@OnPlatform({
  'chrome': Skip('Skip due to potential absence of file loading'),
  'node': Skip('Skip due to potential absence of file loading')
})
import 'dart:convert';
import 'dart:io';
import 'dart:typed_data';

import 'package:pointycastle/pointycastle.dart';
import 'package:pointycastle/src/utils.dart';
import 'package:test/test.dart';

import '../test/src/helpers.dart';

dynamic loadJson(String path) {
  var file = File(path);
  return jsonDecode(file.readAsStringSync());
}

Uint8List nullSafeBytes(dynamic src) {
  if (src == null) {
    return Uint8List(0);
  }
  return createUint8ListFromHexString(src.toString());
}

void main() {
  var acvpToDart = {};
  acvpToDart['SHA2-224'] = 'SHA-224';
  acvpToDart['SHA2-256'] = 'SHA-256';
  acvpToDart['SHA2-384'] = 'SHA-384';
  acvpToDart['SHA2-512'] = 'SHA-512';
  acvpToDart['SHA2-512/224'] = 'SHA-512/224';
  acvpToDart['SHA2-512/256'] = 'SHA-512/256';
  acvpToDart['SHA3-224'] = 'SHA3-224';
  acvpToDart['SHA3-256'] = 'SHA3-256';
  acvpToDart['SHA3-384'] = 'SHA3-384';
  acvpToDart['SHA3-512'] = 'SHA3-512';

  group('KDA OneStep Concat Sp800-56Cr2', () {
    test('run vectors', () {
      //
      // These vectors were generated by NIST's ACVP system.
      // The correct answers were generated by the Bouncy Castle FIPS (Java) Lib
      // and verified by submission to ACVP.
      // "req" files contain the request.
      // "rsp" files contain the response.
      // There are two types of tests, AFT where the IUT is responsible for
      // calculating the DKM and VAL where the IUT is responsible to calculating
      // a DKM that may or may not match the supplied DKM in the request.
      //

      var req = loadJson('test/test_resources/kdf-56c/KDA.req.json');
      var rsp = loadJson('test/test_resources/kdf-56c/KDA.rsp.json');

      //
      // Form a maps of known correct results.
      //

      var validDKMAFT = <String, Uint8List>{};
      var validVALResult = <String, bool>{};

      rsp[1]['testGroups'].forEach((group) {
        group['tests'].forEach((test) {
          if (test['dkm'] != null) {
            validDKMAFT['${group['tgId']}:${test['tcId']}'] =
                createUint8ListFromHexString(test['dkm']);
          } else {
            validVALResult['${group['tgId']}:${test['tcId']}'] =
                test['testPassed'];
          }
        });
      });

      var groups = req[1]['testGroups'];
      groups.forEach((group) {
        var kdfConfig = group['kdfConfiguration'];
        group['tests'].forEach((test) {
          var kdfParams = test['kdfParameter'];
          var t = kdfParams['t'];
          var fpU = test['fixedInfoPartyU'];
          var fpV = test['fixedInfoPartyV'];
          var l = kdfParams['l'];
          var algId = nullSafeBytes(kdfParams['algorithmId']);

          var otherInfo = BytesBuilder();
          otherInfo.add(algId);
          otherInfo.add(nullSafeBytes(fpU['partyId']));
          otherInfo.add(nullSafeBytes(fpU['ephemeralData']));
          otherInfo.add(nullSafeBytes(fpV['partyId']));
          otherInfo.add(nullSafeBytes(fpV['ephemeralData']));
          otherInfo.add(createUint8ListFromHexString(t));

          var Z = createUint8ListFromHexString(kdfParams['z']);

          var c = kdfParams['salt'] != null
              ? HkdfParameters(
                  Z, l, createUint8ListFromHexString(kdfParams['salt']))
              : HkdfParameters(Z, l);

          var concatKdf =
              KeyDerivator(acvpToDart[kdfConfig['auxFunction']] + '/ConcatKDF')
                ..init(c);
          var key = concatKdf.process(otherInfo.toBytes());

