import 'dart:convert';
import 'package:chepuhagram/core/constants.dart';
import 'package:chepuhagram/domain/services/api_service.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import '../screens/settings_screen.dart';
import '../screens/new_chat_screen.dart';
import '../screens/chat_screen.dart';
import 'my_profile_screen.dart';
import '/logic/contact_provider.dart';
import '/logic/auth_provider.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_messaging/firebase_messaging.dart';
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
import 'package:chepuhagram/domain/services/crypto_service.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:chepuhagram/main.dart';
import 'dart:async';
import 'package:http/http.dart' as http;
import 'package:package_info_plus/package_info_plus.dart';
import 'dart:io';
import 'package:dio/dio.dart';
import 'package:path_provider/path_provider.dart';
import 'package:open_filex/open_filex.dart';
import '/data/datasources/ws_client.dart';
import '/data/models/contact_model.dart';
import '/data/models/message_model.dart';
import '/data/repositories/contact_repository.dart';
import 'user_profile_screen.dart';
import 'admin_broadcast_screen.dart';
import 'package:url_launcher/url_launcher.dart';
import 'dart:math' as math;
import 'package:cached_network_image/cached_network_image.dart';

class ContactsScreen extends StatefulWidget {
  final int? targetChatId;

  const ContactsScreen({super.key, this.targetChatId});

  @override
  State<ContactsScreen> createState() => _ContactsScreenState();
}

class _ContactsScreenState extends State<ContactsScreen> with RouteAware {
  static const String _notificationLaunchKey = 'notification_launch_data';
  StreamSubscription<dynamic>? _socketSubscription;
  bool _isDownloading = false;
  double _downloadProgress = 0.0;
  int _downloadedBytes = 0;
  int _downloadTotalBytes = 0;
  int _apkFileSizeBytes = 0;
  CancelToken? _cancelToken = CancelToken();
  String? _latestApkUrl;
  bool _showUpdateBanner = false;
  bool _contactsLoaded = false;
  Timer? _contactLoadTimer;

  Contact? _selectedContact;
  Contact? _profileContact;
  double _contactsPaneWidth = 290;
  double _profilePaneWidth = 360;

  final double _collapsedContactsWidth = 80;
  final double _minExpandedContactsWidth = 290;
  final double _maxExpandedContactsWidth = 500;
  double _dragStartWidth = 0;

  // Адаптивное состояние навигации
  int _currentIndex = 0;
  bool _isLeftRailExpanded = false;

  // Хранилище стабильно загруженных локальных имён
  Map<int, String> _localFullNames = {};

  final Map<int, int> _pendingUnreadCounters = {};

  bool _isSearchMode = false;
  final TextEditingController _searchController = TextEditingController();
  final List<Contact> _searchChatResults = [];
  final List<Contact> _searchNewResults = [];
  bool _isSearchLoading = false;
  String? _searchError;
  Timer? _searchDebounce;

  @override
  void initState() {
    super.initState();
    print('ContactsScreen initState, targetChatId: ${widget.targetChatId}');
    _setupPushNotifications();
    final socketService = Provider.of<SocketService>(context, listen: false);
    _socketSubscription = socketService.messages.listen(_handleIncomingMessage);
    WidgetsBinding.instance.addPostFrameCallback((_) {
      final authProvider = context.read<AuthProvider>();
      final contactProvider = context.read<ContactProvider>();

      print(
        'Setting current user ID in ContactProvider: ${authProvider.currentUserId}',
      );
      contactProvider.setCurrentUserId(authProvider.currentUserId);
      _startContactsLoadTimer();
    });
  }

  // Метод стабильной потокобезопасной подгрузки локальных имён из кэша
  Future<void> _loadLocalNames() async {
    final prefs = await SharedPreferences.getInstance();
    final contactProvider = context.read<ContactProvider>();
    final Map<int, String> tempNames = {};

    for (var contact in contactProvider.contacts) {
      final String? fName = prefs.getString('firstname_${contact.id}');
      final String? lName = prefs.getString('lastname_${contact.id}');
      if (fName != null || lName != null) {
        tempNames[contact.id] = '${fName ?? ''} ${lName ?? ''}'.trim();
      }
    }
    if (mounted) {
      setState(() {
        _localFullNames = tempNames;
      });
    }
  }

  Future<void> _startContactsLoadTimer() async {
    if (_contactLoadTimer != null && _contactLoadTimer!.isActive) return;
    _contactLoadTimer = Timer(const Duration(seconds: 2), () {
      _initContacts();
    });
  }

  Future<void> _initContacts() async {
    if (_contactsLoaded) return;
    final contactProvider = context.read<ContactProvider>();
    await contactProvider.loadContacts();
    await _loadLocalNames(); // Гарантированный вызов после загрузки контактов

    print('Contacts loaded, checking targetChatId: ${widget.targetChatId}');

    WidgetsBinding.instance.addPostFrameCallback((_) {
      _checkAppUpdate();
    });

    if (widget.targetChatId != null) {
      _navigateToTargetChat();
    } else {
      _checkSavedNotificationTarget();
    }
    _contactLoadTimer?.cancel();
    _contactLoadTimer = null;
    _contactsLoaded = true;
  }

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    routeObserver.subscribe(this, ModalRoute.of(context) as PageRoute);
  }

  @override
  void didPopNext() async {
    print("Пользователь вернулся на этот экран!");
    await _refreshData();
  }

  @override
  void dispose() {
    routeObserver.unsubscribe(this);
    _socketSubscription?.cancel();
    _searchController.dispose();
    _searchDebounce?.cancel();
    super.dispose();
  }

  Future<void> _refreshData() async {
    print("Обновляем данные контактов и сообщений...");
    final contactProvider = context.read<ContactProvider>();
    await contactProvider.loadContacts();
    await _loadLocalNames(); // Синхронизируем локальные имена при возврате
  }

  Future<void> _checkSavedNotificationTarget() async {
    final prefs = await SharedPreferences.getInstance();
    final savedData = prefs.getString(_notificationLaunchKey);
    if (savedData == null) {
      print('No saved notification data found in SharedPreferences');
      return;
    }

    try {
      final data = jsonDecode(savedData) as Map<String, dynamic>;
      print('Recovered saved notification data: $data');
      final senderId = int.tryParse(data['sender_id']?.toString() ?? '');
      final type = data['type']?.toString();

      if (senderId != null && (type == null || type == 'enc_message')) {
        print('Recovered targetChatId from saved data: $senderId');
        await prefs.remove(_notificationLaunchKey);
        _navigateToTargetChatWithId(senderId);
        return;
      }

      print('Saved notification data is not a valid payload: $data');
      await prefs.remove(_notificationLaunchKey);
    } catch (e) {
      print('Error parsing saved notification data: $e');
      await prefs.remove(_notificationLaunchKey);
    }
  }

  void _navigateToTargetChat() {
    if (widget.targetChatId == null) return;
    _navigateToTargetChatWithId(widget.targetChatId!);
  }

  void _navigateToTargetChatWithId(int targetChatId) {
    print('_navigateToTargetChat called with targetChatId: $targetChatId');
    final contactProvider = context.read<ContactProvider>();
    try {
      final contact = contactProvider.contacts.firstWhere(
        (c) => c.id == targetChatId,
      );
      print('Auto-navigating to chat with contact: ${contact.username}');
      _selectContact(contact);
    } catch (e) {
      print('Target contact with id $targetChatId not found: $e');
    }
  }

  bool _isMobileLayout(BuildContext context) {
    return MediaQuery.of(context).size.width < 700;
  }

  bool _isTabletLayout(BuildContext context) {
    final width = MediaQuery.of(context).size.width;
    return width >= 700 && width < 1000;
  }

  bool _isDesktopLayout(BuildContext context) {
    return MediaQuery.of(context).size.width >= 1000;
  }

  void _selectContact(Contact contact) {
    setState(() {
      _selectedContact = contact;
      _pendingUnreadCounters.remove(contact.id);
      if (_profileContact != null && _isDesktopLayout(context)) {
        _profileContact = contact;
      }
      currentActiveChatContactId = contact.id;
    });
  }

  void _openProfile(Contact contact) {
    if (_isDesktopLayout(context)) {
      setState(() {
        _profileContact = contact;
      });
      return;
    }

    if (_isTabletLayout(context)) {
      showModalBottomSheet<void>(
        context: context,
        isScrollControlled: true,
        builder: (context) => SizedBox(
          height: MediaQuery.of(context).size.height * 0.85,
          child: UserProfileScreen(
            userId: contact.id,
            username: contact.username,
            name: contact.name,
          ),
        ),
      );
      return;
    }

