using System;
using System.Security.Cryptography;
using System.Text;

using Microsoft.VisualStudio.TestTools.UnitTesting;

using Renci.SshNet.Security;
using Renci.SshNet.Security.Cryptography;
using Renci.SshNet.Tests.Common;

namespace Renci.SshNet.Tests.Classes.Security.Cryptography
{
    /// <summary>
    /// Implements RSA digital signature algorithm.
    /// </summary>
    [TestClass]
    public class RsaDigitalSignatureTest : TestBase
    {
        [TestMethod]
        public void Sha1_SignAndVerify()
        {
            byte[] data = Encoding.UTF8.GetBytes("hello world");

            RsaKey rsaKey = GetRsaKey();

            var digitalSignature = new RsaDigitalSignature(rsaKey); // Verify SHA-1 is the default

            byte[] signedBytes = digitalSignature.Sign(data);

            byte[] expectedSignedBytes = new byte[]
            {
                // echo -n 'hello world' | openssl dgst -sha1 -sign Key.RSA.txt -out test.signed
                0x41, 0x50, 0x12, 0x14, 0xd3, 0x7c, 0xe0, 0x40, 0x50, 0x65, 0xfb, 0x33, 0xd9, 0x17, 0x89, 0xbf,
                0xb2, 0x4b, 0x85, 0x15, 0xbf, 0x9e, 0x57, 0x3b, 0x01, 0x15, 0x2b, 0x99, 0xfa, 0x62, 0x9b, 0x2a,
                0x05, 0xa0, 0x73, 0xc7, 0xb7, 0x5b, 0xd9, 0x01, 0xaa, 0x56, 0x73, 0x95, 0x13, 0x41, 0x33, 0x0d,
                0x7f, 0x83, 0x8a, 0x60, 0x4d, 0x19, 0xdc, 0x9b, 0xba, 0x8e, 0x61, 0xed, 0xd0, 0x8a, 0x3e, 0x38,
                0x71, 0xee, 0x34, 0xc3, 0x55, 0x0f, 0x55, 0x65, 0x89, 0xbb, 0x3e, 0x41, 0xee, 0xdf, 0xf5, 0x2f,
                0xab, 0x9e, 0x89, 0x37, 0x68, 0x1f, 0x9f, 0x38, 0x00, 0x81, 0x29, 0x93, 0xeb, 0x61, 0x37, 0xad,
                0x8d, 0x35, 0xf1, 0x3d, 0x4b, 0x9b, 0x99, 0x74, 0x7b, 0xeb, 0xf4, 0xfb, 0x76, 0xb4, 0xb6, 0xb4,
                0x09, 0x33, 0x5c, 0xfa, 0x6a, 0xad, 0x1e, 0xed, 0x1c, 0xe1, 0xb4, 0x4d, 0xf2, 0xa5, 0xc3, 0x64,
                0x9a, 0x45, 0x81, 0xee, 0x1b, 0xa6, 0x1d, 0x01, 0x3c, 0x4d, 0xb5, 0x62, 0x9e, 0xff, 0x8e, 0xff,
                0x6c, 0x18, 0xed, 0xe9, 0x8e, 0x03, 0x2c, 0xc5, 0x94, 0x81, 0xca, 0x8b, 0x18, 0x3f, 0x25, 0xcd,
                0xe5, 0x42, 0x49, 0x43, 0x23, 0x1f, 0xdc, 0x3f, 0xa2, 0x43, 0xbc, 0xbd, 0x42, 0xf5, 0x60, 0xfb,
                0x01, 0xd3, 0x67, 0x0d, 0x8d, 0x85, 0x7b, 0x51, 0x14, 0xec, 0x26, 0x53, 0x00, 0x61, 0x25, 0x16,
                0x19, 0x10, 0x3c, 0x86, 0x16, 0x59, 0x84, 0x08, 0xd1, 0xf9, 0x1e, 0x05, 0x88, 0xbd, 0x4a, 0x01,
                0x43, 0x4e, 0xec, 0x76, 0x0b, 0xd7, 0x2c, 0xe9, 0x98, 0xb1, 0x4c, 0x0a, 0x13, 0xc6, 0x95, 0xf9,
                0x8f, 0x95, 0x5c, 0x98, 0x4c, 0x8f, 0x97, 0x4a, 0xad, 0x0d, 0xfe, 0x84, 0xf0, 0x56, 0xc3, 0x29,
                0x73, 0x75, 0x55, 0x3c, 0xd9, 0x5e, 0x5b, 0x6f, 0xf9, 0x81, 0xbc, 0xbc, 0x50, 0x75, 0x7d, 0xa8
            };

            CollectionAssert.AreEqual(expectedSignedBytes, signedBytes);

            // Also verify RsaKey uses SHA-1 by default
            CollectionAssert.AreEqual(expectedSignedBytes, rsaKey.Sign(data));

            // The following fails due to the _isPrivate decision in RsaCipher.Transform. Is that really correct?
            //Assert.IsTrue(digitalSignature.Verify(data, signedBytes));

