package org.opentrafficsim.sim0mq.publisher;
   
   import java.rmi.RemoteException;
   import java.util.LinkedHashMap;
   import java.util.List;
   import java.util.Map;
   
   import org.djutils.exceptions.Throw;
   import org.djutils.event.EventProducer;
  import org.djutils.metadata.MetaData;
  import org.djutils.metadata.ObjectDescriptor;
  import org.djutils.serialization.SerializationException;
  import org.opentrafficsim.core.gtu.Gtu;
  import org.opentrafficsim.core.network.Link;
  import org.opentrafficsim.core.network.Network;
  import org.opentrafficsim.road.network.lane.CrossSectionLink;
  import org.sim0mq.Sim0MQException;
  
  /**
   * Publish all available transceivers for an OTS network to a Sim0MQ master and handle its requests. <br>
   * Example sequence of events: <br>
   * <ol>
   * <li>Network is somehow constructed and then a Publisher for that network is constructed.</li>
   * <li>Sim0MQ master requests names of all available subscription handlers</li>
   * <li>Sim0MQ master decides that it wants all GTU MOVE events of all GTUs. To do that it needs to know about all GTUs when they
   * are created and about all GTUs that have already been created. The Sim0MQ master issues to the publisher a request to
   * subscribe to all Network.GTU_ADD_EVENTs of the GTUs_in_network SubscriptionHandler</li>
   * <li>This Publisher requests the GTUs_in_network SubscriptionHandler to subscribe to the add events. From now on, the
   * GTUs_in_network SubscriptionHandler will receive these events generated by the Network and transcribe those into a Sim0MQ
   * events which are transmitted to the Sim0MQ master.</li>
   * <li>Sim0MQ master requests publisher to list all the elements of the GTUs_in_network SubscriptionHandler</li>
   * <li>This Publisher calls the list method of the GTUs_in_network SubscriptionHandler which results in a list of all active
   * GTUs being sent to the Sim0MQ master</li>
   * <li>The Sim0MQ master requests this Publisher to create a subscription for the update events of the GTU_move
   * SubscriptionHandler, providing the GTU id as address. It does that once for every GTU id.</li>
   * <li>This Publishers creates the subscriptions. From now on any GTU.MOVE_EVENT event is transcribed by the GTU_move
   * SubscriptionHandler in to a corresponding Sim0MQ event and sent to the Sim0MQ master.</li>
   * </ol>
   * <p>
   * Copyright (c) 2020-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
   * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
   * </p>
   * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
   * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
   */
  public class Publisher extends AbstractTransceiver
  {
      /** Map Publisher names to the corresponding Publisher object. */
      @SuppressWarnings("checkstyle:visibilitymodifier")
      final Map<String, SubscriptionHandler> subscriptionHandlerMap = new LinkedHashMap<>();
  
      /** Handlers for data not handled directly by this Publisher. */
      private final Map<String, IncomingDataHandler> incomingDataHandlers = new LinkedHashMap<>();
  
      /** The OTS network. */
      @SuppressWarnings("checkstyle:visibilitymodifier")
      final Network network;
  
      /**
       * Construct a Publisher for an OTS network with no additional subscription handlers.
       * @param network Network; the OTS network
       * @throws RemoteException ...
       */
      public Publisher(final Network network) throws RemoteException
      {
          this(network, null, null);
      }
  
      /**
       * Construct a Publisher for an OTS network.
       * @param network Network; the OTS network
       * @param additionalSubscriptionHandlers List&lt;SubscriptionHandler&gt;; list of additional subscription handlers to
       *            register (may be null)
       * @param incomingDataHandlers List&lt;IncomingDataHandler&gt;; handlers for data not handled directly by the Publisher (may
       *            be null).
       * @throws RemoteException ...
       */
      public Publisher(final Network network, final List<SubscriptionHandler> additionalSubscriptionHandlers,
              final List<IncomingDataHandler> incomingDataHandlers) throws RemoteException
      {
          super("Publisher for " + Throw.whenNull(network, "Network may not be null").getId(),
                  new MetaData("Publisher for " + network.getId(), "Publisher",
                          new ObjectDescriptor[] {new ObjectDescriptor("Name of subscription handler", "String", String.class)}),
                  new MetaData("Subscription handlers", "Subscription handlers",
                          new ObjectDescriptor[] {new ObjectDescriptor("Name of subscription handler", "String", String.class)}));
          this.network = network;
  
          if (incomingDataHandlers != null)
          {
              for (IncomingDataHandler incomingDataHandler : incomingDataHandlers)
              {
                  this.incomingDataHandlers.put(incomingDataHandler.getKey(), incomingDataHandler);
              }
          }
  
