import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';

/// 应用数据库管理类
class AppDatabase {
  static final AppDatabase _instance = AppDatabase._internal();
  static Database? _database;

  factory AppDatabase() {
    return _instance;
  }

  AppDatabase._internal();

  /// 获取数据库实例
  Future<Database> get database async {
    if (_database != null) return _database!;
    _database = await _initDatabase();
    return _database!;
  }

  /// 初始化数据库
  Future<Database> _initDatabase() async {
    final documentsDirectory = await getApplicationDocumentsDirectory();
    final path = join(documentsDirectory.path, 'sino_med_cloud.db');

    return await openDatabase(
      path,
      version: 1,
      onCreate: _onCreate,
      onUpgrade: _onUpgrade,
    );
  }

  /// 创建数据库表
  Future<void> _onCreate(Database db, int version) async {
    // 可以在这里创建表
    // 示例：用户表
    // await db.execute('''
    //   CREATE TABLE users (
    //     id INTEGER PRIMARY KEY AUTOINCREMENT,
    //     name TEXT NOT NULL,
    //     email TEXT UNIQUE NOT NULL,
    //     created_at INTEGER NOT NULL
    //   )
    // ''');
  }

  /// 升级数据库
  Future<void> _onUpgrade(Database db, int oldVersion, int newVersion) async {
    // 处理数据库升级逻辑
    if (oldVersion < newVersion) {
      // 执行升级操作
    }
  }

  /// 关闭数据库
  Future<void> close() async {
    final db = await database;
    await db.close();
    _database = null;
  }
}