import 'package:flutter/material.dart';

import '../../features/auth/application/auth_controller.dart';
import '../../features/auth/presentation/login_screen.dart';
import '../../features/dashboard/presentation/dashboard_screen.dart';
import '../../features/profile/presentation/profile_screen.dart';
import '../../features/review/presentation/review_entry_screen.dart';
import '../../features/review_history/presentation/review_history_screen.dart';
import '../../shared/storage/session_store.dart';

class AiContractAppShell extends StatefulWidget {
  const AiContractAppShell({super.key});

  @override
  State<AiContractAppShell> createState() => _AiContractAppShellState();
}

class _AiContractAppShellState extends State<AiContractAppShell> {
  int _currentIndex = 0;
  late final AuthController _authController;

  @override
  void initState() {
    super.initState();
    _authController = AuthController();
  }

  @override
  Widget build(BuildContext context) {
    return ValueListenableBuilder(
      valueListenable: SessionStore.listenable,
      builder: (context, session, _) {
        final destinations = const [
          _ShellDestination(
            label: '工作台',
            icon: Icons.space_dashboard_outlined,
            screen: DashboardScreen(),
          ),
          _ShellDestination(
            label: '发起审查',
            icon: Icons.description_outlined,
            screen: ReviewEntryScreen(),
          ),
          _ShellDestination(
            label: '审查记录',
            icon: Icons.history_outlined,
            screen: ReviewHistoryScreen(),
          ),
          _ShellDestination(
            label: '我的',
            icon: Icons.person_outline,
            screen: ProfileScreen(),
          ),
        ];

        final destination = destinations[_currentIndex];
        final isAuthenticated = session?.isAuthenticated ?? false;

        return Scaffold(
          appBar: AppBar(
            title: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(destination.label),
                Text(
                  isAuthenticated ? '已登录 · ${session!.userDisplayName}' : 'AI 合同平台 · Android First',
                  style: Theme.of(context).textTheme.labelSmall,
                ),
              ],
            ),
          ),
          body: SafeArea(
            child: isAuthenticated
                ? AnimatedSwitcher(
                    duration: const Duration(milliseconds: 240),
                    child: destination.screen,
                  )
                : LoginScreen(controller: _authController),
          ),
          bottomNavigationBar: NavigationBar(
            selectedIndex: _currentIndex,
            onDestinationSelected: (index) {
              setState(() {
                _currentIndex = index;
              });
            },
            destinations: destinations
                .map(
                  (item) => NavigationDestination(
                    icon: Icon(item.icon),
                    label: item.label,
                  ),
                )
                .toList(),
          ),
        );
      },
    );
  }
}

class _ShellDestination {
  const _ShellDestination({
    required this.label,
    required this.icon,
    required this.screen,
  });

  final String label;
  final IconData icon;
  final Widget screen;
}