我有一个Flutter应用程序的基础上这个初学者模板https://github.com/bizz84/starter_architecture_flutter_firebase
如何在此模板上创建基于角色的访问权限？我有一个User模型，它有一个属性String role。如果角色是“admin”，则用户可以访问所有页面。如果角色是“accountant”，则用户不应该访问“/filiais”分支/路由。
我想不出如何用路由器和河荚连接这个。
这是app.dart：

class MyApp extends ConsumerWidget {
  const MyApp({super.key});
  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final goRouter = ref.watch(goRouterProvider);
    return MaterialApp.router(
      routerConfig: goRouter,
      theme: ThemeData(
        primarySwatch: Colors.deepOrange,
        unselectedWidgetColor: Colors.grey,
        appBarTheme: const AppBarTheme(
          elevation: 2.0,
          centerTitle: true,
        ),
        scaffoldBackgroundColor: Colors.grey[200],
        dividerColor: Colors.grey[400],
        // https://github.com/firebase/flutterfire/blob/master/packages/firebase_ui_auth/doc/theming.md
        outlinedButtonTheme: OutlinedButtonThemeData(
          style: ButtonStyle(
            backgroundColor: MaterialStateProperty.all<Color>(Colors.indigo),
            foregroundColor: MaterialStateProperty.all<Color>(Colors.white),
          ),
        ),
      ),
      debugShowCheckedModeBanner: false,
      localizationsDelegates: [
        FirebaseUILocalizations.withDefaultOverrides(LabelOverrides()),
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,
        FirebaseUILocalizations.delegate,
      ],
    );
  }
}

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这是app_router.dart

part 'app_router.g.dart';
// private navigators
final _rootNavigatorKey = GlobalKey<NavigatorState>();
final _estoqueNavigatorKey = GlobalKey<NavigatorState>(debugLabel: 'estoque');
final _filiaisNavigatorKey = GlobalKey<NavigatorState>(debugLabel: 'filiais');
final _pricesNavigatorKey = GlobalKey<NavigatorState>(debugLabel: 'prices');
enum AppRoute {
  onboarding,
  signIn,
  profile,
  filiais,
  filial,
  addFilial,
  editFilial,
  estoque,
  prices
}
@riverpod
// ignore: unsupported_provider_value
GoRouter goRouter(GoRouterRef ref) {
  final authRepository = ref.watch(authRepositoryProvider);
  final onboardingRepository = ref.watch(onboardingRepositoryProvider);
  return GoRouter(
    initialLocation: '/signIn',
    navigatorKey: _rootNavigatorKey,
    debugLogDiagnostics: true,
    redirect: (context, state) {
      final didCompleteOnboarding = onboardingRepository.isOnboardingComplete();
      if (!didCompleteOnboarding) {
        // Always check state.subloc before returning a non-null route
        // https://github.com/flutter/packages/blob/main/packages/go_router/example/lib/redirection.dart#L78
        if (state.location != '/onboarding') {
          return '/onboarding';
        }
      }
      final currentUser = authRepository.currentUser;
      final isLoggedIn = currentUser != null;
      if (isLoggedIn) {
        if (state.location.startsWith('/signIn')) {
          return '/precos';
        }
      } else {
        if (state.location.startsWith('/precos') ||
            state.location.startsWith('/estoque') ||
            state.location.startsWith('/filiais')) {
          return '/signIn';
        }
      }
      return null;
    },
    refreshListenable: GoRouterRefreshStream(authRepository.authStateChanges()),
    routes: [
      GoRoute(
        path: '/onboarding',
        name: AppRoute.onboarding.name,
        pageBuilder: (context, state) => const NoTransitionPage(
          child: OnboardingScreen(),
        ),
      ),
      GoRoute(
        path: '/signIn',
        name: AppRoute.signIn.name,
        pageBuilder: (context, state) => const NoTransitionPage(
          child: CustomSignInScreen(),
        ),
      ),
      // Stateful navigation based on:
      // https://github.com/flutter/packages/blob/main/packages/go_router/example/lib/stateful_shell_route.dart
      StatefulShellRoute.indexedStack(
        builder: (context, state, navigationShell) {
          return ScaffoldWithNestedNavigation(navigationShell: navigationShell);
        },
        branches: [
          StatefulShellBranch(
            navigatorKey: _pricesNavigatorKey,
            routes: [
              GoRoute(
                path: '/precos',
                name: AppRoute.prices.name,
                pageBuilder: (context, state) => const NoTransitionPage(
                  child: PricesScreen(),
                ),
              ),
            ],
          ),
          StatefulShellBranch(
            navigatorKey: _estoqueNavigatorKey,
            routes: [
              GoRoute(
                path: '/estoque',
                name: AppRoute.estoque.name,
                pageBuilder: (context, state) => const NoTransitionPage(
                  child: EstoqueScreen(),
                ),
              ),
            ],
          ),
          // this branch is not accountant related, accountants should not see this
          StatefulShellBranch(
            navigatorKey: _filiaisNavigatorKey,
            routes: [
              GoRoute(
                path: '/filiais',
                name: AppRoute.filiais.name,
                pageBuilder: (context, state) => const NoTransitionPage(
                  child: FiliaisScreen(),
                ),
                routes: [
                  GoRoute(
                    path: 'add',
                    name: AppRoute.addFilial.name,
                    parentNavigatorKey: _rootNavigatorKey,
                    pageBuilder: (context, state) {
                      return const MaterialPage(
                        fullscreenDialog: true,
                        child: EditFilialScreen(),
                      );
                    },
                  ),
                  GoRoute(
                      path: ':id',
                      name: AppRoute.editFilial.name,
                      pageBuilder: (context, state) {
                        final filialId = state.pathParameters['id'];
                        final filial = state.extra as Filial?;
                        return MaterialPage(
                          fullscreenDialog: true,
                          child: EditFilialScreen(filialId: filialId, filial: filial),
                        );
                      }),
                ],
              ),
            ],
          ),
        ],
      ),
    ],
    //errorBuilder: (context, state) => const NotFoundScreen(),
  );
}

型
我还没有尝试过任何东西，因为我无法理解如何处理这个问题。