// SPDX-FileCopyrightText: 2026 FocusFlow contributors
// SPDX-License-Identifier: AGPL-3.0-only

/// Implements Encrypted Backup behavior for the Scheduler Backup package.
library;

import 'dart:convert';
import 'dart:io';
import 'dart:math';
import 'dart:typed_data';

import 'package:cryptography/cryptography.dart';
part 'encrypted_backup/errors/backup_decryption_exception.dart';
part 'encrypted_backup/codec/backup_encryption_codec.dart';
part 'encrypted_backup/errors/backup_exception.dart';
part 'encrypted_backup/paths/backup_file_names.dart';
part 'encrypted_backup/paths/backup_paths.dart';
part 'encrypted_backup/operations/encrypted_backup_operations.dart';

/// Default scheduler data directory name under the user's home directory.
const defaultSchedulerDirectoryName = 'ADHD_Scheduler';

/// Default SQLite database file name used by local scheduler persistence.
const defaultSchedulerDatabaseFileName = 'scheduler.sqlite';

/// Default encrypted backup directory name under the scheduler data directory.
const defaultSchedulerBackupDirectoryName = 'backups';

/// Private file-level value for `_formatMagic`.
/// Keeping this value near the helpers that use it avoids hidden global configuration while still preventing duplicate literals.
const _formatMagic = 'ADHD_SCHEDULER_BACKUP_V1';

/// Private file-level value for `_fileExtension`.
/// Keeping this value near the helpers that use it avoids hidden global configuration while still preventing duplicate literals.
const _fileExtension = '.db.enc';

/// Private file-level value for `_kdfIterations`.
/// Keeping this value near the helpers that use it avoids hidden global configuration while still preventing duplicate literals.
const _kdfIterations = 200000;

/// Private file-level value for `_saltLength`.
/// Keeping this value near the helpers that use it avoids hidden global configuration while still preventing duplicate literals.
const _saltLength = 16;

/// Private file-level value for `_nonceLength`.
/// Keeping this value near the helpers that use it avoids hidden global configuration while still preventing duplicate literals.
const _nonceLength = 12;

/// Private file-level value for `_keyLength`.
/// Keeping this value near the helpers that use it avoids hidden global configuration while still preventing duplicate literals.
const _keyLength = 32;

/// Private file-level value for `_utf8`.
/// Keeping this value near the helpers that use it avoids hidden global configuration while still preventing duplicate literals.
final _utf8 = utf8.encoder;