'use strict';

const common = require('../common');
if (!common.hasCrypto)
  common.skip('missing crypto');

const assert = require('assert');
const crypto = require('crypto');

// The values below (modp2/modp2buf) are for a 1024 bits long prime from
// RFC 2412 E.2, see https://tools.ietf.org/html/rfc2412. */
const modp2buf = Buffer.from([
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc9, 0x0f,
  0xda, 0xa2, 0x21, 0x68, 0xc2, 0x34, 0xc4, 0xc6, 0x62, 0x8b,
  0x80, 0xdc, 0x1c, 0xd1, 0x29, 0x02, 0x4e, 0x08, 0x8a, 0x67,
  0xcc, 0x74, 0x02, 0x0b, 0xbe, 0xa6, 0x3b, 0x13, 0x9b, 0x22,
  0x51, 0x4a, 0x08, 0x79, 0x8e, 0x34, 0x04, 0xdd, 0xef, 0x95,
  0x19, 0xb3, 0xcd, 0x3a, 0x43, 0x1b, 0x30, 0x2b, 0x0a, 0x6d,
  0xf2, 0x5f, 0x14, 0x37, 0x4f, 0xe1, 0x35, 0x6d, 0x6d, 0x51,
  0xc2, 0x45, 0xe4, 0x85, 0xb5, 0x76, 0x62, 0x5e, 0x7e, 0xc6,
  0xf4, 0x4c, 0x42, 0xe9, 0xa6, 0x37, 0xed, 0x6b, 0x0b, 0xff,
  0x5c, 0xb6, 0xf4, 0x06, 0xb7, 0xed, 0xee, 0x38, 0x6b, 0xfb,
  0x5a, 0x89, 0x9f, 0xa5, 0xae, 0x9f, 0x24, 0x11, 0x7c, 0x4b,
  0x1f, 0xe6, 0x49, 0x28, 0x66, 0x51, 0xec, 0xe6, 0x53, 0x81,
  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
]);

function testDH({ publicKey: alicePublicKey, privateKey: alicePrivateKey },
                { publicKey: bobPublicKey, privateKey: bobPrivateKey },
                expectedValue) {
  const buf1 = crypto.diffieHellman({
    privateKey: alicePrivateKey,
    publicKey: bobPublicKey
  });
  const buf2 = crypto.diffieHellman({
    privateKey: bobPrivateKey,
    publicKey: alicePublicKey
  });
  assert.deepStrictEqual(buf1, buf2);

  if (expectedValue !== undefined)
    assert.deepStrictEqual(buf1, expectedValue);
}

module.exports = {
  modp2buf,
  testDH
};
