/*
 * Copyright (c) 2003, KNOPFLERFISH project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following
 * conditions are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials
 *   provided with the distribution.
 *
 * - Neither the name of the KNOPFLERFISH project nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.knopflerfish.bundle.consoletelnet;

/**
 ** This abstract class is designed to make it simpler
 ** to create and add new telnet commands in this implementation.
 **
 ** Each command is a TelnetCommand object, has a callback mechanism
 ** to the to the session it is instantiated in and
 ** has one execute method. 
 **
 */

public abstract class TelnetCommand {
  public TelnetSession ts;	// the instantiating telnet session

  protected int commandCode ;	// the command code of this command
  protected boolean doStatus;	// true if the server is ready to execute the command
  protected boolean show;	// if the command will be shown at initial 
				// command negotiation

  public TelnetCommand () { }	// parameterless dummy constructor

  /**
   ** Parameters in the constructor:
   **
   ** @parameter ts TelnetSession, to provide callback to the telnet session
   ** @parameter int commandCode
   ** @parameter boolean doStatus, if true the command has been asked to be active
   ** @parameter boolean show,     if true the commands is shown 
   */

  public TelnetCommand (TelnetSession ts,
                        int commandCode,
                        boolean doStatus,
                        boolean show ) {
    this.ts = ts;
    this.commandCode = commandCode;
    this.doStatus = doStatus;
    this.show = show;
  }

  /** WILL string of command */

  public String getWILL() {
    return TCC.IAC_string 
           + TCC.WILL_string
           + String.valueOf((char) commandCode);
  }

  /** WONT string of command */

  public String getWONT() {
    return TCC.IAC_string
         + TCC.WONT_string
         + String.valueOf((char) commandCode);
  }

  /** DONT string of command */

  public String getDONT() {
    return TCC.IAC_string
         + TCC.DONT_string
         + String.valueOf((char) commandCode);
  }

  /** DO string of command */

  public String getDO() {
    return TCC.IAC_string
         + TCC.DO_string
         + String.valueOf((char) commandCode);
  }

  public void setDoStatus(boolean state) { doStatus = state; }
  public boolean getDoStatus() { return doStatus; }
  public boolean getShow() { return show; }

  /**
   ** Get all registered commands from the session
   */

  public TelnetCommand [] getCommands() {
    return ts.getCommands();
  }

  /**
   ** Debug printout
   */

  void printCommand(int action, int optionCode, byte[] parameters) {
    System.out.print("Telnet Command code: "
                    + String.valueOf(action)
                    + " option: "
                    + String.valueOf(optionCode)
                    + " status now: "
                    + String.valueOf(doStatus));
    if (parameters != null) {
      System.out.print(" parameters:");
      for (int i = 0; i < parameters.length ; i++) {
        System.out.print(" " + String.valueOf(parameters[i]));
      }
      System.out.println();
    } else {
     // System.out.println(" no parameters");
     System.out.println();
    }
  }

  /**
   ** Option negotiation and execution mechanism
   **
   ** To follow the intentions of RFC 854, a change in status
   ** is always followed by a response but if trying to enter a mode
   ** that we are already in, no response is returned.
   **
   ** This is essential to prevent negotiation loops.
   **
   ** @parameter action, one of the telnet protocol basic actions
   **            DO, DONT, WILL, WONT or SE
   ** @parameter optionCode, the option code
   ** @parameter parameters, a byte array with optional parameters,
   **            addition data to the option command.
   **
   ** @return a String with the response of the command.
   */

  public abstract String execute (int action, int optionCode, byte[] parameters);
}