/*
 * Copyright (c) 2009 Anthony Steed and Manuel Fradinho Oliveira
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the 
 * following conditions are met:
 * 1. Redistributions of source code must retain the above
 *    copyright notice, this list of conditions and the 
 *    following disclaimer.
 * 2. Redistributions in binary form must reproduce the above 
 *    copyright notice, this list of conditions and the 
 *    following disclaimer in the documentation and/or other 
 *    materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of 
 *    this software must display the following acknowledgement:
 *       This product includes software from the book "Networked 
 *       Graphics" written by Anthony Steed and Manuel Fradinho
 *       Oliveira published by Morgan Kaufmann
 * 4. Neither the name of the University nor of the Department
 *    may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 * 5. Neither the name of Cyntelix may be used to enforese or 
 *    promote products derived from this software without prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS 
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, 
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO 
 * EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE FOR ANY 
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION). HOWEVER CAUSED 
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Contact Info: Anthony Steed
 *               a.steed@cs.ucl.ac.uk
 *
 *               Manuel Fradinho Oliveira
 *               mfradinho@cyntelix.com
 *
 */
import javax.media.j3d.*;
import javax.vecmath.*;
import java.util.*;


class FlockBehaviour extends Behavior {
  static float   INERTIA_FACTOR;
  static float   PULL_FACTOR;
  static float   PROXIMITY_DISTANCE;
  static float   PROXIMITY_FACTOR;
  static float   MAX_VELOCITY;

  Flock              _localFlock;
  Vector             _remoteFlocks;
  Vector             _totalFlock;
  Network            _network;

  long               _t0;
  
  WakeupOnElapsedFrames criteria;

  Vector3f center,
           inertia,
           localCenter,
           pull,
           diff,
           auxVel;
  Transform3D trans;

   
  public FlockBehaviour() {
    INERTIA_FACTOR = 0.1f;
    PULL_FACTOR = 1.0f;//0.1f;//3.0f;
    PROXIMITY_DISTANCE = 6.0f;//6.0f;//3.0f;
    PROXIMITY_FACTOR = 5.0f;
    MAX_VELOCITY = 5.0f;

    _localFlock = null;
    _remoteFlocks = new Vector();

    center = new Vector3f();
    inertia = new Vector3f();
    trans = new Transform3D();
    pull = new Vector3f();
    diff = new Vector3f();
    auxVel = new Vector3f();
    localCenter = new Vector3f();
    _totalFlock = new Vector();
  }

  public void addFlock(Flock flock) {
    _remoteFlocks.add(flock);
    extractBoids(flock);
  }

  public void setNetwork(Network network) {
    _network = network;
  }

  public void initialize() {
    setSchedulingBounds(new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0));
    criteria = new WakeupOnElapsedFrames(0);
    _t0 = System.currentTimeMillis();
    wakeupOn(criteria);
  }

  public void setLocalFlock(Flock flock) {
    _localFlock = flock;
    extractBoids(flock);
  }

  private void extractBoids(Flock flock) {
    Object o;
    Enumeration e;
    e = flock.getBoids();
    while (e.hasMoreElements()) {
      o = e.nextElement();
      if (o instanceof Boid) {
	    _totalFlock.addElement(o);
      }
    }
  }
  
  private void updateBoids(float time) {
    Boid thisBoid;
    Boid otherBoid;
    int proximate;
    float averageTotalFlockSize = 1/(float)_totalFlock.size();
    float tempPullScale = time*PULL_FACTOR;

    center.set(0,0,0); 
    inertia.set(0,0,0);
    Enumeration flockIterator;

    for ( flockIterator = _totalFlock.elements(); flockIterator.hasMoreElements();){
      thisBoid = (Boid)flockIterator.nextElement();
      center.add(thisBoid._position);
      inertia.add(thisBoid._velocity);
    }

    center.scale(averageTotalFlockSize);
    inertia.scale(averageTotalFlockSize);
    inertia.scale(INERTIA_FACTOR*time);

    for (Enumeration localIterator = _localFlock.getBoids(); localIterator.hasMoreElements();){
      thisBoid = (Boid)localIterator.nextElement();

      pull.set(center);
      pull.sub(thisBoid._position);
      pull.scale(tempPullScale);
      thisBoid._velocity.add(pull);

      thisBoid._velocity.add(inertia);

      proximate = 0;

      localCenter.set(0,0,0);
      for (flockIterator = _totalFlock.elements(); flockIterator.hasMoreElements();) {
         otherBoid = (Boid)flockIterator.nextElement();
         if (!otherBoid.equals(thisBoid)) {
            diff.set(thisBoid._position);
            diff.sub(otherBoid._position);
            if (diff.length() < PROXIMITY_DISTANCE) {
               proximate++;
               localCenter.add(diff);
            }
         } 
      }

      if (proximate != 0) {
         localCenter.scale(PROXIMITY_FACTOR*time);
         thisBoid._velocity.add(localCenter);
      }

      // Max velocity
      float velocity = thisBoid._velocity.length();
      if (velocity > MAX_VELOCITY)
         thisBoid._velocity.scale(MAX_VELOCITY/velocity);
      
      // Calculate new position
      auxVel.set(thisBoid._velocity);
      auxVel.scale(time);
      thisBoid._position.add(auxVel);

      // World limits
      thisBoid.worldConstraints();
    }
    if (_network !=null)
      _network.send(_localFlock.getBoids());      
  }

  private void drawBoids() {
    Boid thisBoid;
    for (Enumeration flock = _totalFlock.elements(); flock.hasMoreElements();){
      thisBoid = (Boid)flock.nextElement();
      trans.setIdentity();
      trans.rotY(Math.atan2(-thisBoid._velocity.x, -thisBoid._velocity.z));
      trans.setTranslation(thisBoid._position);
      thisBoid.setTransform(trans);
    }
  }

  public void processStimulus(Enumeration en) {

    if (_totalFlock == null) {
      _t0 = System.currentTimeMillis();
    } else {
      long t;
      t = System.currentTimeMillis();
      updateBoids((t-_t0)/ 1000.0f);
      drawBoids();
      _t0 = t;
    }
    wakeupOn(new WakeupOnElapsedFrames(0));
  }

}