    Navigator.push(
      context,
      MaterialPageRoute(
        builder: (_) => UserProfileScreen(
          userId: contact.id,
          username: contact.username,
          name: contact.name,
        ),
      ),
    );
  }

  void _clearSelectedContact() {
    setState(() {
      _selectedContact = null;
      if (!_isDesktopLayout(context)) {
        _profileContact = null;
      }
      currentActiveChatContactId = null;
    });
  }

  void _toggleSearchMode(bool enabled) {
    setState(() {
      _isSearchMode = enabled;
      if (enabled && _contactsPaneWidth <= _collapsedContactsWidth) {
        _contactsPaneWidth = _minExpandedContactsWidth;
      }
      if (!enabled) {
        _searchController.clear();
        _searchChatResults.clear();
        _searchError = null;
        _isSearchLoading = false;
      }
    });
  }

  void _onSearchQueryChanged(String query) {
    setState(() {});
    _searchDebounce?.cancel();
    _searchDebounce = Timer(const Duration(milliseconds: 250), () {
      _executeSearch(query);
    });
  }

  Future<void> _executeSearch(String query) async {
    final trimmedQuery = query.trim();
    if (trimmedQuery.isEmpty) {
      setState(() {
        _searchChatResults.clear();
        _searchError = null;
        _isSearchLoading = false;
      });
      return;
    }

    setState(() {
      _isSearchLoading = true;
      _searchError = null;
    });

    try {
      final contactRepository = ContactRepository();
      final chats = await contactRepository.fetchChatContacts(
        query: trimmedQuery,
      );
      final allUsers = await contactRepository.fetchAllUsers(
        query: trimmedQuery,
      );
      final activeChatIds = chats.map((contact) => contact.id).toSet();
      final otherUsers = allUsers.where((contact) {
        return !activeChatIds.contains(contact.id) &&
            contact.id != context.read<AuthProvider>().currentUserId;
      }).toList();

      setState(() {
        _searchChatResults
          ..clear()
          ..addAll(chats);
        _searchNewResults
          ..clear()
          ..addAll(otherUsers);
        _searchError = null;
        _isSearchLoading = false;
      });
    } catch (e) {
      setState(() {
        _searchError = e.toString();
        _searchChatResults.clear();
        _searchNewResults.clear();
        _isSearchLoading = false;
      });
    }
  }

  Widget _buildSearchTextField(ColorScheme colorScheme) {
    return SizedBox(
      height: 46,
      child: TextField(
        controller: _searchController,
        autofocus: true,
        textInputAction: TextInputAction.search,
        decoration: InputDecoration(
          hintText: 'Найти пользователя или чат',
          prefixIcon: const Icon(Icons.search_rounded),
          suffixIcon: IconButton(
            icon: const Icon(Icons.close_rounded),
            onPressed: () {
              _toggleSearchMode(false);
            },
          ),
          filled: true,
          fillColor: colorScheme.surfaceVariant.withOpacity(0.16),
          border: OutlineInputBorder(
            borderRadius: BorderRadius.circular(14),
            borderSide: BorderSide.none,
          ),
          contentPadding: const EdgeInsets.symmetric(
            horizontal: 12,
            vertical: 10,
          ),
        ),
        onChanged: _onSearchQueryChanged,
        onSubmitted: _executeSearch,
      ),
    );
  }

  Widget _buildSearchResultTile(Contact contact, {required bool isChat}) {
    final localName = _localFullNames[contact.id];
    final displayName = (localName != null && localName.isNotEmpty)
        ? localName
        : '${contact.name != 'Unknown' ? contact.name : ''} ${contact.surname != 'Unknown' ? contact.surname : ''}'
              .trim();
    final title = displayName.isNotEmpty ? displayName : contact.username;
    final subtitle = contact.username.isNotEmpty
        ? '@${contact.username}'
        : 'ID: ${contact.id}';

    return ListTile(
      contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 6),
      leading: CircleAvatar(
        backgroundColor: Theme.of(context).colorScheme.primaryContainer,
        foregroundColor: Theme.of(context).colorScheme.onPrimaryContainer,
        child: Text(
          title
              .split(RegExp(r'\s+'))
              .take(2)
              .map((part) => part.isNotEmpty ? part[0].toUpperCase() : '')
              .join(),
        ),
      ),
      title: Text(title, style: const TextStyle(fontWeight: FontWeight.w600)),
      subtitle: Text(subtitle, maxLines: 1, overflow: TextOverflow.ellipsis),
      trailing: isChat ? null : const Icon(Icons.person_add_outlined, size: 20),
      onTap: () {
        _selectContact(contact);
        _toggleSearchMode(false);
      },
    );
  }

  Widget _buildSearchResults() {
    if (_searchError != null) {
      return Center(
        child: Padding(
          padding: const EdgeInsets.all(24),
          child: Text(
            'Ошибка поиска: $_searchError',
            textAlign: TextAlign.center,
            style: Theme.of(context).textTheme.bodyLarge,
          ),
        ),
      );
    }

    if (_searchController.text.trim().length < 2) {
      return _buildPlaceholder('Введите минимум 2 символа для поиска.');
    }

    if (_isSearchLoading) {
      return const Center(child: CircularProgressIndicator());
    }

    if (_searchChatResults.isEmpty && _searchNewResults.isEmpty) {
      return _buildPlaceholder('Ничего не найдено. Попробуйте другой запрос.');
    }

    final children = <Widget>[];
    if (_searchChatResults.isNotEmpty) {
      children.add(
        Padding(
          padding: const EdgeInsets.fromLTRB(16, 16, 16, 8),
          child: Text(
            'Активные чаты',
            style: Theme.of(context).textTheme.titleMedium,
          ),
        ),
      );
      children.addAll(
        _searchChatResults.map(
          (contact) => _buildSearchResultTile(contact, isChat: true),
        ),
      );
    }
    if (_searchNewResults.isNotEmpty) {
      children.add(
        Padding(
          padding: const EdgeInsets.fromLTRB(16, 24, 16, 8),
          child: Text(
            'Пользователи',
            style: Theme.of(context).textTheme.titleMedium,
          ),
        ),
      );
      children.addAll(
        _searchNewResults.map(
          (contact) => _buildSearchResultTile(contact, isChat: false),
        ),
      );
    }

    return ListView(physics: const BouncingScrollPhysics(), children: children);
  }

  Widget _buildPlaceholder(String text) {
    return Center(
      child: Padding(
        padding: const EdgeInsets.all(24.0),
        child: Text(
          text,
          textAlign: TextAlign.center,
          style: Theme.of(context).textTheme.titleLarge?.copyWith(
            color: Theme.of(context).colorScheme.onSurfaceVariant,
          ),
        ),
      ),
    );
  }

  Widget _buildContactsPane() {
    return Consumer<ContactProvider>(
      builder: (context, contactProvider, child) {
        if (_isSearchMode) {
          return _buildSearchResults();
        }
        if (contactProvider.isLoading) {
          return const Center(child: CircularProgressIndicator());
        }
        if (contactProvider.error != null) {
          return Center(
            child: Text(
              '${contactProvider.error?.replaceAll('Exception: ', '')}',
              style: TextStyle(color: Theme.of(context).colorScheme.error),
              textAlign: TextAlign.center,
            ),
          );
        }

        final isCollapsed =
            !_isMobileLayout(context) &&
            (_contactsPaneWidth <= _collapsedContactsWidth);

        if (contactProvider.contacts.isEmpty) {
          return _buildPlaceholder(
            'Список чатов пуст. Нажмите карандаш, чтобы начать.',
          );
        }

        return ListView.separated(
          physics: const BouncingScrollPhysics(),
          itemCount: contactProvider.contacts.length,
          separatorBuilder: (context, index) => Divider(
            height: 1,
            indent: isCollapsed ? 12 : 84,
            endIndent: 12,
            color: Theme.of(
              context,
            ).colorScheme.outlineVariant.withOpacity(0.15),
          ),
          itemBuilder: (context, index) {
            final contact = contactProvider.contacts[index];
            final colorScheme = Theme.of(context).colorScheme;
            final isSelected = _selectedContact?.id == contact.id;

            final localName = _localFullNames[contact.id];
            final displayName = (localName != null && localName.isNotEmpty)
                ? localName
                : '${contact.name != 'Unknown' ? contact.name : ''} ${contact.surname != 'Unknown' ? contact.surname : ''}'
                      .trim();

            final contactInitials = displayName.isNotEmpty
                ? displayName
                      .trim()
                      .split(RegExp(r'\s+'))
                      .take(2)
                      .map((e) => e[0].toUpperCase())
                      .join()
                : '?';

