import 'dart:math';

import '../../application/application.dart';

final class SystemClock implements Clock {
  const SystemClock();

  @override
  DateTime now() => DateTime.now().toUtc();
}

final class UuidV4Generator implements IdGenerator {
  UuidV4Generator({Random? random}) : _random = random ?? Random.secure();

  final Random _random;

  @override
  String newId() {
    final bytes = List<int>.generate(16, (_) => _random.nextInt(256));
    bytes[6] = (bytes[6] & 0x0f) | 0x40;
    bytes[8] = (bytes[8] & 0x3f) | 0x80;
    final hex = bytes.map((byte) => byte.toRadixString(16).padLeft(2, '0'));
    final value = hex.join();
    return [
      value.substring(0, 8),
      value.substring(8, 12),
      value.substring(12, 16),
      value.substring(16, 20),
      value.substring(20),
    ].join('-');
  }
}