import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter_contacts/flutter_contacts.dart' as fc;
import 'package:url_launcher/url_launcher.dart';
import 'package:provider/provider.dart';
import 'package:share_plus/share_plus.dart';
import '/logic/auth_provider.dart';
import '/data/models/contact_model.dart';
import '/data/repositories/contact_repository.dart';
import 'chat_screen.dart';
import 'package:cached_network_image/cached_network_image.dart';

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

  @override
  State<NewChatScreen> createState() => _NewChatScreenState();
}

class _NewChatScreenState extends State<NewChatScreen> {
  bool _isLoading = true;
  bool _permissionDenied = false;
  String? _error;
  
  List<Map<String, dynamic>> _registeredMatches = [];
  List<fc.Contact> _unregisteredMatches = [];

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

  String _normalizePhone(String p) {
    final digits = p.replaceAll(RegExp(r'\D'), '');
    if (digits.length >= 10) {
      return digits.substring(digits.length - 10);
    }
    return digits;
  }

  Future<void> _requestPermissionAndLoad() async {
    setState(() {
      _isLoading = true;
      _permissionDenied = false;
      _error = null;
    });
    try {
      // 1. Проверяем разрешение на доступ к контактам (запрашиваем при необходимости)
      bool permission = await fc.FlutterContacts.requestPermission(readonly: true);
      if (!permission) {
        setState(() {
          _permissionDenied = true;
          _isLoading = false;
        });
        return;
      }
      
      // 2. Разрешение получено, загружаем контакты устройства
      final deviceContacts = await fc.FlutterContacts.getContacts(withProperties: true);
      
      // 3. Загружаем список зарегистрированных пользователей из нашего репозитория
      final contactRepository = ContactRepository();
      final registeredUsers = await contactRepository.fetchAllUsers();
      
      // Диагностика для отладки сопоставления контактов
      debugPrint('--- NEW CHAT CONTACT MATCHING DEBUG ---');
      debugPrint('Total registered users from server: ${registeredUsers.length}');
      for (var u in registeredUsers) {
        debugPrint('  Server User: ID=${u.id}, Username=${u.username}, Phone="${u.phone}"');
      }
      debugPrint('Total device contacts: ${deviceContacts.length}');
      for (var dc in deviceContacts) {
        final phonesStr = dc.phones.map((p) => '${p.number} (norm: ${_normalizePhone(p.number)})').join(', ');
        debugPrint('  Device Contact: Name="${dc.displayName}", Phones=[$phonesStr]');
      }
      debugPrint('---------------------------------------');
      
      // 4. Группируем и сопоставляем контакты по последним 10 цифрам номера телефона
      final Map<String, Contact> registeredMap = {};
      for (var u in registeredUsers) {
        if (u.phone != null) {
          final norm = _normalizePhone(u.phone!);
          if (norm.isNotEmpty) {
            registeredMap[norm] = u;
          }
        }
      }
      
      final List<Map<String, dynamic>> regMatches = [];
      final List<fc.Contact> unregMatches = [];
      
      for (var dc in deviceContacts) {
        bool matched = false;
        for (var phoneObj in dc.phones) {
          final norm = _normalizePhone(phoneObj.number);
          if (norm.isNotEmpty && registeredMap.containsKey(norm)) {
            final regUser = registeredMap[norm]!;
            regMatches.add({
              'registered': regUser,
              'device': dc,
            });
            matched = true;
            break;
          }
        }
        if (!matched && dc.phones.isNotEmpty) {
          unregMatches.add(dc);
        }
      }
      
      // Сортировка по имени в алфавитном порядке
      regMatches.sort((a, b) => (a['device'] as fc.Contact).displayName.toLowerCase().compareTo((b['device'] as fc.Contact).displayName.toLowerCase()));
      unregMatches.sort((a, b) => a.displayName.toLowerCase().compareTo(b.displayName.toLowerCase()));
      
      setState(() {
        _registeredMatches = regMatches;
        _unregisteredMatches = unregMatches;
        _isLoading = false;
      });
    } catch (e) {
      setState(() {
        _error = e.toString();
        _isLoading = false;
      });
    }
  }

  Future<void> _sendInvitation(String phoneNumber) async {
    final message = 'Привет! Присоединяйся к бета-тесту мессенджера Чепухаграм. Напиши разработчику в Telegram @ArturKarasevich для получения доступа!';
    final uri = Uri.parse('sms:$phoneNumber?body=${Uri.encodeComponent(message)}');
    try {
      if (await canLaunchUrl(uri)) {
        await launchUrl(uri);
      } else {
        throw Exception('Не удалось открыть SMS приложение');
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Ошибка отправки: $e')),
        );
      }
    }
  }

  Future<void> _sendNativeShare(String name) async {
    final message = 'Привет! Присоединяйся к бета-тесту мессенджера Чепухаграм. Напиши разработчику в Telegram @ArturKarasevich для получения доступа!';
    try {
      await Share.share(
        message,
        subject: 'Приглашение в Чепухаграм',
      );
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Ошибка отправки: $e')),
        );
      }
    }
  }

