/**
 * Copyright (c) 2008-2020, MOVES Institute, Naval Postgraduate School (NPS). All rights reserved.
 * This work is provided under a BSD open-source license, see project license.html and license.txt
 */
package OpenDis7Examples;

import edu.nps.moves.dis7.enumerations.VariableRecordType;
import edu.nps.moves.dis7.pdus.CommentPdu;
import edu.nps.moves.dis7.pdus.EntityID;
import edu.nps.moves.dis7.pdus.EntityStatePdu;
import edu.nps.moves.dis7.pdus.FirePdu;
import edu.nps.moves.dis7.pdus.Pdu;
import edu.nps.moves.dis7.utilities.DisThreadedNetworkInterface;
import edu.nps.moves.dis7.utilities.PduFactory;
import java.util.ArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;

public class ExampleSimulationProgram
{
    // class variables
    PduFactory pduFactory = new PduFactory();
    DisThreadedNetworkInterface disNetworkInterface;
    DisThreadedNetworkInterface.PduListener pduListener;
    Pdu receivedPdu;
    
    private String networkAddress = "239.1.2.3";
    private int    networkPort    = 3000;
    
    /**
     * Constructor design goal: additional built-in initialization conveniences can go here
     * to keep student efforts focused on the runSimulation() method.
     */
    public ExampleSimulationProgram()
    {
        // Under consideration.  Constructor is not currently needed.
    }
    
    /**
     * Utility Constructor
     * @param address network address to use
     * @param port corresponding network port to use
     */
    public ExampleSimulationProgram(String address, int port)
    {
        setNetworkAddress(address);
        
        setNetworkPort(port);
    }

    /**
     * @return the networkAddress
     */
    public String getNetworkAddress()
    {
        return networkAddress;
    }

    /**
     * @param networkAddress the networkAddress to set
     */
    public final void setNetworkAddress(String networkAddress)
    {
        this.networkAddress = networkAddress;
    }

    /**
     * @return the networkPort
     */
    public int getNetworkPort()
    {
        return networkPort;
    }

    /**
     * @param networkPort the networkPort to set
     */
    public final void setNetworkPort(int networkPort)
    {
        this.networkPort = networkPort;
    }

    /**
     * Initialize network interface, choosing best available network interface
     */
    public void setUpNetworkInterface()
    {
        disNetworkInterface = new DisThreadedNetworkInterface(getNetworkAddress(), getNetworkPort());
        
        System.out.println("Network confirmation: address=" + disNetworkInterface.getMcastGroup() + " port=" + disNetworkInterface.getDisPort());
        pduListener = new DisThreadedNetworkInterface.PduListener()
        {
            /** Callback handler for listener */
            @Override
            public void incomingPdu(Pdu newPdu)
            {
                receivedPdu = newPdu;
            }
        };
        disNetworkInterface.addListener(pduListener);
    }

    /** All done, release network resources */
    public void tearDownNetworkInterface()
    {
        disNetworkInterface.removeListener(pduListener);
        disNetworkInterface.kill();
        disNetworkInterface = null;
    }

    /** 
     * Send a single Protocol Data Unit (PDU) of any type
     * @param pdu the pdu to send
     */
    private void sendSinglePdu(Pdu pdu)
    {
        try
        {
            disNetworkInterface.send(pdu);
            Thread.sleep(100); // TODO consider refactoring the wait logic and moving externally
        } 
        catch (InterruptedException ex)
        {
            System.err.println(this.getClass().getName() + " Error sending PDU: " + ex.getLocalizedMessage());
            System.exit(1);
        }
    }

    /**
     * Send EntityState, Fire, Comment PDUs
     * @see <a href="https://docs.oracle.com/javase/tutorial/java/javaOO/arguments.html">Passing Information to a Method or a Constructor</a> Arbitrary Number of Arguments
     * @param entityStatePdu the ESPDU to send, if any
     * @param firePdu        the FirePDU to send, if any
     * @param commentType    enumeration value describing the narrative comment
     * @param comments       String array of narrative comments
     */
    public void sendAllPdus(EntityStatePdu entityStatePdu,
                               FirePdu firePdu,
                               VariableRecordType commentType,
                               // vararg... variable length string
                               String... comments)
    {
        if (entityStatePdu != null)
            sendSinglePdu(entityStatePdu);
            
        if (firePdu != null)
            sendSinglePdu(firePdu); // bang
        
        if ((comments != null) && (comments.length > 0))
        {
            ArrayList<String> newCommentsList = new ArrayList<>();
            for (int i = 0; i < comments.length; i++)
            {
                if (!comments[i].isEmpty())
                     newCommentsList.add(comments[i]); // OK found something to send
            }
            if (!newCommentsList.isEmpty())
            {
                if (commentType == null)
                    commentType = VariableRecordType.OTHER;
                CommentPdu commentPdu = pduFactory.makeCommentPdu(commentType, newCommentsList.toArray(new String[0])); // comments);
                sendSinglePdu(commentPdu);
            }
        }
    }
  
