// **********************************************************************
//  EXECUTIVE SUMMARY
// Module Name: Entity.java
// Description: Definition of the Entity class
// Author: Kent A. Watsen, http://www.mbay.net/~watsen
// **********************************************************************

package mil.navy.nps.eaiDemoBoids;

// **********************************************************************
//   IMPORTS
// **********************************************************************


// Standard classes
import java.*;
import java.util.*;

// EAI classes
import vrml.external.Node;
import vrml.external.Browser;
import vrml.external.field.*;
import vrml.external.exception.*;

import netscape.javascript.JSObject;

// NPS library stuff
import mil.navy.nps.dis.*;
import mil.navy.nps.math.*;

// **********************************************************************
//   CLASS
// **********************************************************************

public class Entity extends Object
  {
  static final String vrmlString      = "Shape { appearance Appearance { material Material { diffuseColor 1 1 1 } } geometry IndexedFaceSet { coord Coordinate { point [0 0 -3, -2 0 3, 2 0 3, 0 2 3] } coordIndex [0 2 1 -1, 0 1 3 -1, 0 3 2 -1, 1 2 3 -1] ccw FALSE} }";
  static Hashtable    entityContainer = null;
  Node                myNode[]        = null;
  Node                myTransform[]   = null;
  EventInSFVec3f      myPos           = null;
  EventInSFRotation   myRot           = null;
  float               position[]      = null; // x, y, z
  float               rotation[]      = null; // axis, angle (radians)
  float               eulers[]        = null; // h, p, r
  Quaternion          tmpQuat         = null;
  int                 currFrame       = 0;
  EntityID            entityID        = null;
  EntityStatePdu      espdu           = null;
  float               pduTime         = 0.0f;

  public Entity (Browser browser, EntityID _entityID)
    {
    EventInMFNode tmpAddChildren = null;

    // first set passed args we wish to keep
    entityID = _entityID;

    // now create and add our entity container
    if (entityContainer == null)
      {
      entityContainer = new Hashtable(10);
      }
    entityContainer.put(entityID, this);

    myNode = browser.createVrmlFromString(vrmlString);
    myTransform = browser.createVrmlFromString("Transform {}" );

    tmpAddChildren = (EventInMFNode)myTransform[0].getEventIn("addChildren");
    tmpAddChildren.setValue(myNode);

    myPos = (EventInSFVec3f) myTransform[0].getEventIn("set_translation");
    myRot = (EventInSFRotation) myTransform[0].getEventIn("set_rotation");

    position = new float[3];
    rotation = new float[4];

    eulers = new float[3];
    tmpQuat = new Quaternion(); // allocate up front so runtime efficient
    }

  public void dispose()
    {
    // remove entity from hashtable
    entityContainer.remove(entityID);
    }

  public void setESPDU(EntityStatePdu _espdu)
    {
    espdu = _espdu;

    position[0] = (float) espdu.getEntityLocationX();
    position[1] = (float) espdu.getEntityLocationY();
    position[2] = (float) espdu.getEntityLocationZ();
    eulers[0]   = (float) espdu.getEntityOrientationPsi();   // heading
    eulers[1]   = (float) espdu.getEntityOrientationTheta(); // pitch
    eulers[2]   = (float) espdu.getEntityOrientationPhi();   // roll

    pduTime = 0.0f;
    }

  public EntityStatePdu getESPDU()
    {
    return espdu;
    }

  public void cycle()
    {
    float dt    = 0.1f;  // assume 10Hz
    float hpr[] = null;

    // Increment timer
    pduTime = pduTime + dt;

    // linear dead reackon
    position[0] = position[0] + dt*(float)espdu.getEntityLinearVelocityX();
    position[1] = position[1] + dt*(float)espdu.getEntityLinearVelocityY();
    position[2] = position[2] + dt*(float)espdu.getEntityLinearVelocityZ();
    eulers[0] = eulers[0] + dt*(float)espdu.getEntityAngularVelocityY(); // heading
    eulers[1] = eulers[1] + dt*(float)espdu.getEntityAngularVelocityX(); // pitch
    eulers[2] = eulers[2] + dt*(float)espdu.getEntityAngularVelocityZ(); // roll
    
    // now convert eulers to axis/angle
    tmpQuat.setEulers(eulers);
    tmpQuat.getAxisAngle(rotation);

    // now apply any changes in pos/rot
    myPos.setValue(position);
    myRot.setValue(rotation);
    }

  public static int getNum()
    {
    if (entityContainer == null)
      return 0;
    return entityContainer.size();
    }

  public static Entity get(int index)
    {
    Enumeration enumeration = null;
    Entity      entity      = null;

    if (entityContainer == null)
      return null;
    if (index < 0 || index >= entityContainer.size())
      return null;
    enumeration = entityContainer.elements();
    for (int i=0; i<=index; i++)
      {
      entity = (Entity)enumeration.nextElement();
      }
    return entity;
    }

  public static Entity get(EntityID _entityID)
    {
    if (entityContainer == null)
      return null;
    return (Entity)entityContainer.get(_entityID);
    }

  public Node[] getNode()
    {
    return myTransform;
    }

  public float getPduTime()
    {
    return pduTime;
    }

}