/*****************************************************************
JADE - Java Agent DEvelopment Framework is a framework to develop
multi-agent systems in compliance with the FIPA specifications.
Jade is Copyright (C) 2000 CSELT S.p.A.
This file copyright (c) 2001 Hewlett-Packard Corp.

GNU Lesser General Public License

This library 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,
version 2.1 of the License.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the
Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA  02111-1307, USA.
*****************************************************************/

/*****************************************************************************
 * Source code information
 * -----------------------
 * Original author    Ian Dickinson, HP Labs Bristol
 * Author email       Ian_Dickinson@hp.com
 * Package
 * Created            1 Oct 2001
 * Filename           $RCSfile$
 * Revision           $Revision: 5373 $
 * Release status     Experimental. $State$
 *
 * Last modified on   $Date: 2004-09-22 15:07:26 +0200 (mer, 22 set 2004) $
 *               by   $Author: dominic $
 *
 * See foot of file for terms of use.
 *****************************************************************************/

// Package
///////////////
package examples.party;


// Imports
///////////////

import jade.core.Agent;
import jade.core.AID;

import jade.domain.FIPAException;

import jade.lang.acl.ACLMessage;
import jade.lang.acl.MessageTemplate;

import jade.core.behaviours.CyclicBehaviour;

import jade.domain.FIPAAgentManagement.DFAgentDescription;
import jade.domain.FIPAAgentManagement.ServiceDescription;
import jade.domain.DFService;



/**
 * TODO: Class comment.
 *
 * @author Ian Dickinson, HP Labs (<a href="mailto:Ian_Dickinson@hp.com">email</a>)
 * @version CVS info: $Id: GuestAgent.java 5373 2004-09-22 13:07:26Z dominic $
 */
public class GuestAgent
    extends Agent
{
    // Constants
    //////////////////////////////////


    // Static variables
    //////////////////////////////////


    // Instance variables
    //////////////////////////////////

    protected boolean m_knowRumour = false;


    // Constructors
    //////////////////////////////////


    // External signature methods
    //////////////////////////////////

    /**
     * Set up the agent. Register with the DF, and add a behaviour to process
     * incoming messages.  Also sends a message to the host to say that this
     * guest has arrived.
     */
    protected void setup() {
        try {
            // create the agent descrption of itself
            ServiceDescription sd = new ServiceDescription();
            sd.setType( "PartyGuest" );
            sd.setName( "GuestServiceDescription" );
            DFAgentDescription dfd = new DFAgentDescription();
            dfd.setName( getAID() );
            dfd.addServices( sd );

            // register the description with the DF
            DFService.register( this, dfd );

            // notify the host that we have arrived
            ACLMessage hello = new ACLMessage( ACLMessage.INFORM );
            hello.setContent( HostAgent.HELLO );
            hello.addReceiver( new AID( "host", AID.ISLOCALNAME ) );
            send( hello );

            // add a Behaviour to process incoming messages
            addBehaviour( new CyclicBehaviour( this ) {
                            public void action() {
                                // listen if a greetings message arrives
                                ACLMessage msg = receive( MessageTemplate.MatchPerformative( ACLMessage.INFORM ) );

                                if (msg != null) {
                                    if (HostAgent.GOODBYE.equals( msg.getContent() )) {
                                        // time to go
                                        leaveParty();
                                    }
                                    else if (msg.getContent().startsWith( HostAgent.INTRODUCE )) {
                                        // I am being introduced to another guest
                                        introducing( msg.getContent().substring( msg.getContent().indexOf( " " ) ) );
                                    }
                                    else if (msg.getContent().startsWith( HostAgent.HELLO )) {
                                        // someone saying hello
                                        passRumour( msg.getSender() );
                                    }
                                    else if (msg.getContent().startsWith( HostAgent.RUMOUR )) {
                                        // someone passing a rumour to me
                                        hearRumour();
                                    }
                                    else {
                                        System.out.println( "Guest received unexpected message: " + msg );
                                    }
                                }
                                else {
                                    // if no message is arrived, block the behaviour
                                    block();
                                }
                            }
                        } );
        }
        catch (Exception e) {
            System.out.println( "Saw exception in GuestAgent: " + e );
            e.printStackTrace();
        }

    }


    // Internal implementation methods
    //////////////////////////////////

    /**
     * To leave the party, we deregister with the DF and delete the agent from
     * the platform.
     */
    protected void leaveParty() {
        try {
            DFService.deregister( this );
            doDelete();
        }
        catch (FIPAException e) {
            System.err.println( "Saw FIPAException while leaving party: " + e );
            e.printStackTrace();
        }
    }


    /**
     * Host is introducing this guest to the named guest.  Say hello to the guest,
     * and ask the host for another introduction.
     *
     * @param agentName The string form of the AID of the other guest.
     */
    protected void introducing( String agentName ) {
        // get the AID of the guest and send them a hello message
        AID aID = new AID( agentName, AID.ISGUID); 

        ACLMessage m = new ACLMessage( ACLMessage.INFORM );
        m.setContent( HostAgent.HELLO );
        m.addReceiver( aID );

        send( m );

        // request another introduction from the host
        ACLMessage m1 = new ACLMessage( ACLMessage.REQUEST );
        m1.setContent( HostAgent.INTRODUCE );
        m1.addReceiver( new AID( "host", AID.ISLOCALNAME ) );
        send( m1 );
    }


    /**
     * Pass the rumour to the named guest, if we know it.
     *
     * @param agent Another guest we will send the rumour message to, but only if we
     *              know the rumour already.
     */
    protected void passRumour( AID agent ) {
        if (m_knowRumour) {
            ACLMessage m = new ACLMessage( ACLMessage.INFORM );
            m.setContent( HostAgent.RUMOUR );
            m.addReceiver( agent );
            send( m );
        }
    }


    /**
     * Someone has told this agent the rumour, we tell the host that we now know it.
     */
    protected void hearRumour() {
        // if I hear the rumour for the first time, tell the host
        if (!m_knowRumour) {
            ACLMessage m = new ACLMessage( ACLMessage.INFORM );
            m.setContent( HostAgent.RUMOUR );
            m.addReceiver( new AID( "host", AID.ISLOCALNAME ) );
            send( m );

            m_knowRumour = true;
        }
    }



    //==============================================================================
    // Inner class definitions
    //==============================================================================

}