package lava.net.psyc.packages;

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

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

   /**
    *
    **/
   public final static String requestLinkTag = "_request_link";

   /**
    *
    **/
   protected final static String[] requestLinkAliases = //
   {"request_link"};

   /**
    *
    **/
   public final static String requestUnlinkTag = "_request_unlink";

   /**
    *
    **/
   protected final static String[] requestUnlinkAliases = //
   {"request_unlink"};

   /**
    *
    **/
   public final static String statusLinkedTag = "_status_linked";

   /**
    *
    **/
   protected final static String[] statusLinkedAliases = //
   {"status_linked"};

   /**
    *
    **/
   public final static String statusUnlinkedTag = "_status_unlinked";

   /**
    *
    **/
   protected final static String[] statusUnlinkedAliases = //
   {"status_unlinked"};

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

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

   }

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

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

   /**
    *
    **/
   public boolean link = true;

   /**
    *
    **/
   // TODO: auto-relink (only if no unlink request sent)
   // -1 = no
   //  0 = unlimited
   // >0 = how often
   // public int relinkTries = -1;
   // private Hashtable relinkCounters = new Hashtable();
   private final static Integer USER_DEFINED = new Integer(-1);

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

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

   /**
    *
    **/
   private final static Integer UNLINK_REQUEST_SENT = new Integer(2);

   /**
    *
    **/
   public LinkPeer(LinkPeerListener listener)
   {
      this (listener,true);
   }

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

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

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

   /**
    *
    **/
   public void registerCenter(PSYCMessageCenter center)
   {
      super.registerCenter(center);
      if(link)
         try
         {
            link();
         }
         catch(PSYCDeliveryException e)
         {
         }
   }

   /**
    *
    **/
   public void received(UNL source, String method, String body)
   {
      // We'll ever get the method name we've registered,
      // even if a submethod were called
      if(statusLinkedTag.equals(method))
      {
         if(isLinked(source))
         {
            addLinked(source,LINK_ACCEPTED);
            listener.serverLinked(source,body);
         }
      }
      else
         if(statusUnlinkedTag.equals(method))
         {
            if(isLinked(source))
            {
               removeLinked(source);
               listener.serverUnlinked(source,body);
            }
         }
   }

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

   /**
    *
    **/
   public boolean isLinked()
   {
      if(center.getIdentification(null) == null)
         return false;
      return isLinked(center.getIdentification(null));
   }

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

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

   /**
    *
    **/
   public void addLinked(UNL server)
   {
      linked.put(server,USER_DEFINED);
   }

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

   /**
    *
    **/
   public void link(UNL server) throws PSYCDeliveryException
   {
      center.sendChecked(server,LinkServer.PackageName,//
      requestLinkTag,null);
      addLinked(server,LINK_REQUEST_SENT);
   }

   /**
    *
    **/
   public void link() throws PSYCDeliveryException
   {
      if(center.getIdentification(null) == null)
         return;
      link(center.getIdentification(null));
   }

   /**
    *
    **/
   public void unlink(UNL server) throws PSYCDeliveryException
   {
      center.sendChecked(server,LinkServer.PackageName,//
      requestUnlinkTag,null);
      addLinked(server,UNLINK_REQUEST_SENT);
   }

   /**
    *
    **/
   public void unlink() throws PSYCDeliveryException
   {
      if(center.getIdentification(null) == null)
         return;
      unlink(center.getIdentification(null));
   }

}