            // 'Workaround': use a key with no private key information
            var digitalSignaturePublic = new RsaDigitalSignature(new RsaKey(rsaKey.Modulus, rsaKey.Exponent, default, default, default, default));
            Assert.IsTrue(digitalSignaturePublic.Verify(data, signedBytes));
        }

        [TestMethod]
        public void Sha256_SignAndVerify()
        {
            byte[] data = Encoding.UTF8.GetBytes("hello world");

            RsaKey rsaKey = GetRsaKey();

            var digitalSignature = new RsaDigitalSignature(rsaKey, HashAlgorithmName.SHA256);

            byte[] signedBytes = digitalSignature.Sign(data);

            CollectionAssert.AreEqual(new byte[]
            {
                // echo -n 'hello world' | openssl dgst -sha256 -sign Key.RSA.txt -out test.signed
                0x2e, 0xef, 0x01, 0x49, 0x5c, 0x66, 0x37, 0x56, 0xc2, 0xfb, 0x7b, 0xfa, 0x80, 0x2f, 0xdb, 0xaa,
                0x0d, 0x15, 0xd9, 0x8d, 0xa9, 0xad, 0x81, 0x4f, 0x09, 0x2e, 0x53, 0x9e, 0xce, 0x5d, 0x68, 0x07,
                0xae, 0xb9, 0xc0, 0x45, 0xfa, 0x30, 0xd0, 0xf7, 0xd6, 0xa6, 0x8d, 0x19, 0x24, 0x3a, 0xea, 0x91,
                0x3e, 0xa2, 0x4a, 0x42, 0x2e, 0x21, 0xf1, 0x48, 0x57, 0xca, 0x2b, 0x6c, 0x9f, 0x79, 0x54, 0x91,
                0x3e, 0x3a, 0x4d, 0xd1, 0x70, 0x87, 0x3d, 0xbe, 0x22, 0x97, 0xc9, 0xb0, 0x02, 0xf0, 0xa2, 0xae,
                0x7a, 0xbb, 0x8b, 0xaf, 0xc0, 0x3b, 0xab, 0x71, 0xe8, 0x29, 0x1c, 0x18, 0x88, 0xca, 0x74, 0x1b,
                0x34, 0x4f, 0xd1, 0x83, 0x39, 0x6e, 0x8f, 0x69, 0x3d, 0x7e, 0xef, 0xef, 0x57, 0x7c, 0xff, 0x21,
                0x9c, 0x10, 0x2b, 0xd1, 0x4f, 0x26, 0xbe, 0xaa, 0xd2, 0xd9, 0x03, 0x14, 0x75, 0x97, 0x11, 0xaf,
                0xf0, 0x28, 0xf2, 0xd3, 0x07, 0x79, 0x5b, 0x27, 0xdc, 0x97, 0xd8, 0xce, 0x4e, 0x78, 0x89, 0x16,
                0x91, 0x2a, 0xb2, 0x47, 0x53, 0x94, 0xe9, 0xa1, 0x15, 0x98, 0x29, 0x0c, 0xa1, 0xf5, 0xe2, 0x8e,
                0x11, 0xdc, 0x0c, 0x1c, 0x10, 0xa4, 0xf2, 0x46, 0x5c, 0x78, 0x0c, 0xc1, 0x4a, 0x65, 0x21, 0x8a,
                0x2e, 0x32, 0x6c, 0x72, 0x06, 0xf9, 0x7f, 0xa1, 0x6c, 0x2e, 0x13, 0x06, 0x41, 0xaa, 0x23, 0xdd,
                0xc8, 0x1c, 0x61, 0xb6, 0x96, 0x87, 0xc4, 0x84, 0xc8, 0x61, 0xec, 0x4e, 0xdd, 0x49, 0x9e, 0x4f,
                0x0d, 0x8c, 0xf1, 0x7f, 0xf2, 0x6c, 0x73, 0x5a, 0xa6, 0x3b, 0xbf, 0x4e, 0xba, 0x57, 0x6b, 0xb3,
                0x1e, 0x6c, 0x57, 0x76, 0x87, 0x9f, 0xb4, 0x3b, 0xcb, 0xcd, 0xe5, 0x10, 0x7a, 0x4c, 0xeb, 0xc0,
                0xc4, 0xc3, 0x75, 0x51, 0x5f, 0xb7, 0x7c, 0xbc, 0x55, 0x8d, 0x05, 0xc7, 0xed, 0xc7, 0x52, 0x4a
            }, signedBytes);


            // The following fails due to the _isPrivate decision in RsaCipher.Transform. Is that really correct?
            //Assert.IsTrue(digitalSignature.Verify(data, signedBytes));

            // 'Workaround': use a key with no private key information
            var digitalSignaturePublic = new RsaDigitalSignature(
                new RsaKey(rsaKey.Modulus, rsaKey.Exponent, default, default, default, default),
                HashAlgorithmName.SHA256);
            Assert.IsTrue(digitalSignaturePublic.Verify(data, signedBytes));
        }

        [TestMethod]
        public void Sha512_SignAndVerify()
        {
            byte[] data = Encoding.UTF8.GetBytes("hello world");

