import 'dart:convert';

import 'package:shared_preferences/shared_preferences.dart';

class SharedPrefsWrapper<T> {
  const SharedPrefsWrapper({
    required this.key,
    required this.fromJson,
  });

  static SharedPreferences? _sp;
  final String key;
  final T Function(dynamic json) fromJson;

  Future<void> set(
    T e, [
    List<String> tags = const [],
  ]) async {
    _sp ??= await SharedPreferences.getInstance();
    await _sp!.setString(
      key + tags.join('.'),
      jsonEncode(e),
    );
  }

  Future<T?> get([
    List<String> filter = const [],
  ]) async {
    _sp ??= await SharedPreferences.getInstance();
    final source = _sp!.getString(
      key + filter.join('.'),
    );
    if (source == null) return null;
    final json = jsonDecode(source);
    return fromJson(json);
  }
}