import 'package:flutter/material.dart';
import 'package:pad_scanner/services/app_config_service.dart';
import 'package:pad_scanner/pages/settings_page.dart';
import 'package:pad_scanner/pages/registration_page.dart';
import 'package:pad_scanner/pages/boxing_page.dart';
import 'package:pad_scanner/services/api_service.dart';

/// Module type enum for each available feature card
enum ModuleType { registration, boxing, shelfQuery }

/// Module status for PRD state tracking
enum ModuleStatus { online, developing, planning }

/// Function card data model per PRD §3.3
class FeatureCard {
  final ModuleType type;
  final IconData icon;
  final String title;
  final String description;
  final ModuleStatus status;
  final String? version;
  final String route;

  const FeatureCard({
    required this.type,
    required this.icon,
    required this.title,
    required this.description,
    required this.status,
    this.version,
    required this.route,
  });
}

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

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  final _apiService = ApiService();
  bool _isCheckingConnection = false;
  bool _isConnected = false;
  String _apiAddress = '';

  /// Module registry from PRD §3.4
  static const _modules = [
    FeatureCard(
      type: ModuleType.registration,
      icon: Icons.local_shipping_outlined,
      title: '上架登记',
      description: '扫码绑定总排号与货位',
      status: ModuleStatus.online,
      version: 'v1.0',
      route: '/registration',
    ),
    FeatureCard(
      type: ModuleType.boxing,
      icon: Icons.view_list_outlined,
      title: '装箱编号',
      description: '查询箱号、录入装箱明细',
      status: ModuleStatus.online,
      version: 'v1.0',
      route: '/boxing',
    ),
    FeatureCard(
      type: ModuleType.shelfQuery,
      icon: Icons.search_outlined,
      title: '货架查询',
      description: '按合同查询货架库存',
      status: ModuleStatus.planning,
      version: null,
      route: '',
    ),
  ];

  @override
  void initState() {
    super.initState();
    _checkConnection();
  }

  Future<void> _checkConnection() async {
    final configService = AppConfigService();
    final url = await configService.getString('api_url') ?? '';
    if (url.isEmpty) {
      setState(() {
        _isConnected = false;
        _apiAddress = '';
        _isCheckingConnection = false;
      });
      return;
    }

    setState(() => _isCheckingConnection = true);
    final ok = await _apiService.testConnection(url);
    if (!mounted) return;
    setState(() {
      _isConnected = ok;
      _apiAddress = url;
      _isCheckingConnection = false;
    });
  }

  void _onCardTap(FeatureCard card) {
    switch (card.status) {
      case ModuleStatus.online:
        _navigateToModule(card.type);
      case ModuleStatus.developing:
        _showToast('该功能正在开发中');
      case ModuleStatus.planning:
        _showToast('该功能规划中');
    }
  }

  void _showToast(String message) {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text(message), duration: const Duration(seconds: 2)),
    );
  }

  void _navigateToModule(ModuleType type) {
    late Widget targetPage;
    switch (type) {
      case ModuleType.registration:
        targetPage = const RegistrationPage();
        break;
      case ModuleType.boxing:
        targetPage = const BoxingPage();
        break;
      case ModuleType.shelfQuery:
        return; // 规划中，不导航
    }
    Navigator.push(
      context,
      MaterialPageRoute(builder: (_) => targetPage),
    ).then((_) => _checkConnection());
  }

  void _navigateToSettings() {
    Navigator.push(
      context,
      MaterialPageRoute(builder: (_) => const SettingsPage()),
    ).then((_) => _checkConnection());
  }

  Color _getConnectionStatusColor() {
    if (_isCheckingConnection) return Colors.orange;
    return _isConnected ? Colors.green : Colors.red;
  }

  String _getConnectionStatusText() {
    if (_isCheckingConnection) return '● 正在检测连接...';
    if (!_isConnected || _apiAddress.isEmpty) return '● 未连接，请检查设置';
    return '● 已连接 $_apiAddress';
  }

