package org.metricshub.ipmi.core.sm.states;
   
   /*-
    * ╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲
    * IPMI Java Client
    * ჻჻჻჻჻჻
    * Copyright 2023 Verax Systems, MetricsHub
    * ჻჻჻჻჻჻
    * This program is free software: you can redistribute it and/or modify
   * it under the terms of the GNU Lesser General Public License as
   * published by the Free Software Foundation, either version 3 of the
   * License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Lesser Public License for more details.
   *
   * You should have received a copy of the GNU General Lesser Public
   * License along with this program.  If not, see
   * <http://www.gnu.org/licenses/lgpl-3.0.html>.
   * ╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱
   */
  
  import org.metricshub.ipmi.core.coding.Encoder;
  import org.metricshub.ipmi.core.coding.PayloadCoder;
  import org.metricshub.ipmi.core.coding.commands.IpmiVersion;
  import org.metricshub.ipmi.core.coding.commands.session.CloseSession;
  import org.metricshub.ipmi.core.coding.protocol.AuthenticationType;
  import org.metricshub.ipmi.core.coding.protocol.Ipmiv20Message;
  import org.metricshub.ipmi.core.coding.protocol.PayloadType;
  import org.metricshub.ipmi.core.coding.protocol.decoder.ProtocolDecoder;
  import org.metricshub.ipmi.core.coding.protocol.decoder.Protocolv20Decoder;
  import org.metricshub.ipmi.core.coding.protocol.encoder.Protocolv20Encoder;
  import org.metricshub.ipmi.core.coding.rmcp.RmcpMessage;
  import org.metricshub.ipmi.core.coding.security.CipherSuite;
  import org.metricshub.ipmi.core.sm.StateMachine;
  import org.metricshub.ipmi.core.sm.actions.ErrorAction;
  import org.metricshub.ipmi.core.sm.actions.MessageAction;
  import org.metricshub.ipmi.core.sm.events.Sendv20Message;
  import org.metricshub.ipmi.core.sm.events.StateMachineEvent;
  import org.metricshub.ipmi.core.sm.events.Timeout;
  
  /**
   * {@link State} in which the session is valid and sending IPMI commands to the
   * remote machine is enabled.
   * <ul>
   * <li>Sends an IPMI v2.0 message on
   * {@link Sendv20Message}
   * <li>Transits to {@link Authcap} on {@link Timeout}
   * <li>Sends {@link CloseSession}
   * and transits to {@link Authcap} on {@link org.metricshub.ipmi.core.coding.commands.session.CloseSession}</li>
   * </ul>
   */
  public class SessionValid extends State {
  
  	private CipherSuite cipherSuite;
  
  	private int sessionId;
  
  	public CipherSuite getCipherSuite() {
  		return cipherSuite;
  	}
  
  	/**
  	 * Initiates the state.
  	 *
  	 * @param cipherSuite
  	 *        - {@link CipherSuite} used during the session.
  	 */
  	public SessionValid(CipherSuite cipherSuite, int sessionId) {
  		this.cipherSuite = cipherSuite;
  		this.sessionId = sessionId;
  	}
  
  	@Override
  	public void doTransition(StateMachine stateMachine, StateMachineEvent machineEvent) {
  		if (machineEvent instanceof Sendv20Message) {
  			Sendv20Message event = (Sendv20Message) machineEvent;
  			try {
  				stateMachine.sendMessage(encode(event));
  			} catch (Exception e) {
  				stateMachine.doExternalAction(new ErrorAction(e));
  			}
  		} else if (machineEvent instanceof Timeout) {
  			stateMachine.setCurrent(new Authcap());
  		} else if (machineEvent instanceof org.metricshub.ipmi.core.sm.events.CloseSession) {
  			org.metricshub.ipmi.core.sm.events.CloseSession event = (org.metricshub.ipmi.core.sm.events.CloseSession) machineEvent;
  
  			try {
  				stateMachine.setCurrent(new Authcap());
  				stateMachine.sendMessage(
  						Encoder.encode(
  								new Protocolv20Encoder(),
  								closeSession(event.getSessionId()),
  								event.getMessageSequenceNumber(),
  								event.getSessionSequenceNumber(),
  								event.getSessionId()));
  			} catch (Exception e) {
 				stateMachine.setCurrent(this);
 				stateMachine.doExternalAction(new ErrorAction(e));
 			}
 		} else {
 			stateMachine.doExternalAction(new ErrorAction(new IllegalArgumentException("Invalid transition")));
 		}
 
 	}
 
 	/**
 	 * Encodes the command of the event with the parameters of this session. The session signs and encrypts the
 	 * message, so the command carries no session parameters of its own: they are set on it and the message encoded
 	 * under the lock of the coder, as one command instance may be sent on several connections at once.
 	 */
 	private byte[] encode(Sendv20Message event) throws Exception {
 		PayloadCoder coder = event.getPayloadCoder();
 		synchronized (coder) {
 			coder.setSessionParameters(IpmiVersion.V20, cipherSuite, AuthenticationType.RMCPPlus);
 			return Encoder.encode(
 					new Protocolv20Encoder(),
 					coder,
 					event.getMessageSequenceNumber(),
 					event.getSessionSequenceNumber(),
 					event.getSessionId());
 		}
 	}
 
 	private CloseSession closeSession(int closedSessionId) {
 		CloseSession closeSession = new CloseSession(closedSessionId);
 		closeSession.setSessionParameters(IpmiVersion.V20, cipherSuite, AuthenticationType.RMCPPlus);
 		return closeSession;
 	}
 
 	@Override
 	public void doAction(StateMachine stateMachine, RmcpMessage message) {
 		if (ProtocolDecoder.decodeAuthenticationType(message) != AuthenticationType.RMCPPlus) {
 			return; // this isn't IPMI v2.0 message so we ignore it
 		}
 		if (Protocolv20Decoder.decodeSessionID(message) == 0) {
 			return; // this is a sessionless message so we drop it
 		}
 		Protocolv20Decoder decoder = new Protocolv20Decoder(cipherSuite);
 		PayloadType payloadType = Protocolv20Decoder.decodePayloadType(message.getData()[1]);
 
 		if (payloadType != PayloadType.Ipmi && payloadType != PayloadType.Sol) {
 			return;
 		}
 		if (Protocolv20Decoder.decodeSessionID(message) != sessionId) {
 			return; // this message belongs to other session so we ignore it
 		}
 		try {
 			Ipmiv20Message message20 = (Ipmiv20Message) decoder.decode(message);
 			if (message20.getSessionID() == sessionId) {
 				stateMachine.doExternalAction(new MessageAction(message20));
 			}
 		} catch (Exception e) {
 			// A message that fails the integrity check or cannot be decoded is discarded (IPMI 2.0 section 6.12.4):
 			// the request it may have answered is sent again when it times out
 		}
 	}
 
 }