using System;
using System.Collections;

using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.CryptoPro;
using Org.BouncyCastle.Asn1.GM;
using Org.BouncyCastle.Asn1.Misc;
using Org.BouncyCastle.Asn1.Nist;
using Org.BouncyCastle.Asn1.Pkcs;
using Org.BouncyCastle.Asn1.Oiw;
using Org.BouncyCastle.Asn1.Rosstandart;
using Org.BouncyCastle.Asn1.TeleTrust;
using Org.BouncyCastle.Asn1.UA;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.Crypto.Digests;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Utilities;

namespace Org.BouncyCastle.Security
{
    /// <remarks>
    ///  Utility class for creating IDigest objects from their names/Oids
    /// </remarks>
    public sealed class DigestUtilities
    {
        private enum DigestAlgorithm {
            BLAKE2B_160, BLAKE2B_256, BLAKE2B_384, BLAKE2B_512,
            BLAKE2S_128, BLAKE2S_160, BLAKE2S_224, BLAKE2S_256,
            DSTU7564_256, DSTU7564_384, DSTU7564_512,
            GOST3411,
            GOST3411_2012_256, GOST3411_2012_512,
            KECCAK_224, KECCAK_256, KECCAK_288, KECCAK_384, KECCAK_512,
            MD2, MD4, MD5,
            NONE,
            RIPEMD128, RIPEMD160, RIPEMD256, RIPEMD320,
            SHA_1, SHA_224, SHA_256, SHA_384, SHA_512,
            SHA_512_224, SHA_512_256,
            SHA3_224, SHA3_256, SHA3_384, SHA3_512,
            SHAKE128, SHAKE256,
            SM3,
            TIGER,
            WHIRLPOOL,
        };

        private DigestUtilities()
        {
        }

        private static readonly IDictionary algorithms = Platform.CreateHashtable();
        private static readonly IDictionary oids = Platform.CreateHashtable();

        static DigestUtilities()
        {
            // Signal to obfuscation tools not to change enum constants
            ((DigestAlgorithm)Enums.GetArbitraryValue(typeof(DigestAlgorithm))).ToString();

            algorithms[PkcsObjectIdentifiers.MD2.Id] = "MD2";
            algorithms[PkcsObjectIdentifiers.MD4.Id] = "MD4";
            algorithms[PkcsObjectIdentifiers.MD5.Id] = "MD5";

            algorithms["SHA1"] = "SHA-1";
            algorithms[OiwObjectIdentifiers.IdSha1.Id] = "SHA-1";
            algorithms["SHA224"] = "SHA-224";
            algorithms[NistObjectIdentifiers.IdSha224.Id] = "SHA-224";
            algorithms["SHA256"] = "SHA-256";
            algorithms[NistObjectIdentifiers.IdSha256.Id] = "SHA-256";
            algorithms["SHA384"] = "SHA-384";
            algorithms[NistObjectIdentifiers.IdSha384.Id] = "SHA-384";
            algorithms["SHA512"] = "SHA-512";
            algorithms[NistObjectIdentifiers.IdSha512.Id] = "SHA-512";
            algorithms["SHA512/224"] = "SHA-512/224";
            algorithms[NistObjectIdentifiers.IdSha512_224.Id] = "SHA-512/224";
            algorithms["SHA512/256"] = "SHA-512/256";
            algorithms[NistObjectIdentifiers.IdSha512_256.Id] = "SHA-512/256";

            algorithms["RIPEMD-128"] = "RIPEMD128";
            algorithms[TeleTrusTObjectIdentifiers.RipeMD128.Id] = "RIPEMD128";
            algorithms["RIPEMD-160"] = "RIPEMD160";
            algorithms[TeleTrusTObjectIdentifiers.RipeMD160.Id] = "RIPEMD160";
            algorithms["RIPEMD-256"] = "RIPEMD256";
            algorithms[TeleTrusTObjectIdentifiers.RipeMD256.Id] = "RIPEMD256";
            algorithms["RIPEMD-320"] = "RIPEMD320";
//			algorithms[TeleTrusTObjectIdentifiers.RipeMD320.Id] = "RIPEMD320";

