import 'dart:convert';

import 'package:injectable/injectable.dart';
import 'package:shared_preferences/shared_preferences.dart';

import '../../../common/constant/local_storage_key.dart';
import '../unit_dtos.dart';

/// Satuan berjumlah sedikit dan jarang berubah, jadi cukup disimpan sebagai
/// satu blob JSON di SharedPreferences — tidak perlu tabel sqflite sendiri.
@injectable
class UnitLocalDataProvider {
  final SharedPreferences _sharedPreferences;

  UnitLocalDataProvider(this._sharedPreferences);

  Future<void> saveUnits(List<UnitDto> units) async {
    final jsonString = jsonEncode(units.map((e) => e.toJson()).toList());
    await _sharedPreferences.setString(LocalStorageKey.units, jsonString);
  }

  List<UnitDto> getUnits() {
    final jsonString = _sharedPreferences.getString(LocalStorageKey.units);
    if (jsonString == null || jsonString.isEmpty) return const [];

    final decoded = jsonDecode(jsonString);
    if (decoded is! List) return const [];

    return decoded
        .whereType<Map<String, dynamic>>()
        .map(UnitDto.fromJson)
        .toList();
  }

  Future<void> clearUnits() async {
    await _sharedPreferences.remove(LocalStorageKey.units);
  }
}