            String timeText = '';
            if (contact.lastMessageTime != null) {
              final localTime = contact.lastMessageTime!.toLocal();
              timeText =
                  '${localTime.hour.toString().padLeft(2, '0')}:${localTime.minute.toString().padLeft(2, '0')}';
            }

            final bool isLastMessageEmpty =
                contact.lastMessage != null &&
                contact.lastMessage!.trim().isEmpty;
            final String displayLastMessage = isLastMessageEmpty
                ? contact.lastMessageType != null
                      ? MessageModel.getMediaPreview(contact.lastMessageType!)
                      : 'Вложение'
                : (contact.lastMessage ?? 'Нет сообщений');

            return Padding(
              // ФИКС ОВЕРФЛОУ: уменьшаем внешний отступ при сжатии до 4px (было 8)
              padding: EdgeInsets.symmetric(
                horizontal: isCollapsed ? 4 : 8,
                vertical: 2,
              ),
              child: InkWell(
                onTap: () => _selectContact(contact),
                borderRadius: BorderRadius.circular(16),
                child: AnimatedContainer(
                  duration: const Duration(milliseconds: 150),
                  // ФИКС ОВЕРФЛОУ: уменьшаем внутренний отступ при сжатии до 6px (было 12)
                  padding: EdgeInsets.symmetric(
                    horizontal: isCollapsed ? 6 : 12,
                    vertical: 10,
                  ),
                  decoration: BoxDecoration(
                    color: isSelected
                        ? colorScheme.primaryContainer.withOpacity(0.4)
                        : Colors.transparent,
                    borderRadius: BorderRadius.circular(16),
                  ),
                  child: Row(
                    // Центрируем аватарку по оси, когда колонка зажата
                    mainAxisAlignment: isCollapsed
                        ? MainAxisAlignment.center
                        : MainAxisAlignment.start,
                    children: [
                      ContactAvatar(
                        key: ValueKey('avatar_${contact.id}'),
                        initials: contactInitials,
                        avatarUrl: contact.avatarUrl,
                        isOnline: contact.isOnline,
                        isSelected: isSelected,
                        colorScheme: colorScheme,
                      ),

                      if (!isCollapsed) ...[
                        const SizedBox(width: 14),
                        Expanded(
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children: [
                              Row(
                                mainAxisAlignment:
                                    MainAxisAlignment.spaceBetween,
                                children: [
                                  Expanded(
                                    child: Text(
                                      displayName,
                                      style: const TextStyle(
                                        fontWeight: FontWeight.bold,
                                        fontSize: 16,
                                        letterSpacing: -0.3,
                                      ),
                                      maxLines: 1,
                                      overflow: TextOverflow.ellipsis,
                                    ),
                                  ),
                                  if (timeText.isNotEmpty)
                                    Text(
                                      timeText,
                                      style: TextStyle(
                                        color: colorScheme.outline,
                                        fontSize: 12,
                                        fontWeight: FontWeight.w500,
                                      ),
                                    ),
                                ],
                              ),
                              const SizedBox(height: 5),
                              const SizedBox(height: 5),
                              Row(
                                mainAxisAlignment:
                                    MainAxisAlignment.spaceBetween,
                                children: [
                                  Expanded(
                                    child: AnimatedSwitcher(
                                      duration: const Duration(
                                        milliseconds: 600,
                                      ),
                                      reverseDuration: const Duration(
                                        milliseconds: 200,
                                      ),
                                      switchInCurve: Curves.easeInOutCubic,
                                      switchOutCurve: Curves.easeInOutCubic,
                                      transitionBuilder:
                                          (
                                            Widget child,
                                            Animation<double> animation,
                                          ) {
                                            return Align(
                                              alignment: Alignment.centerLeft,
                                              child: FadeTransition(
                                                opacity: animation,
                                                child: SlideTransition(
                                                  position: Tween<Offset>(
                                                    begin: const Offset(
                                                      0.0,
                                                      0.15,
                                                    ),
                                                    end: Offset.zero,
                                                  ).animate(animation),
                                                  child: child,
                                                ),
                                              ),
                                            );
                                          },
                                      child: _buildAnimatedLastMessage(
                                        contact: contact,
                                        displayLastMessage: displayLastMessage,
                                        isLastMessageEmpty: isLastMessageEmpty,
                                        colorScheme: colorScheme,
                                      ),
                                    ),
                                  ),
                                  if (contact.unreadCount > 0)
                                    Container(
                                      padding: const EdgeInsets.symmetric(
                                        horizontal: 7,
                                        vertical: 3,
                                      ),
                                      decoration: BoxDecoration(
                                        color: colorScheme.primary,
                                        borderRadius: BorderRadius.circular(10),
                                      ),
                                      constraints: const BoxConstraints(
                                        minWidth: 20,
                                      ),
                                      child: Text(
                                        '${contact.unreadCount}',
                                        style: const TextStyle(
                                          color: Colors.white,
                                          fontSize: 11,
                                          fontWeight: FontWeight.bold,
                                        ),
                                        textAlign: TextAlign.center,
                                      ),
                                    ),
                                ],
                              ),
                            ],
                          ),
                        ),
                      ],
                    ],
                  ),
                ),
              ),
            );
          },
        );
      },
    );
  }

  Widget _buildAnimatedLastMessage({
    required Contact contact,
    required String displayLastMessage,
    required bool isLastMessageEmpty,
    required ColorScheme colorScheme,
  }) {
    if (contact.lastMessage == null) {
      return Text(
        'Нет сообщений',
        key: ValueKey('empty_${contact.id}'),
        style: TextStyle(
          color: colorScheme.onSurfaceVariant.withOpacity(0.5),
          fontSize: 14,
        ),
        maxLines: 1,
        overflow: TextOverflow.ellipsis,
      );
    }

    // Состояние дешифровки
    if (!contact.isLastMsgDecrypted) {
      return Row(
        key: ValueKey('decrypting_${contact.id}'),
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          SizedBox(
            width: 10,
            height: 10,
            child: CircularProgressIndicator(
              strokeWidth: 1.2,
              valueColor: AlwaysStoppedAnimation<Color>(
                colorScheme.primary.withOpacity(0.6),
              ),
            ),
          ),
          const SizedBox(width: 6),

          // КРИТИЧЕСКИЙ ФИКС: Flexible защищает от Overflow, если колонка чатов сильно сжата
          Flexible(
            child: Text(
              'Дешифровка...', // Сократили текст, чтобы он гарантированно не ломал UI
              style: TextStyle(
                color: colorScheme.primary.withOpacity(0.7),
                fontSize: 13,
                fontWeight: FontWeight.w500,
              ),
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
            ),
          ),
        ],
      );
    }

    // Полностью расшифрованный текст
    return Text(
      displayLastMessage,
      key: ValueKey('decrypted_${contact.id}_$displayLastMessage'),
      style: TextStyle(
        color: colorScheme.onSurfaceVariant,
        fontSize: 14,
        fontStyle: isLastMessageEmpty ? FontStyle.italic : FontStyle.normal,
      ),
      maxLines: 1,
      overflow: TextOverflow.ellipsis,
    );
  }

  Widget _buildChatPane() {
    if (_selectedContact == null) {
      return _buildPlaceholder('Выберите чат слева, чтобы начать переписку.');
    }
    return ChatScreen(
      key: ValueKey(_selectedContact!.id),
      contact: _selectedContact!,
      onOpenProfile: _openProfile,
      onBack: _clearSelectedContact,
      showBackButton: false,
      onMessageRead: (contactId, nextAnchorId) {
        final contactProvider = context.read<ContactProvider>();
        final contact = contactProvider.contacts.firstWhere(
          (c) => c.id == contactId,
          orElse: () => _selectedContact!,
        );

        int currentUnread =
            _pendingUnreadCounters[contactId] ?? contact.unreadCount;

        if (contact.unreadCount > currentUnread &&
            !_pendingUnreadCounters.containsKey(contactId)) {
          currentUnread = contact.unreadCount;
        }

        if (currentUnread > 0) {
          final newCount = currentUnread - 1;

