using System;
using Org.BouncyCastle.Crypto.Digests;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Utilities;

namespace Org.BouncyCastle.Crypto.Macs;

public class SkeinMac : IMac
{
	public const int SKEIN_256 = 256;

	public const int SKEIN_512 = 512;

	public const int SKEIN_1024 = 1024;

	private readonly SkeinEngine engine;

	public string AlgorithmName => "Skein-MAC-" + engine.BlockSize * 8 + "-" + engine.OutputSize * 8;

	public SkeinMac(int stateSizeBits, int digestSizeBits)
	{
		engine = new SkeinEngine(stateSizeBits, digestSizeBits);
	}

	public SkeinMac(SkeinMac mac)
	{
		engine = new SkeinEngine(mac.engine);
	}

	public void Init(ICipherParameters parameters)
	{
		SkeinParameters skeinParameters;
		if (parameters is SkeinParameters)
		{
			skeinParameters = (SkeinParameters)parameters;
		}
		else
		{
			if (!(parameters is KeyParameter))
			{
				throw new ArgumentException("Invalid parameter passed to Skein MAC init - " + Platform.GetTypeName(parameters));
			}
			skeinParameters = new SkeinParameters.Builder().SetKey(((KeyParameter)parameters).GetKey()).Build();
		}
		if (skeinParameters.GetKey() == null)
		{
			throw new ArgumentException("Skein MAC requires a key parameter.");
		}
		engine.Init(skeinParameters);
	}

	public int GetMacSize()
	{
		return engine.OutputSize;
	}

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

	public void Update(byte inByte)
	{
		engine.Update(inByte);
	}

	public void BlockUpdate(byte[] input, int inOff, int len)
	{
		engine.Update(input, inOff, len);
	}

	public int DoFinal(byte[] output, int outOff)
	{
		return engine.DoFinal(output, outOff);
	}
}