            algorithms[CryptoProObjectIdentifiers.GostR3411.Id] = "GOST3411";

            algorithms["KECCAK224"] = "KECCAK-224";
            algorithms["KECCAK256"] = "KECCAK-256";
            algorithms["KECCAK288"] = "KECCAK-288";
            algorithms["KECCAK384"] = "KECCAK-384";
            algorithms["KECCAK512"] = "KECCAK-512";

            algorithms[NistObjectIdentifiers.IdSha3_224.Id] = "SHA3-224";
            algorithms[NistObjectIdentifiers.IdSha3_256.Id] = "SHA3-256";
            algorithms[NistObjectIdentifiers.IdSha3_384.Id] = "SHA3-384";
            algorithms[NistObjectIdentifiers.IdSha3_512.Id] = "SHA3-512";
            algorithms[NistObjectIdentifiers.IdShake128.Id] = "SHAKE128";
            algorithms[NistObjectIdentifiers.IdShake256.Id] = "SHAKE256";

            algorithms[GMObjectIdentifiers.sm3.Id] = "SM3";

            algorithms[MiscObjectIdentifiers.id_blake2b160.Id] = "BLAKE2B-160";
            algorithms[MiscObjectIdentifiers.id_blake2b256.Id] = "BLAKE2B-256";
            algorithms[MiscObjectIdentifiers.id_blake2b384.Id] = "BLAKE2B-384";
            algorithms[MiscObjectIdentifiers.id_blake2b512.Id] = "BLAKE2B-512";
            algorithms[MiscObjectIdentifiers.id_blake2s128.Id] = "BLAKE2S-128";
            algorithms[MiscObjectIdentifiers.id_blake2s160.Id] = "BLAKE2S-160";
            algorithms[MiscObjectIdentifiers.id_blake2s224.Id] = "BLAKE2S-224";
            algorithms[MiscObjectIdentifiers.id_blake2s256.Id] = "BLAKE2S-256";

            algorithms[RosstandartObjectIdentifiers.id_tc26_gost_3411_12_256.Id] = "GOST3411-2012-256";
            algorithms[RosstandartObjectIdentifiers.id_tc26_gost_3411_12_512.Id] = "GOST3411-2012-512";

            algorithms[UAObjectIdentifiers.dstu7564digest_256.Id] = "DSTU7564-256";
            algorithms[UAObjectIdentifiers.dstu7564digest_384.Id] = "DSTU7564-384";
            algorithms[UAObjectIdentifiers.dstu7564digest_512.Id] = "DSTU7564-512";

