// Helpers of the tests of the random sources and of the age writer: the
// deterministic source of a seed named as the vectors name it, and a source
// that records the draws of another one. They read no file.

import 'dart:typed_data';

import 'package:datekeys/datekeys.dart' show toHex;
import 'package:datekeys/src/bytes.dart' show utf8Bytes;
import 'package:datekeys/src/random.dart';

typedef Json = Map<String, Object?>;

/// Whether the tests run compiled to JavaScript.
const isWeb = identical(0, 0.0);

List<Json> listOf(Object? v) => (v! as List).cast<Json>();

/// A source that records every draw of another one: its size and bytes.
final class RecordingSource implements RandomSource {
  RecordingSource(this._inner);

  final RandomSource _inner;

  /// The draws, in order.
  final List<Uint8List> draws = [];

  @override
  void fill(Uint8List out) {
    _inner.fill(out);
    draws.add(Uint8List.fromList(out));
  }

  /// The draws as the vectors write them.
  List<Json> get json => [
    for (final d in draws) {'n': d.length, 'hex': toHex(d)},
  ];
}

/// The deterministic source of [seed], a string, as the vectors name it.
SeededRandomSource seeded(String seed) => SeededRandomSource(utf8Bytes(seed));