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

/// Shell for the admin panel. On screens 640px wide and below it shows a
/// bottom NavigationBar; on wider viewports it switches to a NavigationRail
/// so admins can sweep through tabs with a single click on web/desktop.
class AdminShell extends StatelessWidget {
  const AdminShell({super.key, required this.child});

  final Widget child;

  static const _tabs = <_AdminTab>[
    _AdminTab(
      label: 'EVENTS',
      icon: Icons.event_outlined,
      activeIcon: Icons.event,
      path: '/admin/events',
    ),
    _AdminTab(
      label: 'TEAMS',
      icon: Icons.groups_outlined,
      activeIcon: Icons.groups,
      path: '/admin/teams',
    ),
    _AdminTab(
      label: 'BRACKETS',
      icon: Icons.account_tree_outlined,
      activeIcon: Icons.account_tree,
      path: '/admin/brackets',
    ),
    _AdminTab(
      label: 'IDEAS',
      icon: Icons.lightbulb_outline,
      activeIcon: Icons.lightbulb,
      path: '/admin/suggestions',
    ),
    _AdminTab(
      label: 'PENDING',
      icon: Icons.pending_actions_outlined,
      activeIcon: Icons.pending_actions,
      path: '/admin/pending',
    ),
  ];

  int _currentIndex(BuildContext context) {
    final location = GoRouterState.of(context).uri.path;
    final idx = _tabs.indexWhere((t) => location.startsWith(t.path));
    return idx < 0 ? 0 : idx;
  }

  @override
  Widget build(BuildContext context) {
    final currentIndex = _currentIndex(context);
    return Scaffold(
      appBar: AppBar(
        title: const Text('ADMIN'),
        leading: IconButton(
          icon: const Icon(Icons.arrow_back),
          tooltip: 'Back to app',
          onPressed: () => context.go('/events'),
        ),
      ),
      body: LayoutBuilder(
        builder: (context, constraints) {
          final isWide = constraints.maxWidth >= 640;
          if (isWide) {
            return Row(
              children: <Widget>[
                NavigationRail(
                  selectedIndex: currentIndex,
                  onDestinationSelected: (i) => context.go(_tabs[i].path),
                  labelType: NavigationRailLabelType.all,
                  destinations: _tabs
                      .map(
                        (t) => NavigationRailDestination(
                          icon: Icon(t.icon),
                          selectedIcon: Icon(t.activeIcon),
                          label: Text(t.label),
                        ),
                      )
                      .toList(),
                ),
                const VerticalDivider(width: 1),
                Expanded(child: child),
              ],
            );
          }
          return child;
        },
      ),
      bottomNavigationBar: LayoutBuilder(
        builder: (context, constraints) {
          final isWide = constraints.maxWidth >= 640;
          if (isWide) return const SizedBox.shrink();
          return Column(
            mainAxisSize: MainAxisSize.min,
            children: <Widget>[
              Container(height: 1, color: const Color(0xFF8B30C8)),
              NavigationBar(
                selectedIndex: currentIndex,
                onDestinationSelected: (i) => context.go(_tabs[i].path),
                destinations: _tabs
                    .map(
                      (t) => NavigationDestination(
                        icon: Icon(t.icon),
                        selectedIcon: Icon(t.activeIcon),
                        label: t.label,
                      ),
                    )
                    .toList(),
              ),
            ],
          );
        },
      ),
    );
  }
}

class _AdminTab {
  const _AdminTab({
    required this.label,
    required this.icon,
    required this.activeIcon,
    required this.path,
  });

  final String label;
  final IconData icon;
  final IconData activeIcon;
  final String path;
}