using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;

using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.Utilities.Collections;

namespace Org.BouncyCastle.Bcpg.OpenPgp
{
    /// <remarks>
    /// Often a PGP key ring file is made up of a succession of master/sub-key key rings.
    /// If you want to read an entire public key file in one hit this is the class for you.
    /// </remarks>
    public class PgpPublicKeyRingBundle
    {
        private readonly IDictionary<long, PgpPublicKeyRing> m_pubRings;
        private readonly IList<long> m_order;

		private PgpPublicKeyRingBundle(IDictionary<long, PgpPublicKeyRing> pubRings, IList<long> order)
        {
            m_pubRings = pubRings;
            m_order = order;
        }

		public PgpPublicKeyRingBundle(byte[] encoding)
            : this(new MemoryStream(encoding, false))
        {
        }

		/// <summary>Build a PgpPublicKeyRingBundle from the passed in input stream.</summary>
		/// <param name="inputStream">Input stream containing data.</param>
		/// <exception cref="IOException">If a problem parsing the stream occurs.</exception>
		/// <exception cref="PgpException">If an object is encountered which isn't a PgpPublicKeyRing.</exception>
		public PgpPublicKeyRingBundle(Stream inputStream)
			: this(new PgpObjectFactory(inputStream).AllPgpObjects())
		{
        }

		public PgpPublicKeyRingBundle(IEnumerable<PgpObject> e)
        {
			m_pubRings = new Dictionary<long, PgpPublicKeyRing>();
			m_order = new List<long>();

			foreach (var obj in e)
            {
                // Marker packets must be ignored
                if (obj is PgpMarker)
                    continue;

				if (!(obj is PgpPublicKeyRing pgpPub))
					throw new PgpException(Platform.GetTypeName(obj) + " found where PgpPublicKeyRing expected");

				long key = pgpPub.GetPublicKey().KeyId;
                m_pubRings.Add(key, pgpPub);
				m_order.Add(key);
            }
        }

		/// <summary>Return the number of key rings in this collection.</summary>
        public int Count
        {
			get { return m_order.Count; }
        }

		/// <summary>Allow enumeration of the public key rings making up this collection.</summary>
        public IEnumerable<PgpPublicKeyRing> GetKeyRings()
        {
			return CollectionUtilities.Proxy(KeyRings);
        }

		/// <summary>Allow enumeration of the key rings associated with the passed in userId.</summary>
		/// <param name="userId">The user ID to be matched.</param>
		/// <returns>An <c>IEnumerable</c> of key rings which matched (possibly none).</returns>
		public IEnumerable<PgpPublicKeyRing> GetKeyRings(string userId)
		{
			return GetKeyRings(userId, false, false);
		}

		/// <summary>Allow enumeration of the key rings associated with the passed in userId.</summary>
		/// <param name="userId">The user ID to be matched.</param>
		/// <param name="matchPartial">If true, userId need only be a substring of an actual ID string to match.</param>
		/// <returns>An <c>IEnumerable</c> of key rings which matched (possibly none).</returns>
        public IEnumerable<PgpPublicKeyRing> GetKeyRings(string userId, bool matchPartial)
        {
			return GetKeyRings(userId, matchPartial, false);
        }

		/// <summary>Allow enumeration of the key rings associated with the passed in userId.</summary>
		/// <param name="userID">The user ID to be matched.</param>
		/// <param name="matchPartial">If true, userId need only be a substring of an actual ID string to match.</param>
		/// <param name="ignoreCase">If true, case is ignored in user ID comparisons.</param>
		/// <returns>An <c>IEnumerable</c> of key rings which matched (possibly none).</returns>
		public IEnumerable<PgpPublicKeyRing> GetKeyRings(string userID, bool matchPartial, bool ignoreCase)
		{
			var compareInfo = CultureInfo.InvariantCulture.CompareInfo;
			var compareOptions = ignoreCase ? CompareOptions.OrdinalIgnoreCase : CompareOptions.Ordinal;

			foreach (PgpPublicKeyRing pubRing in KeyRings)
			{
				foreach (string nextUserID in pubRing.GetPublicKey().GetUserIds())
				{
					if (matchPartial)
					{
						if (compareInfo.IndexOf(nextUserID, userID, compareOptions) >= 0)
							yield return pubRing;
					}
					else
					{
						if (compareInfo.Compare(nextUserID, userID, compareOptions) == 0)
							yield return pubRing;
					}
				}
			}
		}

