using System.Collections;
using Org.BouncyCastle.Asn1.X9;
using Org.BouncyCastle.Math;
using Org.BouncyCastle.Math.EC;
using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.Utilities.Collections;
using Org.BouncyCastle.Utilities.Encoders;

namespace Org.BouncyCastle.Asn1.Anssi;

public class AnssiNamedCurves
{
	internal class Frp256v1Holder : X9ECParametersHolder
	{
		internal static readonly X9ECParametersHolder Instance = new Frp256v1Holder();

		private Frp256v1Holder()
		{
		}

		protected override X9ECParameters CreateParameters()
		{
			BigInteger q = FromHex("F1FD178C0B3AD58F10126DE8CE42435B3961ADBCABC8CA6DE8FCF353D86E9C03");
			BigInteger a = FromHex("F1FD178C0B3AD58F10126DE8CE42435B3961ADBCABC8CA6DE8FCF353D86E9C00");
			BigInteger b = FromHex("EE353FCA5428A9300D4ABA754A44C00FDFEC0C9AE4B1A1803075ED967B7BB73F");
			byte[] seed = null;
			BigInteger bigInteger = FromHex("F1FD178C0B3AD58F10126DE8CE42435B53DC67E140D2BF941FFDD459C6D655E1");
			BigInteger one = BigInteger.One;
			ECCurve eCCurve = ConfigureCurve(new FpCurve(q, a, b, bigInteger, one));
			X9ECPoint g = new X9ECPoint(eCCurve, Hex.Decode("04B6B3D4C356C139EB31183D4749D423958C27D2DCAF98B70164C97A2DD98F5CFF6142E0F7C8B204911F9271F0F3ECEF8C2701C307E8E4C9E183115A1554062CFB"));
			return new X9ECParameters(eCCurve, g, bigInteger, one, seed);
		}
	}

	private static readonly IDictionary objIds;

	private static readonly IDictionary curves;

	private static readonly IDictionary names;

	public static IEnumerable Names => new EnumerableProxy(names.Values);

	private static ECCurve ConfigureCurve(ECCurve curve)
	{
		return curve;
	}

	private static BigInteger FromHex(string hex)
	{
		return new BigInteger(1, Hex.Decode(hex));
	}

	private static void DefineCurve(string name, DerObjectIdentifier oid, X9ECParametersHolder holder)
	{
		objIds.Add(Platform.ToUpperInvariant(name), oid);
		names.Add(oid, name);
		curves.Add(oid, holder);
	}

	static AnssiNamedCurves()
	{
		objIds = Platform.CreateHashtable();
		curves = Platform.CreateHashtable();
		names = Platform.CreateHashtable();
		DefineCurve("FRP256v1", AnssiObjectIdentifiers.FRP256v1, Frp256v1Holder.Instance);
	}

	public static X9ECParameters GetByName(string name)
	{
		DerObjectIdentifier oid = GetOid(name);
		if (oid != null)
		{
			return GetByOid(oid);
		}
		return null;
	}

	public static X9ECParameters GetByOid(DerObjectIdentifier oid)
	{
		return ((X9ECParametersHolder)curves[oid])?.Parameters;
	}

	public static DerObjectIdentifier GetOid(string name)
	{
		return (DerObjectIdentifier)objIds[Platform.ToUpperInvariant(name)];
	}

	public static string GetName(DerObjectIdentifier oid)
	{
		return (string)names[oid];
	}
}