using System;

namespace Org.BouncyCastle.Asn1.X509
{
    public class V2Form
        : Asn1Encodable
    {
        internal GeneralNames        issuerName;
        internal IssuerSerial        baseCertificateID;
        internal ObjectDigestInfo    objectDigestInfo;

		public static V2Form GetInstance(
            Asn1TaggedObject	obj,
            bool				explicitly)
        {
            return GetInstance(Asn1Sequence.GetInstance(obj, explicitly));
        }

		public static V2Form GetInstance(
            object obj)
        {
            if (obj is V2Form)
            {
                return (V2Form) obj;
            }

			if (obj is Asn1Sequence)
            {
                return new V2Form((Asn1Sequence) obj);
            }

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

		public V2Form(
            GeneralNames issuerName)
        {
            this.issuerName = issuerName;
        }

		private V2Form(
            Asn1Sequence seq)
        {
			if (seq.Count > 3)
			{
				throw new ArgumentException("Bad sequence size: " + seq.Count);
			}

			int index = 0;

			if (!(seq[0] is Asn1TaggedObject))
            {
                index++;
                this.issuerName = GeneralNames.GetInstance(seq[0]);
            }

			for (int i = index; i != seq.Count; i++)
            {
				Asn1TaggedObject o = Asn1TaggedObject.GetInstance(seq[i]);
				if (o.TagNo == 0)
                {
                    baseCertificateID = IssuerSerial.GetInstance(o, false);
                }
                else if (o.TagNo == 1)
                {
                    objectDigestInfo = ObjectDigestInfo.GetInstance(o, false);
                }
				else
				{
					throw new ArgumentException("Bad tag number: " + o.TagNo);
				}
			}
        }

		public GeneralNames IssuerName
        {
            get { return issuerName; }
        }

		public IssuerSerial BaseCertificateID
        {
            get { return baseCertificateID; }
        }

		public ObjectDigestInfo ObjectDigestInfo
        {
            get { return objectDigestInfo; }
        }

		/**
         * Produce an object suitable for an Asn1OutputStream.
         * <pre>
         *  V2Form ::= Sequence {
         *       issuerName            GeneralNames  OPTIONAL,
         *       baseCertificateID     [0] IssuerSerial  OPTIONAL,
         *       objectDigestInfo      [1] ObjectDigestInfo  OPTIONAL
         *         -- issuerName MUST be present in this profile
         *         -- baseCertificateID and objectDigestInfo MUST NOT
         *         -- be present in this profile
         *  }
         * </pre>
         */
        public override Asn1Object ToAsn1Object()
        {
            Asn1EncodableVector v = new Asn1EncodableVector();

			if (issuerName != null)
            {
                v.Add(issuerName);
            }

			if (baseCertificateID != null)
            {
                v.Add(new DerTaggedObject(false, 0, baseCertificateID));
            }

			if (objectDigestInfo != null)
            {
                v.Add(new DerTaggedObject(false, 1, objectDigestInfo));
            }

			return new DerSequence(v);
        }
    }
}