using System;
using System.Collections.Generic;

using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.Cms;
using Org.BouncyCastle.Asn1.Kisa;
using Org.BouncyCastle.Asn1.Nist;
using Org.BouncyCastle.Asn1.Ntt;
using Org.BouncyCastle.Asn1.Pkcs;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Asn1.X9;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Operators;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.X509;

namespace Org.BouncyCastle.Cms
{
	/**
	* General class for generating a CMS enveloped-data message.
	*
	* A simple example of usage.
	*
	* <pre>
	*      CMSEnvelopedDataGenerator  fact = new CMSEnvelopedDataGenerator();
	*
	*      fact.addKeyTransRecipient(cert);
	*
	*      CMSEnvelopedData         data = fact.generate(content, algorithm, "BC");
	* </pre>
	*/
	public abstract class CmsEnvelopedGenerator
	{
		// Note: These tables are complementary: If rc2Table[i]==j, then rc2Ekb[j]==i
		internal static readonly short[] rc2Table =
		{
			0xbd, 0x56, 0xea, 0xf2, 0xa2, 0xf1, 0xac, 0x2a, 0xb0, 0x93, 0xd1, 0x9c, 0x1b, 0x33, 0xfd, 0xd0,
			0x30, 0x04, 0xb6, 0xdc, 0x7d, 0xdf, 0x32, 0x4b, 0xf7, 0xcb, 0x45, 0x9b, 0x31, 0xbb, 0x21, 0x5a,
			0x41, 0x9f, 0xe1, 0xd9, 0x4a, 0x4d, 0x9e, 0xda, 0xa0, 0x68, 0x2c, 0xc3, 0x27, 0x5f, 0x80, 0x36,
			0x3e, 0xee, 0xfb, 0x95, 0x1a, 0xfe, 0xce, 0xa8, 0x34, 0xa9, 0x13, 0xf0, 0xa6, 0x3f, 0xd8, 0x0c,
			0x78, 0x24, 0xaf, 0x23, 0x52, 0xc1, 0x67, 0x17, 0xf5, 0x66, 0x90, 0xe7, 0xe8, 0x07, 0xb8, 0x60,
			0x48, 0xe6, 0x1e, 0x53, 0xf3, 0x92, 0xa4, 0x72, 0x8c, 0x08, 0x15, 0x6e, 0x86, 0x00, 0x84, 0xfa,
			0xf4, 0x7f, 0x8a, 0x42, 0x19, 0xf6, 0xdb, 0xcd, 0x14, 0x8d, 0x50, 0x12, 0xba, 0x3c, 0x06, 0x4e,
			0xec, 0xb3, 0x35, 0x11, 0xa1, 0x88, 0x8e, 0x2b, 0x94, 0x99, 0xb7, 0x71, 0x74, 0xd3, 0xe4, 0xbf,
			0x3a, 0xde, 0x96, 0x0e, 0xbc, 0x0a, 0xed, 0x77, 0xfc, 0x37, 0x6b, 0x03, 0x79, 0x89, 0x62, 0xc6,
			0xd7, 0xc0, 0xd2, 0x7c, 0x6a, 0x8b, 0x22, 0xa3, 0x5b, 0x05, 0x5d, 0x02, 0x75, 0xd5, 0x61, 0xe3,
			0x18, 0x8f, 0x55, 0x51, 0xad, 0x1f, 0x0b, 0x5e, 0x85, 0xe5, 0xc2, 0x57, 0x63, 0xca, 0x3d, 0x6c,
			0xb4, 0xc5, 0xcc, 0x70, 0xb2, 0x91, 0x59, 0x0d, 0x47, 0x20, 0xc8, 0x4f, 0x58, 0xe0, 0x01, 0xe2,
			0x16, 0x38, 0xc4, 0x6f, 0x3b, 0x0f, 0x65, 0x46, 0xbe, 0x7e, 0x2d, 0x7b, 0x82, 0xf9, 0x40, 0xb5,
			0x1d, 0x73, 0xf8, 0xeb, 0x26, 0xc7, 0x87, 0x97, 0x25, 0x54, 0xb1, 0x28, 0xaa, 0x98, 0x9d, 0xa5,
			0x64, 0x6d, 0x7a, 0xd4, 0x10, 0x81, 0x44, 0xef, 0x49, 0xd6, 0xae, 0x2e, 0xdd, 0x76, 0x5c, 0x2f,
			0xa7, 0x1c, 0xc9, 0x09, 0x69, 0x9a, 0x83, 0xcf, 0x29, 0x39, 0xb9, 0xe9, 0x4c, 0xff, 0x43, 0xab
		};

