import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../ui/app_shell.dart';
import '../ui/async_state_views.dart';
import '../../features/auth/data/auth_providers.dart';
import '../../features/auth/presentation/login_screen.dart';
import '../../features/profile/presentation/profile_screen.dart';
import '../../features/recipes/presentation/recipes_screen.dart';

final appRouterProvider = Provider<GoRouter>((ref) {
  final authState = ref.watch(authStateProvider);

  return GoRouter(
    initialLocation: '/',
    redirect: (context, state) {
      final isLoading = authState.isLoading;
      final token = authState.valueOrNull;
      final isLoggedIn = token != null && token.isNotEmpty;
      final location = state.matchedLocation;
      final isSplash = location == '/';
      final isLogin = location == '/login';

      // Keep user on splash while auth state is being resolved from storage.
      if (isLoading) {
        return isSplash ? null : '/';
      }

      // Redirect away from splash once auth is known.
      if (isSplash) {
        return isLoggedIn ? '/recipes' : '/login';
      }

      // Unauthenticated user trying to reach a protected route.
      if (!isLoggedIn && !isLogin) {
        return '/login';
      }

      // Authenticated user landing on login.
      if (isLoggedIn && isLogin) {
        return '/recipes';
      }

      return null;
    },
    routes: [
      GoRoute(
        path: '/',
        builder: (context, state) => const Scaffold(
          body: LoadingStateView(label: 'Startar...'),
        ),
      ),
      GoRoute(
        path: '/login',
        builder: (context, state) => const LoginScreen(),
      ),
      ShellRoute(
        builder: (context, state, child) {
          return AppShell(location: state.uri.path, child: child);
        },
        routes: [
          GoRoute(
            path: '/recipes',
            builder: (context, state) => const RecipesScreen(),
          ),
          GoRoute(
            path: '/profile',
            builder: (context, state) => const ProfileScreen(),
          ),
        ],
      ),
    ],
  );
});