          _pendingUnreadCounters[contactId] = newCount;

          contactProvider.updateContact(
            contactId,
            unreadCount: newCount,
            firstUnreadMessageId: nextAnchorId,
          );
        }
      },
    );
  }

  Widget _buildProfilePane() {
    final contact = _profileContact;
    if (contact == null) {
      return _buildPlaceholder('Профиль выбранного пользователя будет здесь.');
    }
    return UserProfileScreen(
      key: ValueKey(contact.id),
      userId: contact.id,
      username: contact.username,
      name: contact.name,
      onClose: () {
        setState(() {
          _profileContact = null;
        });
      },
    );
  }

  Widget _buildContactsListWithScaffold(bool isPhone) {
    final colorScheme = Theme.of(context).colorScheme;
    final isCollapsed =
        !isPhone && (_contactsPaneWidth <= _collapsedContactsWidth);

    Widget bodyWidget;
    String titleText = "Chepuhagram";
    bool showSearch = true;

    if (isPhone) {
      switch (_currentIndex) {
        case 2:
          titleText = "Профиль";
          showSearch = false;
          bodyWidget = const MyProfileScreen(isFromList: true);
          break;
        case 1:
          titleText = "Настройки";
          showSearch = false;
          bodyWidget = const SettingsScreen(isFromList: true);
          break;
        case 0:
        default:
          titleText = "Chepuhagram";
          showSearch = true;
          bodyWidget = _buildContactsPane();
          break;
      }
    } else {
      bodyWidget = _buildContactsPane();
    }

    return Scaffold(
      backgroundColor: isPhone ? colorScheme.background : Colors.transparent,
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        elevation: 0,
        scrolledUnderElevation: 0,
        title: _isSearchMode
            ? _buildSearchTextField(colorScheme)
            : Text(
                titleText,
                style: TextStyle(
                  color: colorScheme.onBackground,
                  fontWeight: FontWeight.w800,
                  fontSize: 24,
                  letterSpacing: -0.5,
                ),
              ),
        centerTitle: false,
        actions: [
          if (showSearch && !_isSearchMode)
            Padding(
              padding: const EdgeInsets.only(right: 16.0),
              child: ClipOval(
                child: Material(
                  child: IconButton(
                    icon: Icon(Icons.search_rounded, size: 22),
                    color: colorScheme.onBackground,
                    onPressed: () {
                      if (_isSearchMode) {
                        _toggleSearchMode(false);
                      } else {
                        _toggleSearchMode(true);
                      }
                    },
                  ),
                ),
              ),
            ),
        ],
      ),
      body: Column(
        children: [
          Expanded(child: bodyWidget),
          if (_showUpdateBanner)
            SafeArea(top: false, child: _buildUpdateBanner(isPhone)),
        ],
      ),
      floatingActionButton: null,
      /* (isCollapsed || (isPhone && _currentIndex != 0))
          ? null
          : AnimatedPadding(
              duration: const Duration(milliseconds: 150),
              curve: Curves.easeInOut,
              padding: EdgeInsets.only(
                bottom: _showUpdateBanner
                    ? _isDownloading
                          ? 150.0
                          : 100.0
                    : 16.0,
              ),
              child: FloatingActionButton(
                onPressed: () => Navigator.push(
                  context,
                  MaterialPageRoute(builder: (_) => const NewChatScreen()),
                ),
                child: const Icon(Icons.edit_note_rounded),
              ),
            ),*/
      bottomNavigationBar: isPhone
          ? BottomNavigationBar(
              currentIndex: _currentIndex,
              elevation: 8,
              onTap: (index) => setState(() => _currentIndex = index),
              items: const [
                BottomNavigationBarItem(
                  icon: Icon(Icons.chat_bubble_outline_rounded),
                  activeIcon: Icon(Icons.chat_bubble_rounded),
                  label: "Чаты",
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.settings_outlined),
                  activeIcon: Icon(Icons.settings_rounded),
                  label: "Настройки",
                ),
                BottomNavigationBarItem(
                  icon: Icon(Icons.person_outline_rounded),
                  activeIcon: Icon(Icons.person_rounded),
                  label: "Профиль",
                ),
              ],
            )
          : null,
    );
  }

  Widget _buildUpdateBanner(bool isPhone) {
    final isCollapsed =
        !isPhone && (_contactsPaneWidth <= _collapsedContactsWidth);
    if (isCollapsed) return const SizedBox.shrink();
    final colorScheme = Theme.of(context).colorScheme;

    return Container(
      // Сделали аккуратные отступы сверху для баннера
      margin: const EdgeInsets.fromLTRB(16, 4, 16, 12),
      child: Material(
        elevation: 6,
        borderRadius: BorderRadius.circular(12),
        child: Container(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
          decoration: BoxDecoration(
            gradient: LinearGradient(
              colors: [Colors.orange.shade600, Colors.deepOrange.shade400],
              begin: Alignment.topLeft,
              end: Alignment.bottomRight,
            ),
            borderRadius: BorderRadius.circular(12),
          ),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Row(
                children: [
                  Expanded(
                    child: Text(
                      _isDownloading
                          ? 'Скачивание ${(_downloadProgress * 100).toStringAsFixed(0)}%'
                          : _apkFileSizeBytes > 0
                          ? 'Доступно новое обновление: ${_formatBytes(_apkFileSizeBytes)}'
                          : 'Доступно новое обновление!',
                      style: TextStyle(
                        color: Colors.white,
                        fontWeight: FontWeight.bold,
                        fontSize: 16,
                      ),
                      maxLines: 2,
                      overflow: TextOverflow.ellipsis,
                    ),
                  ),
                  TextButton(
                    onPressed: () async {
                      if (_isDownloading) {
                        _cancelToken?.cancel("Пользователь отменил загрузку");
                        setState(() {
                          _isDownloading = false;
                          _downloadProgress = 0.0;
                        });
                      } else {
                        setState(() {
                          _isDownloading = true;
                          _cancelToken = CancelToken();
                        });
                        await _startDownload();
                      }
                    },
                    style: TextButton.styleFrom(
                      backgroundColor: colorScheme.onPrimary.withOpacity(0.12),
                      shape: RoundedRectangleBorder(
                        borderRadius: BorderRadius.circular(8),
                      ),
                    ),
                    child: Text(
                      _isDownloading ? "Отмена" : "Обновить",
                      style: const TextStyle(
                        color: Colors.white,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                  ),
                ],
              ),
              if (_isDownloading) ...[
                const SizedBox(height: 12),
                LinearProgressIndicator(
                  value: _downloadProgress,
                  color: Colors.white,
                  backgroundColor: Colors.white54,
                ),
                const SizedBox(height: 8),
                Align(
                  alignment: Alignment.centerLeft,
                  child: Text(
                    '${_formatBytes(_downloadedBytes)} из ${_formatBytes(_downloadTotalBytes)}',
                    style: TextStyle(color: Colors.white, fontSize: 14),
                  ),
                ),
              ],
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildWindowsNavigationRail() {
    final double railWidth = _isLeftRailExpanded ? 220 : 68;
    final colorScheme = Theme.of(context).colorScheme;

    return AnimatedContainer(
      duration: const Duration(milliseconds: 250),
      curve: Curves.fastOutSlowIn,
      width: railWidth,
      color: colorScheme.surfaceVariant.withOpacity(0.12),
      child: Column(
        children: [
          const SizedBox(height: 12),
          IconButton(
            icon: Icon(
              _isLeftRailExpanded
                  ? Icons.menu_open_rounded
                  : Icons.menu_rounded,
            ),
            onPressed: () =>
                setState(() => _isLeftRailExpanded = !_isLeftRailExpanded),
          ),
          const Divider(height: 24, indent: 12, endIndent: 12),

          _buildRailItem(
            Icons.chat_bubble_outline_rounded,
            Icons.chat_bubble_rounded,
            "Чаты",
            0,
            onTap: () => setState(() => _currentIndex = 0),
          ),

          const SizedBox(height: 8),
          const Divider(height: 12, indent: 12, endIndent: 12),

          _buildRailItem(
            Icons.settings_outlined,
            Icons.settings_rounded,
            "Настройки",
            1,
            onTap: () => _showSettingsDialog(),
          ),
          _buildRailItem(
            Icons.person_outline_rounded,
            Icons.person_rounded,
            "Профиль",
            2,
            onTap: () => _showProfileDialog(),
          ),
        ],
      ),
    );
  }

