import 'dart:convert';
import 'dart:io';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';

/// Сервис для синхронизации с Nanaxe Server
/// Поддерживает работу с mindmaps через REST API
class NanaxeServerService {
  static final NanaxeServerService _instance = NanaxeServerService._internal();
  factory NanaxeServerService() => _instance;
  NanaxeServerService._internal();

  String? _baseUrl;
  String? _authToken;
  
  static const String _prefsUrlKey = 'nanaxe_server_url';
  static const String _prefsTokenKey = 'nanaxe_server_token';

  /// Инициализация сервиса
  Future<void> initialize() async {
    final prefs = await SharedPreferences.getInstance();
    _baseUrl = prefs.getString(_prefsUrlKey);
    _authToken = prefs.getString(_prefsTokenKey);
  }

  /// Настройка сервера
  Future<void> configure(String baseUrl, {String? token}) async {
    _baseUrl = baseUrl.replaceAll(RegExp(r'/+$'), ''); // Remove trailing slashes
    _authToken = token;
    
    final prefs = await SharedPreferences.getInstance();
    await prefs.setString(_prefsUrlKey, _baseUrl!);
    if (token != null) {
      await prefs.setString(_prefsTokenKey, token);
    }
  }

  /// Очистка конфигурации
  Future<void> clearConfiguration() async {
    _baseUrl = null;
    _authToken = null;
    
    final prefs = await SharedPreferences.getInstance();
    await prefs.remove(_prefsUrlKey);
    await prefs.remove(_prefsTokenKey);
  }

  /// Проверка, настроен ли сервер
  bool get isConfigured => _baseUrl != null;

  /// Получение базового URL
  String? get baseUrl => _baseUrl;

  // ==================== AUTH ====================

  /// Регистрация нового пользователя
  Future<Map<String, dynamic>> register(String email, String password, String username) async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.post(
      Uri.parse('$_baseUrl/api/auth/register'),
      headers: {'Content-Type': 'application/json'},
      body: jsonEncode({
        'email': email,
        'password': password,
        'username': username,
      }),
    );

    final data = jsonDecode(response.body);
    
    if (response.statusCode == 201) {
      _authToken = data['token'];
      final prefs = await SharedPreferences.getInstance();
      await prefs.setString(_prefsTokenKey, _authToken!);
      return data;
    } else {
      throw Exception(data['error'] ?? 'Registration failed');
    }
  }

  /// Вход в систему
  Future<Map<String, dynamic>> login(String email, String password) async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.post(
      Uri.parse('$_baseUrl/api/auth/login'),
      headers: {'Content-Type': 'application/json'},
      body: jsonEncode({
        'email': email,
        'password': password,
      }),
    );

    final data = jsonDecode(response.body);
    
    if (response.statusCode == 200) {
      _authToken = data['token'];
      final prefs = await SharedPreferences.getInstance();
      await prefs.setString(_prefsTokenKey, _authToken!);
      return data;
    } else {
      throw Exception(data['error'] ?? 'Login failed');
    }
  }

  /// Проверка валидности токена
  Future<bool> validateToken() async {
    if (_baseUrl == null || _authToken == null) return false;

    try {
      final response = await http.get(
        Uri.parse('$_baseUrl/api/auth/validate'),
        headers: _getHeaders(),
      );

      final data = jsonDecode(response.body);
      return data['valid'] == true;
    } catch (e) {
      return false;
    }
  }

  // ==================== MINDMAPS ====================

  /// Получение списка всех mindmaps
  Future<List<Map<String, dynamic>>> getMindMaps() async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.get(
      Uri.parse('$_baseUrl/api/mindmaps'),
      headers: _getHeaders(),
    );

    if (response.statusCode == 200) {
      final data = jsonDecode(response.body);
      return List<Map<String, dynamic>>.from(data['mindmaps'] ?? []);
    } else {
      throw Exception('Failed to load mindmaps');
    }
  }

  /// Получение одной mindmap
  Future<Map<String, dynamic>> getMindMap(String id) async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.get(
      Uri.parse('$_baseUrl/api/mindmaps/$id'),
      headers: _getHeaders(),
    );

    if (response.statusCode == 200) {
      return jsonDecode(response.body);
    } else {
      throw Exception('Failed to load mindmap');
    }
  }