          GtuIdTransceiver gtuIdTransceiver = new GtuIdTransceiver(network);
          GtuTransceiver gtuTransceiver = new GtuTransceiver(network, gtuIdTransceiver);
          SubscriptionHandler gtuSubscriptionHandler =
                  new SubscriptionHandler("GTU move", gtuTransceiver, new LookupEventProducer()
                 {
                     @Override
                     public EventProducer lookup(final Object[] address, final ReturnWrapper returnWrapper)
                             throws Sim0MQException, SerializationException
                     {
                         String bad = AbstractTransceiver.verifyMetaData(getAddressMetaData(), address);
                         if (bad != null)
                         {
                             returnWrapper.nack(bad);
                             return null;
                         }
                         EventProducer result = network.getGTU((String) address[0]);
                         if (null == result)
                         {
                             returnWrapper.nack("No GTU with id \"" + address[0] + "\" found");
                         }
                         return result;
                     }
 
                     private final MetaData metaData = new MetaData("GTU Id", "GTU Id",
                             new ObjectDescriptor[] {new ObjectDescriptor("GTU ID", "GTU Id", String.class)});
 
                     @Override
                     public MetaData getAddressMetaData()
                     {
                         return this.metaData;
                     }
                 }, null, null, Gtu.MOVE_EVENT, null);
         addSubscriptionHandler(gtuSubscriptionHandler);
         addSubscriptionHandler(new SubscriptionHandler("GTUs in network", gtuIdTransceiver, new LookupEventProducer()
         {
             @Override
             public EventProducer lookup(final Object[] address, final ReturnWrapper returnWrapper)
                     throws Sim0MQException, SerializationException
             {
                 String bad = AbstractTransceiver.verifyMetaData(getAddressMetaData(), address);
                 if (bad != null)
                 {
                     returnWrapper.nack(bad);
                     return null;
                 }
                 return network;
             }
 
             @Override
             public String toString()
             {
                 return "Subscription handler for GTUs in network";
             }
 
             @Override
             public MetaData getAddressMetaData()
             {
                 return MetaData.EMPTY;
             }
         }, Network.GTU_ADD_EVENT, Network.GTU_REMOVE_EVENT, null, gtuSubscriptionHandler));
         LinkIdTransceiver linkIdTransceiver = new LinkIdTransceiver(network);
         LinkTransceiver linkTransceiver = new LinkTransceiver(network, linkIdTransceiver);
         SubscriptionHandler linkSubscriptionHandler = new SubscriptionHandler("Link change", linkTransceiver, this.lookupLink,
                 Link.GTU_ADD_EVENT, Link.GTU_REMOVE_EVENT, null, null);
         addSubscriptionHandler(linkSubscriptionHandler);
         addSubscriptionHandler(new SubscriptionHandler("Links in network", linkIdTransceiver, new LookupEventProducer()
         {
             @Override
             public EventProducer lookup(final Object[] address, final ReturnWrapper returnWrapper)
                     throws Sim0MQException, SerializationException
             {
                 String bad = AbstractTransceiver.verifyMetaData(getAddressMetaData(), address);
                 if (bad != null)
                 {
                     returnWrapper.nack(bad);
                     return null;
                 }
                 return network;
             }
 
             @Override
             public String toString()
             {
                 return "Subscription handler for Links in network";
             }
 
             @Override
             public MetaData getAddressMetaData()
             {
                 return MetaData.EMPTY;
             }
         }, Network.LINK_ADD_EVENT, Network.LINK_REMOVE_EVENT, null, linkSubscriptionHandler));
         NodeIdTransceiver nodeIdTransceiver = new NodeIdTransceiver(network);
         NodeTransceiver nodeTransceiver = new NodeTransceiver(network, nodeIdTransceiver);
         // addTransceiver(nodeIdTransceiver);
         // addTransceiver(new NodeTransceiver(network, nodeIdTransceiver));
         SubscriptionHandler nodeSubscriptionHandler =
                 new SubscriptionHandler("Node change", nodeTransceiver, new LookupEventProducer()
                 {
                     @Override
                     public EventProducer lookup(final Object[] address, final ReturnWrapper returnWrapper)
                     {
                         return null; // Nodes do not emit events
                     }
 