  Widget _buildRailItem(
    IconData icon,
    IconData activeIcon,
    String label,
    int index, {
    Function()? onTap,
  }) {
    final isSelected = _currentIndex == index;
    final colorScheme = Theme.of(context).colorScheme;
    final color = isSelected ? colorScheme.primary : colorScheme.onSurface;

    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
      child: LayoutBuilder(
        builder: (itemContext, itemConstraints) {
          final bool showLabel =
              _isLeftRailExpanded && itemConstraints.maxWidth >= 140;
          return InkWell(
            onTap: onTap ?? () => setState(() => _currentIndex = index),
            borderRadius: BorderRadius.circular(12),
            child: Container(
              height: 48,
              padding: EdgeInsets.symmetric(horizontal: showLabel ? 12 : 8),
              decoration: BoxDecoration(
                color: isSelected
                    ? colorScheme.primary.withOpacity(0.08)
                    : Colors.transparent,
                borderRadius: BorderRadius.circular(12),
              ),
              child: Row(
                mainAxisAlignment: showLabel
                    ? MainAxisAlignment.start
                    : MainAxisAlignment.center,
                children: [
                  Icon(isSelected ? activeIcon : icon, color: color, size: 22),
                  if (showLabel) ...[
                    const SizedBox(width: 16),
                    Expanded(
                      child: Text(
                        label,
                        style: TextStyle(
                          color: color,
                          fontWeight: isSelected
                              ? FontWeight.bold
                              : FontWeight.normal,
                          fontSize: 14,
                        ),
                        overflow: TextOverflow.ellipsis,
                      ),
                    ),
                  ],
                ],
              ),
            ),
          );
        },
      ),
    );
  }

  void _showSettingsDialog() {
    // Создаем нотификатор высоты с начальным значением
    final heightNotifier = ValueNotifier<double>(450.0);
    showDialog(
      context: context,
      builder: (ctx) {
        return ValueListenableBuilder<double>(
          valueListenable: heightNotifier,
          builder: (context, currentHeight, child) {
            return Dialog(
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(16),
              ),
              clipBehavior: Clip.antiAlias,
              insetPadding: const EdgeInsets.symmetric(
                vertical: 16,
                horizontal: 24,
              ),
              child: SizedBox(
                width: 520,
                height: currentHeight, // Примет идеальную высоту контента
                child: Navigator(
                  onGenerateRoute: (settings) {
                    return MaterialPageRoute(
                      builder: (ctx2) => SettingsScreen(
                        isFromList: true,
                        // Передаем коллбек для замера высоты
                        onHeightMeasured: (measuredHeight) {
                          final maxHeight = MediaQuery.of(ctx).size.height - 32;
                          // Обновляем высоту, не превышая размеры экрана
                          heightNotifier.value = measuredHeight.clamp(
                            200.0,
                            maxHeight,
                          );
                        },
                      ),
                    );
                  },
                ),
              ),
            );
          },
        );
      },
    );
  }

  void _showProfileDialog() {
    final heightNotifier = ValueNotifier<double>(400.0);
    showDialog(
      context: context,
      builder: (ctx) {
        return ValueListenableBuilder<double>(
          valueListenable: heightNotifier,
          builder: (context, currentHeight, child) {
            return Dialog(
              shape: RoundedRectangleBorder(
                borderRadius: BorderRadius.circular(16),
              ),
              clipBehavior: Clip.antiAlias,
              insetPadding: const EdgeInsets.symmetric(
                vertical: 16,
                horizontal: 24,
              ),
              child: SizedBox(
                width: 520,
                height: currentHeight, // Примет идеальную высоту контента
                child: Navigator(
                  onGenerateRoute: (settings) {
                    return MaterialPageRoute(
                      builder: (ctx2) => MyProfileScreen(
                        isFromList: true,
                        // Передаем коллбек для замера высоты
                        onHeightMeasured: (measuredHeight) {
                          final maxHeight = MediaQuery.of(ctx).size.height - 32;
                          heightNotifier.value = measuredHeight.clamp(
                            200.0,
                            maxHeight,
                          );
                        },
                      ),
                    );
                  },
                ),
              ),
            );
          },
        );
      },
    );
  }

  Widget _buildResizableDivider({
    required Function(DragUpdateDetails) onPanUpdate,
    Function(DragStartDetails)? onPanStart,
  }) {
    return GestureDetector(
      onPanStart: onPanStart,
      onPanUpdate: onPanUpdate,
      child: MouseRegion(
        cursor: SystemMouseCursors.resizeColumn,
        child: Container(
          width: 8,
          color: Colors.transparent,
          alignment: Alignment.center,
          child: VerticalDivider(
            width: 1,
            thickness: 1,
            color: Theme.of(context).dividerColor.withOpacity(0.4),
          ),
        ),
      ),
    );
  }

  Widget _buildResponsiveBody(bool isPhone) {
    final media = MediaQuery.of(context);
    // Проверка физического форм-фактора (надежнее, чем Platform.isAndroid)
    final bool isPhoneFormFactor = media.size.shortestSide < 600;
    //final bool isPhoneFormFactor = true;

    // 1. ЛОГИКА ДЛЯ СМАРТФОНОВ (любая ОС, если экран маленький)
    if (isPhoneFormFactor) {
      if (_selectedContact != null) {
        return ChatScreen(
          contact: _selectedContact!,
          onOpenProfile: _openProfile,
          onBack: _clearSelectedContact,
          showBackButton: true,
        );
      }
      return _buildContactsListWithScaffold(true);
    }

    // 2. ЛОГИКА ДЛЯ ПЛАНШЕТОВ И КОМПЬЮТЕРОВ (Широкие экраны)
    Widget centerPane;

    switch (_currentIndex) {
      case 1:
        centerPane = const Expanded(child: MyProfileScreen(isFromList: false));
        break;
      case 2:
        centerPane = const Expanded(child: SettingsScreen(isFromList: false));
        break;
      case 3:
        centerPane = const Expanded(
          child: Center(child: Text('Трекер задач (пока не реализован)')),
        );
        break;
      case 4:
        centerPane = const Expanded(
          child: Center(child: Text('Хранилище файлов (пока не реализовано)')),
        );
        break;
      case 0:
      default:
        centerPane = Expanded(
          child: LayoutBuilder(
            builder: (ctx, constraints) {
              final available = constraints.maxWidth;
              final bool profileRequested =
                  _profileContact != null && _isDesktopLayout(context);
              const double profileMin = 280;
              const double chatMin = 320;
              const double dividerWidth = 8;
              final double reservedForProfile = profileRequested
                  ? profileMin + dividerWidth
                  : 0;

              // Вычисляем допустимую ширину панели контактов
              final double maxContactsAllowed =
                  (available - reservedForProfile - chatMin - dividerWidth)
                      .clamp(
                        _collapsedContactsWidth,
                        _maxExpandedContactsWidth,
                      );
              final double contactsWidth = _contactsPaneWidth.clamp(
                _collapsedContactsWidth,
                maxContactsAllowed,
              );

              // Если места на экране для профиля совсем нет — скрываем его
              final bool showProfile =
                  profileRequested &&
                  (available >
                      (contactsWidth + dividerWidth + chatMin + profileMin));

              return Row(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  // ИСПРАВЛЕНО: Убран Flexible. Левая панель занимает строго contactsWidth
                  SizedBox(
                    width: contactsWidth,
                    child: _buildContactsListWithScaffold(false),
                  ),
                  _buildResizableDivider(
                    onPanStart: (details) =>
                        _dragStartWidth = _contactsPaneWidth,
                    onPanUpdate: (details) {
                      setState(() {
                        final newWidth = details.globalPosition.dx;
                        if (_dragStartWidth > _collapsedContactsWidth) {
                          if (newWidth < (_minExpandedContactsWidth / 2)) {
                            _contactsPaneWidth = _collapsedContactsWidth;
                          } else {
                            _contactsPaneWidth = newWidth.clamp(
                              _minExpandedContactsWidth,
                              _maxExpandedContactsWidth,
                            );
                          }
                        } else {
                          if (newWidth > (_minExpandedContactsWidth / 2) + 40) {
                            _contactsPaneWidth = newWidth.clamp(
                              _minExpandedContactsWidth,
                              _maxExpandedContactsWidth,
                            );
                          }
                        }
                      });
                    },
                  ),
                  // Чат расширяется на всё оставшееся до самого края или до профиля пространство
                  Expanded(child: _buildChatPane()),
                  if (showProfile) ...[
                    _buildResizableDivider(
                      onPanUpdate: (details) {
                        setState(() {
                          final screenWidth = MediaQuery.of(context).size.width;
                          _profilePaneWidth =
                              (screenWidth - details.globalPosition.dx).clamp(
                                280,
                                500,
                              );
                        });
                      },
                    ),
                    // ИСПРАВЛЕНО: Убран Flexible. Правая панель занимает строго _profilePaneWidth
                    SizedBox(
                      width: _profilePaneWidth,
                      child: _buildProfilePane(),
                    ),
                  ],
                ],
              );
            },
          ),
        );
        break;
    }

