mobile-app/lib/core/widgets/app_shell.dart

import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:real_estate_mobile/core/services/push_notification_service.dart';
import 'package:real_estate_mobile/core/widgets/app_bottom_nav_bar.dart';
import 'package:real_estate_mobile/features/home/presentation/widgets/home_header.dart';

/// Root shell that provides the persistent header and bottom nav bar.
/// Only the content area (child) swaps when navigating between tabs.
class AppShell extends StatefulWidget {
  final Widget child;

  const AppShell({super.key, required this.child});

  @override
  State<AppShell> createState() => _AppShellState();
}

class _AppShellState extends State<AppShell> {
  @override
  void initState() {
    super.initState();
    // Wire push notification taps to GoRouter navigation
    PushNotificationService().onNotificationTap = (actionUrl) {
      if (mounted && actionUrl != null && actionUrl.isNotEmpty) {
        context.go(actionUrl);
      } else if (mounted) {
        context.go('/notifications');
      }
    };
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      body: Column(
        children: [
          SafeArea(
            bottom: false,
            child: const HomeHeader(),
          ),
          Expanded(
            child: AnimatedSwitcher(
              duration: const Duration(milliseconds: 150),
              switchOutCurve: Curves.easeIn,
              switchInCurve: Curves.easeOut,
              layoutBuilder: (currentChild, previousChildren) {
                return Stack(
                  children: [
                    ...previousChildren,
                    if (currentChild != null) currentChild,
                  ],
                );
              },
              transitionBuilder: (child, animation) {
                return FadeTransition(
                  opacity: animation,
                  child: child,
                );
              },
              child: KeyedSubtree(
                key: ValueKey(GoRouterState.of(context).uri.toString()),
                child: widget.child,
              ),
            ),
          ),
        ],
      ),
      bottomNavigationBar: const AppBottomNavBar(),
    );
  }
}