  Future<void> _showInviteDialog(String name, String phone) async {
    final colorScheme = Theme.of(context).colorScheme;
    showDialog(
      context: context,
      builder: (context) => AlertDialog(
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(24)),
        title: Text('Пригласить $name', style: const TextStyle(fontWeight: FontWeight.bold)),
        content: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            const Text(
              'Этого человека ещё нет в Чепухаграм. Выберите способ приглашения:',
              style: TextStyle(color: Colors.grey, fontSize: 14),
            ),
            const SizedBox(height: 20),
            ListTile(
              contentPadding: EdgeInsets.zero,
              leading: Container(
                padding: const EdgeInsets.all(8),
                decoration: BoxDecoration(
                  color: colorScheme.primary.withOpacity(0.1),
                  shape: BoxShape.circle,
                ),
                child: Icon(Icons.sms_rounded, color: colorScheme.primary, size: 20),
              ),
              title: const Text('Отправить SMS', style: TextStyle(fontWeight: FontWeight.w600)),
              subtitle: Text(phone, style: const TextStyle(fontSize: 12)),
              onTap: () {
                Navigator.pop(context);
                _sendInvitation(phone);
              },
            ),
            const SizedBox(height: 8),
            ListTile(
              contentPadding: EdgeInsets.zero,
              leading: Container(
                padding: const EdgeInsets.all(8),
                decoration: BoxDecoration(
                  color: colorScheme.primary.withOpacity(0.1),
                  shape: BoxShape.circle,
                ),
                child: Icon(Icons.share_rounded, color: colorScheme.primary, size: 20),
              ),
              title: const Text('Другие мессенджеры', style: TextStyle(fontWeight: FontWeight.w600)),
              subtitle: const Text('Нативное меню выбора (Telegram, WhatsApp и др.)', style: TextStyle(fontSize: 12)),
              onTap: () {
                Navigator.pop(context);
                _sendNativeShare(name);
              },
            ),
          ],
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context),
            child: const Text('Отмена'),
          ),
        ],
      ),
    );
  }

  Widget _buildHeader(String title, ColorScheme colorScheme) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(16, 16, 16, 8),
      child: Text(
        title.toUpperCase(),
        style: TextStyle(
          fontSize: 11,
          fontWeight: FontWeight.w700,
          color: colorScheme.primary,
          letterSpacing: 1.0,
        ),
      ),
    );
  }

  Widget _buildList(ColorScheme colorScheme) {
    if (_registeredMatches.isEmpty && _unregisteredMatches.isEmpty) {
      return const Center(child: Text('Контакты в телефонной книге не найдены.'));
    }

    final List<Widget> listItems = [];

    if (_registeredMatches.isNotEmpty) {
      listItems.add(_buildHeader('Контакты в Чепухаграм', colorScheme));
      for (int i = 0; i < _registeredMatches.length; i++) {
        final m = _registeredMatches[i];
        final Contact regUser = m['registered'];
        final fc.Contact devContact = m['device'];
        
        final String dispName = devContact.displayName.isNotEmpty 
            ? devContact.displayName 
            : regUser.name;

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

        listItems.add(
          ListTile(
            contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
            leading: Container(
              width: 40,
              height: 40,
              decoration: BoxDecoration(
                shape: BoxShape.circle,
                color: colorScheme.primaryContainer,
              ),
              child: ClipOval(
                child: Stack(
                  alignment: Alignment.center,
                  children: [
                    Text(
                      initials,
                      style: TextStyle(
                        fontSize: 16,
                        fontWeight: FontWeight.bold,
                        color: colorScheme.onPrimaryContainer,
                      ),
                    ),
                    if (regUser.effectiveAvatarUrl != null && regUser.effectiveAvatarUrl!.isNotEmpty)
                      CachedNetworkImage(
                        imageUrl: regUser.effectiveAvatarUrl!,
                        fit: BoxFit.cover,
                        width: 40,
                        height: 40,
                        placeholder: (context, url) => const SizedBox.shrink(),
                        errorWidget: (context, url, error) => const SizedBox.shrink(),
                      ),
                  ],
                ),
              ),
            ),
            title: Text(
              dispName,
              style: const TextStyle(fontWeight: FontWeight.w600, fontSize: 16),
            ),
            subtitle: Text(
              '@${regUser.username} • ${regUser.phone ?? ''}',
              style: TextStyle(color: colorScheme.onSurface.withOpacity(0.6), fontSize: 13),
            ),
            trailing: Container(
              padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 4),
              decoration: BoxDecoration(
                color: Colors.green.withOpacity(0.15),
                borderRadius: BorderRadius.circular(8),
              ),
              child: const Text(
                'В Чепухаграм',
                style: TextStyle(color: Colors.green, fontSize: 11, fontWeight: FontWeight.bold),
              ),
            ),
            onTap: () {
              // Открываем чат с этим контактом
              Navigator.pushReplacement(
                context,
                MaterialPageRoute(
                  builder: (_) => ChatScreen(contact: regUser),
                ),
              );
            },
          ),
        );
        if (i < _registeredMatches.length - 1) {
          listItems.add(
            Divider(
              height: 1,
              indent: 72,
              endIndent: 16,
              color: colorScheme.outlineVariant.withOpacity(0.15),
            ),
          );
        }
      }
      listItems.add(const SizedBox(height: 16));
    }

