// Times the age writer of datekeys-dart, stage 6a, on the VM and compiled
// to JavaScript: the throughput of a large PAYLOAD_AGE encrypted in
// streaming, in pieces of 1 MiB, 64 MiB on the VM and 16 MiB in Node.js; and
// the header of each file of a capsule: PAYLOAD_AGE for one X25519
// recipient, INNER_ACCESS_AGE for 16 and a control of 103 bytes,
// OUTER_TIME_AGE for the tlock recipient, and the file of an author key, a
// scrypt recipient with logN 16. Each is the median of a few runs. The
// random values come from the CSPRNG of the platform, as in production.
//
//   dart run tool/age_writer_bench.dart
//
//   dart compile js -O2 -o age_writer_bench.js tool/age_writer_bench.dart
//   node -e "globalThis.self = globalThis; require('./age_writer_bench.js')"
//
// ignore_for_file: avoid_print
import 'dart:typed_data';

import 'package:datekeys/datekeys.dart' show quicknet;
import 'package:datekeys/src/age_writer.dart';
import 'package:datekeys/src/random.dart';
import 'package:datekeys/src/recipient.dart';

const isWeb = identical(0, 0.0);

double median(List<double> xs) => (xs..sort())[xs.length ~/ 2];

/// The median time of [f], in milliseconds, over [runs] runs.
double time(int runs, void Function() f) {
  final times = <double>[];
  for (var i = 0; i < runs; i++) {
    final sw = Stopwatch()..start();
    f();
    times.add(sw.elapsedMicroseconds / 1000);
  }
  return median(times);
}

void main() {
  final id = generateX25519Identity();
  final payload = X25519Recipient.of(id);
  final slots = [
    for (var i = 0; i < 16; i++) X25519Recipient.of(generateX25519Identity()),
  ];
  final tlock = TimeRecipient(quicknet(), 1000);
  final scrypt = ScryptRecipient('a passphrase', workFactor: 16);
  final control = Uint8List(103);

  print('age writer, ${isWeb ? 'Node.js' : 'VM'}');
  print(
    'PAYLOAD_AGE header, one X25519 stanza: '
    '${time(15, () => AgeEncryptor([payload]).close()).toStringAsFixed(2)} ms',
  );
  print(
    'INNER_ACCESS_AGE, 16 X25519 stanzas, 103 bytes: '
    '${time(7, () => ageEncrypt(control, slots)).toStringAsFixed(1)} ms',
  );
  print(
    'OUTER_TIME_AGE, the tlock stanza of round 1000, 2128 bytes: '
    '${time(5, () => ageEncrypt(Uint8List(1773), [tlock])).toStringAsFixed(0)} ms',
  );
  print(
    'an author key file, scrypt with logN 16: '
    '${time(3, () => ageEncrypt(Uint8List(120), [scrypt])).toStringAsFixed(0)} ms',
  );

  // The throughput in streaming, in pieces of 1 MiB.
  final mib = isWeb ? 16 : 64;
  final piece = Uint8List(1 << 20);
  for (var i = 0; i < piece.length; i++) {
    piece[i] = (31 * i + 7) & 0xff;
  }
  final ms = time(3, () {
    final e = AgeEncryptor([payload], random: secureRandom);
    var n = e.header.length + e.nonce.length;
    for (var i = 0; i < mib; i++) {
      for (final c in e.add(piece)) {
        n += c.length;
      }
    }
    n += e.close().length;
    if (n != ageFileLength([x25519StanzaLength], mib << 20)) {
      throw StateError('$n bytes');
    }
  });
  print(
    '$mib MiB in streaming: ${(ms / 1000).toStringAsFixed(2)} s, '
    '${(mib / ms * 1000).toStringAsFixed(1)} MiB/s',
  );
}