend_origin.dart';
import 'package:shuffle/features/auth/domain/validation/email_format.dart';
import 'package:shuffle/features/auth/presentation/check_email/resend_controller.dart';
import 'package:shuffle/features/auth/presentation/login/login_state.dart';
import 'package:shuffle/features/auth/presentation/providers/auth_providers.dart';
import 'package:shuffle/features/auth/presentation/providers/auth_redirect.dart';

part 'login_controller.g.dart';

/// Logic of the sign-in form (KTO-01 Kriterien 5, 6 und 7).
@riverpod
class LoginController extends _$LoginController {
  @override
  LoginState build() => const LoginState();

  void emailChanged(String value) {
    state = state.copyWith(email: value);
  }

  void passwordChanged(String value) {
    state = state.copyWith(password: value);
  }

  /// Field left: show its error.
  void fieldBlurred(LoginField field) {
    state = state.copyWith(visibleFields: {...state.visibleFields, field});
  }

  /// Validates and signs in. Returns the path to continue to on success
  /// (the validated `from` target, otherwise the start page), `null` if the
  /// user stays on the screen. A second call while one runs does nothing.
  Future<String?> submit({String? from}) async {
    if (state.isSubmitting) {
      return null;
    }
    state = state.copyWith(
      status: LoginStatus.submitting,
      visibleFields: LoginField.values.toSet(),
      bannerFailure: null,
      unconfirmedEmail: null,
      focusField: null,
    );
    // A new attempt starts without the result of an earlier resend.
    ref.invalidate(resendControllerProvider);

    final invalid = state.firstInvalidField;
    if (invalid != null) {
      state = state.copyWith(
        status: LoginStatus.editing,
        focusField: invalid,
        focusRequest: state.focusRequest + 1,
      );
      return null;
    }

    final email = EmailFormat.normalize(state.email);
    final result = await ref
        .read(authRepositoryProvider)
        .signIn(email, state.password);
    final failure = result.errorOrNull;
    if (failure == null) {
      // Success: the target is returned even if the screen is already gone
      // (the router redirect can remove it before this future completes), so
      // the caller can still finish the autofill context. The status stays
      // `submitting`, the form is not reused after a successful sign-in.
      return safeFromPath(from) ?? AppRoutes.home;
    }
    if (!ref.mounted) {
      return null;
    }
    state = state.copyWith(
      status: LoginStatus.editing,
      bannerFailure: failure,
      unconfirmedEmail: failure is EmailNotConfirmed ? email : null,
    );
    return null;
  }

  /// "Resend confirmation email" after `emailNotConfirmed` (Kriterium 6).
  /// The password was right, so a mail-limit answer is shown (F12).
  Future<void> resendConfirmation() async {
    final email = state.unconfirmedEmail;
    if (email == null) {
      return;
    }
    await ref
        .read(resendControllerProvider.notifier)
        .resend(email, origin: ResendOrigin.login);
  }
}