  /// Создание новой mindmap
  Future<Map<String, dynamic>> createMindMap({
    required String title,
    String? description,
    List<Map<String, dynamic>>? nodes,
    Map<String, dynamic>? settings,
  }) async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.post(
      Uri.parse('$_baseUrl/api/mindmaps'),
      headers: _getHeaders(),
      body: jsonEncode({
        'title': title,
        'description': description ?? '',
        'nodes': nodes ?? [],
        'settings': settings ?? {},
      }),
    );

    if (response.statusCode == 201) {
      return jsonDecode(response.body);
    } else {
      final data = jsonDecode(response.body);
      throw Exception(data['error'] ?? 'Failed to create mindmap');
    }
  }

  /// Обновление mindmap
  Future<Map<String, dynamic>> updateMindMap(
    String id, {
    String? title,
    String? description,
    List<Map<String, dynamic>>? nodes,
    Map<String, dynamic>? settings,
  }) async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final body = <String, dynamic>{};
    if (title != null) body['title'] = title;
    if (description != null) body['description'] = description;
    if (nodes != null) body['nodes'] = nodes;
    if (settings != null) body['settings'] = settings;

    final response = await http.put(
      Uri.parse('$_baseUrl/api/mindmaps/$id'),
      headers: _getHeaders(),
      body: jsonEncode(body),
    );

    if (response.statusCode == 200) {
      return jsonDecode(response.body);
    } else {
      throw Exception('Failed to update mindmap');
    }
  }

  /// Удаление mindmap
  Future<void> deleteMindMap(String id) async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.delete(
      Uri.parse('$_baseUrl/api/mindmaps/$id'),
      headers: _getHeaders(),
    );

    if (response.statusCode != 200) {
      throw Exception('Failed to delete mindmap');
    }
  }

  /// Получение mindmap как Markdown
  Future<String> getMindMapAsMarkdown(String id) async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.get(
      Uri.parse('$_baseUrl/api/mindmaps/$id/markdown'),
      headers: _getHeaders(),
    );

    if (response.statusCode == 200) {
      return response.body;
    } else {
      throw Exception('Failed to load markdown');
    }
  }

  /// Сохранение mindmap из Markdown
  Future<Map<String, dynamic>> saveMindMapFromMarkdown(
    String id,
    String markdown,
  ) async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.post(
      Uri.parse('$_baseUrl/api/mindmaps/$id/markdown'),
      headers: _getHeaders(),
      body: jsonEncode({'markdown': markdown}),
    );

    if (response.statusCode == 200) {
      return jsonDecode(response.body);
    } else {
      throw Exception('Failed to save markdown');
    }
  }

  // ==================== SYNC ====================

  /// Получение статуса синхронизации
  Future<Map<String, dynamic>> getSyncStatus() async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.get(
      Uri.parse('$_baseUrl/api/sync/status'),
      headers: _getHeaders(),
    );

    if (response.statusCode == 200) {
      return jsonDecode(response.body);
    } else {
      throw Exception('Failed to get sync status');
    }
  }

  /// Push изменений в Gitea
  Future<Map<String, dynamic>> pushToGitea({String? commitMessage}) async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.post(
      Uri.parse('$_baseUrl/api/sync/gitea/push'),
      headers: _getHeaders(),
      body: jsonEncode({
        'commitMessage': commitMessage ?? 'Sync from Nanaxe CRM',
      }),
    );

    if (response.statusCode == 200) {
      return jsonDecode(response.body);
    } else {
      throw Exception('Failed to push to Gitea');
    }
  }

  /// Pull изменений из Gitea
  Future<Map<String, dynamic>> pullFromGitea() async {
    if (_baseUrl == null) throw Exception('Server not configured');

    final response = await http.post(
      Uri.parse('$_baseUrl/api/sync/gitea/pull'),
      headers: _getHeaders(),
      body: jsonEncode({}),
    );

    if (response.statusCode == 200) {
      return jsonDecode(response.body);
    } else {
      throw Exception('Failed to pull from Gitea');
    }
  }

  // ==================== HELPERS ====================

  Map<String, String> _getHeaders() {
    final headers = {
      'Content-Type': 'application/json',
    };
    
    if (_authToken != null) {
      headers['Authorization'] = 'Bearer $_authToken';
    }
    
    return headers;
  }

  /// Проверка соединения с сервером
  Future<bool> checkConnection() async {
    if (_baseUrl == null) return false;

    try {
      final response = await http
          .get(Uri.parse('$_baseUrl/health'))
          .timeout(const Duration(seconds: 5));
      return response.statusCode == 200;
    } catch (e) {
      return false;
    }
  }
}

/// Провайдер для работы с сервером
class ServerConfig {
  final String baseUrl;
  final String? token;
  final bool isConnected;

  ServerConfig({
    required this.baseUrl,
    this.token,
    this.isConnected = false,
  });
}