    /**
     * Main method is first executed when a program instance is loaded.
     * @see <a href="https://docs.oracle.com/javase/tutorial/getStarted/application/index.html">Java Tutorials: A Closer Look at the "Hello World!" Application</a>
     * @param args command-line arguments are an array of optional String parameters that are passed from execution environment during invocation
     */
    public static void main(String[] args)
    {
        ExampleSimulationProgram thisProgram = new ExampleSimulationProgram(); // creates instance
        
        // initial execution: can handle args array of initialization arguments here
        if (args.length == 2)
        {
            if ((args[0] != null) && !args[0].isEmpty())
                thisProgram.setNetworkAddress(args[0]);
            
            if ((args[1] != null) && !args[1].isEmpty())
                thisProgram.setNetworkPort(Integer.parseInt(args[1]));
        }
        else if (args.length != 0)
        {
            System.err.println("Usage: " + thisProgram.getClass().getName() + " [address port]");
            System.exit(-1);
        }
        // OK here we go...

        thisProgram.setUpNetworkInterface();

        thisProgram.runSimulation (); // customization code goes in there

        thisProgram.tearDownNetworkInterface();
    }
    
    /**
     * Programmer-modifiable method for defining and running a new simulation of interest.
     * Support include DIS EntityStatePdu, FirePdu and CommentPdu all available for 
     * modification and sending in a simulation loop.
     */
    @SuppressWarnings("SleepWhileInLoop")
    public void runSimulation ()
    {
      try
      {
        final double LOOP_DURATION_SECONDS  =  1.0; // seconds
        final int    MAX_LOOP_COUNT = 10;
              int    loopCount = 0;
        VariableRecordType narrativeType = VariableRecordType.OTHER; // of potential use
        boolean simulationComplete = false; // sentinel variable as termination condition
        
        // TODO reset clock to zero each time for consistent outputs.
        
        // your model setup: who's who in this zoo?
        // create PDU objects and set their values
        
        EntityID       entityID_1    = new EntityID();
        entityID_1.setSiteID(1).setApplicationID(2).setEntityID(3); // made-up example ID

        EntityStatePdu entityStatePdu = pduFactory.makeEntityStatePdu();
        entityStatePdu.setEntityID(entityID_1);

        FirePdu               firePdu = pduFactory.makeFirePdu();
        // should we customize this munition?  what is it for your simulation?
        
        while (loopCount < MAX_LOOP_COUNT) // loop the simulation while allowed, can set additional conditions to break
        {
            String narrativeMessage1, narrativeMessage2, narrativeMessage3;
            // initialize loop variables
            loopCount++;
            
            // =============================================================================================
            // your own simulation code starts here!
            
            // compute a track, update an ESPDU, whatever it is that your model is doing...
            
            // Where is my entity?
            entityStatePdu.getEntityLocation().setX(entityStatePdu.getEntityLocation().getX() + 1.0); // 1m per timestep
            
            // decide whether to fire, and then update the firePdu.  Hmmm, you might want a target to shoort at!
            
            // etc. etc. your code goes here
                
            
            
            
            
            // make your reports: narrative code for CommentPdu here (set all to empty strings to avoid sending)
            narrativeMessage1 = "MV3500 ExampleSimulationProgram";
            narrativeMessage2 = "runSimulation() loop " + loopCount;
            narrativeMessage3 = ""; // intentionally blank for testing

            // your loop termination condition goes here
            if (loopCount > 4) // for example
            {
                simulationComplete = true;
            }      
            // your own simulation code is finished here!
            // =============================================================================================
            
            // keep track of timestep: wait duration for elapsed time in this loop
            // Thread.sleep needs a (long) parameter for milliseconds, which are clumsy to use sometimes
            Thread.sleep((long)(LOOP_DURATION_SECONDS * 1000)); // seconds * (1000 msec/sec) = milliseconds
            System.out.println ("... Pausing for " + LOOP_DURATION_SECONDS + " seconds");
            
            // send the status PDUs for this loop and continue
            System.out.println ("sending PDUs for simulation step " + loopCount + ", monitor loopback to confirm sent");
            sendAllPdus(entityStatePdu, firePdu, null, narrativeMessage1, narrativeMessage2, narrativeMessage3);
            System.out.println ("... PDUs successfully sent");
            
            // ===============================
            // loop now finished, thus terminate if simulation complete, otherwise send latest PDUs and continue
            if (simulationComplete || (loopCount > 10000)) // for example; including fail-safe condition is good
            {
                System.out.println ("... Termination condition met, simulationComplete=" + simulationComplete);
                break;
            }
        }   // end of while loop
      } 
      catch (Exception ex) // handle any exception that your code might choose to provoke!
      {
        Logger.getLogger(ExampleSimulationProgram.class.getName()).log(Level.SEVERE, null, ex);
      }
    }
}