            oids["MD2"] = PkcsObjectIdentifiers.MD2;
            oids["MD4"] = PkcsObjectIdentifiers.MD4;
            oids["MD5"] = PkcsObjectIdentifiers.MD5;
            oids["SHA-1"] = OiwObjectIdentifiers.IdSha1;
            oids["SHA-224"] = NistObjectIdentifiers.IdSha224;
            oids["SHA-256"] = NistObjectIdentifiers.IdSha256;
            oids["SHA-384"] = NistObjectIdentifiers.IdSha384;
            oids["SHA-512"] = NistObjectIdentifiers.IdSha512;
            oids["SHA-512/224"] = NistObjectIdentifiers.IdSha512_224;
            oids["SHA-512/256"] = NistObjectIdentifiers.IdSha512_256;
            oids["SHA3-224"] = NistObjectIdentifiers.IdSha3_224;
            oids["SHA3-256"] = NistObjectIdentifiers.IdSha3_256;
            oids["SHA3-384"] = NistObjectIdentifiers.IdSha3_384;
            oids["SHA3-512"] = NistObjectIdentifiers.IdSha3_512;
            oids["SHAKE128"] = NistObjectIdentifiers.IdShake128;
            oids["SHAKE256"] = NistObjectIdentifiers.IdShake256;
            oids["RIPEMD128"] = TeleTrusTObjectIdentifiers.RipeMD128;
            oids["RIPEMD160"] = TeleTrusTObjectIdentifiers.RipeMD160;
            oids["RIPEMD256"] = TeleTrusTObjectIdentifiers.RipeMD256;
            oids["GOST3411"] = CryptoProObjectIdentifiers.GostR3411;
            oids["SM3"] = GMObjectIdentifiers.sm3;
            oids["BLAKE2B-160"] = MiscObjectIdentifiers.id_blake2b160;
            oids["BLAKE2B-256"] = MiscObjectIdentifiers.id_blake2b256;
            oids["BLAKE2B-384"] = MiscObjectIdentifiers.id_blake2b384;
            oids["BLAKE2B-512"] = MiscObjectIdentifiers.id_blake2b512;
            oids["BLAKE2S-128"] = MiscObjectIdentifiers.id_blake2s128;
            oids["BLAKE2S-160"] = MiscObjectIdentifiers.id_blake2s160;
            oids["BLAKE2S-224"] = MiscObjectIdentifiers.id_blake2s224;
            oids["BLAKE2S-256"] = MiscObjectIdentifiers.id_blake2s256;
            oids["GOST3411-2012-256"] = RosstandartObjectIdentifiers.id_tc26_gost_3411_12_256;
            oids["GOST3411-2012-512"] = RosstandartObjectIdentifiers.id_tc26_gost_3411_12_512;
            oids["DSTU7564-256"] = UAObjectIdentifiers.dstu7564digest_256;
            oids["DSTU7564-384"] = UAObjectIdentifiers.dstu7564digest_384;
            oids["DSTU7564-512"] = UAObjectIdentifiers.dstu7564digest_512;
        }

        /// <summary>
        /// Returns a ObjectIdentifier for a given digest mechanism.
        /// </summary>
        /// <param name="mechanism">A string representation of the digest meanism.</param>
        /// <returns>A DerObjectIdentifier, null if the Oid is not available.</returns>

        public static DerObjectIdentifier GetObjectIdentifier(
            string mechanism)
        {
            if (mechanism == null)
                throw new System.ArgumentNullException("mechanism");

            mechanism = Platform.ToUpperInvariant(mechanism);
            string aliased = (string) algorithms[mechanism];

            if (aliased != null)
                mechanism = aliased;

            return (DerObjectIdentifier) oids[mechanism];
        }

        public static ICollection Algorithms
        {
            get { return oids.Keys; }
        }

        public static IDigest GetDigest(
            DerObjectIdentifier id)
        {
            return GetDigest(id.Id);
        }

        public static IDigest GetDigest(
            string algorithm)
        {
            string upper = Platform.ToUpperInvariant(algorithm);
            string mechanism = (string) algorithms[upper];

            if (mechanism == null)
            {
                mechanism = upper;
            }

            try
            {
                DigestAlgorithm digestAlgorithm = (DigestAlgorithm)Enums.GetEnumValue(
                    typeof(DigestAlgorithm), mechanism);