    if (_unregisteredMatches.isNotEmpty) {
      listItems.add(_buildHeader('Пригласить в Чепухаграм', colorScheme));
      for (int i = 0; i < _unregisteredMatches.length; i++) {
        final dc = _unregisteredMatches[i];
        final phoneNum = dc.phones.isNotEmpty ? dc.phones.first.number : '';
        
        final initials = dc.displayName.isNotEmpty
            ? dc.displayName
                  .trim()
                  .split(RegExp(r'\s+'))
                  .take(2)
                  .map((e) => e.isNotEmpty ? e[0].toUpperCase() : '')
                  .join()
            : '?';

        listItems.add(
          ListTile(
            contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
            leading: CircleAvatar(
              backgroundColor: colorScheme.surfaceVariant.withOpacity(0.4),
              foregroundColor: colorScheme.outline,
              child: Text(
                initials,
                style: const TextStyle(fontWeight: FontWeight.bold),
              ),
            ),
            title: Text(
              dc.displayName,
              style: const TextStyle(fontWeight: FontWeight.w600, fontSize: 16),
            ),
            subtitle: Text(
              phoneNum,
              style: TextStyle(color: colorScheme.onSurface.withOpacity(0.6), fontSize: 13),
            ),
            trailing: OutlinedButton(
              onPressed: () => _showInviteDialog(dc.displayName, phoneNum),
              style: OutlinedButton.styleFrom(
                foregroundColor: colorScheme.primary,
                side: BorderSide(color: colorScheme.primary.withOpacity(0.5)),
                shape: RoundedRectangleBorder(
                  borderRadius: BorderRadius.circular(20),
                ),
                padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
              ),
              child: const Text('Пригласить', style: TextStyle(fontWeight: FontWeight.bold, fontSize: 12)),
            ),
            onTap: () => _showInviteDialog(dc.displayName, phoneNum),
          ),
        );
        if (i < _unregisteredMatches.length - 1) {
          listItems.add(
            Divider(
              height: 1,
              indent: 72,
              endIndent: 16,
              color: colorScheme.outlineVariant.withOpacity(0.15),
            ),
          );
        }
      }
    }

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

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

    return Scaffold(
      backgroundColor: colorScheme.background,
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        elevation: 0,
        scrolledUnderElevation: 0,
        iconTheme: IconThemeData(color: colorScheme.onBackground),
        title: Text(
          'Новый чат',
          style: TextStyle(
            color: colorScheme.onBackground,
            fontWeight: FontWeight.w800,
            fontSize: 24,
            letterSpacing: -0.5,
          ),
        ),
        centerTitle: false,
      ),
      body: _isLoading
          ? const Center(child: CircularProgressIndicator())
          : _permissionDenied
              ? Center(
                  child: Padding(
                    padding: const EdgeInsets.all(24.0),
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        Icon(
                          Icons.contacts_rounded,
                          size: 80,
                          color: colorScheme.outline.withOpacity(0.4),
                        ),
                        const SizedBox(height: 24),
                        const Text(
                          'Для поиска контактов необходимо разрешение',
                          style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
                          textAlign: TextAlign.center,
                        ),
                        const SizedBox(height: 12),
                        const Text(
                          'Чепухаграм сопоставит номера из вашей телефонной книги, чтобы вы могли общаться с друзьями.',
                          style: TextStyle(color: Colors.grey, fontSize: 14),
                          textAlign: TextAlign.center,
                        ),
                        const SizedBox(height: 24),
                        ElevatedButton(
                          onPressed: _requestPermissionAndLoad,
                          style: ElevatedButton.styleFrom(
                            backgroundColor: colorScheme.primary,
                            foregroundColor: colorScheme.onPrimary,
                            shape: RoundedRectangleBorder(
                              borderRadius: BorderRadius.circular(20),
                            ),
                            padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12),
                          ),
                          child: const Text('Предоставить доступ', style: TextStyle(fontWeight: FontWeight.bold)),
                        ),
                      ],
                    ),
                  ),
                )
              : _error != null
                  ? Center(
                      child: Padding(
                        padding: const EdgeInsets.all(16.0),
                        child: Column(
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: [
                            Icon(Icons.error_outline_rounded, size: 60, color: colorScheme.error),
                            const SizedBox(height: 16),
                            Text('Ошибка: $_error', textAlign: TextAlign.center),
                            const SizedBox(height: 24),
                            ElevatedButton(
                              onPressed: _requestPermissionAndLoad,
                              style: ElevatedButton.styleFrom(
                                backgroundColor: colorScheme.primary,
                                foregroundColor: colorScheme.onPrimary,
                                shape: RoundedRectangleBorder(
                                  borderRadius: BorderRadius.circular(20),
                                ),
                                padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 12),
                              ),
                              child: const Text('Повторить попытку', style: TextStyle(fontWeight: FontWeight.bold)),
                            ),
                          ],
                        ),
                      ),
                    )
                  : _buildList(colorScheme),
    );
  }
}