using System;

using Org.BouncyCastle.Asn1.X509;

namespace Org.BouncyCastle.Asn1.Pkcs
{
    /**
     * The EncryptedData object.
     * <pre>
     *      EncryptedData ::= Sequence {
     *           version Version,
     *           encryptedContentInfo EncryptedContentInfo
     *      }
     *
     *
     *      EncryptedContentInfo ::= Sequence {
     *          contentType ContentType,
     *          contentEncryptionAlgorithm  ContentEncryptionAlgorithmIdentifier,
     *          encryptedContent [0] IMPLICIT EncryptedContent OPTIONAL
     *    }
     *
     *    EncryptedContent ::= OCTET STRING
     * </pre>
     */
    public class EncryptedData
        : Asn1Encodable
    {
        private readonly Asn1Sequence data;
//        private readonly DerObjectIdentifier bagId;
//        private readonly Asn1Object bagValue;

		public static EncryptedData GetInstance(
             object obj)
        {
			if (obj is EncryptedData)
			{
				return (EncryptedData) obj;
			}

			if (obj is Asn1Sequence)
			{
				return new EncryptedData((Asn1Sequence) obj);
			}

			throw new ArgumentException("unknown object in factory: " + obj.GetType().Name, "obj");
        }

		private EncryptedData(
            Asn1Sequence seq)
        {
			if (seq.Count != 2)
				throw new ArgumentException("Wrong number of elements in sequence", "seq");

			int version = ((DerInteger) seq[0]).Value.IntValue;
			if (version != 0)
            {
                throw new ArgumentException("sequence not version 0");
            }

			this.data = (Asn1Sequence) seq[1];
        }

		public EncryptedData(
            DerObjectIdentifier	contentType,
            AlgorithmIdentifier	encryptionAlgorithm,
            Asn1Encodable		content)
        {
			data = new BerSequence(
				contentType,
				encryptionAlgorithm.ToAsn1Object(),
				new BerTaggedObject(false, 0, content));
        }

		public DerObjectIdentifier ContentType
        {
            get { return (DerObjectIdentifier) data[0]; }
        }

		public AlgorithmIdentifier EncryptionAlgorithm
        {
			get { return AlgorithmIdentifier.GetInstance(data[1]); }
        }

		public Asn1OctetString Content
        {
			get
			{
				if (data.Count == 3)
				{
					DerTaggedObject o = (DerTaggedObject) data[2];

					return Asn1OctetString.GetInstance(o.GetObject());
				}

				return null;
			}
        }

		public override Asn1Object ToAsn1Object()
        {
			return new BerSequence(new DerInteger(0), data);
        }
    }
}
