/*
    * This file is part of Waarp Project (named also Waarp or GG).
    *
    *  Copyright (c) 2019, Waarp SAS, and individual contributors by the @author
    *  tags. See the COPYRIGHT.txt in the distribution for a full listing of
    * individual contributors.
    *
    *  All Waarp Project is free software: you can redistribute it and/or
    * modify it under the terms of the GNU General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or (at your
   * option) any later version.
   *
   * Waarp 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 Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License along with
   * Waarp . If not, see <http://www.gnu.org/licenses/>.
   */
  package org.waarp.openr66.protocol.localhandler.packet;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.ByteBufAllocator;
  import io.netty.buffer.Unpooled;
  import org.waarp.common.utility.WaarpNettyUtil;
  import org.waarp.openr66.protocol.exception.OpenR66ProtocolPacketException;
  import org.waarp.openr66.protocol.localhandler.LocalChannelReference;
  
  /**
   * Keep Alive class
   * <p>
   * header = empty middle = way end = empty
   */
  public class KeepAlivePacket extends AbstractLocalPacket {
    private static final byte ASKVALIDATE = 0;
  
    private static final byte ANSWERVALIDATE = 1;
  
    private byte way;
  
    /**
     * @param headerLength
     * @param middleLength
     * @param endLength
     * @param buf
     *
     * @return the new EndTransferPacket from buffer
     *
     * @throws OpenR66ProtocolPacketException
     */
    public static KeepAlivePacket createFromBuffer(final int headerLength,
                                                   final int middleLength,
                                                   final int endLength,
                                                   final ByteBuf buf)
        throws OpenR66ProtocolPacketException {
      if (middleLength != 1) {
        throw new OpenR66ProtocolPacketException("Not enough data");
      }
      final byte valid = buf.readByte();
      return new KeepAlivePacket(valid);
    }
  
    /**
     * @param valid
     */
    private KeepAlivePacket(final byte valid) {
      way = valid;
    }
  
    /**
     *
     */
    public KeepAlivePacket() {
      way = ASKVALIDATE;
    }
  
    @Override
    public final boolean hasGlobalBuffer() {
      return true;
    }
  
    @Override
    public final synchronized void createAllBuffers(
        final LocalChannelReference lcr, final int networkHeader) {
      final int globalSize = networkHeader + LOCAL_HEADER_SIZE + 1;
      final int offset = networkHeader + LOCAL_HEADER_SIZE;
      global = ByteBufAllocator.DEFAULT.ioBuffer(globalSize, globalSize);
      middle = WaarpNettyUtil.slice(global, offset, 1);
      middle.writeByte(way);
      end = Unpooled.EMPTY_BUFFER;
      header = Unpooled.EMPTY_BUFFER;
    }
  
    @Override
    public final byte getType() {
      return LocalPacketFactory.KEEPALIVEPACKET;
    }
  
    @Override
   public final String toString() {
     return "KeepAlivePacket: " + way;
   }
 
   /**
    * @return True if this packet is to be validated
    */
   public final boolean isToValidate() {
     return way == ASKVALIDATE;
   }
 
   /**
    * Validate the connection
    */
   public final void validate() {
     way = ANSWERVALIDATE;
     clear();
   }
 }