package org.hyperion.rs2.net;

import java.nio.ByteBuffer;
import java.util.logging.Logger;

import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.CumulativeProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolCodecFilter;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
import org.hyperion.Server;
import org.hyperion.rs2.model.PlayerDetails;
import org.hyperion.rs2.model.World;
import org.hyperion.rs2.net.ondemand.OnDemandPool;
import org.hyperion.rs2.net.ondemand.OnDemandRequest;
import org.hyperion.rs2.util.XTEADecipher;
import org.hyperion.util.Buffers;
import org.hyperion.util.CommonConstants;

/**
 * Login protocol decoding class.
 * @author Graham Edgecombe, Flamable
 *
 */
public class RS2LoginDecoder extends CumulativeProtocolDecoder {

	private static final Logger logger = Logger.getLogger(RS2LoginDecoder.class.getName());

	public static final int STATE_OPCODE = 0;
	public static final int STATE_lOGINBLOCK_DECYPT = 1;
	public static final int STATE_UPDATE = -1;

	public static final int OPCODE_GAME = 14;
	public static final int OPCODE_UPDATE = 15;

	@Override
	protected boolean doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception {
		int state = (Integer) session.getAttribute("state", STATE_OPCODE);
		switch(state) {
		case STATE_UPDATE:
			/**
			 * TODO update so works with 666
			 */
			if(in.remaining() >= 4) {
				int priority = in.get() & 0xFF;
				int cacheId = in.get() & 0xFF;
				int fileId = ((in.get() & 0xFF) << 8) | (in.get() & 0xFF);
				/*
				 * We push the request into the ondemand pool so it can be served.
				 */
				if (priority == 0 || priority == 1)
				OnDemandPool.getOnDemandPool().pushRequest(new OnDemandRequest(session, cacheId, fileId, priority));
				return true;
			} else {
				in.rewind();
				return false;
			}
		case STATE_OPCODE:
			if(in.remaining() >= 1) {
				int opcode = in.get() & 0xFF;
				switch(opcode) {
				case OPCODE_GAME:
					session.write(new PacketBuilder().put((byte) 0).toPacket());
					session.setAttribute("state", STATE_lOGINBLOCK_DECYPT);
					return true;
				case OPCODE_UPDATE:
					int revision = in.getInt();
					if (revision == 666) {
					System.out.print(revision);
					PacketBuilder pb = new PacketBuilder();
					pb.put((byte) 0);
					for (int dlen : CommonConstants.STAGE_DELTA)
					pb.putInt(dlen);
					session.write(pb.toPacket());
					} else {
					session.write(new PacketBuilder().put((byte) 6).toPacket());
					}
					session.setAttribute("state", STATE_UPDATE);
					return true;
					default:
					logger.info("Invalid opcode : " + opcode);
				session.close(false);
				break;
				}
			} else {
				in.rewind();
				return false;
			}
			break;

		case STATE_lOGINBLOCK_DECYPT:
			int loginSize = 0;
			int loginOpcode = 0;
			String username = "";
			@SuppressWarnings("unused")
			String settingVerificationString = "";
			int graphicMode = 0;

			/**
			 * Gets the Login Opcode and the LoginBlockPayload Len
			 */
			if(in.remaining() >= 3) {
				loginOpcode = in.get() & 0xFF;
				if(loginOpcode != 16 && loginOpcode != 18) {
					logger.info("Invalid login opcode : " + loginOpcode);
					session.close(false);
					in.rewind();
					return false;
				}
				loginSize = in.getShort() & 0xFFFF;
			}

			/**
			 * Decypts the LoginBlock
			 */
			if(in.remaining() >= loginSize) {
				int version = in.getInt();
				if(version != Server.VERSION) {
					logger.info("Incorrect version : " + version);
					session.close(false);
					in.rewind();
					return false;
				}

				/**
				 * Decoder The Rsa buffer
				 */
				byte[] rsaPayload = new byte[in.getShort() & 0xffff];
				in.get(rsaPayload);
				ByteBuffer rsaBuffer = ByteBuffer.wrap(rsaPayload/*new BigInteger(rsaData).modPow(ServerConstants.PRIVATE_KEY, ServerConstants.MODULE).toByteArray()*/);
				int rsaHeaderKey = rsaBuffer.get();
				if (rsaHeaderKey != 10) {
					logger.info("Incorrect Header : " + version);
					session.close(false);
					in.rewind();
					return false;
				}
				int[] xtea = new int[] {rsaBuffer.getInt(), rsaBuffer.getInt(), rsaBuffer.getInt(), rsaBuffer.getInt()};
				rsaBuffer.getLong();
				String password = Buffers.readString(rsaBuffer);
				long clientKey = rsaBuffer.getLong();//?
				long serverKey = rsaBuffer.getLong();//?

				/**
				 * Decoder The xteaed Payload Block
				 */
				byte[] xteaPayload = new byte[in.remaining()];
				in.get(xteaPayload);
				byte[] is = XTEADecipher.decryptXTEA(xtea, xteaPayload, 0, xteaPayload.length);
				ByteBuffer xteaBuffer = ByteBuffer.wrap(is);

				switch (loginOpcode) {
				/**
				 * Lobby
				 */
				case 19:
					/**
					 * TODO consider if want serperate server for lobby or not
					 */
					break;

					/**
					 * World Login
					 */
				case 16:
				case 18:
				//case 29:
					username = Buffers.readString(xteaBuffer);
					xteaBuffer.get();
					graphicMode = xteaBuffer.get();
					xteaBuffer.getShort();
					xteaBuffer.getShort();
					xteaBuffer.get();

					/**
					 * Setting values
					 * TODO Check them to see if it is the client or not
					 */
					for (int i = 0; i < 24; i++) {
						xteaBuffer.get();
					}
					settingVerificationString = Buffers.readString(xteaBuffer);
					xteaBuffer.getInt();

					byte[] unhandledBytes = new byte[xteaBuffer.get()];
					xteaBuffer.get(unhandledBytes);
					System.out.println("Name " + username + " password " + password);
					break;
				}

				/**
				 * Isacc
				 */
				int[] sessionKey = new int[4];
				sessionKey[0] = (int) (clientKey >> 32);
				sessionKey[1] = (int) clientKey;
				sessionKey[2] = (int) (serverKey >> 32);
				sessionKey[3] = (int) serverKey;

				session.removeAttribute("state");
				session.removeAttribute("serverKey");
				session.removeAttribute("size");
				session.removeAttribute("encryptSize");

				ISAACCipher inCipher = new ISAACCipher(sessionKey);
				for(int i = 0; i < 4; i++) {
					sessionKey[i] += 50;
				}
				ISAACCipher outCipher = new ISAACCipher(sessionKey);

				session.getFilterChain().remove("protocol");
				session.getFilterChain().addFirst("protocol", new ProtocolCodecFilter(RS2CodecFactory.GAME));

				PlayerDetails pd = new PlayerDetails(session, username, password, inCipher, outCipher, graphicMode);
				World.getWorld().load(pd);
			}
			break;
		}
		in.rewind();
		return false;
	}

}