worldhopper/lib/screens/shell/main_shell_screen.dart

import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import 'package:worldhopper/config/router.dart';
import 'package:worldhopper/l10n/app_localizations.dart';
import 'package:worldhopper/helpers/responsive_helper.dart';
import 'package:worldhopper/providers/navigation_provider.dart';

/// Shell widget that provides the bottom navigation bar
/// and handles tab switching for the main app sections
class MainShellScreen extends ConsumerStatefulWidget {
  final StatefulNavigationShell navigationShell;

  const MainShellScreen({
    super.key,
    required this.navigationShell,
  });

  @override
  ConsumerState<MainShellScreen> createState() => _MainShellScreenState();
}

class _MainShellScreenState extends ConsumerState<MainShellScreen> {
  bool _initialized = false;

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();

    if (!_initialized) {
      _initialized = true;
      // Load saved tab index and navigate to it
      final savedIndex = ref.read(navigationStateProvider);
      if (savedIndex != widget.navigationShell.currentIndex) {
        // Delay navigation to allow widget tree to build
        WidgetsBinding.instance.addPostFrameCallback((_) {
          widget.navigationShell.goBranch(savedIndex, initialLocation: true);
        });
      }
    }
  }

  void _onDestinationSelected(int index) {
    // Persist the tab change
    ref.read(navigationStateProvider.notifier).setTabIndex(index);

    // If re-tapping the same tab, pop any Navigator-pushed routes
    // (e.g. sub-settings screens) back to the branch root
    if (index == widget.navigationShell.currentIndex) {
      final navigatorKey = AppRouter.branchNavigatorKeys[index];
      navigatorKey.currentState?.popUntil((route) => route.isFirst);
    }

    // Navigate to the selected tab
    widget.navigationShell.goBranch(
      index,
      initialLocation: index == widget.navigationShell.currentIndex,
    );
  }

  @override
  Widget build(BuildContext context) {
    final l10n = AppLocalizations.of(context);
    final wide = isWideScreen(MediaQuery.of(context).size.width);

    if (wide) {
      return Scaffold(
        body: Row(
          children: [
            NavigationRail(
              labelType: NavigationRailLabelType.all,
              selectedIndex: widget.navigationShell.currentIndex,
              onDestinationSelected: _onDestinationSelected,
              destinations: [
                NavigationRailDestination(
                  icon: const Icon(Icons.auto_stories_outlined),
                  selectedIcon: const Icon(Icons.auto_stories),
                  label: Text(l10n.navLibrary),
                ),
                NavigationRailDestination(
                  icon: const Icon(Icons.dns_outlined),
                  selectedIcon: const Icon(Icons.dns),
                  label: Text(l10n.navServers),
                ),
                NavigationRailDestination(
                  icon: const Icon(Icons.settings_outlined),
                  selectedIcon: const Icon(Icons.settings),
                  label: Text(l10n.navSettings),
                ),
              ],
            ),
            const VerticalDivider(thickness: 1, width: 1),
            Expanded(child: widget.navigationShell),
          ],
        ),
      );
    }

    return Scaffold(
      body: widget.navigationShell,
      bottomNavigationBar: NavigationBar(
        selectedIndex: widget.navigationShell.currentIndex,
        onDestinationSelected: _onDestinationSelected,
        destinations: [
          NavigationDestination(
            icon: const Icon(Icons.auto_stories_outlined),
            selectedIcon: const Icon(Icons.auto_stories),
            label: l10n.navLibrary,
          ),
          NavigationDestination(
            icon: const Icon(Icons.dns_outlined),
            selectedIcon: const Icon(Icons.dns),
            label: l10n.navServers,
          ),
          NavigationDestination(
            icon: const Icon(Icons.settings_outlined),
            selectedIcon: const Icon(Icons.settings),
            label: l10n.navSettings,
          ),
        ],
      ),
    );
  }
}