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

namespace Org.BouncyCastle.Crypto.Engines;

public class Gost28147Engine : IBlockCipher
{
	private const int BlockSize = 8;

	private int[] workingKey = null;

	private bool forEncryption;

	private byte[] S = Sbox_Default;

	private static readonly byte[] Sbox_Default;

	private static readonly byte[] ESbox_Test;

	private static readonly byte[] ESbox_A;

	private static readonly byte[] ESbox_B;

	private static readonly byte[] ESbox_C;

	private static readonly byte[] ESbox_D;

	private static readonly byte[] DSbox_Test;

	private static readonly byte[] DSbox_A;

	private static readonly IDictionary sBoxes;

	public virtual string AlgorithmName => "Gost28147";

	public virtual bool IsPartialBlockOkay => false;

	static Gost28147Engine()
	{
		Sbox_Default = new byte[128]
		{
			4, 10, 9, 2, 13, 8, 0, 14, 6, 11,
			1, 12, 7, 15, 5, 3, 14, 11, 4, 12,
			6, 13, 15, 10, 2, 3, 8, 1, 0, 7,
			5, 9, 5, 8, 1, 13, 10, 3, 4, 2,
			14, 15, 12, 7, 6, 0, 9, 11, 7, 13,
			10, 1, 0, 8, 9, 15, 14, 4, 6, 12,
			11, 2, 5, 3, 6, 12, 7, 1, 5, 15,
			13, 8, 4, 10, 9, 14, 0, 3, 11, 2,
			4, 11, 10, 0, 7, 2, 1, 13, 3, 6,
			8, 5, 9, 12, 15, 14, 13, 11, 4, 1,
			3, 15, 5, 9, 0, 10, 14, 7, 6, 8,
			2, 12, 1, 15, 13, 0, 5, 7, 10, 4,
			9, 2, 3, 14, 6, 11, 8, 12
		};
		ESbox_Test = new byte[128]
		{
			4, 2, 15, 5, 9, 1, 0, 8, 14, 3,
			11, 12, 13, 7, 10, 6, 12, 9, 15, 14,
			8, 1, 3, 10, 2, 7, 4, 13, 6, 0,
			11, 5, 13, 8, 14, 12, 7, 3, 9, 10,
			1, 5, 2, 4, 6, 15, 0, 11, 14, 9,
			11, 2, 5, 15, 7, 1, 0, 13, 12, 6,
			10, 4, 3, 8, 3, 14, 5, 9, 6, 8,
			0, 13, 10, 11, 7, 12, 2, 1, 15, 4,
			8, 15, 6, 11, 1, 9, 12, 5, 13, 3,
			7, 10, 0, 14, 2, 4, 9, 11, 12, 0,
			3, 6, 7, 5, 4, 8, 14, 15, 1, 10,
			2, 13, 12, 6, 5, 2, 11, 0, 9, 13,
			3, 14, 7, 10, 15, 4, 1, 8
		};
		ESbox_A = new byte[128]
		{
			9, 6, 3, 2, 8, 11, 1, 7, 10, 4,
			14, 15, 12, 0, 13, 5, 3, 7, 14, 9,
			8, 10, 15, 0, 5, 2, 6, 12, 11, 4,
			13, 1, 14, 4, 6, 2, 11, 3, 13, 8,
			12, 15, 5, 10, 0, 7, 1, 9, 14, 7,
			10, 12, 13, 1, 3, 9, 0, 2, 11, 4,
			15, 8, 5, 6, 11, 5, 1, 9, 8, 13,
			15, 0, 14, 4, 2, 3, 12, 7, 10, 6,
			3, 10, 13, 12, 1, 2, 0, 11, 7, 5,
			9, 4, 8, 15, 14, 6, 1, 13, 2, 9,
			7, 10, 6, 0, 8, 12, 4, 5, 15, 3,
			11, 14, 11, 10, 15, 5, 0, 12, 14, 8,
			6, 2, 3, 9, 1, 7, 13, 4
		};
		ESbox_B = new byte[128]
		{
			8, 4, 11, 1, 3, 5, 0, 9, 2, 14,
			10, 12, 13, 6, 7, 15, 0, 1, 2, 10,
			4, 13, 5, 12, 9, 7, 3, 15, 11, 8,
			6, 14, 14, 12, 0, 10, 9, 2, 13, 11,
			7, 5, 8, 15, 3, 6, 1, 4, 7, 5,
			0, 13, 11, 6, 1, 2, 3, 10, 12, 15,