//		internal static readonly short[] rc2Ekb =
//		{
//			0x5d, 0xbe, 0x9b, 0x8b, 0x11, 0x99, 0x6e, 0x4d, 0x59, 0xf3, 0x85, 0xa6, 0x3f, 0xb7, 0x83, 0xc5,
//			0xe4, 0x73, 0x6b, 0x3a, 0x68, 0x5a, 0xc0, 0x47, 0xa0, 0x64, 0x34, 0x0c, 0xf1, 0xd0, 0x52, 0xa5,
//			0xb9, 0x1e, 0x96, 0x43, 0x41, 0xd8, 0xd4, 0x2c, 0xdb, 0xf8, 0x07, 0x77, 0x2a, 0xca, 0xeb, 0xef,
//			0x10, 0x1c, 0x16, 0x0d, 0x38, 0x72, 0x2f, 0x89, 0xc1, 0xf9, 0x80, 0xc4, 0x6d, 0xae, 0x30, 0x3d,
//			0xce, 0x20, 0x63, 0xfe, 0xe6, 0x1a, 0xc7, 0xb8, 0x50, 0xe8, 0x24, 0x17, 0xfc, 0x25, 0x6f, 0xbb,
//			0x6a, 0xa3, 0x44, 0x53, 0xd9, 0xa2, 0x01, 0xab, 0xbc, 0xb6, 0x1f, 0x98, 0xee, 0x9a, 0xa7, 0x2d,
//			0x4f, 0x9e, 0x8e, 0xac, 0xe0, 0xc6, 0x49, 0x46, 0x29, 0xf4, 0x94, 0x8a, 0xaf, 0xe1, 0x5b, 0xc3,
//			0xb3, 0x7b, 0x57, 0xd1, 0x7c, 0x9c, 0xed, 0x87, 0x40, 0x8c, 0xe2, 0xcb, 0x93, 0x14, 0xc9, 0x61,
//			0x2e, 0xe5, 0xcc, 0xf6, 0x5e, 0xa8, 0x5c, 0xd6, 0x75, 0x8d, 0x62, 0x95, 0x58, 0x69, 0x76, 0xa1,
//			0x4a, 0xb5, 0x55, 0x09, 0x78, 0x33, 0x82, 0xd7, 0xdd, 0x79, 0xf5, 0x1b, 0x0b, 0xde, 0x26, 0x21,
//			0x28, 0x74, 0x04, 0x97, 0x56, 0xdf, 0x3c, 0xf0, 0x37, 0x39, 0xdc, 0xff, 0x06, 0xa4, 0xea, 0x42,
//			0x08, 0xda, 0xb4, 0x71, 0xb0, 0xcf, 0x12, 0x7a, 0x4e, 0xfa, 0x6c, 0x1d, 0x84, 0x00, 0xc8, 0x7f,
//			0x91, 0x45, 0xaa, 0x2b, 0xc2, 0xb1, 0x8f, 0xd5, 0xba, 0xf2, 0xad, 0x19, 0xb2, 0x67, 0x36, 0xf7,
//			0x0f, 0x0a, 0x92, 0x7d, 0xe3, 0x9d, 0xe9, 0x90, 0x3e, 0x23, 0x27, 0x66, 0x13, 0xec, 0x81, 0x15,
//			0xbd, 0x22, 0xbf, 0x9f, 0x7e, 0xa9, 0x51, 0x4b, 0x4c, 0xfb, 0x02, 0xd3, 0x70, 0x86, 0x31, 0xe7,
//			0x3b, 0x05, 0x03, 0x54, 0x60, 0x48, 0x65, 0x18, 0xd2, 0xcd, 0x5f, 0x32, 0x88, 0x0e, 0x35, 0xfd
//		};