          if (group['testType'] == 'AFT') {
            //
            // AFT test, IUT must generate a DKM that must match what NIST
            // is expecting.
            //
            var knownDKM = validDKMAFT['${group['tgId']}:${test['tcId']}'];
            expect(key, equals(knownDKM));
          } else {
            // VAL test
            // DKM is supplied in request, the IUT must generate a DKM that may
            // or may not equal the supplied DKM in the request.
            //

            var dkm = createUint8ListFromHexString(test['dkm']);
            var tp = constantTimeAreEqual(dkm, key);
            expect(
                validVALResult['${group['tgId']}:${test['tcId']}'], equals(tp));
          }
        });
      });
    });
  });

  group('RFC7518', () {
    test('Test concatKDF from RFC 7518 Appendix C', () {
      var kdf = KeyDerivator('SHA-256/ConcatKDF');
      var Z = Uint8List.fromList([
        158,
        86,
        217,
        29,
        129,
        113,
        53,
        211,
        114,
        131,
        66,
        131,
        191,
        132,
        38,
        156,
        251,
        49,
        110,
        163,
        218,
        128,
        106,
        72,
        246,
        218,
        167,
        121,
        140,
        254,
        144,
        196
      ]);
      var otherData = Uint8List.fromList([
        0,
        0,
        0,
        7,
        65,
        49,
        50,
        56,
        71,
        67,
        77,
        0,
        0,
        0,
        5,
        65,
        108,
        105,
        99,
        101,
        0,
        0,
        0,
        3,
        66,
        111,
        98,
        0,
        0,
        0,
        128
      ]);
      var params = HkdfParameters(Z, 128);
      kdf.init(params);

      var key = kdf.process(otherData);
      expect(
          key,
          Uint8List.fromList([
            86,
            170,
            141,
            234,
            248,
            35,
            109,
            32,
            92,
            34,
            40,
            205,
            113,
            167,
            16,
            26
          ]));
    });

    test('Test concatKdf A1 derived from jose4j', () {
      var z = base64Url.decode('Sq8rGLm4rEtzScmnSsY5r1n-AqBl_iBU8FxN80Uc0S0=');
      var alg = 'A256CBC-HS512';
      var otherInfo = computerOtherInfo(alg, 512);
      var c = HkdfParameters(z, 512);
      var concatKdf = KeyDerivator('SHA-256/ConcatKDF')..init(c);
      var key = concatKdf.process(otherInfo);
      var keyencoded = base64UrlEncode(key);
      expect(
          'pgs50IOZ6BxfqvTSie4t9OjWxGr4whiHo1v9Dti93CRiJE2PP60FojLatVVrcjg3BxpuFjnlQxL97GOwAfcwLA==',
          keyencoded);
    });

    test('Test concatKdf A2 derived from jose4j', () {
      var z = base64Url.decode('LfkHot2nGTVlmfxbgxQfMg==');
      var alg = 'A128CBC-HS256';
      var otherInfo = computerOtherInfo(alg, 256);
      var c = HkdfParameters(z, 256);
      var concatKdf = KeyDerivator('SHA-256/ConcatKDF')..init(c);
      var key = concatKdf.process(otherInfo);
      var keyencoded = base64UrlEncode(key);
      expect('vphyobtvExGXF7TaOvAkx6CCjHQNYamP2ET8xkhTu-0=', keyencoded);
    });
  });
}

// Helpers for ECDH-ES
Uint8List computerOtherInfo(String encryptionAlgorithmName, int keybitLength) {
  var l = encryptionAlgorithmName.codeUnits.length.toUnsigned(32);
  var ll = _convertToBigEndian(l);
  var a = Uint8List.fromList(encryptionAlgorithmName.codeUnits);
//TODO: add apu, apv, fixed to empty for now
  var zero = _convertToBigEndian(0);
  var k = _convertToBigEndian(keybitLength);
  return Uint8List.fromList([...ll, ...a, ...zero, ...zero, ...k]);
}

Uint8List _convertToBigEndian(int l) {
  var ll = Uint8List(4);
  ll[0] = (l >> 24) & 255;
  ll[1] = (l >> 16) & 255;
  ll[2] = (l >> 8) & 255;
  ll[3] = l & 255;
  return ll;
}