// age against test/vectors/age.json, which filippo.io/age v1.3.2 and the
// agewrap package of datekeys-go wrote and read (tool/gen_age_vectors.go):
// X25519 and scrypt files, their truncations and manipulations, a corpus of
// headers against the grammar and the 2 MiB limit, the stanza rules and
// the identities of agewrap, with the text of Go's error for every case.
@TestOn('vm')
library;

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

import 'package:datekeys/datekeys.dart';
import 'package:datekeys/src/age.dart';
import 'package:datekeys/src/agewrap.dart';
import 'package:datekeys/src/sha256.dart';
import 'package:test/test.dart';

import 'age_support.dart';

final Map<String, Object?> vectors = jsonDecode(
  File('test/vectors/age.json').readAsStringSync(),
) as Map<String, Object?>;

List<Map<String, Object?>> section(String name) =>
    (vectors[name]! as List).cast<Map<String, Object?>>();

Map<String, Object?> asMap(Object? v) => v! as Map<String, Object?>;

List<AgeStanza> stanzasOf(Object? list) => [
  for (final s in (list! as List).cast<Map<String, Object?>>())
    AgeStanza(
      s['type']! as String,
      (s['args']! as List).cast<String>(),
      Uint8List(0),
    ),
];

Map<String, Object?> describe(AgeStanza s) => {
  'type': s.type,
  'args': s.args,
  'body_length': s.body.length,
  'body_sha256': toHex(sha256(s.body)),
};

String? errorOf(void Function() f) {
  try {
    f();
    return null;
  } on DateKeysException catch (e) {
    return e.message;
  }
}

void main() {
  final ids = asMap(vectors['identities']);
  final files = <String, Uint8List>{
    for (final f in section('files'))
      f['name']! as String: fromHex(f['hex']! as String),
  };

  group('the large files, rebuilt', () {
    for (final f in section('large')) {
      test(f['name'], () {
        final header = fromHex(f['header']! as String);
        final nonce = fromHex(f['nonce']! as String);
        final file = concatBytes([
          header,
          nonce,
          streamSeal(
            fromHex(f['file_key']! as String),
            nonce,
            pattern(f['length']! as int),
          ),
        ]);
        expect(file.length, f['file_length']);
        expect(toHex(sha256(file)), f['file_sha256']);
        files[f['name']! as String] = file;
      });
    }
  });

  test('each file decrypts to its plaintext', () {
    for (final f in section('files')) {
      final h = parseAgeHeader(files[f['name']]!);
      expect(h.stanzas, isNotEmpty);
    }
    final main = X25519Identity.parse(ids['main']! as String);
    expect(main.recipientString, ids['main_recipient']);
    expect(toHex(main.recipient), ids['main_recipient_raw']);
    expect(main.toString(), ids['main']);
    expect(ageDecrypt(files['x25519_100']!, [main]), pattern(100));
  });

  test('the cases: decryption, truncation and manipulation, as Go', () {
    var n = 0;
    for (final c in section('cases')) {
      var file = Uint8List.fromList(files[c['file']]!);
      final e = c['edit'] as Map<String, Object?>?;
      if (e != null) {
        if (e['truncate'] != null) {
          file = Uint8List.sublistView(file, 0, e['truncate']! as int);
        }
        if (e['at'] != null) {
          final x = fromHex(e['xor']! as String);
          for (var i = 0; i < x.length; i++) {
            file[(e['at']! as int) + i] ^= x[i];
          }
        }
        if (e['append'] != null) {
          file = concatBytes([file, fromHex(e['append']! as String)]);
        }
      }
      final identities = [
        for (final s in (c['identities']! as List).cast<Map<String, Object?>>())
          identityOf(s),
      ];
      expect(
        resultOf(file, identities),
        c['result'],
        reason: c['name'] as String?,
      );
      n++;
    }
    expect(n, greaterThan(150));
  });

  test('the STREAM fed in pieces gives the same results', () {
    final r = Random(5);
    final main = [X25519Identity.parse(ids['main']! as String)];
    for (final c in section('cases')) {
      if (!(c['file']! as String).startsWith('x25519_large') ||
          c['edit'] == null) {
        continue;
      }
      final e = c['edit']! as Map<String, Object?>;
      var file = Uint8List.fromList(files[c['file']]!);
      if (e['truncate'] != null) {
        file = Uint8List.sublistView(file, 0, e['truncate']! as int);
      }
      if (e['at'] != null) {
        file[e['at']! as int] ^= fromHex(e['xor']! as String)[0];
      }
      if (e['append'] != null) {
        file = concatBytes([file, fromHex(e['append']! as String)]);
      }
      for (final step in [() => 1 + r.nextInt(100000), () => 65552, () => 7]) {
        if (step() == 7 && file.length > 70000) continue;
        expect(
          resultInPieces(file, main, step),
          c['result'],
          reason: c['name'] as String?,
        );
      }
    }
  });

