import '../security/secret_store.dart';

/// Remembers when the last automatic backup ran, so the app only makes a fresh
/// copy once the interval has elapsed. Backed by the OS keystore (via
/// [SecretStore]) to honour the "no plaintext at rest" rule — mirrors
/// [OnboardingStore]; there is no shared_preferences here.
class AutoBackupStore {
  AutoBackupStore(this._store);

  final SecretStore _store;

  static const _lastKey = 'tane.auto_backup.last';

  /// When the last automatic backup succeeded, or null if none has run yet.
  Future<DateTime?> lastBackupAt() async {
    final raw = await _store.read(_lastKey);
    if (raw == null) return null;
    return DateTime.tryParse(raw);
  }

  /// Records that an automatic backup succeeded at [when].
  Future<void> markBackupAt(DateTime when) =>
      _store.write(_lastKey, when.toIso8601String());
}