    return Scaffold(
      backgroundColor: Theme.of(context).colorScheme.background,
      body: SizedBox.expand(
        child: Row(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [_buildWindowsNavigationRail(), centerPane],
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final bool isPhoneFormFactor =
        MediaQuery.of(context).size.shortestSide < 600;

    return PopScope(
      canPop: _selectedContact == null || !isPhoneFormFactor,
      onPopInvokedWithResult: (didPop, result) {
        if (didPop) return;

        if (_selectedContact != null && isPhoneFormFactor) {
          _clearSelectedContact();
        }
      },
      child: _buildResponsiveBody(isPhoneFormFactor),
    );
  }

  Future<void> _checkAppUpdate() async {
    print('Проверка обновлений...');
    PackageInfo packageInfo = await PackageInfo.fromPlatform();

    // Определяем платформу для сервера
    String platformQuery = Platform.isWindows ? 'windows' : 'android';

    try {
      final response = await http.get(
        Uri.parse(
          '${AppConstants.baseUrl}/check-update?platform=$platformQuery',
        ),
      );
      if (response.statusCode == 200) {
        final data = jsonDecode(response.body);
        final String latestVersion = data['latest_version'];

        if (latestVersion != packageInfo.version) {
          setState(() {
            _showUpdateBanner = true;
            _latestApkUrl = data['download_url'] ?? data['apk_url'];
          });
          if (_latestApkUrl != null) {
            final size = await _fetchApkSize(_latestApkUrl!);
            if (mounted) {
              setState(() => _apkFileSizeBytes = size);
            }
          }
        }
      }
    } catch (e) {
      print("Ошибка проверки обновлений: $e");
    }
  }

  Future<void> _setupPushNotifications() async {
    try {
      if (Firebase.apps.isEmpty) {
        print('Firebase is not initialized, skipping push notification setup.');
        return;
      }
      await FirebaseMessaging.instance.requestPermission();
      String? token = await FirebaseMessaging.instance.getToken();
      if (token != null) {
        ApiService apiService = ApiService();
        await apiService.updateFcmToken(token);
      }
      FirebaseMessaging.instance.onTokenRefresh.listen((newToken) {
        ApiService apiService = ApiService();
        apiService.updateFcmToken(newToken);
      });
      FirebaseMessaging.onMessage.listen(_handleIncomingMessage);
      FirebaseMessaging.onMessageOpenedApp.listen((RemoteMessage message) {
        if (message.data['type'] == 'enc_message') {
          final senderId = int.tryParse(
            message.data['sender_id']?.toString() ?? '',
          );
          if (senderId != null) _navigateToChatFromNotification(senderId);
        }
      });
    } catch (e) {
      print('Push notification setup failed: $e');
    }
  }

  void _navigateToChatFromNotification(int senderId) {
    final contactProvider = context.read<ContactProvider>();
    if (contactProvider.contacts.isEmpty) {
      Future.delayed(const Duration(milliseconds: 500), () {
        if (mounted) _navigateToChatFromNotification(senderId);
      });
      return;
    }
    try {
      final contact = contactProvider.contacts.firstWhere(
        (c) => c.id == senderId,
      );
      _selectContact(contact);
    } catch (_) {}
  }

  Future<void> _handleIncomingMessage(dynamic data) async {
    if (data is RemoteMessage) {
      await _handleFCMMessage(data);
    } else if (data is Map<String, dynamic>) {
      print('WebSocket message received in ContactsScreen: $data');
      final contactProvider = context.read<ContactProvider>();

      if (data['type'] == 'private_message') {
        final senderId = int.tryParse(data['sender_id']?.toString() ?? '');

        // Обрабатываем сообщение ТОЛЬКО если оно от другого чата
        if (senderId != null && senderId != currentActiveChatContactId) {
          var contact = contactProvider.contacts
              .where((c) => c.id == senderId)
              .firstOrNull;

          if (contact == null) {
            await contactProvider.updateContact(senderId);
            contact = contactProvider.contacts
                .where((c) => c.id == senderId)
                .firstOrNull;
          }

          if (contact != null) {
            final currentUnread = contact.unreadCount;
            final msgId = int.tryParse(data['id']?.toString() ?? '');

            final newAnchor = (currentUnread == 0)
                ? msgId
                : contact.firstUnreadMessageId;

            String decryptedText = 'Новое сообщение';
            bool isDecrypted = false;

            try {
              final myPrivKey = await CryptoService().getPrivateKey();
              if (myPrivKey != null && contact.publicKey != null) {
                final sharedSecret = await CryptoService().deriveSharedSecret(
                  myPrivKey,
                  contact.publicKey!,
                  contactId: senderId,
                );
                decryptedText = await CryptoService().decryptMessage(
                  data['content'],
                  sharedSecret,
                );
                isDecrypted = true;
              }
            } catch (_) {}

            DateTime now = DateTime.now();

            Duration offset = now.timeZoneOffset;

            final timestamp =
                data['timestamp'] ?? DateTime.now().toIso8601String();

            // Список недопустимых системных строк
            final invalidValues = {'unknown', 'uncnown', 'null', ''};

            // Функция очистки полей контакта
            String cleanField(String? value) {
              if (value == null) return '';
              final trimmed = value.trim();
              return invalidValues.contains(trimmed.toLowerCase())
                  ? ''
                  : trimmed;
            }

            String cleanName = cleanField(contact.name);
            String cleanSurname = cleanField(contact.surname);
            String cleanUsername = cleanField(contact.username);

            // Формируем полное имя
            final String localFullName = '$cleanName $cleanSurname'.trim();

            // Задаем итоговый заголовок. Если всё пусто или unknown — пишем «Без имени»
            final String title = localFullName.isNotEmpty
                ? localFullName
                : (cleanUsername.isNotEmpty ? cleanUsername : 'Без имени');

            final msgHashCode =
                msgId ?? (DateTime.now().microsecondsSinceEpoch % 1000000000);

            print('show notification from $senderId $title: $decryptedText');
            await _showLocalNotification(
              senderId: senderId,
              title: title, // Теперь здесь гарантированно не будет unknown
              body: decryptedText,
              timestamp: timestamp,
              messageHashCode: msgHashCode,
            );
            await contactProvider.updateContact(
              senderId,
              lastMessage: decryptedText,
              lastMessageTime: DateTime.tryParse(
                data['timestamp'] ?? '',
              )?.add(offset),
              isLastMsgDecrypted: isDecrypted,
              unreadCount:
                  data['unread_count'] ??
                  currentUnread + 1, // Увеличиваем счетчик
              firstUnreadMessageId:
                  newAnchor, // Сохраняем анкер для будущего прыжка!
            );
          }
        }
      }

      if (data['type'] == 'message_read') {
        // message_id — сообщение, которое стало прочитанным
        // sender_id — ID того, чье сообщение прочитали (наш собеседник)
        // receiver_id — ID того, кто прочитал (наш текущий пользователь)

        final senderId = int.tryParse(data['sender_id']?.toString() ?? '');
        final receiverId = int.tryParse(data['receiver_id']?.toString() ?? '');
        final myId = context.read<AuthProvider>().currentUserId;

        // Проверяем: если уведомление пришло нам (мы — receiver_id)
        if (receiverId == myId && senderId != null) {
          final contactProvider = context.read<ContactProvider>();

          // Ищем контакт в списке
          final contact = contactProvider.contacts.firstWhere(
            (c) => c.id == senderId,
            orElse: () =>
                Contact(id: senderId, username: '', name: '', surname: ''),
          );

