/*_############################################################################
  _## 
  _##  SNMP4J-AgentX - AgentXClosePDU.java  
  _## 
  _##  Copyright (C) 2005-2026  Frank Fock (SNMP4J.org)
  _##  
  _##  This program is free software; you can redistribute it and/or modify
  _##  it under the terms of the GNU General Public License version 2 as 
  _##  published by the Free Software Foundation.
  _##
  _##  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 Public License for more details.
  _##
  _##  You should have received a copy of the GNU General Public License
  _##  along with this program; if not, write to the Free Software
  _##  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
  _##  MA  02110-1301  USA
  _##  
  _##########################################################################*/

package org.snmp4j.agent.agentx;

import java.io.*;
import java.nio.*;

/**
 * The {@link AgentXClosePDU} represents the agentx-Close-PDU from RFC 2741.
 */
public class AgentXClosePDU extends AgentXPDU {

    @Serial
    private static final long serialVersionUID = -8999433267014947249L;

    /**
     * The reason for closing the session, see {@link AgentXProtocol#REASON_OTHER} for example.
     */
    private byte reason;

    /**
     * Creates a {@link AgentXClosePDU} from a {@link AgentXMessageHeader}.
     * @param header
     *    the message header.
     */
    public AgentXClosePDU(AgentXMessageHeader header) {
        super(header);
        if (header.getType() != AGENTX_CLOSE_PDU) {
            throw new IllegalArgumentException("Incompatible PDU type");
        }
    }

    /**
     * Creates a {@link AgentXClosePDU} from a close reason.
     * @param reason
     *    the reason to close, see {@link AgentXProtocol#REASON_OTHER} for example.
     */
    public AgentXClosePDU(byte reason) {
        super(AGENTX_CLOSE_PDU);
        this.reason = reason;
    }

    public void decodePayload(ByteBuffer buf, int length) throws IOException {
        reason = buf.get();
    }

    /**
     * Gets the reason for the close.
     * @return
     *   the close reason, {@link AgentXProtocol#REASON_OTHER} for example.
     */
    public byte getReason() {
        return reason;
    }

    /**
     * Sets the close reason, see {@link AgentXProtocol#REASON_OTHER} for example.
     * @param reason
     *    a AgentX close reason.
     */
    public void setReason(byte reason) {
        this.reason = reason;
    }

    public int getPayloadLength() {
        return AgentXProtocol.AGENTX_INT_SIZE;
    }

    public void encodePayload(ByteBuffer buf) {
        buf.put(reason);
        buf.put(new byte[] { 0,0,0 }); // reserved
    }

    protected void beforeEncode() {
    }
}