		// TODO Create named constants for all of these
		public static readonly string DesEde3Cbc		= PkcsObjectIdentifiers.DesEde3Cbc.Id;
		public static readonly string RC2Cbc			= PkcsObjectIdentifiers.RC2Cbc.Id;
		public const string IdeaCbc						= "1.3.6.1.4.1.188.7.1.1.2";
		public const string Cast5Cbc					= "1.2.840.113533.7.66.10";
		public static readonly string Aes128Cbc			= NistObjectIdentifiers.IdAes128Cbc.Id;
		public static readonly string Aes192Cbc			= NistObjectIdentifiers.IdAes192Cbc.Id;
		public static readonly string Aes256Cbc			= NistObjectIdentifiers.IdAes256Cbc.Id;
		public static readonly string Camellia128Cbc	= NttObjectIdentifiers.IdCamellia128Cbc.Id;
		public static readonly string Camellia192Cbc	= NttObjectIdentifiers.IdCamellia192Cbc.Id;
		public static readonly string Camellia256Cbc	= NttObjectIdentifiers.IdCamellia256Cbc.Id;
		public static readonly string SeedCbc			= KisaObjectIdentifiers.IdSeedCbc.Id;

		public static readonly string DesEde3Wrap		= PkcsObjectIdentifiers.IdAlgCms3DesWrap.Id;
		public static readonly string Aes128Wrap		= NistObjectIdentifiers.IdAes128Wrap.Id;
		public static readonly string Aes192Wrap		= NistObjectIdentifiers.IdAes192Wrap.Id;
		public static readonly string Aes256Wrap		= NistObjectIdentifiers.IdAes256Wrap.Id;
		public static readonly string Camellia128Wrap	= NttObjectIdentifiers.IdCamellia128Wrap.Id;
		public static readonly string Camellia192Wrap	= NttObjectIdentifiers.IdCamellia192Wrap.Id;
		public static readonly string Camellia256Wrap	= NttObjectIdentifiers.IdCamellia256Wrap.Id;
		public static readonly string SeedWrap			= KisaObjectIdentifiers.IdNpkiAppCmsSeedWrap.Id;

		public static readonly string ECDHSha1Kdf		= X9ObjectIdentifiers.DHSinglePassStdDHSha1KdfScheme.Id;
		public static readonly string ECMqvSha1Kdf		= X9ObjectIdentifiers.MqvSinglePassSha1KdfScheme.Id;

		internal readonly IList<RecipientInfoGenerator> recipientInfoGenerators = new List<RecipientInfoGenerator>();
		internal readonly SecureRandom m_random;

        internal CmsAttributeTableGenerator unprotectedAttributeGenerator = null;

        protected CmsEnvelopedGenerator()
			: this(CryptoServicesRegistrar.GetSecureRandom())
		{
		}

		/// <summary>Constructor allowing specific source of randomness</summary>
		/// <param name="random">Instance of <c>SecureRandom</c> to use.</param>
		protected CmsEnvelopedGenerator(SecureRandom random)
		{
			if (random == null)
				throw new ArgumentNullException(nameof(random));

			m_random = random;
		}

        public CmsAttributeTableGenerator UnprotectedAttributeGenerator
        {
            get { return this.unprotectedAttributeGenerator; }
            set { this.unprotectedAttributeGenerator = value; }
        }