			4, 14, 9, 8, 2, 7, 12, 15, 9, 5,
			10, 11, 1, 4, 0, 13, 6, 8, 14, 3,
			8, 3, 2, 6, 4, 13, 14, 11, 12, 1,
			7, 15, 10, 0, 9, 5, 5, 2, 10, 11,
			9, 1, 12, 3, 7, 4, 13, 0, 6, 15,
			8, 14, 0, 4, 11, 14, 8, 3, 7, 1,
			10, 2, 9, 6, 15, 13, 5, 12
		};
		ESbox_C = new byte[128]
		{
			1, 11, 12, 2, 9, 13, 0, 15, 4, 5,
			8, 14, 10, 7, 6, 3, 0, 1, 7, 13,
			11, 4, 5, 2, 8, 14, 15, 12, 9, 10,
			6, 3, 8, 2, 5, 0, 4, 9, 15, 10,
			3, 7, 12, 13, 6, 14, 1, 11, 3, 6,
			0, 1, 5, 13, 10, 8, 11, 2, 9, 7,
			14, 15, 12, 4, 8, 13, 11, 0, 4, 5,
			1, 2, 9, 3, 12, 14, 6, 15, 10, 7,
			12, 9, 11, 1, 8, 14, 2, 4, 7, 3,
			6, 5, 10, 0, 15, 13, 10, 9, 6, 8,
			13, 14, 2, 0, 15, 3, 5, 11, 4, 1,
			12, 7, 7, 4, 0, 5, 10, 2, 15, 14,
			12, 6, 1, 11, 13, 9, 3, 8
		};
		ESbox_D = new byte[128]
		{
			15, 12, 2, 10, 6, 4, 5, 0, 7, 9,
			14, 13, 1, 11, 8, 3, 11, 6, 3, 4,
			12, 15, 14, 2, 7, 13, 8, 0, 5, 10,
			9, 1, 1, 12, 11, 0, 15, 14, 6, 5,
			10, 13, 4, 8, 9, 3, 7, 2, 1, 5,
			14, 12, 10, 7, 0, 13, 6, 2, 11, 4,
			9, 3, 15, 8, 0, 12, 8, 9, 13, 2,
			10, 11, 7, 3, 6, 5, 4, 14, 15, 1,
			8, 0, 15, 3, 2, 5, 14, 11, 1, 10,
			4, 7, 12, 9, 13, 6, 3, 0, 6, 15,
			1, 14, 9, 2, 13, 8, 12, 4, 11, 10,
			5, 7, 1, 10, 6, 8, 15, 11, 0, 4,
			12, 3, 5, 9, 7, 13, 2, 14
		};
		DSbox_Test = new byte[128]
		{
			4, 10, 9, 2, 13, 8, 0, 14, 6, 11,
			1, 12, 7, 15, 5, 3, 14, 11, 4, 12,
			6, 13, 15, 10, 2, 3, 8, 1, 0, 7,
			5, 9, 5, 8, 1, 13, 10, 3, 4, 2,
			14, 15, 12, 7, 6, 0, 9, 11, 7, 13,
			10, 1, 0, 8, 9, 15, 14, 4, 6, 12,
			11, 2, 5, 3, 6, 12, 7, 1, 5, 15,
			13, 8, 4, 10, 9, 14, 0, 3, 11, 2,
			4, 11, 10, 0, 7, 2, 1, 13, 3, 6,
			8, 5, 9, 12, 15, 14, 13, 11, 4, 1,
			3, 15, 5, 9, 0, 10, 14, 7, 6, 8,
			2, 12, 1, 15, 13, 0, 5, 7, 10, 4,
			9, 2, 3, 14, 6, 11, 8, 12
		};
		DSbox_A = new byte[128]
		{
			10, 4, 5, 6, 8, 1, 3, 7, 13, 12,
			14, 0, 9, 2, 11, 15, 5, 15, 4, 0,
			2, 13, 11, 9, 1, 7, 6, 3, 12, 14,
			10, 8, 7, 15, 12, 14, 9, 4, 1, 0,
			3, 11, 5, 2, 6, 10, 8, 13, 4, 10,
			7, 12, 0, 15, 2, 8, 14, 1, 6, 5,
			13, 11, 9, 3, 7, 6, 4, 11, 9, 12,
			2, 10, 1, 8, 0, 14, 15, 13, 3, 5,
			7, 6, 2, 4, 13, 9, 15, 0, 10, 1,
			5, 11, 8, 14, 12, 3, 13, 14, 4, 1,
			7, 0, 5, 10, 3, 12, 8, 15, 6, 2,
			9, 11, 1, 3, 10, 9, 5, 11, 4, 15,
			8, 6, 7, 14, 13, 0, 2, 12
		};
		sBoxes = Platform.CreateHashtable();
		AddSBox("Default", Sbox_Default);
		AddSBox("E-TEST", ESbox_Test);
		AddSBox("E-A", ESbox_A);
		AddSBox("E-B", ESbox_B);
		AddSBox("E-C", ESbox_C);
		AddSBox("E-D", ESbox_D);
		AddSBox("D-TEST", DSbox_Test);
		AddSBox("D-A", DSbox_A);
	}