          // Если этот контакт имел непрочитанные сообщения, уменьшаем счетчик
          if (contact.unreadCount > 0) {
            await contactProvider.updateContact(
              senderId,
              unreadCount: data['unread_count'] ?? contact.unreadCount - 1,
            );
            print(
              'DEBUG: Счетчик для чата с пользователем $senderId уменьшен на 1',
            );
          }
        }
        return;
      }

      if (data['type'] == 'all_chat_read') {
        // message_id — сообщение, которое стало прочитанным
        // sender_id — ID того, чье сообщение прочитали (наш собеседник)
        // receiver_id — ID того, кто прочитал (наш текущий пользователь)

        final senderId = int.tryParse(data['sender_id']?.toString() ?? '');
        final receiverId = int.tryParse(data['reader_id']?.toString() ?? '');
        final myId = context.read<AuthProvider>().currentUserId;

        // Проверяем: если уведомление пришло нам (мы — receiver_id)
        if (receiverId == myId && senderId != null) {
          final contactProvider = context.read<ContactProvider>();

          // Ищем контакт в списке
          final contact = contactProvider.contacts.firstWhere(
            (c) => c.id == senderId,
            orElse: () =>
                Contact(id: senderId, username: '', name: '', surname: ''),
          );

          // Если этот контакт имел непрочитанные сообщения, уменьшаем счетчик
          if (contact.unreadCount > 0) {
            await contactProvider.updateContact(senderId, unreadCount: 0);
            print(
              'DEBUG: Счетчик для чата с пользователем $senderId установлен в 0',
            );
          }
        }
        return;
      }

      if (data['type'] == 'message_sent') {
        final receiverId = int.tryParse(data['receiver_id']?.toString() ?? '');
        if (receiverId != null) {
          var contact = contactProvider.contacts
              .where((c) => c.id == receiverId)
              .firstOrNull;

          if (contact == null) {
            await contactProvider.updateContact(receiverId);
            contact = contactProvider.contacts
                .where((c) => c.id == receiverId)
                .firstOrNull;
          }

          if (contact != null) {
            final messageType = MessageModel.parseMessageType(
              data['message_type']?.toString() ?? 'text',
            );
            String lastMessage = MessageModel.getMediaPreview(messageType);
            bool isDecrypted = false;

            if (data['content'] != null &&
                data['content'].toString().isNotEmpty) {
              try {
                final myPrivKey = await CryptoService().getPrivateKey();
                if (myPrivKey != null && contact.publicKey != null) {
                  final sharedSecret = await CryptoService().deriveSharedSecret(
                    myPrivKey,
                    contact.publicKey!,
                    contactId: receiverId,
                  );
                  final _lastMessage = await CryptoService().decryptMessage(
                    data['content'],
                    sharedSecret,
                  );
                  if (_lastMessage.trim().isNotEmpty) {
                    lastMessage = _lastMessage;
                  }
                  isDecrypted = true;
                }
              } catch (_) {
                lastMessage = data['content']?.toString() ?? lastMessage;
              }
            }

            DateTime now = DateTime.now();

            Duration offset = now.timeZoneOffset;

            final timestamp = DateTime.tryParse(
              data['timestamp']?.toString() ?? '',
            )?.add(offset);
            final serverId = int.tryParse(data['server_id']?.toString() ?? '');

            await contactProvider.updateContactLastMessage(
              receiverId,
              lastMessage: lastMessage.isNotEmpty ? lastMessage : null,
              lastMessageTime: timestamp,
              isLastMsgDecrypted: isDecrypted,
              lastMessageId: serverId,
            );

            if (_selectedContact != null &&
                _selectedContact!.id == receiverId) {
              _selectedContact = _selectedContact!.copyWith(
                lastMessage: lastMessage.isNotEmpty ? lastMessage : null,
                lastMessageTime: timestamp ?? _selectedContact!.lastMessageTime,
                isLastMsgDecrypted:
                    isDecrypted || _selectedContact!.isLastMsgDecrypted,
                lastMessageId: serverId ?? _selectedContact!.lastMessageId,
              );
            }
          }
        }
      }

      if (data['type'] == 'user_updated') {
        final userId = int.tryParse(data['user_id']?.toString() ?? '');
        if (userId != null) {
          await contactProvider.updateContact(userId);
          await _loadLocalNames(); // Синхронно обновляем кэш имен на сокет
        }
      }

      if (data['type'] == 'user_online') {
        final userId = int.tryParse(data['user_id']?.toString() ?? '');
        if (userId != null) {
          contactProvider.updateContactOnlineStatus(userId, true);
          if (mounted) {
            setState(() {
              if (_selectedContact != null && _selectedContact!.id == userId) {
                _selectedContact = contactProvider.contacts.firstWhere(
                  (c) => c.id == userId,
                  orElse: () => _selectedContact!,
                );
              }
            });
          }
        }
      }
      if (data['type'] == 'user_offline') {
        final userId = int.tryParse(data['user_id']?.toString() ?? '');
        if (userId != null) {
          contactProvider.updateContactOnlineStatus(userId, false);
          if (mounted) {
            setState(() {
              if (_selectedContact != null && _selectedContact!.id == userId) {
                _selectedContact = contactProvider.contacts.firstWhere(
                  (c) => c.id == userId,
                  orElse: () => _selectedContact!,
                );
              }
            });
          }
        }
      }

      if (data['type'] == 'message_edited') {
        final messageId = int.tryParse(data['message_id']?.toString() ?? '');
        final senderId = int.tryParse(data['sender_id']?.toString() ?? '');
        if (messageId != null && senderId != null) {
          var contact = contactProvider.contacts
              .where((c) => c.id == senderId)
              .firstOrNull;
          if (contact == null) {
            await contactProvider.updateContact(senderId);
            contact = contactProvider.contacts
                .where((c) => c.id == senderId)
                .firstOrNull;
          }
          if (contact != null) {
            final editedAt = DateTime.tryParse(
              data['edited_at']?.toString() ?? '',
            );
            String lastMessageText = contact.lastMessage ?? '';
            bool isDecrypted = false;

            final myPrivKey = await CryptoService().getPrivateKey();
            if (myPrivKey != null && contact.publicKey != null) {
              try {
                final sharedSecret = await CryptoService().deriveSharedSecret(
                  myPrivKey,
                  contact.publicKey!,
                  contactId: senderId,
                );
                lastMessageText = await CryptoService().decryptMessage(
                  data['content']?.toString() ?? '',
                  sharedSecret,
                );
                isDecrypted = true;
              } catch (_) {}
            }
            await contactProvider.updateContactLastMessage(
              contact.id,
              lastMessage: lastMessageText,
              lastMessageTime: editedAt,
              isLastMsgDecrypted: isDecrypted,
              lastMessageId: messageId,
              isEdited: true,
            );
          }
        }
      }

      if (data['type'] == 'message_deleted') {
        final messageId = int.tryParse(data['message_id']?.toString() ?? '');
        if (messageId != null) {
          final contactIndex = contactProvider.contacts.indexWhere(
            (c) => c.lastMessageId == messageId,
          );
          if (contactIndex != -1) {
            await contactProvider.refreshContactLastMessage(
              contactProvider.contacts[contactIndex].id,
            );
          }
        }
      }
    }
  }

  Future<void> _handleFCMMessage(RemoteMessage message) async {
    try {
      // 1. Быстрый парсинг и валидация ID отправителя на самом старте
      final senderIdRaw = message.data['sender_id']?.toString() ?? '';
      final senderId = int.tryParse(senderIdRaw);
      if (senderId == null) return;

      // 2. Блокировка дубликатов, если чат уже открыт
      if (currentActiveChatContactId == senderId) return;

      // 3. Безопасное получение SocketService (лучше через GetIt, пример с context ниже)
      // Если метод вызывается строго в Foreground, проверяем mounted
      if (!mounted) return;
      final socketService = Provider.of<SocketService>(context, listen: false);
      if (socketService.isConnected()) return;

      // 4. Криптография
      final crypto = CryptoService();
      final myPrivKey = await crypto.getPrivateKey();
      if (myPrivKey == null) return;

      final publicKey = message.data['public_key'];
      final encryptedContent = message.data['content'];
      if (publicKey == null || encryptedContent == null) return;

      final sharedSecret = await crypto.deriveSharedSecret(
        myPrivKey,
        publicKey,
        contactId: senderId,
      );
      final decryptedText = await crypto.decryptMessage(
        encryptedContent,
        sharedSecret,
      );

      // 5. Работа с локальным кэшем имен
      final prefs = await SharedPreferences.getInstance();
      String? firstName = prefs.getString('firstname_$senderIdRaw');
      String? lastName = prefs.getString('lastname_$senderIdRaw');

