using System;

using Org.BouncyCastle.Utilities;

namespace Org.BouncyCastle.Asn1.Cms
{
    public class SignerIdentifier
        : Asn1Encodable, IAsn1Choice
    {
        private Asn1Encodable id;

		public SignerIdentifier(
            IssuerAndSerialNumber id)
        {
            this.id = id;
        }

		public SignerIdentifier(
            Asn1OctetString id)
        {
            this.id = new DerTaggedObject(false, 0, id);
        }

		public SignerIdentifier(
            Asn1Object id)
        {
            this.id = id;
        }

		/**
         * return a SignerIdentifier object from the given object.
         *
         * @param o the object we want converted.
         * @exception ArgumentException if the object cannot be converted.
         */
        public static SignerIdentifier GetInstance(
            object o)
        {
            if (o == null || o is SignerIdentifier)
                return (SignerIdentifier) o;

			if (o is IssuerAndSerialNumber)
                return new SignerIdentifier((IssuerAndSerialNumber) o);

			if (o is Asn1OctetString)
                return new SignerIdentifier((Asn1OctetString) o);

			if (o is Asn1Object)
                return new SignerIdentifier((Asn1Object) o);

			throw new ArgumentException(
                "Illegal object in SignerIdentifier: " + Platform.GetTypeName(o));
        }

		public bool IsTagged
		{
			get { return (id is Asn1TaggedObject); }
		}

		public Asn1Encodable ID
        {
            get
            {
                if (id is Asn1TaggedObject)
                {
                    return Asn1OctetString.GetInstance((Asn1TaggedObject)id, false);
                }

				return id;
            }
        }

		/**
         * Produce an object suitable for an Asn1OutputStream.
         * <pre>
         * SignerIdentifier ::= CHOICE {
         *     issuerAndSerialNumber IssuerAndSerialNumber,
         *     subjectKeyIdentifier [0] SubjectKeyIdentifier
         * }
         *
         * SubjectKeyIdentifier ::= OCTET STRING
         * </pre>
         */
        public override Asn1Object ToAsn1Object()
        {
            return id.ToAsn1Object();
        }
    }
}