	private static void AddSBox(string sBoxName, byte[] sBox)
	{
		sBoxes.Add(Platform.ToUpperInvariant(sBoxName), sBox);
	}

	public virtual void Init(bool forEncryption, ICipherParameters parameters)
	{
		if (parameters is ParametersWithSBox)
		{
			ParametersWithSBox parametersWithSBox = (ParametersWithSBox)parameters;
			byte[] sBox = parametersWithSBox.GetSBox();
			if (sBox.Length != Sbox_Default.Length)
			{
				throw new ArgumentException("invalid S-box passed to GOST28147 init");
			}
			S = Arrays.Clone(sBox);
			if (parametersWithSBox.Parameters != null)
			{
				workingKey = generateWorkingKey(forEncryption, ((KeyParameter)parametersWithSBox.Parameters).GetKey());
			}
		}
		else if (parameters is KeyParameter)
		{
			workingKey = generateWorkingKey(forEncryption, ((KeyParameter)parameters).GetKey());
		}
		else if (parameters != null)
		{
			throw new ArgumentException("invalid parameter passed to Gost28147 init - " + Platform.GetTypeName(parameters));
		}
	}

	public virtual int GetBlockSize()
	{
		return 8;
	}

	public virtual int ProcessBlock(byte[] input, int inOff, byte[] output, int outOff)
	{
		if (workingKey == null)
		{
			throw new InvalidOperationException("Gost28147 engine not initialised");
		}
		Check.DataLength(input, inOff, 8, "input buffer too short");
		Check.OutputLength(output, outOff, 8, "output buffer too short");
		Gost28147Func(workingKey, input, inOff, output, outOff);
		return 8;
	}

	public virtual void Reset()
	{
	}

	private int[] generateWorkingKey(bool forEncryption, byte[] userKey)
	{
		this.forEncryption = forEncryption;
		if (userKey.Length != 32)
		{
			throw new ArgumentException("Key length invalid. Key needs to be 32 byte - 256 bit!!!");
		}
		int[] array = new int[8];
		for (int i = 0; i != 8; i++)
		{
			array[i] = bytesToint(userKey, i * 4);
		}
		return array;
	}

