/*
   * 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
  */
  
  
  
  package zeus.concepts;
  
  import java.util.*;
  import zeus.util.*;
  import zeus.concepts.fn.*;
  import zeus.actors.ZeusTask;
  import zeus.actors.AgentContext;
  //import zeus.ontology.service.*; not in open source version
  
  public abstract class Task extends AbstractTask {
     protected Vector constraints = new Vector();
     protected ValueFunction time = ZeusParser.Expression(SystemProps.getProperty("task.default.time"));
     protected ValueFunction cost = ZeusParser.Expression(SystemProps.getProperty("task.default.cost"));
  
     transient ResolutionContext resolution_context = null;
  
     public void setTimeFn(String time) {
        ValueFunction fn = ZeusParser.Expression(time);
        if ( fn != null )
           this.time = fn;
     }
     
     
     public void setTimeFn(ValueFunction fn) {
        this.time = fn;
     }
     
     
     public void setCostFn(String cost) {
        ValueFunction fn = ZeusParser.Expression(cost);
        if ( fn != null )
           this.cost = fn;
     }
     
     
     public void setCostFn(ValueFunction fn) {
        this.cost = fn;
     }
  
     public ValueFunction getTimeFn() { return time; }
     public ValueFunction getCostFn() { return cost; }
  
     public int getTime() {
        int t = SystemProps.getInt("task.default.time");
        // added by simon 14/2/01 - deal with elaborations
        if (time instanceof ElseFn) { 
          ValueFunction evaledFn = time.evaluationFn(); 
          time = evaledFn; }
          
        if (time instanceof ArithmeticFn) { 
          ValueFunction timef = ((ArithmeticFn)time).evaluationFn(); 
          if (timef instanceof  IntFn) {  
                t = ((IntFn)time).getValue(); 
          } 
          else if (timef instanceof RealFn) { 
              double td = ((RealFn) time).getValue(); 
              Double tconv = new Double (td); 
              t = tconv.intValue(); 
          }
        }
       
        // end of add
        if ( !time.isDeterminate() || !(time instanceof IntFn) ) {
           Core.USER_ERROR("Task " +  name +
              " is improperly defined.\nCannot evaluates its " +
              " duration given required effect.\nCurrent value: \'" +
  	    time + "\'\nSetting duration to " + t );
        }
         else {
           t = ((IntFn)time).getValue();
        }
        return t;
     }
     
  
     public double getCost() {
       
       double c = SystemProps.getDouble("task.default.cost");
           // added by simon 14/2/01 - deal with elaborations
       debug ("cost= " + cost.toString()); 
       Fact [] postConds = getPostconditions(); 
       
       for (int i = 0 ; i<postConds.length; i++) { 
         debug ("post  = " +  postConds[i].toString()); 
       }
       if (cost instanceof ElseFn) { 
         ValueFunction evaledFn = cost.evaluationFn(); 
         debug ("elseed" + evaledFn.toString()); 
         cost = evaledFn; 
         }
         
       if (cost instanceof ArithmeticFn) { 
         ValueFunction costf = ((ArithmeticFn)cost).evaluationFn(); 
         if (costf instanceof  IntFn) {  
               c = ((IntFn)time).getValue(); 
               debug ("arith then int"); 
               return c; 
         } 
         else if (costf instanceof RealFn) { 
          c = ((RealFn) time).getValue(); 
          debug ("arith then real"); 
          return c;    
       }
       }
       // end of add
       if ( !cost.isDeterminate() || !(cost instanceof PrimitiveNumericFn) ) {
          Core.USER_ERROR("Task " +  name +
             " is improperly defined.\nCannot evaluates its " +
             " cost given required effect.\nCurrent value: \'" +
 	    cost + "\'\nSetting cost to " + c );
       }
       else {
          c =  ((PrimitiveNumericFn)cost).doubleValue();
       }
       return c;
    }
 
    public abstract Fact[]            getPostconditions();
    public abstract Fact[]            getPreconditions();
    public abstract ResolutionContext getContext();
 
    public boolean applyConstraints(Bindings bindings) {
       Bindings local = new Bindings(bindings);
 
       ResolutionContext context = getContext();
       LogicalFn fn;
       for(int i = 0; i < constraints.size(); i++ ) {
          fn = (LogicalFn)constraints.elementAt(i);
          fn = (LogicalFn)fn.resolve(context,local);
 	 if ( fn == null )
 	    return false;
 	 if ( fn.evaluate() != LogicalFn.TRUE )
             return false;
       }
       return bindings.add(local);
    }
 
    public void setConstraints(Vector List) {
       constraints.removeAllElements();
       for(int i = 0; i < List.size(); i++)
          constraints.addElement((LogicalFn)List.elementAt(i));
    }
    
    
    public void setConstraints(LogicalFn[] List) {
       constraints.removeAllElements();
       for(int i = 0; i < List.length; i++)
          constraints.addElement(List[i]);
 
    }
    
    
    public LogicalFn[] getConstraints() {
       LogicalFn[] out = new LogicalFn[constraints.size()];
 
       for(int i = 0; i < constraints.size(); i++)
          out[i] = (LogicalFn)constraints.elementAt(i);
       return out;
    }
    
    /***
     *This generates the service description from the task stub
     *by using reflection... 
     *@since 1.3
     *@author Simon Thompson
     *but not in the opensource version it doesn't
     */
     public String getServiceDesc(AgentContext context) {
 
         return null; // sorry!
     }
    
   
   /*** 
    *since 2.0 
    *@author Nick Giles
    *not opensource. 
    */
   public String getInstanceDetails(AgentContext context) {
 
       return null;
     
   }
 
   /*** 
    *since 2.0 
    *@author Nick Giles
    *not opensource. 
    */
      public String getInstanceRange(AgentContext context) {
 
       return null; 
   }
   
   /*** 
    *since 2.0 
    *@author Nick Giles
    *not opensource. 
    */
   public String getProcessModel(AgentContext context) {
 
       return null;
 
   }
 
    public void debug (String str) { 
   //  System.out.println("task>> " + str); 
    } 
    
 }