		/**
		 * add a recipient.
		 *
		 * @param cert recipient's public key certificate
		 * @exception ArgumentException if there is a problem with the certificate
		 */
		public void AddKeyTransRecipient(
			X509Certificate cert)
		{
			TbsCertificateStructure recipientTbsCert = CmsUtilities.GetTbsCertificateStructure(cert);
			SubjectPublicKeyInfo info = recipientTbsCert.SubjectPublicKeyInfo;
			this.AddRecipientInfoGenerator(new KeyTransRecipientInfoGenerator(cert, new Asn1KeyWrapper(info.AlgorithmID.Algorithm, info.AlgorithmID.Parameters, cert)));
		}

		/**
		* add a recipient
		*
		* @param key the public key used by the recipient
		* @param subKeyId the identifier for the recipient's public key
		* @exception ArgumentException if there is a problem with the key
		*/
		public void AddKeyTransRecipient(
			AsymmetricKeyParameter	pubKey,
			byte[]					subKeyId)
		{
			SubjectPublicKeyInfo info = SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(pubKey);
			this.AddRecipientInfoGenerator(new KeyTransRecipientInfoGenerator(subKeyId, new Asn1KeyWrapper(info.AlgorithmID.Algorithm, info.AlgorithmID.Parameters, pubKey)));
		}

		/**
		 * add a KEK recipient.
		 * @param key the secret key to use for wrapping
		 * @param keyIdentifier the byte string that identifies the key
		 */
		public void AddKekRecipient(
			string			keyAlgorithm, // TODO Remove need for this parameter
			KeyParameter	key,
			byte[]			keyIdentifier)
		{
			AddKekRecipient(keyAlgorithm, key, new KekIdentifier(keyIdentifier, null, null));
		}

		/**
		* add a KEK recipient.
		* @param key the secret key to use for wrapping
		* @param keyIdentifier the byte string that identifies the key
		*/
		public void AddKekRecipient(
			string			keyAlgorithm, // TODO Remove need for this parameter
			KeyParameter	key,
			KekIdentifier	kekIdentifier)
		{
			KekRecipientInfoGenerator kekrig = new KekRecipientInfoGenerator();
			kekrig.KekIdentifier = kekIdentifier;
			kekrig.KeyEncryptionKeyOID = keyAlgorithm;
			kekrig.KeyEncryptionKey = key;

			recipientInfoGenerators.Add(kekrig);
		}

		public void AddPasswordRecipient(
			CmsPbeKey	pbeKey,
			string		kekAlgorithmOid)
		{
			Pbkdf2Params p = new Pbkdf2Params(pbeKey.Salt, pbeKey.IterationCount);

			PasswordRecipientInfoGenerator prig = new PasswordRecipientInfoGenerator();
			prig.KeyDerivationAlgorithm = new AlgorithmIdentifier(PkcsObjectIdentifiers.IdPbkdf2, p);
			prig.KeyEncryptionKeyOID = kekAlgorithmOid;
			prig.KeyEncryptionKey = pbeKey.GetEncoded(kekAlgorithmOid);

			recipientInfoGenerators.Add(prig);
		}

		/**
		* Add a key agreement based recipient.
		*
		* @param agreementAlgorithm key agreement algorithm to use.
		* @param senderPrivateKey private key to initialise sender side of agreement with.
		* @param senderPublicKey sender public key to include with message.
		* @param recipientCert recipient's public key certificate.
		* @param cekWrapAlgorithm OID for key wrapping algorithm to use.
		* @exception SecurityUtilityException if the algorithm requested cannot be found
		* @exception InvalidKeyException if the keys are inappropriate for the algorithm specified
		*/
		public void AddKeyAgreementRecipient(
			string					agreementAlgorithm,
			AsymmetricKeyParameter	senderPrivateKey,
			AsymmetricKeyParameter	senderPublicKey,
			X509Certificate			recipientCert,
			string					cekWrapAlgorithm)
		{
            var recipientCerts = new List<X509Certificate>(1);
			recipientCerts.Add(recipientCert);

			AddKeyAgreementRecipients(agreementAlgorithm, senderPrivateKey, senderPublicKey,
				recipientCerts, cekWrapAlgorithm);
		}

