tablet-app/lib/Helpers/DatabaseHelper.dart

import 'dart:convert';

import 'package:manager_api_new/api.dart';
import 'package:path/path.dart';
import 'package:sqflite/sqflite.dart';
import 'package:tablet_app/Models/tabletContext.dart';

class DatabaseHelper {
  static final _databaseName = "tablet_database.db";
  static final _databaseVersion = 1;

  static final table = 'tabletAppContext';

  static final columnId = 'id';
  static final columnDeviceId = 'deviceId';
  static final columnHost = 'host';
  static final columnConfiguration = 'configuration';
  static final columnLanguage = 'language';
  static final columnInstanceId = 'instanceId';

  DatabaseHelper._privateConstructor();
  static final DatabaseHelper instance = DatabaseHelper._privateConstructor();

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

  _initDatabase() async {
    String path = join(await getDatabasesPath(), _databaseName);
    return await openDatabase(path,
        version: _databaseVersion, onCreate: _onCreate);
  }

  // SQL code to create the database table
  Future _onCreate(Database db, int version) async {
    await db.execute('''
          CREATE TABLE $table (
            $columnId TEXT NOT NULL PRIMARY KEY,
            $columnDeviceId TEXT NOT NULL,
            $columnHost TEXT NOT NULL,
            $columnConfiguration TEXT,
            $columnLanguage TEXT NOT NULL,     
            $columnInstanceId TEXT NOT NULL     
          )
          ''');
  }

  Future<int> insert(TabletAppContext tabletAppContext) async {
    Database db = await instance.database;

    var res = await db.insert(table, tabletAppContext.toMap());
    return res;
  }

  Future<void> update(TabletAppContext tabletAppContext) async {
    // Get a reference to the database.
    final db = await instance.database;

    await db.update(
      'tabletAppContext',
      tabletAppContext.toMap(),
      where: "id = ?",
      whereArgs: [tabletAppContext.id],
    );
  }

  Future<List<Map<String, dynamic>>> queryAllRows() async {
    Database db = await instance.database;
    var res = await db.query(table, orderBy: "$columnId DESC");
    return res;
  }

  Future<int> delete(String email) async {
    Database db = await instance.database;
    return await db.delete(table, where: '$columnId = ?', whereArgs: [email]);
  }

  Future<List<Map<String, Object?>>> clearTable() async {
    Database db = await instance.database;
    return await db.rawQuery("DELETE FROM $table");
  }

  Future<TabletAppContext?> getData() async {
    TabletAppContext? tabletAppContext;

    await DatabaseHelper.instance.queryAllRows().then((value) {
      value.forEach((element) {
        print("DB - CONTEXT --- ");

        // Configuration is store in SQLite in JSON Format
        var configuration = element['configuration'] == null ? null: ConfigurationDTO.fromJson(jsonDecode(element['configuration']));

        tabletAppContext = TabletAppContext(
            id: element["id"],
            instanceId: element["instanceId"],
            deviceId: element["deviceId"],
            host: element["host"],
            configuration: configuration,
            language: element["language"]
        );
      });
    }).catchError((error) {
      print(error);
      return null;
    });

    return tabletAppContext;
  }
}