using System;
using System.Text;

using Lidgren.Network;
using System.Security;

namespace UnitTests
{
	public static class EncryptionTests
	{
		public static void Run(NetPeer peer)
		{
			//
			// Test XTEA
			//
			NetXtea xtea = new NetXtea("TopSecret");

			byte[] original = new byte[16];
			NetRandom.Instance.NextBytes(original);

			byte[] encrypted = new byte[original.Length];
			xtea.EncryptBlock(original, 0, encrypted, 0);
			xtea.EncryptBlock(original, 8, encrypted, 8);

			byte[] decrypted = new byte[original.Length];
			xtea.DecryptBlock(encrypted, 0, decrypted, 0);
			xtea.DecryptBlock(encrypted, 8, decrypted, 8);

			// compare!
			for (int i = 0; i < original.Length; i++)
				if (original[i] != decrypted[i])
					throw new NetException("XTEA fail!");

			Console.WriteLine("XTEA OK");

			NetOutgoingMessage om = peer.CreateMessage();
			om.Write("Hallon");
			om.Write(42);
			om.Write(5, 5);
			om.Write(true);
			om.Write("kokos");
			om.Encrypt(xtea);

			// convert to incoming message
			NetIncomingMessage im = Program.CreateIncomingMessage(om.PeekDataBuffer(), om.LengthBits);
			im.Decrypt(xtea);

			if (im.ReadString() != "Hallon")
				throw new NetException("fail");
			if (im.ReadInt32() != 42)
				throw new NetException("fail");
			if (im.ReadInt32(5) != 5)
				throw new NetException("fail");
			if (im.ReadBoolean() != true)
				throw new NetException("fail");
			if (im.ReadString() != "kokos")
				throw new NetException("fail");

			byte[] salt = NetSRP.CreateRandomKey(16);
			byte[] x = NetSRP.ComputePrivateKey("user", "password", salt);

			byte[] v = NetSRP.ComputeServerVerifier(x);
			//Console.WriteLine("v = " + NetUtility.ToHexString(v));

			byte[] a = NetSRP.CreateRandomKey(32); //  NetUtility.ToByteArray("393ed364924a71ba7258633cc4854d655ca4ec4e8ba833eceaad2511e80db2b5");
			byte[] A = NetSRP.ComputeClientEphemeral(a);
			//Console.WriteLine("A = " + NetUtility.ToHexString(A));

			byte[] b = NetSRP.CreateRandomKey(32); // NetUtility.ToByteArray("cc4d87a90db91067d52e2778b802ca6f7d362490c4be294b21b4a57c71cf55a9");
			byte[] B = NetSRP.ComputeServerEphemeral(b, v);
			//Console.WriteLine("B = " + NetUtility.ToHexString(B));

			byte[] u = NetSRP.ComputeU(A, B);
			//Console.WriteLine("u = " + NetUtility.ToHexString(u));

			byte[] Ss = NetSRP.ComputeServerSessionValue(A, v, u, b);
			//Console.WriteLine("Ss = " + NetUtility.ToHexString(Ss));

			byte[] Sc = NetSRP.ComputeClientSessionValue(B, x, u, a);
			//Console.WriteLine("Sc = " + NetUtility.ToHexString(Sc));

			if (Ss.Length != Sc.Length)
				throw new NetException("SRP non matching lengths!");

			for (int j = 0; j < Ss.Length; j++)
			{
				if (Ss[j] != Sc[j])
					throw new NetException("SRP non matching session values!");
			}

			var test = NetSRP.CreateEncryption(Ss);

			Console.WriteLine("Message encryption OK");
		}
	}
}