import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:tatlock_ui/routing/app_router.dart';
import 'package:tatlock_ui/shared/layouts/widgets/top_header_bar.dart';

/// Main application scaffold with top header navigation.
///
/// Layout structure per UI_LAYOUT.md:
/// ```
/// ┌─────────────────────────────────────────────────────────────────┐
/// │  HEADER: [Logo] [Room Tabs] [Profile]                           │
/// ├─────────────────────────────────────────────────────────────────┤
/// │  BODY: Room page content (may include room-specific sidebar)    │
/// └─────────────────────────────────────────────────────────────────┘
/// ```
class AppScaffold extends StatelessWidget {
  const AppScaffold({super.key, required this.child});

  final Widget child;

  // Header height must match TopHeaderBar._headerHeight
  static const double _headerHeight = 56.0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: [
          // Main content area with top padding for header
          Positioned.fill(
            child: Padding(
              padding: const EdgeInsets.only(top: _headerHeight),
              child: child,
            ),
          ),

          // Top header overlays content (bulge extends into content area)
          Positioned(
            top: 0,
            left: 0,
            right: 0,
            child: TopHeaderBar(
              selectedIndex: _selectedIndex(context),
              onRoomSelected: (index) => _onNavSelected(context, index),
            ),
          ),
        ],
      ),
    );
  }

  int _selectedIndex(BuildContext context) {
    final location = GoRouterState.of(context).matchedLocation;

    if (location.startsWith(AppRoutes.controlRoom)) return 1;
    if (location.startsWith(AppRoutes.parlor)) return 2;
    // Settings is no longer in main nav (accessed via Profile dropdown)
    return 0; // Front Hall
  }

  void _onNavSelected(BuildContext context, int index) {
    final route = switch (index) {
      0 => AppRoutes.frontHall,
      1 => AppRoutes.controlRoom,
      2 => AppRoutes.parlor,
      _ => AppRoutes.frontHall,
    };
    context.go(route);
  }
}