import 'package:dio/dio.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../core/auth_storage.dart';
import '../core/team_selection_storage.dart';
import '../shared/api_client.dart';
import '../shared/models/user.dart';

class AuthState {
  const AuthState({
    this.user,
    this.accessToken,
    this.refreshToken,
    this.loading = false,
    this.error,
  });

  final User? user;
  final String? accessToken;
  final String? refreshToken;
  final bool loading;
  final String? error;

  bool get isAuthenticated =>
      accessToken != null && accessToken!.isNotEmpty && user != null;

  AuthState copyWith({
    User? user,
    String? accessToken,
    String? refreshToken,
    bool? loading,
    String? error,
    bool clearError = false,
  }) {
    return AuthState(
      user: user ?? this.user,
      accessToken: accessToken ?? this.accessToken,
      refreshToken: refreshToken ?? this.refreshToken,
      loading: loading ?? this.loading,
      error: clearError ? null : (error ?? this.error),
    );
  }
}

class AuthNotifier extends StateNotifier<AuthState> {
  AuthNotifier() : super(const AuthState());

  void setSession({
    required User user,
    required String accessToken,
    required String refreshToken,
  }) {
    state = AuthState(
      user: user,
      accessToken: accessToken,
      refreshToken: refreshToken,
      loading: false,
    );
    AuthStorage.save(
      user: user,
      accessToken: accessToken,
      refreshToken: refreshToken,
    );
  }

  Future<void> restoreSession() async {
    final stored = await AuthStorage.load();
    if (stored == null) return;
    state = AuthState(
      user: stored.user,
      accessToken: stored.accessToken,
      refreshToken: stored.refreshToken,
      loading: false,
    );
  }

  /// Dopo restore: verifica token o rinnova con refresh (evita 401 su /teams).
  Future<bool> validateOrRefreshSession() async {
    if (!state.isAuthenticated) return false;

    final client = ApiClient(accessToken: state.accessToken);
    try {
      final user = await client.me();
      state = state.copyWith(user: user);
      await AuthStorage.save(
        user: user,
        accessToken: state.accessToken!,
        refreshToken: state.refreshToken!,
      );
      return true;
    } on DioException catch (e) {
      if (e.response?.statusCode != 401) {
        return true;
      }
    } catch (_) {
      return true;
    }

    return refreshSession();
  }

  Future<bool> refreshSession() async {
    final refreshToken = state.refreshToken;
    if (refreshToken == null || refreshToken.isEmpty) {
      logout();
      return false;
    }

    try {
      final client = ApiClient();
      final result = await client.refreshSession(refreshToken);
      setSession(
        user: result.user,
        accessToken: result.tokens.accessToken,
        refreshToken: result.tokens.refreshToken,
      );
      return true;
    } catch (_) {
      logout();
      return false;
    }
  }

  void setLoading(bool loading) {
    state = state.copyWith(loading: loading, clearError: true);
  }

  void setError(String message) {
    state = state.copyWith(loading: false, error: message);
  }

  void logout() {
    state = const AuthState();
    AuthStorage.clear();
    TeamSelectionStorage.clear();
  }
}

final authProvider = StateNotifierProvider<AuthNotifier, AuthState>(
  (ref) => AuthNotifier(),
);