import 'dart:ui';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:chepuhagram/logic/auth_provider.dart';
import 'package:chepuhagram/presentation/screens/contacts_screen.dart';
import 'package:chepuhagram/domain/services/crypto_service.dart';
import 'package:chepuhagram/domain/services/api_service.dart';
import 'package:chepuhagram/presentation/screens/account_setup_screen.dart';
import 'dart:convert';
import 'package:http/http.dart' as http;
import 'package:chepuhagram/core/constants.dart';
import 'package:chepuhagram/core/theme_manager.dart';
import 'dart:io';

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

  @override
  State<KeyRecoveryScreen> createState() => _KeyRecoveryScreenState();
}

class _KeyRecoveryScreenState extends State<KeyRecoveryScreen> with SingleTickerProviderStateMixin {
  bool _isLoading = false;
  String? _errorMessage;
  final _passwordController = TextEditingController();
  final _formKey = GlobalKey<FormState>();

  late AnimationController _animationController;
  late Animation<double> _fadeAnimation;
  late Animation<Offset> _slideAnimation;

  @override
  void initState() {
    super.initState();
    _animationController = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 900),
    );

    _fadeAnimation =
        Tween<double>(begin: 0.0, end: 1.0).animate(CurvedAnimation(
      parent: _animationController,
      curve: Curves.easeIn,
    ));

    _slideAnimation =
        Tween<Offset>(begin: const Offset(0, 0.3), end: Offset.zero).animate(
            CurvedAnimation(
      parent: _animationController,
      curve: Curves.fastOutSlowIn,
    ));

    _animationController.forward();
  }

  Future<void> _startFresh() async {
    setState(() {
      _isLoading = true;
      _errorMessage = null;
    });

    try {
      final authProvider = context.read<AuthProvider>();
      
      try {
        final api = ApiService();
        await api.deleteAllMessages();
      } catch (e) {
        print('Ошибка при удалении сообщений: $e');
      }

      await authProvider.resetKeys();

      if (mounted) {
        Navigator.pushReplacement(
          context,
          MaterialPageRoute(builder: (_) => const AccountSetupScreen()),
        );
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _errorMessage = 'Ошибка: ${e.toString()}';
          _isLoading = false;
        });
      }
    }
  }

  Future<void> _recoverKeys() async {
    if (!_formKey.currentState!.validate()) return;
    FocusScope.of(context).unfocus();

    setState(() {
      _isLoading = true;
      _errorMessage = null;
    });

    try {
      final authProvider = context.read<AuthProvider>();
      final apiService = ApiService();
      final cryptoService = CryptoService();

      final token = await apiService.getAccessToken();
      if (token == null) throw Exception('Не авторизован');

      final response = await http.get(
        Uri.parse('${AppConstants.baseUrl}/users/me'),
        headers: {'Authorization': 'Bearer $token'},
      );

      if (response.statusCode != 200) {
        throw Exception('Не удалось получить данные пользователя');
      }

      final data = jsonDecode(utf8.decode(response.bodyBytes)) as Map;
      final encryptedPrivateKey = data['encrypted_private_key'];

      if (encryptedPrivateKey == null || encryptedPrivateKey.isEmpty) {
        throw Exception('Зашифрованный ключ не найден на сервере');
      }

      final decryptedPrivateKey = await cryptoService.decryptPrivateKey(
        encryptedPrivateKey,
        _passwordController.text,
      );

      await cryptoService.savePrivateKey(decryptedPrivateKey);

      await authProvider.tryAutoLogin();

      if (mounted) {
        Navigator.pushReplacement(
          context,
          MaterialPageRoute(builder: (_) => const ContactsScreen()),
        );
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _errorMessage = 'Ошибка восстановления: ${e.toString().replaceAll('Exception: ', '')}';
          _isLoading = false;
        });
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final themeProv = context.watch<ThemeProvider>();
    final colorScheme = Theme.of(context).colorScheme;

    return Scaffold(
      body: Stack(
        children: [
          if (themeProv.wallpaperPath != null)
            Container(
              decoration: BoxDecoration(
                image: DecorationImage(
                  image: FileImage(File(themeProv.wallpaperPath!)),
                  fit: BoxFit.cover,
                ),
              ),
            ),
          if (themeProv.wallpaperPath != null)
            BackdropFilter(
              filter: ImageFilter.blur(sigmaX: 15, sigmaY: 15),
              child: Container(
                color: Colors.black.withOpacity(0.1),
              ),
            ),

          SafeArea(
            child: SingleChildScrollView(
              padding: const EdgeInsets.all(24.0),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  const SizedBox(height: 32),
                  SlideTransition(
                    position: _slideAnimation,
                    child: FadeTransition(
                      opacity: _fadeAnimation,
                      child: Column(
                        children: [
                          Icon(
                            Icons.security_outlined,
                            size: 80,
                            color: colorScheme.primary,
                          ),
                          const SizedBox(height: 24),
                          Text(
                            'Восстановление ключей',
                            textAlign: TextAlign.center,
                            style: TextStyle(
                              fontSize: 28,
                              fontWeight: FontWeight.bold,
                              color: colorScheme.primary,
                            ),
                          ),
                          const SizedBox(height: 16),
                          Text(
                            'Вы переустановили приложение или вошли на новом устройстве. Выберите один из вариантов:',
                            textAlign: TextAlign.center,
                            style: TextStyle(fontSize: 16, color: colorScheme.outline),
                          ),
                        ],
                      ),
                    ),
                  ),
                  const SizedBox(height: 32),
                  