      // Очистка некорректных значений имен
      final invalidNames = {'unknown', 'uncnown', 'null', ''};
      if (firstName == null ||
          invalidNames.contains(firstName.toLowerCase().trim())) {
        firstName = 'Без имени';
      }
      if (lastName == null ||
          invalidNames.contains(lastName.toLowerCase().trim())) {
        lastName = '';
      }

      final String localFullName = '$firstName $lastName'.trim();
      final String title = localFullName.isNotEmpty
          ? localFullName
          : (message.data['username'] ?? 'Unknown');

      final timestamp =
          message.data['timestamp'] ?? DateTime.now().toIso8601String();

      // 6. Показ локального уведомления (ID берем от senderId, чтобы не плодить путаницу)
      await _showLocalNotification(
        senderId: senderId,
        title: title,
        body: decryptedText,
        timestamp: timestamp,
        messageHashCode: senderId.toUnsigned(31),
      );

      // 7. Безопасное обновление провайдера контактов (только если экран активен)
      if (message.data['type'] == 'enc_message' && mounted) {
        final unreadCountRaw = message.data['unread_count'];

        context.read<ContactProvider>().updateContact(
          senderId,
          lastMessage: decryptedText,
          lastMessageTime: DateTime.tryParse(timestamp),
          isLastMsgDecrypted: true,
          unreadCount: unreadCountRaw != null
              ? int.tryParse(unreadCountRaw.toString())
              : null,
        );
      }
    } catch (e, stackTrace) {
      print('Error processing foreground FCM: $e');
      print(stackTrace); // Поможет быстрее найти баг при изменении API
    }
  }

  Future<void> _showLocalNotification({
    required int senderId,
    required String title,
    required String body,
    required String timestamp,
    required int messageHashCode,
  }) async {
    const String channelId = 'Messages';
    const String channelName = 'Новые сообщения';
    final String groupKey = 'ru.chepuhagram.app.$senderId';

    // Создаем канал (безопасно вызывать многократно)
    const AndroidNotificationChannel channel = AndroidNotificationChannel(
      channelId,
      channelName,
      description: 'Chat messages notifications',
      importance: Importance.high,
    );

    await flutterLocalNotificationsPlugin
        .resolvePlatformSpecificImplementation<
          AndroidFlutterLocalNotificationsPlugin
        >()
        ?.createNotificationChannel(channel);

    // Показываем Summary (группировщик)

    if (Platform.isAndroid) {
      await flutterLocalNotificationsPlugin.show(
        id: senderId, // ID группы - это ID отправителя
        title: '',
        body: '',
        notificationDetails: NotificationDetails(
          android: AndroidNotificationDetails(
            channelId,
            channelName,
            groupKey: groupKey,
            setAsGroupSummary: true,
            importance: Importance.high,
            priority: Priority.high,
            groupAlertBehavior: GroupAlertBehavior.all,
          ),
        ),
      );
    }

    // Показываем само сообщение
    await flutterLocalNotificationsPlugin.show(
      id: messageHashCode, // Уникальный ID для каждого сообщения
      title: title,
      body: body,
      notificationDetails: NotificationDetails(
        android: AndroidNotificationDetails(
          channelId,
          channelName,
          groupKey: groupKey,
          importance: Importance.high,
          priority: Priority.high,
          showWhen: true,
        ),
      ),
      payload: jsonEncode({
        'type': 'enc_message',
        'sender_id': senderId,
        'timestamp': timestamp,
      }),
    );
  }

  Future<void> _startDownload() async {
    if (_latestApkUrl == null) return;

    if (Platform.isWindows) {
      setState(() => _isDownloading = true);

      final tempDir = await getTemporaryDirectory();
      final savePath = '${tempDir.path}\\chepuhagram_setup.exe';
      final file = File(savePath);

      if (await file.exists()) await file.delete();

      try {
        setState(() {
          _downloadProgress = 0.0;
          _downloadedBytes = 0;
          _downloadTotalBytes = 0;
        });
        await Dio().download(
          _latestApkUrl!,
          savePath,
          cancelToken: _cancelToken,
          onReceiveProgress: (rec, total) {
            if (mounted) {
              setState(() {
                _downloadProgress = total > 0 ? rec / total : 0.0;
                _downloadedBytes = rec;
                _downloadTotalBytes = total;
              });
            }
          },
        );

        await Process.start(savePath, ['/update', '/VERYSILENT']);

        exit(0);
      } catch (e) {
        print("Ошибка при обновлении: $e");
        setState(() => _isDownloading = false);
      }
      return;
    }

    // Логика для Android (Остается без изменений)
    setState(() => _isDownloading = true);

    Directory? dir = await getExternalStorageDirectory();
    final path = '${dir!.path}/update.apk';
    final file = File(path);

    if (await file.exists()) await file.delete();

    try {
      setState(() {
        _downloadProgress = 0.0;
        _downloadedBytes = 0;
        _downloadTotalBytes = 0;
      });
      await Dio().download(
        _latestApkUrl!,
        path,
        cancelToken: _cancelToken,
        onReceiveProgress: (rec, total) {
          if (mounted) {
            setState(() {
              _downloadedBytes = rec;
              _downloadTotalBytes = total > 0 ? total : 0;
              _downloadProgress = total > 0 ? rec / total : 0.0;
            });
          }
        },
      );
      await OpenFilex.open(path);
    } catch (_) {
    } finally {
      if (mounted) {
        setState(() {
          _isDownloading = false;
          _downloadProgress = 0.0;
        });
      }
    }
  }

  Future<int> _fetchApkSize(String url) async {
    try {
      final response = await http.head(Uri.parse(url));
      return int.tryParse(response.headers['content-length'] ?? '') ?? 0;
    } catch (_) {
      return 0;
    }
  }

  String _formatBytes(int bytes) {
    if (bytes <= 0) return '0 B';
    const kb = 1024;
    const mb = kb * 1024;
    if (bytes < kb) return '$bytes B';
    if (bytes < mb) return '${(bytes / kb).toStringAsFixed(1)} KB';
    return '${(bytes / mb).toStringAsFixed(1)} MB';
  }
}

class ContactAvatar extends StatelessWidget {
  final String initials;
  final String? avatarUrl;
  final bool isOnline;
  final bool isSelected;
  final ColorScheme colorScheme;

  const ContactAvatar({
    super.key,
    required this.initials,
    required this.avatarUrl,
    required this.isOnline,
    required this.isSelected,
    required this.colorScheme,
  });

  @override
  Widget build(BuildContext context) {
    return Stack(
      clipBehavior: Clip.none,
      children: [
        Container(
          width: 52,
          height: 52,
          decoration: BoxDecoration(
            shape: BoxShape.circle,
            color: colorScheme.primaryContainer,
          ),
          child: ClipOval(
            child: Stack(
              alignment: Alignment.center,
              children: [
                Text(
                  initials,
                  style: TextStyle(
                    fontSize: 20,
                    fontWeight: FontWeight.bold,
                    color: colorScheme.onPrimaryContainer,
                  ),
                ),
                if (avatarUrl != null)
                  CachedNetworkImage(
                    imageUrl: avatarUrl!,
                    fit: BoxFit.cover,
                    width: 52,
                    height: 52,
                    placeholder: (context, url) => const SizedBox.shrink(),
                    errorWidget: (context, url, error) =>
                        const SizedBox.shrink(),
                  ),
              ],
            ),
          ),
        ),
        Positioned(
          right: -1,
          bottom: -1,
          child: AnimatedSwitcher(
            duration: const Duration(milliseconds: 250),
            transitionBuilder: (Widget child, Animation<double> animation) {
              return ScaleTransition(
                scale: CurvedAnimation(
                  parent: animation,
                  curve: Curves.easeInOut,
                ),
                child: FadeTransition(opacity: animation, child: child),
              );
            },
            child: isOnline
                ? Container(
                    key: const ValueKey('online_dot'),
                    width: 14,
                    height: 14,
                    decoration: BoxDecoration(
                      color: Colors.green.shade500,
                      shape: BoxShape.circle,
                      border: Border.all(
                        color: isSelected
                            ? Color.alphaBlend(
                                colorScheme.primaryContainer.withOpacity(0.4),
                                colorScheme.background,
                              )
                            : colorScheme.background,
                        width: 2.5,
                      ),
                    ),
                  )
                : const SizedBox.shrink(key: ValueKey('offline_dot')),
          ),
        ),
      ],
    );
  }
}