            RsaKey rsaKey = GetRsaKey();

            var digitalSignature = new RsaDigitalSignature(rsaKey, HashAlgorithmName.SHA512);

            byte[] signedBytes = digitalSignature.Sign(data);

            CollectionAssert.AreEqual(new byte[]
            {
                // echo -n 'hello world' | openssl dgst -sha512 -sign Key.RSA.txt -out test.signed
                0x69, 0x70, 0xb5, 0x9f, 0x32, 0x86, 0x3b, 0xae, 0xc0, 0x79, 0x6e, 0xdb, 0x35, 0xd5, 0xa6, 0x22,
                0xcd, 0x2b, 0x4b, 0xd2, 0x68, 0x1a, 0x65, 0x41, 0xa6, 0xd9, 0x20, 0x54, 0x31, 0x9a, 0xb1, 0x44,
                0x6e, 0x8f, 0x56, 0x4b, 0xfc, 0x27, 0x7f, 0x3f, 0xe7, 0x47, 0xcb, 0x78, 0x03, 0x05, 0x79, 0x8a,
                0x16, 0x7b, 0x12, 0x01, 0x3a, 0xa2, 0xd5, 0x0d, 0x2b, 0x16, 0x38, 0xef, 0x84, 0x6b, 0xd7, 0x19,
                0xeb, 0xac, 0x54, 0x01, 0x9d, 0xa6, 0x80, 0x74, 0x43, 0xa8, 0x6e, 0x5e, 0x33, 0x05, 0x06, 0x1d,
                0x6d, 0xfe, 0x32, 0x4f, 0xe3, 0xcb, 0x3e, 0x2d, 0x4e, 0xe1, 0x47, 0x03, 0x69, 0xb4, 0x59, 0x80,
                0x59, 0x05, 0x15, 0xa0, 0x11, 0x34, 0x47, 0x58, 0xd7, 0x93, 0x2d, 0x40, 0xf2, 0x2c, 0x37, 0x48,
                0x6b, 0x3c, 0xd3, 0x03, 0x09, 0x32, 0x74, 0xa0, 0x2d, 0x33, 0x11, 0x99, 0x10, 0xb4, 0x09, 0x31,
                0xec, 0xa3, 0x2c, 0x63, 0xba, 0x50, 0xd1, 0x02, 0x45, 0xae, 0xb5, 0x75, 0x7e, 0xfa, 0xfc, 0x06,
                0xb6, 0x6a, 0xb2, 0xa1, 0x73, 0x14, 0xa5, 0xaa, 0x17, 0x88, 0x03, 0x19, 0x14, 0x9b, 0xe1, 0x10,
                0xf8, 0x2f, 0x73, 0x01, 0xc7, 0x8d, 0x37, 0xef, 0x98, 0x69, 0xc2, 0xe2, 0x7a, 0x11, 0xd5, 0xb8,
                0xc9, 0x35, 0x45, 0xcb, 0x56, 0x4b, 0x92, 0x4a, 0xe0, 0x4c, 0xd6, 0x82, 0xae, 0xad, 0x5b, 0xe9,
                0x40, 0x7e, 0x2a, 0x48, 0x7d, 0x57, 0xc5, 0xfd, 0xe9, 0x98, 0xe0, 0xbb, 0x09, 0xa1, 0xf5, 0x48,
                0x45, 0xcb, 0xee, 0xb9, 0x99, 0x81, 0x44, 0x15, 0x2e, 0x50, 0x39, 0x64, 0x58, 0x4c, 0x34, 0x86,
                0xf8, 0x81, 0x9e, 0x1d, 0xb6, 0x97, 0xe0, 0xce, 0x16, 0xca, 0x20, 0x46, 0xe9, 0x49, 0x8f, 0xe6,
                0xa0, 0x23, 0x08, 0x80, 0xa6, 0x37, 0x70, 0x06, 0xcc, 0x8f, 0xf4, 0xa0, 0x74, 0x53, 0x26, 0x38
            }, signedBytes);

            // The following fails due to the _isPrivate decision in RsaCipher.Transform. Is that really correct?
            //Assert.IsTrue(digitalSignature.Verify(data, signedBytes));

            // 'Workaround': use a key with no private key information
            var digitalSignaturePublic = new RsaDigitalSignature(
                new RsaKey(rsaKey.Modulus, rsaKey.Exponent, default, default, default, default),
                HashAlgorithmName.SHA512);
            Assert.IsTrue(digitalSignaturePublic.Verify(data, signedBytes));
        }

        [TestMethod]
        public void Constructor_InvalidHashAlgorithm_ThrowsArgumentException()
        {
            ArgumentException exception = Assert.ThrowsException<ArgumentException>(
                () => new RsaDigitalSignature(GetRsaKey(), new HashAlgorithmName("invalid")));

            Assert.AreEqual("hashAlgorithmName", exception.ParamName);
        }

        private static RsaKey GetRsaKey()
        {
            using (var stream = GetData("Key.RSA.txt"))
            {
                return (RsaKey) new PrivateKeyFile(stream).Key;
            }
        }
    }
}