                     @Override
                     public String toString()
                     {
                         return "Subscription handler for Node change";
                     }
 
                     private final MetaData metaData = new MetaData("Node Id", "Node Id",
                             new ObjectDescriptor[] {new ObjectDescriptor("Node ID", "Node Id", String.class)});
 
                     @Override
                     public MetaData getAddressMetaData()
                     {
                         return this.metaData;
                     }
                 }, null, null, null, null);
         addSubscriptionHandler(nodeSubscriptionHandler);
         addSubscriptionHandler(new SubscriptionHandler("Nodes in network", nodeIdTransceiver, new LookupEventProducer()
         {
             @Override
             public EventProducer lookup(final Object[] address, final ReturnWrapper returnWrapper)
                     throws Sim0MQException, SerializationException
             {
                 String bad = AbstractTransceiver.verifyMetaData(getAddressMetaData(), address);
                 if (bad != null)
                 {
                     returnWrapper.nack(bad);
                     return null;
                 }
                 return network;
             }
 
             @Override
             public String toString()
             {
                 return "Subscription handler for Nodes in network";
             }
 
             @Override
             public MetaData getAddressMetaData()
             {
                 return MetaData.EMPTY;
             }
         }, Network.NODE_ADD_EVENT, Network.NODE_REMOVE_EVENT, null, nodeSubscriptionHandler));
         SubscriptionHandler linkGTUIdSubscriptionHandler = new SubscriptionHandler("GTUs on Link",
                 new LinkGtuIdTransceiver(network), this.lookupLink, Link.GTU_ADD_EVENT, Link.GTU_REMOVE_EVENT, null, null);
         addSubscriptionHandler(linkGTUIdSubscriptionHandler);
         addSubscriptionHandler(new SubscriptionHandler("Cross section elements on Link",
                 new CrossSectionElementTransceiver(network), this.lookupLink, CrossSectionLink.LANE_ADD_EVENT,
                 CrossSectionLink.LANE_REMOVE_EVENT, null, linkGTUIdSubscriptionHandler));
         // addTransceiver(new LaneGtuIdTransceiver(network));
         SimulatorStateTransceiver stt = new SimulatorStateTransceiver(network.getSimulator());
         SubscriptionHandler simulatorStateSubscriptionHandler = new SubscriptionHandler("Simulator running", stt,
                 stt.getLookupEventProducer(), null, null, SimulatorStateTransceiver.SIMULATOR_STATE_CHANGED, null);
         addSubscriptionHandler(simulatorStateSubscriptionHandler);
 
         if (additionalSubscriptionHandlers != null)
         {
             for (SubscriptionHandler sh : additionalSubscriptionHandlers)
             {
                 addSubscriptionHandler(sh);
             }
         }
 
         addSubscriptionHandler(new SubscriptionHandler("", this, null, null, null, null, null)); // The meta transceiver
     }
 
     /** Lookup a CrossSectionLink in the network. */
     private LookupEventProducer lookupLink = new LookupEventProducer()
     {
         @Override
         public EventProducer lookup(final Object[] address, final ReturnWrapper returnWrapper)
                 throws IndexOutOfBoundsException, Sim0MQException, SerializationException
         {
             Throw.whenNull(address, "LookupLink requires the name of a link");
             Throw.when(address.length != 1 || !(address[1] instanceof String), IllegalArgumentException.class, "Bad address");
             Link link = Publisher.this.network.getLink((String) address[0]);
             if (null == link)
             {
                 returnWrapper.nack("Network does not contain a Link with id " + address[0]);
                 return null;
             }
             if (!(link instanceof EventProducer))
             {
                 returnWrapper.nack("Link \"" + address[0] + "\" is not able to handle subscriptions");
                 return null;
             }
             return (CrossSectionLink) link;
         }
 
         @Override
         public String toString()
         {
             return "LookupProducerInterface that looks up a Link in the network";
         }
 
         @Override
         public MetaData getAddressMetaData()
         {
             return new MetaData("Link id", "Name of a link in the network",
                     new ObjectDescriptor[] {new ObjectDescriptor("Link id", "Name of a link in the network", String.class)});
         }
     };
 
     /**
      * Add a SubscriptionHandler to the map.
      * @param subscriptionHandler SubscriptionHandler; the subscription handler to add to the map
      */
     private void addSubscriptionHandler(final SubscriptionHandler subscriptionHandler)
     {
         this.subscriptionHandlerMap.put(subscriptionHandler.getId(), subscriptionHandler);
     }
 