		/**
		 * Add multiple key agreement based recipients (sharing a single KeyAgreeRecipientInfo structure).
		 *
		 * @param agreementAlgorithm key agreement algorithm to use.
		 * @param senderPrivateKey private key to initialise sender side of agreement with.
		 * @param senderPublicKey sender public key to include with message.
		 * @param recipientCerts recipients' public key certificates.
		 * @param cekWrapAlgorithm OID for key wrapping algorithm to use.
		 * @exception SecurityUtilityException if the algorithm requested cannot be found
		 * @exception InvalidKeyException if the keys are inappropriate for the algorithm specified
		 */
		public void AddKeyAgreementRecipients(
			string					agreementAlgorithm,
			AsymmetricKeyParameter	senderPrivateKey,
			AsymmetricKeyParameter	senderPublicKey,
			IEnumerable<X509Certificate> recipientCerts,
			string					cekWrapAlgorithm)
		{
			if (!senderPrivateKey.IsPrivate)
				throw new ArgumentException("Expected private key", "senderPrivateKey");
			if (senderPublicKey.IsPrivate)
				throw new ArgumentException("Expected public key", "senderPublicKey");

			/* TODO
			 * "a recipient X.509 version 3 certificate that contains a key usage extension MUST
			 * assert the keyAgreement bit."
			 */

			KeyAgreeRecipientInfoGenerator karig = new KeyAgreeRecipientInfoGenerator();
			karig.KeyAgreementOID = new DerObjectIdentifier(agreementAlgorithm);
			karig.KeyEncryptionOID = new DerObjectIdentifier(cekWrapAlgorithm);
			karig.RecipientCerts = new List<X509Certificate>(recipientCerts);
			karig.SenderKeyPair = new AsymmetricCipherKeyPair(senderPublicKey, senderPrivateKey);

			recipientInfoGenerators.Add(karig);
		}

        /// <summary>
        /// Add a generator to produce the recipient info required.
        /// </summary>
        /// <param name="recipientInfoGenerator">a generator of a recipient info object.</param>
	    public void AddRecipientInfoGenerator(RecipientInfoGenerator recipientInfoGenerator)
	    {
	        recipientInfoGenerators.Add(recipientInfoGenerator);
	    }


        protected internal virtual AlgorithmIdentifier GetAlgorithmIdentifier(
			string					encryptionOid,
			KeyParameter			encKey,
			Asn1Encodable			asn1Params,
			out ICipherParameters	cipherParameters)
		{
			Asn1Object asn1Object;
			if (asn1Params != null)
			{
				asn1Object = asn1Params.ToAsn1Object();
				cipherParameters = ParameterUtilities.GetCipherParameters(
					encryptionOid, encKey, asn1Object);
			}
			else
			{
				asn1Object = DerNull.Instance;
				cipherParameters = encKey;
			}

			return new AlgorithmIdentifier(
				new DerObjectIdentifier(encryptionOid),
				asn1Object);
		}

		protected internal virtual Asn1Encodable GenerateAsn1Parameters(
			string	encryptionOid,
			byte[]	encKeyBytes)
		{
			Asn1Encodable asn1Params = null;

			try
			{
				if (encryptionOid.Equals(RC2Cbc))
				{
					byte[] iv = new byte[8];
                    m_random.NextBytes(iv);

					// TODO Is this detailed repeat of Java version really necessary?
					int effKeyBits = encKeyBytes.Length * 8;
					int parameterVersion;

					if (effKeyBits < 256)
					{
						parameterVersion = rc2Table[effKeyBits];
					}
					else
					{
						parameterVersion = effKeyBits;
					}

					asn1Params = new RC2CbcParameter(parameterVersion, iv);
				}
				else
				{
					asn1Params = ParameterUtilities.GenerateParameters(encryptionOid, m_random);
				}
			}
			catch (SecurityUtilityException)
			{
				// No problem... no parameters generated
			}

			return asn1Params;
		}
	}
}