/*
   * The contents of this file are subject to the BT "ZEUS" Open Source 
   * Licence (L77741), Version 1.0 (the "Licence"); you may not use this file 
   * except in compliance with the Licence. You may obtain a copy of the Licence
   * from $ZEUS_INSTALL/licence.html or alternatively from
   * http://www.labs.bt.com/projects/agents/zeus/licence.htm
   * 
   * Except as stated in Clause 7 of the Licence, software distributed under the
   * Licence is distributed WITHOUT WARRANTY OF ANY KIND, either express or 
  * implied. See the Licence for the specific language governing rights and 
  * limitations under the Licence.
  * 
  * The Original Code is within the package zeus.*.
  * The Initial Developer of the Original Code is British Telecommunications
  * public limited company, whose registered office is at 81 Newgate Street, 
  * London, EC1A 7AJ, England. Portions created by British Telecommunications 
  * public limited company are Copyright 1996-9. All Rights Reserved.
  * 
  * THIS NOTICE MUST BE INCLUDED ON ANY COPY OF THIS FILE
  */
  
  /*
   * @(#)d1.java 1.03b
   */
  
  package zeus.actors.graphs;
  
  import java.util.*;
  import zeus.util.*;
  import zeus.concepts.*;
  import zeus.actors.*;
  import zeus.actors.rtn.*;
  import zeus.actors.rtn.util.*;
  
  public class d1 extends Node {
  
    protected static final int NOT_FOUND = 0;
    protected static final int SEARCHING = 1;
    protected static final int NOT_SOUGHT = 2;
  
  /***
     Purpose: get all agents for given goal - if oragnisationDb
     does not contain applicable agents, then contact registered
     facilitators through the organisationDb
  */
  
  // ST 050500 1.03bB node description due to CVB
     private String node_desc = "do/find sellers; do/find service";
     
     
     public final String getDesc()
        {return node_desc;}
     
     
     public final void setDesc(String node_desc) 
        {this.node_desc = node_desc;}
     // ST 050500 1.03bE
     
     public d1() {
        super("d1");
     }
  
     // memory useful for backtracking
  
     protected int abilitySought(String type) {
        /***
        First we should clear 'queryTable' of entries older the a predefined
        age so that our agent should query known facilitators for the ability.
        This way, our agent is periodically kept up-to-date
        */
  
        String name;
        KeyValue data;
  
        double now = context.now();
        Hashtable queryTable = context.queryTable();
        Enumeration enum = queryTable.keys();
  
        while( enum.hasMoreElements() ) {
           name = (String) enum.nextElement();
           data = (KeyValue)queryTable.get(name);
           if ( data.value-now >= context.getFacilitatorRefresh() ) {
              queryTable.remove(name);
              context.MsgHandler().removeRule(data.key);
           }
        }
  
        data = (KeyValue)queryTable.get(type);
        if ( data == null ) return NOT_SOUGHT;
  
        if ( data.value < context.now() )
           return NOT_FOUND;
        else
           return SEARCHING;
     }
  
     protected String findAgents(AbilitySpec a) {
        if ( context.facilitators().isEmpty() ) return null;
        AbilitySpec a1;
       Hashtable queryTable = context.queryTable();
 
       String type = a.getType();
       switch( abilitySought(type) ) {
          case NOT_FOUND:
               return null;
 
          case SEARCHING:
               KeyValue struct = (KeyValue)queryTable.get(type);
               return struct.key;
 
          case NOT_SOUGHT:
               // try contacting known facilitators to find agents with
               // required ability
               OntologyDb ontology = context.OntologyDb();
               a1 = new AbilitySpec(ontology.getFact(Fact.VARIABLE,type),0,0);
 
               Performative msg;
               MailBox mbox = context.MailBox();
               String key = context.newId();
               String[] pattern = { "type", "inform", "in-reply-to", key };
 
               context.MsgHandler().addRule(new MessageRuleImpl(key, pattern,
 	         MessageActionImpl.EXECUTE_ONCE,context.Engine(),
 		 "agentWithAbilityFound")
               );
 
               for(int i = 0; i < context.facilitators().size(); i++ ) {
                  msg = new Performative("query-ref");
                  msg.setReceiver((String)context.facilitators().elementAt(i));
                  msg.setContent("has_ability " + a1);
                  msg.setReplyWith(key);
                  mbox.sendMsg(msg);
               }
               // add ability to list of abilities which are being sought
               double t = context.now();
               if ( !context.facilitators().isEmpty() )
                  t += context.getFacilitatorTimeout();
               queryTable.put(type,new KeyValue(key,t));
               return key;
       }
       Assert.notNull(null);
       return null;
    }
 
    protected int exec() {
       OrganisationDb db = context.OrganisationDb();
 
       DStruct ds = (DStruct)input;
       // assume ds.goal has one element only
       Goal goal = (Goal)ds.goal.elementAt(0);
       ds.agents = db.anyAgent(goal,ds.ignore);
 
       Core.DEBUG(2, getDescription() + " anyAgent: " + ds.agents);
 
       if ( ds.agents.isEmpty() ) {
          timeout = context.now() + context.getFacilitatorTimeout();
 
          // Adjust for confirm & reply times
 	 Time t = goal.getConfirmTime();
          if ( t != null )
          timeout = Math.min(timeout,t.getTime());
          t = goal.getReplyTime();
          if ( t != null )
          timeout = Math.min(timeout,t.getTime());
 
          msg_wait_key = findAgents(goal.getAbility());
          Core.DEBUG(2, getDescription() + " msg_wait_key: " + msg_wait_key);
          return (msg_wait_key != null) ? WAIT : FAIL;
       }
       output = ds;
       return ds.agents.isEmpty() ? FAIL : OK;
    }
 
    protected int continue_exec() {
       OrganisationDb db = context.OrganisationDb();
 
       DStruct ds = (DStruct)input;
       // assume ds.goal has one element only
       Goal goal = (Goal)ds.goal.elementAt(0);
       ds.agents = db.anyAgent(goal,ds.ignore);
 
       Core.DEBUG(2, getDescription() + " continue anyAgent: " + ds.agents);
       output = ds;
       return  ds.agents.isEmpty() ? FAIL : OK;
    }
 
    protected void reset() {
       // reset any state changed by exec()
       DStruct ds = (DStruct) input;
       ds.agents = null;
    }
 }