     /** {@inheritDoc} */
     @Override
     public Object[] get(final Object[] address, final ReturnWrapper returnWrapper)
             throws Sim0MQException, SerializationException
     {
         Throw.whenNull(returnWrapper, "returnWrapper may not be null");
         String bad = verifyMetaData(getAddressFields(), address);
         if (bad != null)
         {
             returnWrapper.nack("Bad address (should be the name of a transceiver): " + bad);
             return null;
         }
         SubscriptionHandler subscriptionHandler = this.subscriptionHandlerMap.get(address[0]);
         if (null == subscriptionHandler)
         {
             returnWrapper.nack("No transceiver with name \"" + address[0] + "\"");
             return null;
         }
         return new Object[] {subscriptionHandler};
     }
 
     /** Returned by the getIdSource method. */
     private final TransceiverInterface idSource = new TransceiverInterface()
     {
         @Override
         public String getId()
         {
             return "Transceiver for names of available transceivers in Publisher";
         }
 
         @Override
         public MetaData getAddressFields()
         {
             return MetaData.EMPTY;
         }
 
         /** Result of getResultFields. */
         private MetaData resultMetaData =
                 new MetaData("Transceiver names available in Publisher", "String array", new ObjectDescriptor[] {
                         new ObjectDescriptor("Transceiver names available in Publisher", "String array", String[].class)});
 
         @Override
         public MetaData getResultFields()
         {
             return this.resultMetaData;
         }
 
         @Override
         public Object[] get(final Object[] address, final ReturnWrapper returnWrapper)
                 throws RemoteException, Sim0MQException, SerializationException
         {
             Object[] result = new Object[Publisher.this.subscriptionHandlerMap.size()];
             int index = 0;
             for (String key : Publisher.this.subscriptionHandlerMap.keySet())
             {
                 result[index++] = key;
             }
             return result;
         }
     };
 
     /** {@inheritDoc} */
     @Override
     public TransceiverInterface getIdSource(final int addressLevel, final ReturnWrapper returnWrapper)
             throws Sim0MQException, SerializationException
     {
         if (0 != addressLevel)
         {
             returnWrapper.encodeReplyAndTransmit("Address should be 0");
             return null;
         }
         return this.idSource;
     }
 
     /** {@inheritDoc} */
     @Override
     public boolean hasIdSource()
     {
         return true;
     }
 
     /**
      * Execute one command.
      * @param subscriptionHandlerName String; name of the SubscriptionHandler for which the command is destined
      * @param command SubscriptionHandler.Command; the operation to perform
      * @param address Object[]; the address on which to perform the operation
      * @param returnWrapper ReturnWrapper; to transmit the result
      * @throws RemoteException on RMI network failure
      * @throws SerializationException on illegal type in serialization
      * @throws Sim0MQException on communication error
      */
     public void executeCommand(final String subscriptionHandlerName, final SubscriptionHandler.Command command,
             final Object[] address, final ReturnWrapper returnWrapper)
             throws RemoteException, Sim0MQException, SerializationException
     {
         SubscriptionHandler subscriptionHandler = this.subscriptionHandlerMap.get(subscriptionHandlerName);
         if (null == subscriptionHandler)
         {
             returnWrapper.nack("No subscription handler for \"" + subscriptionHandlerName + "\"");
             return;
         }
         subscriptionHandler.executeCommand(command, address, returnWrapper);
     }
 
     /**
      * Execute one command.
      * @param subscriptionHandlerName String; name of the SubscriptionHandler for which the command is destined
      * @param commandString String; the operation to perform
      * @param address Object[]; the address on which to perform the operation
      * @param returnWrapper ReturnWrapper; to transmit the result
      * @throws RemoteException on RMI network failure
      * @throws SerializationException on illegal type in serialization
      * @throws Sim0MQException on communication error
      */
     public void executeCommand(final String subscriptionHandlerName, final String commandString, final Object[] address,
             final ReturnWrapperImpl returnWrapper) throws RemoteException, Sim0MQException, SerializationException
     {
         executeCommand(subscriptionHandlerName,
                 Throw.whenNull(SubscriptionHandler.lookupCommand(commandString), "Invalid command (%s)", commandString),
                 address, returnWrapper);
     }
 
     /**
      * Find the IncomingDataHandler for a particular key.
      * @param key String; the key of the IncomingDataHandler
      * @return IncomingDataHandler; or null if there is no IncomingDataHandler for the key
      */
     public IncomingDataHandler lookupIncomingDataHandler(final String key)
     {
         return this.incomingDataHandlers.get(key);
     }
 
 }