problem_check_system/lib/data/providers/local_database.dart

import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';
import 'package:uuid/uuid.dart';
import '../models/problem_model.dart';

class LocalDatabase {
  static final LocalDatabase _instance = LocalDatabase._internal();
  factory LocalDatabase() => _instance;
  static Database? _database;
  static const String _tableName = 'problems';

  LocalDatabase._internal();

  Future<Database> get database async {
    if (_database != null) return _database!;
    _database = await _initDatabase();
    return _database!;
  }

  Future<Database> _initDatabase() async {
    String path = join(await getDatabasesPath(), 'problems.db');
    return await openDatabase(path, version: 1, onCreate: _onCreate);
  }

  Future<void> _onCreate(Database db, int version) async {
    await db.execute('''
      CREATE TABLE $_tableName(
        id TEXT PRIMARY KEY,
        description TEXT NOT NULL,
        location TEXT NOT NULL,
        imageUrls TEXT NOT NULL,
        createdAt INTEGER NOT NULL,
        isUploaded INTEGER NOT NULL,
        censorTaskId TEXT,
        bindData TEXT
      )
    ''');
  }

  Future<int> insertProblem(Problem problem) async {
    final db = await database;
    problem.id = const Uuid().v4();
    return await db.insert(_tableName, problem.toMap());
  }

  Future<int> updateProblem(Problem problem) async {
    final db = await database;
    return await db.update(
      _tableName,
      problem.toMap(),
      where: 'id = ?',
      whereArgs: [problem.id],
    );
  }

  Future<int> deleteProblem(String id) async {
    final db = await database;
    return await db.delete(_tableName, where: 'id = ?', whereArgs: [id]);
  }

  /// 通用查询方法
  /// 根据可选的参数筛选问题。
  /// 时间范围、
  /// 上传状态
  /// 绑定状态
  Future<List<Problem>> getProblems({
    DateTime? startDate,
    DateTime? endDate,
    String? uploadStatus, // '已上传', '未上传', '全部'
    String? bindStatus, // '已绑定', '未绑定', '全部'
  }) async {
    final db = await database;

    // 使用可变列表来构建筛选条件
    final List<String> whereClauses = [];
    final List<dynamic> whereArgs = [];

    // 根据 startDate 添加筛选条件
    if (startDate != null) {
      whereClauses.add('createdAt >= ?');
      whereArgs.add(startDate.millisecondsSinceEpoch);
    }

    // 根据 endDate 添加筛选条件
    if (endDate != null) {
      whereClauses.add('createdAt <= ?');
      whereArgs.add(endDate.millisecondsSinceEpoch);
    }

    // 根据 uploadStatus 添加筛选条件
    if (uploadStatus != null && uploadStatus != '全部') {
      whereClauses.add('isUploaded = ?');
      whereArgs.add(uploadStatus == '已上传' ? 1 : 0);
    }

    // 根据 bindStatus 添加筛选条件
    if (bindStatus != null && bindStatus != '全部') {
      if (bindStatus == '已绑定') {
        whereClauses.add('censorTaskId IS NOT NULL');
      } else {
        whereClauses.add('censorTaskId IS NULL');
      }
    }

    // 将所有条件用 ' AND ' 连接起来
    final String whereString = whereClauses.join(' AND ');

    final List<Map<String, dynamic>> maps = await db.query(
      _tableName,
      where: whereString.isEmpty ? null : whereString,
      whereArgs: whereArgs.isEmpty ? null : whereArgs,
      orderBy: 'createdAt DESC',
    );

    return List.generate(maps.length, (i) {
      return Problem.fromMap(maps[i]);
    });
  }
}