	private int Gost28147_mainStep(int n1, int key)
	{
		int num = key + n1;
		int num2 = S[num & 0xF];
		num2 += S[16 + ((num >> 4) & 0xF)] << 4;
		num2 += S[32 + ((num >> 8) & 0xF)] << 8;
		num2 += S[48 + ((num >> 12) & 0xF)] << 12;
		num2 += S[64 + ((num >> 16) & 0xF)] << 16;
		num2 += S[80 + ((num >> 20) & 0xF)] << 20;
		num2 += S[96 + ((num >> 24) & 0xF)] << 24;
		num2 += S[112 + ((num >> 28) & 0xF)] << 28;
		int num3 = num2 << 11;
		int num4 = num2 >>> 21;
		return num3 | num4;
	}

	private void Gost28147Func(int[] workingKey, byte[] inBytes, int inOff, byte[] outBytes, int outOff)
	{
		int num = bytesToint(inBytes, inOff);
		int num2 = bytesToint(inBytes, inOff + 4);
		if (forEncryption)
		{
			for (int i = 0; i < 3; i++)
			{
				for (int j = 0; j < 8; j++)
				{
					int num3 = num;
					int num4 = Gost28147_mainStep(num, workingKey[j]);
					num = num2 ^ num4;
					num2 = num3;
				}
			}
			for (int num5 = 7; num5 > 0; num5--)
			{
				int num3 = num;
				num = num2 ^ Gost28147_mainStep(num, workingKey[num5]);
				num2 = num3;
			}
		}
		else
		{
			for (int k = 0; k < 8; k++)
			{
				int num3 = num;
				num = num2 ^ Gost28147_mainStep(num, workingKey[k]);
				num2 = num3;
			}
			for (int l = 0; l < 3; l++)
			{
				int num6 = 7;
				while (num6 >= 0 && (l != 2 || num6 != 0))
				{
					int num3 = num;
					num = num2 ^ Gost28147_mainStep(num, workingKey[num6]);
					num2 = num3;
					num6--;
				}
			}
		}
		num2 ^= Gost28147_mainStep(num, workingKey[0]);
		intTobytes(num, outBytes, outOff);
		intTobytes(num2, outBytes, outOff + 4);
	}

	private static int bytesToint(byte[] inBytes, int inOff)
	{
		return (int)((inBytes[inOff + 3] << 24) & 0xFF000000u) + ((inBytes[inOff + 2] << 16) & 0xFF0000) + ((inBytes[inOff + 1] << 8) & 0xFF00) + (inBytes[inOff] & 0xFF);
	}

	private static void intTobytes(int num, byte[] outBytes, int outOff)
	{
		outBytes[outOff + 3] = (byte)(num >> 24);
		outBytes[outOff + 2] = (byte)(num >> 16);
		outBytes[outOff + 1] = (byte)(num >> 8);
		outBytes[outOff] = (byte)num;
	}

	public static byte[] GetSBox(string sBoxName)
	{
		byte[] array = (byte[])sBoxes[Platform.ToUpperInvariant(sBoxName)];
		if (array == null)
		{
			throw new ArgumentException("Unknown S-Box - possible types: \"Default\", \"E-Test\", \"E-A\", \"E-B\", \"E-C\", \"E-D\", \"D-Test\", \"D-A\".");
		}
		return Arrays.Clone(array);
	}

	public static string GetSBoxName(byte[] sBox)
	{
		foreach (string key in sBoxes.Keys)
		{
			byte[] a = (byte[])sBoxes[key];
			if (Arrays.AreEqual(a, sBox))
			{
				return key;
			}
		}
		throw new ArgumentException("SBOX provided did not map to a known one");
	}
}