                switch (digestAlgorithm)
                {
                    case DigestAlgorithm.BLAKE2B_160: return new Blake2bDigest(160);
                    case DigestAlgorithm.BLAKE2B_256: return new Blake2bDigest(256);
                    case DigestAlgorithm.BLAKE2B_384: return new Blake2bDigest(384);
                    case DigestAlgorithm.BLAKE2B_512: return new Blake2bDigest(512);
                    case DigestAlgorithm.BLAKE2S_128: return new Blake2sDigest(128);
                    case DigestAlgorithm.BLAKE2S_160: return new Blake2sDigest(160);
                    case DigestAlgorithm.BLAKE2S_224: return new Blake2sDigest(224);
                    case DigestAlgorithm.BLAKE2S_256: return new Blake2sDigest(256);
                    case DigestAlgorithm.DSTU7564_256: return new Dstu7564Digest(256);
                    case DigestAlgorithm.DSTU7564_384: return new Dstu7564Digest(384);
                    case DigestAlgorithm.DSTU7564_512: return new Dstu7564Digest(512);
                    case DigestAlgorithm.GOST3411: return new Gost3411Digest();
                    case DigestAlgorithm.GOST3411_2012_256: return new GOST3411_2012_256Digest();
                    case DigestAlgorithm.GOST3411_2012_512: return new GOST3411_2012_512Digest();
                    case DigestAlgorithm.KECCAK_224: return new KeccakDigest(224);
                    case DigestAlgorithm.KECCAK_256: return new KeccakDigest(256);
                    case DigestAlgorithm.KECCAK_288: return new KeccakDigest(288);
                    case DigestAlgorithm.KECCAK_384: return new KeccakDigest(384);
                    case DigestAlgorithm.KECCAK_512: return new KeccakDigest(512);
                    case DigestAlgorithm.MD2: return new MD2Digest();
                    case DigestAlgorithm.MD4: return new MD4Digest();
                    case DigestAlgorithm.MD5: return new MD5Digest();
                    case DigestAlgorithm.NONE: return new NullDigest();
                    case DigestAlgorithm.RIPEMD128: return new RipeMD128Digest();
                    case DigestAlgorithm.RIPEMD160: return new RipeMD160Digest();
                    case DigestAlgorithm.RIPEMD256: return new RipeMD256Digest();
                    case DigestAlgorithm.RIPEMD320: return new RipeMD320Digest();
                    case DigestAlgorithm.SHA_1: return new Sha1Digest();
                    case DigestAlgorithm.SHA_224: return new Sha224Digest();
                    case DigestAlgorithm.SHA_256: return new Sha256Digest();
                    case DigestAlgorithm.SHA_384: return new Sha384Digest();
                    case DigestAlgorithm.SHA_512: return new Sha512Digest();
                    case DigestAlgorithm.SHA_512_224: return new Sha512tDigest(224);
                    case DigestAlgorithm.SHA_512_256: return new Sha512tDigest(256);
                    case DigestAlgorithm.SHA3_224: return new Sha3Digest(224);
                    case DigestAlgorithm.SHA3_256: return new Sha3Digest(256);
                    case DigestAlgorithm.SHA3_384: return new Sha3Digest(384);
                    case DigestAlgorithm.SHA3_512: return new Sha3Digest(512);
                    case DigestAlgorithm.SHAKE128: return new ShakeDigest(128);
                    case DigestAlgorithm.SHAKE256: return new ShakeDigest(256);
                    case DigestAlgorithm.SM3: return new SM3Digest();
                    case DigestAlgorithm.TIGER: return new TigerDigest();
                    case DigestAlgorithm.WHIRLPOOL: return new WhirlpoolDigest();
                }
            }
            catch (ArgumentException)
            {
            }

            throw new SecurityUtilityException("Digest " + mechanism + " not recognised.");
        }

        public static string GetAlgorithmName(
            DerObjectIdentifier oid)
        {
            return (string) algorithms[oid.Id];
        }

        public static byte[] CalculateDigest(string algorithm, byte[] input)
        {
            IDigest digest = GetDigest(algorithm);
            digest.BlockUpdate(input, 0, input.Length);
            return DoFinal(digest);
        }

        public static byte[] DoFinal(
            IDigest digest)
        {
            byte[] b = new byte[digest.GetDigestSize()];
            digest.DoFinal(b, 0);
            return b;
        }

        public static byte[] DoFinal(
            IDigest	digest,
            byte[]	input)
        {
            digest.BlockUpdate(input, 0, input.Length);
            return DoFinal(digest);
        }
    }
}