  test('the headers: the grammar of spec §28.1 and the limits of age', () {
    final main = X25519Identity.parse(ids['main']! as String);
    for (final c in section('headers')) {
      final file = build(c['parts'] as List?);
      expect(file.length, c['length'], reason: c['name'] as String?);
      expect(toHex(sha256(file)), c['sha256']);
      expect(resultOf(file, [main]), c['result'], reason: c['name'] as String?);
      final probe = asMap(c['probe']);
      try {
        final ss = ageStanzas(file);
        expect(probe['error'], isNull, reason: c['name'] as String?);
        expect(ss.length, probe['count']);
        if (probe['stanzas'] != null) {
          expect([for (final s in ss) describe(s)], probe['stanzas']);
        } else {
          expect(describe(ss.first), probe['first']);
          expect(describe(ss.last), probe['last']);
        }
      } on DateKeysException catch (e) {
        expect(e.message, probe['error'], reason: c['name'] as String?);
        expect(e.code, ErrorCode.integrity);
      }
    }
  });

  test('a prefix longer than 2 MiB parses as the whole file', () {
    // parseAgeHeader of the first 2 MiB + 1 bytes of a file gives what the
    // file gives, whatever follows.
    for (final c in section('headers')) {
      final file = build(c['parts'] as List?);
      if (file.length <= maxAgeHeaderLength + 1) continue;
      final prefix = Uint8List.sublistView(file, 0, maxAgeHeaderLength + 1);
      String outcome(Uint8List b) {
        try {
          return '${parseAgeHeader(b).length}';
        } on AgeException catch (e) {
          return e.message;
        }
      }

      expect(outcome(prefix), outcome(file), reason: c['name'] as String?);
    }
  });

  test('the stanza rules of agewrap', () {
    final time = asMap(vectors['time_stanzas']);
    for (final c in (time['cases']! as List).cast<Map<String, Object?>>()) {
      expect(
        errorOf(
          () => checkTimeStanzas(
            stanzasOf(c['stanzas']),
            round: c['round']! as int,
            chainHashHex: time['chain_hash']! as String,
            profileId: time['profile_id']! as String,
          ),
        ),
        c['error'],
        reason: c['name'] as String?,
      );
    }
    for (final c in section('payload_stanzas')) {
      expect(
        errorOf(() => checkPayloadStanzas(stanzasOf(c['stanzas']))),
        c['error'],
        reason: c['name'] as String?,
      );
    }
    for (final c in section('access_stanzas')) {
      expect(
        errorOf(
          () => checkAccessStanzas(stanzasOf(c['stanzas']), c['slots']! as int),
        ),
        c['error'],
        reason: '${c['name']}, ${c['slots']} slots',
      );
    }
  });

  test('the identities of agewrap', () {
    for (final c in section('agewrap')) {
      final raws = [
        for (final r in (c['raw_identities']! as List).cast<String>())
          fromHex(r),
      ];
      final file = fromHex(c['file']! as String);
      Map<String, Object?> result;
      try {
        final AgeIdentity id = c['kind'] == 'payload'
            ? PayloadIdentity(raws.single)
            : AccessIdentity(c['slots']! as int, [
                for (final r in raws) x25519IdentityFromRaw(r),
              ]);
        result = resultOf(file, [id]);
      } on DateKeysException catch (e) {
        result = {'error': e.message, 'phase': 'identity'};
      }
      expect(result, c['result'], reason: c['name'] as String?);
    }
    expect(
      () => AccessIdentity(-1, [X25519Identity(Uint8List(32))]),
      throwsArgumentError,
    );
    // Null entries are dropped, as in Go.
    expect(
      errorOf(() => AccessIdentity(16, [null])),
      'agewrap: time_and_key needs an access identity: ERR_ACCESS_REQUIRED',
    );
  });

  test('age.ParseX25519Identity', () {
    for (final c in section('parse_identity')) {
      final s = c['input']! as String;
      try {
        final id = X25519Identity.parse(s);
        expect(c['error'], isNull, reason: s);
        expect(toHex(id.secretKey), c['raw']);
        expect(id.recipientString, c['recipient']);
        expect(id.toString(), c['string']);
      } on AgeException catch (e) {
        expect(e.message, c['error'], reason: s);
      }
    }
  });
}