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;

    return Scaffold(
      appBar: AppBar(
        title: const Text('CargoTrace'),
        actions: [
          Padding(
            padding: const EdgeInsets.only(right: 8),
            child: IconButton(
              icon: const Icon(Icons.settings),
              onPressed: _navigateToSettings,
            ),
          ),
        ],
      ),
      body: Column(
        children: [
          // Function cards area
          Expanded(
            child: ListView.builder(
              padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
              itemCount: _modules.length,
              itemBuilder: (context, index) {
                final card = _modules[index];
                return _buildFeatureCard(context, card);
              },
            ),
          ),

          // Bottom connection status bar
          Container(
            width: double.infinity,
            padding: const EdgeInsets.symmetric(vertical: 10, horizontal: 16),
            color: colorScheme.surfaceContainerHighest,
            child: Row(
              children: [
                Container(
                  width: 8,
                  height: 8,
                  decoration: BoxDecoration(
                    color: _getConnectionStatusColor(),
                    shape: BoxShape.circle,
                  ),
                ),
                const SizedBox(width: 8),
                Expanded(
                  child: Text(
                    _getConnectionStatusText(),
                    style: const TextStyle(fontSize: 13),
                    overflow: TextOverflow.ellipsis,
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildFeatureCard(BuildContext context, FeatureCard card) {
    final Color statusBgColor;
    final TextStyle statusTextStyle;
    final String statusText;

    switch (card.status) {
      case ModuleStatus.online:
        statusBgColor = Colors.green.shade700;
        statusTextStyle = const TextStyle(color: Colors.white, fontSize: 12);
        statusText = card.version ?? '已上线';
        break;
      case ModuleStatus.developing:
        statusBgColor = Colors.blue.shade700;
        statusTextStyle = const TextStyle(color: Colors.white, fontSize: 12);
        statusText = '开发中';
        break;
      case ModuleStatus.planning:
        statusBgColor = Colors.grey.shade500;
        statusTextStyle = const TextStyle(color: Colors.white, fontSize: 12);
        statusText = '规划中';
        break;
    }

    final canNavigate = card.status == ModuleStatus.online;

    return Padding(
      padding: const EdgeInsets.only(bottom: 16),
      child: InkWell(
        onTap: () => _onCardTap(card),
        borderRadius: BorderRadius.circular(8),
        child: Container(
          padding: const EdgeInsets.all(16),
          decoration: BoxDecoration(
            color: canNavigate ? Colors.white : Colors.grey.shade200,
            borderRadius: BorderRadius.circular(8),
            boxShadow: [
              BoxShadow(
                color: Colors.black.withValues(alpha: 0.05),
                blurRadius: 4,
                offset: const Offset(0, 2),
              ),
            ],
          ),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              // First row: icon + module name
              Row(
                children: [
                  Icon(
                    card.icon,
                    size: 22,
                    color: canNavigate ? Colors.blue : Colors.grey,
                  ),
                  const SizedBox(width: 8),
                  Text(
                    card.title,
                    style: TextStyle(
                      fontSize: 16,
                      fontWeight: FontWeight.bold,
                      color: canNavigate ? Colors.black87 : Colors.grey,
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 6),
              // Second row: description
              Text(
                card.description,
                style: TextStyle(fontSize: 13, color: Colors.grey.shade600),
              ),
              const SizedBox(height: 10),
              // Third row: status badge (right aligned)
              Align(
                alignment: Alignment.centerRight,
                child: Container(
                  padding: const EdgeInsets.symmetric(
                    horizontal: 8,
                    vertical: 3,
                  ),
                  decoration: BoxDecoration(
                    color: statusBgColor,
                    borderRadius: BorderRadius.circular(4),
                  ),
                  child: Row(
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Text(statusText, style: statusTextStyle),
                      if (card.status == ModuleStatus.online) ...[
                        const SizedBox(width: 6),
                        Container(
                          width: 6,
                          height: 6,
                          decoration: const BoxDecoration(
                            color: Colors.white,
                            shape: BoxShape.circle,
                          ),
                        ),
                      ] else ...[
                        const SizedBox(width: 6),
                        Container(
                          width: 6,
                          height: 6,
                          decoration: BoxDecoration(
                            color: Colors.white.withValues(alpha: 0.5),
                            shape: BoxShape.circle,
                          ),
                        ),
                      ],
                    ],
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}