		/// <summary>Return the PGP public key associated with the given key id.</summary>
		/// <param name="keyId">The ID of the public key to return.</param>
        public PgpPublicKey GetPublicKey(long keyId)
        {
            foreach (PgpPublicKeyRing pubRing in KeyRings)
            {
                PgpPublicKey pub = pubRing.GetPublicKey(keyId);
				if (pub != null)
                    return pub;
            }

			return null;
        }

		/// <summary>Return the public key ring which contains the key referred to by keyId</summary>
		/// <param name="keyId">key ID to match against</param>
        public PgpPublicKeyRing GetPublicKeyRing(long keyId)
        {
			if (m_pubRings.TryGetValue(keyId, out var keyRing))
				return keyRing;

			foreach (PgpPublicKeyRing pubRing in KeyRings)
            {
                if (pubRing.GetPublicKey(keyId) != null)
                    return pubRing;
            }

			return null;
        }

        /// <summary>Return the PGP public key associated with the given key fingerprint.</summary>
        /// <param name="fingerprint">the public key fingerprint to match against.</param>
        public PgpPublicKey GetPublicKey(byte[] fingerprint)
        {
            foreach (PgpPublicKeyRing pubRing in KeyRings)
            {
                PgpPublicKey pub = pubRing.GetPublicKey(fingerprint);
                if (pub != null)
                    return pub;
            }

            return null;
        }

        /// <summary>Return the public key ring which contains the key associated with the given key fingerprint.
        /// </summary>
        /// <param name="fingerprint">the public key fingerprint to match against.</param>
        public PgpPublicKeyRing GetPublicKeyRing(byte[] fingerprint)
        {
            foreach (PgpPublicKeyRing pubRing in KeyRings)
            {
                if (pubRing.GetPublicKey(fingerprint) != null)
                    return pubRing;
            }

            return null;
        }

        /// <summary>
        /// Return true if a key matching the passed in key ID is present, false otherwise.
        /// </summary>
        /// <param name="keyID">key ID to look for.</param>
        public bool Contains(long keyID)
		{
			return GetPublicKey(keyID) != null;
		}

		public byte[] GetEncoded()
        {
            MemoryStream bOut = new MemoryStream();
			Encode(bOut);
			return bOut.ToArray();
        }

		public void Encode(Stream outStr)
        {
			BcpgOutputStream bcpgOut = BcpgOutputStream.Wrap(outStr);

			foreach (long key in m_order)
            {
                m_pubRings[key].Encode(bcpgOut);
            }
        }

        private ICollection<PgpPublicKeyRing> KeyRings => m_pubRings.Values;

        /// <summary>
        /// Return a new bundle containing the contents of the passed in bundle and
        /// the passed in public key ring.
        /// </summary>
        /// <param name="bundle">The <c>PgpPublicKeyRingBundle</c> the key ring is to be added to.</param>
        /// <param name="publicKeyRing">The key ring to be added.</param>
        /// <returns>A new <c>PgpPublicKeyRingBundle</c> merging the current one with the passed in key ring.</returns>
        /// <exception cref="ArgumentException">If the keyId for the passed in key ring is already present.</exception>
        public static PgpPublicKeyRingBundle AddPublicKeyRing(PgpPublicKeyRingBundle bundle,
            PgpPublicKeyRing publicKeyRing)
        {
            long key = publicKeyRing.GetPublicKey().KeyId;

			if (bundle.m_pubRings.ContainsKey(key))
                throw new ArgumentException("Bundle already contains a key with a keyId for the passed in ring.");

			var newPubRings = new Dictionary<long, PgpPublicKeyRing>(bundle.m_pubRings);
            var newOrder = new List<long>(bundle.m_order);

			newPubRings[key] = publicKeyRing;
			newOrder.Add(key);

			return new PgpPublicKeyRingBundle(newPubRings, newOrder);
        }

		/// <summary>
		/// Return a new bundle containing the contents of the passed in bundle with
		/// the passed in public key ring removed.
		/// </summary>
		/// <param name="bundle">The <c>PgpPublicKeyRingBundle</c> the key ring is to be removed from.</param>
		/// <param name="publicKeyRing">The key ring to be removed.</param>
		/// <returns>A new <c>PgpPublicKeyRingBundle</c> not containing the passed in key ring.</returns>
		/// <exception cref="ArgumentException">If the keyId for the passed in key ring is not present.</exception>
        public static PgpPublicKeyRingBundle RemovePublicKeyRing(PgpPublicKeyRingBundle bundle,
            PgpPublicKeyRing publicKeyRing)
        {
            long key = publicKeyRing.GetPublicKey().KeyId;

			if (!bundle.m_pubRings.ContainsKey(key))
                throw new ArgumentException("Bundle does not contain a key with a keyId for the passed in ring.");

			var newPubRings = new Dictionary<long, PgpPublicKeyRing>(bundle.m_pubRings);
			var newOrder = new List<long>(bundle.m_order);

			newPubRings.Remove(key);
			newOrder.Remove(key);

			return new PgpPublicKeyRingBundle(newPubRings, newOrder);
        }
    }
}