package lava.net.psyc.packages;

import java.util.Enumeration;
import java.util.Hashtable;
import lava.net.common.UNL;
import lava.net.common.Value;
import lava.net.psyc.PSYCDeliveryException;
import lava.net.psyc.PSYCMessageCenter;
import lava.net.psyc.PSYCPackage;

/**
 *
 **/
public class LinkServer extends Skeleton 
{
   /**
    *
    **/
   public final static String PackageName = "LinkServer";

   /**
    *
    **/
   public final static int PackageMajorVersion = 1;

   /**
    *
    **/
   public final static int PackageMinorVersion = 0;

   class DummyListener implements LinkServerListener
   {
      /**
       *
       **/
      public void peerLinkRequest(UNL server, String body)
      {
      }

      /**
       *
       **/
      public void peerUnlinked(UNL server, String body)
      {
      }

   }

   /**
    *
    **/
   private LinkServerListener listener = new DummyListener();

   /**
    *
    **/
   private Hashtable linked = new Hashtable();

   /**
    *
    **/
   private final static Integer USER_DEFINED = new Integer(-1);

   /**
    *
    **/
   private final static Integer LINK_REQUEST_RCVD = new Integer(0);

   /**
    *
    **/
   private final static Integer LINKED = new Integer(1);

   /**
    *
    **/
   public LinkServer(LinkServerListener listener)
   {
      super();
      setPackageName(PackageName);
      addPackageMethod(LinkPeer.requestLinkTag,//
      LinkPeer.requestLinkAliases,true);
      addPackageMethod(LinkPeer.requestUnlinkTag,//
      LinkPeer.requestUnlinkAliases,true);
      addPackageMethod(LinkPeer.statusLinkedTag,//
      LinkPeer.statusLinkedAliases,false);
      addPackageMethod(LinkPeer.statusUnlinkedTag,//
      LinkPeer.statusUnlinkedAliases,false);
      if(listener != null)
         this.listener = listener;
   }

   /**
    *
    **/
   public boolean understands()
   {
      return !(listener instanceof DummyListener);
   }

   /**
    *
    **/
   public boolean wantsErrors()
   {
      return true;
   }

   /**
    *
    **/
   public void received(UNL source, String method, String body)
   {
      if(LinkPeer.requestLinkTag.equals(method))
      {
         setLinked(source,LINK_REQUEST_RCVD);
         listener.peerLinkRequest(source,body);
      }
      else
         if(LinkPeer.requestUnlinkTag.equals(method))
         {
            if(isLinked(source))
            {
               unlink(source);
               listener.peerUnlinked(source,body);
            }
         }
   }

   /**
    *
    **/
   public void reset(UNL source)
   {
      if(isLinked(source))
      {
         removeLinked(source);
         listener.peerUnlinked(source,null);
      }
   }

   /**
    *
    **/
   public Enumeration getAllLinked()
   {
      return linked.keys();
   }

   /**
    *
    **/
   public boolean isLinked(UNL client)
   {
      return linked.get(client) != null;
   }

   /**
    *
    **/
   public boolean wantsLink(UNL client)
   {
      return linked.get(client) == LINK_REQUEST_RCVD;
   }

   /**
    *
    **/
   private void setLinked(UNL client, Integer state)
   {
      linked.put(client,state);
   }

   /**
    *
    **/
   public void setLinked(UNL client)
   {
      linked.put(client,USER_DEFINED);
   }

   /**
    *
    **/
   public void removeLinked(UNL client)
   {
      linked.remove(client);
   }

   /**
    *
    **/
   public void link(UNL client, String body)
   {
      setLinked(client,LINKED);
      try
      {
         center.sendChecked(client,LinkPeer.PackageName,//
         LinkPeer.statusLinkedTag,body);
      }
      catch(PSYCDeliveryException e)
      {
         removeLinked(client);
         listener.peerUnlinked(client,null);
      }
   }

   /**
    *
    **/
   public void link(UNL client)
   {
      link(client,null);
   }

   /**
    *
    **/
   public void unlink(UNL client, String body)
   {
      removeLinked(client);
      try
      {
         center.sendChecked(client,LinkPeer.PackageName,//
         LinkPeer.statusUnlinkedTag,body);
      }
      catch(PSYCDeliveryException e)
      {
      }
   }

   /**
    *
    **/
   public void unlink(UNL client)
   {
      unlink(client,null);
   }

}