using System;
using System.Collections.Generic;

using Org.BouncyCastle.Utilities;

namespace Org.BouncyCastle.Asn1.X509
{
	public class CrlEntry
		: Asn1Encodable
	{
		internal Asn1Sequence	seq;
		internal DerInteger		userCertificate;
		internal Time			revocationDate;
		internal X509Extensions	crlEntryExtensions;

		public CrlEntry(Asn1Sequence seq)
		{
			if (seq.Count < 2 || seq.Count > 3)
				throw new ArgumentException("Bad sequence size: " + seq.Count);

			this.seq = seq;

			userCertificate = DerInteger.GetInstance(seq[0]);
			revocationDate = Time.GetInstance(seq[1]);
		}

		public DerInteger UserCertificate
		{
			get { return userCertificate; }
		}

		public Time RevocationDate
		{
			get { return revocationDate; }
		}

		public X509Extensions Extensions
		{
			get
			{
				if (crlEntryExtensions == null && seq.Count == 3)
				{
					crlEntryExtensions = X509Extensions.GetInstance(seq[2]);
				}

				return crlEntryExtensions;
			}
		}

		public override Asn1Object ToAsn1Object()
		{
			return seq;
		}
	}

	/**
     * PKIX RFC-2459 - TbsCertList object.
     * <pre>
     * TbsCertList  ::=  Sequence  {
     *      version                 Version OPTIONAL,
     *                                   -- if present, shall be v2
     *      signature               AlgorithmIdentifier,
     *      issuer                  Name,
     *      thisUpdate              Time,
     *      nextUpdate              Time OPTIONAL,
     *      revokedCertificates     Sequence OF Sequence  {
     *           userCertificate         CertificateSerialNumber,
     *           revocationDate          Time,
     *           crlEntryExtensions      Extensions OPTIONAL
     *                                         -- if present, shall be v2
     *                                }  OPTIONAL,
     *      crlExtensions           [0]  EXPLICIT Extensions OPTIONAL
     *                                         -- if present, shall be v2
     *                                }
     * </pre>
     */
    public class TbsCertificateList
        : Asn1Encodable
    {
		private class RevokedCertificatesEnumeration
			: IEnumerable<CrlEntry>
		{
			private readonly IEnumerable<Asn1Encodable> en;

			internal RevokedCertificatesEnumeration(IEnumerable<Asn1Encodable> en)
			{
				this.en = en;
			}

			System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
            {
				return GetEnumerator();
            }

			public IEnumerator<CrlEntry> GetEnumerator()
			{
				return new RevokedCertificatesEnumerator(en.GetEnumerator());
			}

			private sealed class RevokedCertificatesEnumerator
				: IEnumerator<CrlEntry>
			{
				private readonly IEnumerator<Asn1Encodable> e;

				internal RevokedCertificatesEnumerator(IEnumerator<Asn1Encodable> e)
				{
					this.e = e;
				}

				public void Dispose()
				{
					e.Dispose();
                    GC.SuppressFinalize(this);
                }

                public bool MoveNext()
				{
					return e.MoveNext();
				}

				public void Reset()
				{
					e.Reset();
				}

				object System.Collections.IEnumerator.Current
                {
					get { return Current; }
                }

				public CrlEntry Current
				{
					get { return new CrlEntry(Asn1Sequence.GetInstance(e.Current)); }
				}
			}
		}

		internal Asn1Sequence			seq;
		internal DerInteger				version;
        internal AlgorithmIdentifier	signature;
        internal X509Name				issuer;
        internal Time					thisUpdate;
        internal Time					nextUpdate;
		internal Asn1Sequence			revokedCertificates;
		internal X509Extensions			crlExtensions;

		public static TbsCertificateList GetInstance(object obj)
        {
			if (obj == null)
				return null;
			if (obj is TbsCertificateList tbsCertificateList)
				return tbsCertificateList;
			return new TbsCertificateList(Asn1Sequence.GetInstance(obj));
        }

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

        private TbsCertificateList(Asn1Sequence seq)
        {
			if (seq.Count < 3 || seq.Count > 7)
				throw new ArgumentException("Bad sequence size: " + seq.Count);

			int seqPos = 0;

			this.seq = seq;

			if (seq[seqPos] is DerInteger derInteger)
            {
				version = derInteger;
				++seqPos;
			}
            else
            {
                version = new DerInteger(0);
            }

			signature = AlgorithmIdentifier.GetInstance(seq[seqPos++]);
            issuer = X509Name.GetInstance(seq[seqPos++]);
            thisUpdate = Time.GetInstance(seq[seqPos++]);

			if (seqPos < seq.Count
                && (seq[seqPos] is Asn1UtcTime
                   || seq[seqPos] is Asn1GeneralizedTime
                   || seq[seqPos] is Time))
            {
                nextUpdate = Time.GetInstance(seq[seqPos++]);
            }

			if (seqPos < seq.Count
                && !(seq[seqPos] is Asn1TaggedObject))
            {
				revokedCertificates = Asn1Sequence.GetInstance(seq[seqPos++]);
			}

			if (seqPos < seq.Count
                && seq[seqPos] is Asn1TaggedObject)
            {
				crlExtensions = X509Extensions.GetInstance(seq[seqPos]);
			}
        }

		public int Version
        {
            get { return version.IntValueExact + 1; }
        }

		public DerInteger VersionNumber
        {
            get { return version; }
        }

		public AlgorithmIdentifier Signature
        {
            get { return signature; }
        }

		public X509Name Issuer
        {
            get { return issuer; }
        }

		public Time ThisUpdate
        {
            get { return thisUpdate; }
        }

		public Time NextUpdate
        {
            get { return nextUpdate; }
        }

		public CrlEntry[] GetRevokedCertificates()
        {
			if (revokedCertificates == null)
			{
				return new CrlEntry[0];
			}

			CrlEntry[] entries = new CrlEntry[revokedCertificates.Count];

			for (int i = 0; i < entries.Length; i++)
			{
				entries[i] = new CrlEntry(Asn1Sequence.GetInstance(revokedCertificates[i]));
			}

			return entries;
		}

		public IEnumerable<CrlEntry> GetRevokedCertificateEnumeration()
		{
			if (revokedCertificates == null)
				return new List<CrlEntry>(0);

			return new RevokedCertificatesEnumeration(revokedCertificates);
		}

		public X509Extensions Extensions
        {
            get { return crlExtensions; }
        }

		public override Asn1Object ToAsn1Object()
        {
            return seq;
        }
    }
}