import traer.physics.*;
import traer.animation.*;

final float EDGE_LENGTH = 20;
final float EDGE_STRENGTH = 0.01;
final float SPACER_STRENGTH = 1100;
final float RANDOM_INIT = 100;
final float ZOOM = 1.2;

class ForceDirectedGraph extends ParticleSystem {
  Smoother3D centroid;
  ForceDirectedGraph() {
    this(0.25, 0.95);
  }
  ForceDirectedGraph(float friction, float smoothness) {
    super(0, friction);
    centroid = new Smoother3D(smoothness);
    reset();
  }
  void reset() {
    clear();
    centroid.setValue(0, 0, 1);
  }
  Vector3D remap(float x, float y) {
    return new Vector3D(
    centroid.x() + (x - width/2) / centroid.z(),
    centroid.y() + (y - height/2) / centroid.z(),
    0);
  }
  Particle addVertex() {
    Particle p = makeParticle();
    for(int i = 0; i < numberOfParticles(); i++) {
      Particle t = getParticle(i);
      if(t != p)
        makeAttraction(p, t, -SPACER_STRENGTH, 15);
    }
    p.moveTo(random(-RANDOM_INIT, RANDOM_INIT), random(-RANDOM_INIT, RANDOM_INIT), random(-RANDOM_INIT, RANDOM_INIT));
    return p;
  }
  Spring addEdge(Particle a, Particle b) {
    return makeSpring(a, b, EDGE_STRENGTH, EDGE_STRENGTH, EDGE_LENGTH);
  }
  Spring addEdge(Particle a, Particle b, float edgeLength) {
    return makeSpring(a, b, EDGE_STRENGTH, EDGE_STRENGTH, edgeLength);    
  }
  void reposition() {
    centroid.tick();
    translate(width/2 - centroid.x(), height/2 - centroid.y());
    rotateY(frameCount * rotationSpeed);
    scale(centroid.z());
    float 
      xMax = Float.NEGATIVE_INFINITY, 
    xMin = Float.POSITIVE_INFINITY, 
    yMin = Float.POSITIVE_INFINITY, 
    yMax = Float.NEGATIVE_INFINITY;

    for(int i = 0; i < numberOfParticles(); i++) {
      Vector3D p = getParticle(i).position();
      float
        curX = screenX(p.x(), p.y(), p.z()) - width/2,
      curY = screenY(p.x(), p.y(), p.z()) - height/2;
      xMax = max(xMax, curX);
      xMin = min(xMin, curX);
      yMin = min(yMin, curY);
      yMax = max(yMax, curY);
    }

    float deltaX = xMax - xMin;
    float deltaY = yMax - yMin;
    float xOff = lerp(xMin, xMax, .5);
    float yOff = lerp(yMin, yMax, .5);
    float zoom = deltaY > deltaX ?
      height / deltaY:
      width / deltaX;
    centroid.setTarget(
      centroid.x() + xOff,
      centroid.y() + yOff,
      zoom * ZOOM);
  }
}