using System;

using Org.BouncyCastle.Math;

namespace Org.BouncyCastle.Bcpg
{
	/// <remarks>Base class for a DSA public key.</remarks>
	public class DsaPublicBcpgKey
		: BcpgObject, IBcpgKey
    {
        private readonly MPInteger p, q, g, y;

		/// <param name="bcpgIn">The stream to read the packet from.</param>
		public DsaPublicBcpgKey(
			BcpgInputStream bcpgIn)
		{
			this.p = new MPInteger(bcpgIn);
			this.q = new MPInteger(bcpgIn);
			this.g = new MPInteger(bcpgIn);
			this.y = new MPInteger(bcpgIn);
		}

		public DsaPublicBcpgKey(
			BigInteger	p,
			BigInteger	q,
			BigInteger	g,
			BigInteger	y)
		{
			this.p = new MPInteger(p);
			this.q = new MPInteger(q);
			this.g = new MPInteger(g);
			this.y = new MPInteger(y);
		}

		/// <summary>The format, as a string, always "PGP".</summary>
		public string Format
		{
			get { return "PGP"; }
		}

		/// <summary>Return the standard PGP encoding of the key.</summary>
        public override byte[] GetEncoded()
        {
            try
            {
            	return base.GetEncoded();
            }
            catch (Exception)
            {
                return null;
            }
        }

		public override void Encode(
			BcpgOutputStream bcpgOut)
		{
			bcpgOut.WriteObjects(p, q, g, y);
		}

		public BigInteger G
		{
			get { return g.Value; }
		}

		public BigInteger P
		{
			get { return p.Value; }
		}

		public BigInteger Q
		{
			get { return q.Value; }
		}

		public BigInteger Y
		{
			get { return y.Value; }
		}
    }
}