                  // Вариант 1: Начать с чистого листа
                  _buildOptionCard(
                    icon: Icons.restart_alt_outlined,
                    title: 'Начать с чистого листа',
                    description: 'Создаются новые ключи шифрования. Старые сообщения не будут расшифрованы.',
                    buttonText: 'Продолжить',
                    onPressed: _startFresh,
                  ),
                  const SizedBox(height: 24),

                  // Вариант 2: Восстановить из облака
                  _buildRecoveryCard(),
                  const SizedBox(height: 24),

                  // Сообщение об ошибке
                  if (_errorMessage != null)
                    Container(
                      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
                      decoration: BoxDecoration(
                        color: colorScheme.errorContainer.withOpacity(0.3),
                        borderRadius: BorderRadius.circular(12),
                      ),
                      child: Text(
                        _errorMessage!,
                        style: TextStyle(color: colorScheme.onErrorContainer, fontWeight: FontWeight.w500),
                        textAlign: TextAlign.center,
                      ),
                    ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildOptionCard({
    required IconData icon,
    required String title,
    required String description,
    required String buttonText,
    required VoidCallback onPressed,
  }) {
    final colorScheme = Theme.of(context).colorScheme;
    return ClipRRect(
      borderRadius: BorderRadius.circular(24),
      child: BackdropFilter(
        filter: ImageFilter.blur(sigmaX: 5, sigmaY: 5),
        child: Container(
          padding: const EdgeInsets.all(20),
          decoration: BoxDecoration(
            color: colorScheme.surfaceVariant.withOpacity(0.35),
            borderRadius: BorderRadius.circular(24),
            border: Border.all(
              color: colorScheme.outlineVariant.withOpacity(0.15),
              width: 1,
            ),
          ),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Row(
                children: [
                  Icon(icon, color: colorScheme.primary, size: 28),
                  const SizedBox(width: 12),
                  Expanded(
                    child: Text(
                      title,
                      style: const TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 12),
              Text(description, style: TextStyle(color: colorScheme.outline, fontSize: 14)),
              const SizedBox(height: 20),
              SizedBox(
                width: double.infinity,
                child: ElevatedButton(
                  onPressed: _isLoading ? null : onPressed,
                  style: ElevatedButton.styleFrom(
                    padding: const EdgeInsets.symmetric(vertical: 16),
                    shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
                    backgroundColor: colorScheme.primary,
                    foregroundColor: colorScheme.onPrimary,
                  ),
                  child: _isLoading
                      ? const SizedBox(height: 20, width: 20, child: CircularProgressIndicator(strokeWidth: 2, color: Colors.white))
                      : Text(buttonText, style: const TextStyle(fontSize: 16, fontWeight: FontWeight.bold)),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildRecoveryCard() {
    final colorScheme = Theme.of(context).colorScheme;
    return ClipRRect(
      borderRadius: BorderRadius.circular(24),
      child: BackdropFilter(
        filter: ImageFilter.blur(sigmaX: 5, sigmaY: 5),
        child: Container(
          padding: const EdgeInsets.all(20),
          decoration: BoxDecoration(
            color: colorScheme.surfaceVariant.withOpacity(0.35),
            borderRadius: BorderRadius.circular(24),
            border: Border.all(
              color: colorScheme.outlineVariant.withOpacity(0.15),
              width: 1,
            ),
          ),
          child: Form(
            key: _formKey,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Row(
                  children: [
                    Icon(Icons.cloud_download_outlined, color: colorScheme.primary, size: 28),
                    const SizedBox(width: 12),
                    const Expanded(
                      child: Text(
                        'Восстановить из облака',
                        style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 12),
                Text(
                  'Введите мастер-пароль для восстановления ключей шифрования',
                  style: TextStyle(color: colorScheme.outline, fontSize: 14),
                ),
                const SizedBox(height: 16),
                _buildTextField(
                  controller: _passwordController,
                  label: "Мастер-пароль",
                  icon: Icons.lock_outline,
                  obscureText: true,
                  validator: (value) => value!.isEmpty ? "Введите мастер-пароль" : null,
                ),
                const SizedBox(height: 20),
                SizedBox(
                  width: double.infinity,
                  child: ElevatedButton(
                    onPressed: _isLoading ? null : _recoverKeys,
                    style: ElevatedButton.styleFrom(
                      padding: const EdgeInsets.symmetric(vertical: 16),
                      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(16)),
                      backgroundColor: colorScheme.primary,
                      foregroundColor: colorScheme.onPrimary,
                    ),
                    child: _isLoading
                        ? const SizedBox(height: 20, width: 20, child: CircularProgressIndicator(strokeWidth: 2, color: Colors.white))
                        : const Text('Восстановить', style: TextStyle(fontSize: 16, fontWeight: FontWeight.bold)),
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
  
  Widget _buildTextField({
    required TextEditingController controller,
    required String label,
    required IconData icon,
    bool obscureText = false,
    String? Function(String?)? validator,
  }) {
    final colorScheme = Theme.of(context).colorScheme;

    return ClipRRect(
      borderRadius: BorderRadius.circular(16),
      child: Container( // No blur here, it's inside the card
        decoration: BoxDecoration(
          color: colorScheme.surface.withOpacity(0.5),
          borderRadius: BorderRadius.circular(16),
        ),
        child: TextFormField(
          controller: controller,
          obscureText: obscureText,
          validator: validator,
          decoration: InputDecoration(
            labelText: label,
            labelStyle: TextStyle(color: colorScheme.outline),
            prefixIcon: Icon(icon, color: colorScheme.outline),
            border: InputBorder.none,
            contentPadding: const EdgeInsets.symmetric(horizontal: 20, vertical: 18),
          ),
        ),
      ),
    );
  }

  @override
  void dispose() {
    _passwordController.dispose();
    _animationController.dispose();
    super.dispose();
  }
}