package org.metricshub.ipmi.core.coding.protocol.encoder;
   
   /*-
    * ╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲╱╲
    * 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.protocol.AuthenticationType;
  import org.metricshub.ipmi.core.coding.protocol.IpmiMessage;
  import org.metricshub.ipmi.core.coding.protocol.Ipmiv15Message;
  import org.metricshub.ipmi.core.common.TypeConverter;
  
  import java.security.InvalidKeyException;
  
  /**
   * Encodes IPMI v1.5 message
   */
  public class Protocolv15Encoder extends ProtocolEncoder {
  
      /**
       * @param ipmiMessage
       *            - IPMI message to be encoded. Must be {@link Ipmiv15Message}.
       * @throws InvalidKeyException
       *             - when initiation of the confidentiality algorithm fails
       * @throws IllegalArgumentException
       *             when IPMI protocol version is incorrect.
       * @see Ipmiv15Message
       */
      @Override
      public byte[] encode(IpmiMessage ipmiMessage) throws InvalidKeyException {
          if (!(ipmiMessage instanceof Ipmiv15Message)) {
              throw new IllegalArgumentException(
                      "IPMIMessage must be in 1.5 version.");
          }
          Ipmiv15Message message = (Ipmiv15Message) ipmiMessage;
  
          byte[] raw = new byte[getMessageLength(message)];
  
          raw[0] = encodeAuthenticationType(message.getAuthenticationType());
  
          int offset = 1;
  
          encodeSessionSequenceNumber(message.getSessionSequenceNumber(), raw,
                  offset);
          offset += 4;
  
          encodeSessionId(message.getSessionID(), raw, offset);
          offset += 4;
  
          if (message.getAuthenticationType() != AuthenticationType.None) {
              encodeAuthenticationCode(message.getAuthCode(), raw, offset);
              offset += message.getAuthCode().length;
          }
  
          byte[] payload = message.getPayload().getEncryptedPayload();
  
          if (payload == null) {
              message.getPayload().encryptPayload(
                      message.getConfidentialityAlgorithm());
              payload = message.getPayload().getEncryptedPayload();
          }
  
          encodePayloadLength(payload.length, raw, offset);
          ++offset;
  
          offset = encodePayload(payload, raw, offset);
  
          encodeSessionTrailer(raw, offset);
  
          return raw;
      }
  
      private int getMessageLength(IpmiMessage ipmiMessage) {
          int length = 11
                  + ipmiMessage.getConfidentialityAlgorithm()
                          .getConfidentialityOverheadSize(
                                  ipmiMessage.getPayloadLength())
                  + ipmiMessage.getPayloadLength();
  
          if (ipmiMessage.getAuthenticationType() != AuthenticationType.None) {
              length += 16;
          }
 
         return length;
     }
 
     /**
      * Inserts authentication code into message at given offset.
      *
      * @param authCode
      * @param message
      *            - message being encoded
      * @param offset
      * @throws IndexOutOfBoundsException
      *             when message is too short to hold value at given offset
      */
     private void encodeAuthenticationCode(byte[] authCode, byte[] message, int offset) {
         if (authCode.length + offset > message.length) {
             throw new IndexOutOfBoundsException("Message is too short");
         }
         System.arraycopy(authCode, 0, message, offset, authCode.length);
     }
 
     @Override
     protected void encodePayloadLength(int value, byte[] message, int offset) {
         message[offset] = TypeConverter.intToByte(value);
     }
 
     /**
      * Creates session trailer. <br>
      * Creates an inserts Legacy PAD.
      *
      * @param message
      *            - IPMI message being created
      * @param offset
      *            - Should point at the beginning of the session trailer.
      * @throws IndexOutOfBoundsException
      *             when message is too short to hold value at given offset
      * @return Offset pointing after Authorization Code
      */
     private int encodeSessionTrailer(byte[] message, int offset) {
         if (1 + offset > message.length) {
             throw new IndexOutOfBoundsException("Message is too short");
         }
 
         message[offset] = 0;
 
         return offset + 1;
     }
 }