/** applet No. 1152
 *
 * meteor 3-body - astro object 2D (discrete element method)
 * - multi thread  AO2D :: display - asynchronous
 *
 * Created by Ikeuchi Mitsuru on April 07 2007.
 * Copyright (c) 2007 Ikeuchi Mitsuru. All rights reserved.
 *
 * ver 0.0.1   2007.04.07  created
 * ver 0.0.2   2007.06.19  improved code
 *
 */

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class meteor3BodyMtAO2D extends Applet
  implements MouseListener, MouseMotionListener,
    ItemListener, ActionListener, AdjustmentListener, Runnable {

  // ------------------------------------ preset field -----------

  Thread th = null; // for run()-paint() thread
  AO2D d2d = null;
  DisplayD2D dsp = new DisplayD2D();

  // for event
  Choice ch_mat,ch_view;
  Button bt_reset, bt_startStop, bt_step;
  Scrollbar sc_vx0, sc_scale;

  // for off-paint buffer
  Dimension dim;
  Image imgOff;
  Graphics gOff;

  int dgX, dgY, dgXb, dgYb;

  int sleepTime = 30;
  int dispMode = 0;
  int thCount = 0;


  // ------------------------------ applet main thread -----------

  public void init() {
    resize(630,460);
    setBackground(Color.white);

    dim = getSize();
    imgOff = createImage(dim.width,dim.height);
    gOff = imgOff.getGraphics();

    ch_mat = new Choice();
    ch_mat.add("fixed");
    ch_mat.add("A");
    ch_mat.add("B");
    ch_mat.add("C");
    ch_mat.addItemListener(this);
    ch_mat.select("B");

    ch_view = new Choice();
    ch_view.add("ball");
    ch_view.add("openBall"); 
    ch_view.add("velocity");
    ch_view.addItemListener(this);
    ch_view.select("ball");

    bt_reset = new Button("reset");
    bt_reset.addActionListener(this);

    bt_startStop = new Button("start/stop");
    bt_startStop.addActionListener(this);

    bt_step = new Button("step");
    bt_step.addActionListener(this);

    sc_vx0 = new Scrollbar(Scrollbar.HORIZONTAL,135,10,0,210);
    sc_vx0.addAdjustmentListener(this);

    sc_scale = new Scrollbar(Scrollbar.HORIZONTAL,100,10,50,510);
    sc_scale.addAdjustmentListener(this);

    addMouseListener(this);  
    addMouseMotionListener(this);

    setLayout(new BorderLayout());
    Panel pnl = new Panel();
    pnl.setLayout(new GridLayout(1,6,5,0));
    /* pnl.add(new Label("  ")); */
    pnl.add(bt_reset);
    pnl.add(bt_startStop);
    pnl.add(sc_vx0);
    pnl.add(new Label("  "));
    pnl.add(sc_scale);
    pnl.add(ch_view);
    add(pnl,"North");

  }

  public void start() {
    if (d2d == null) {
      d2d = new AO2D();
      d2d.start();
    }
    if (th == null) {
      th = new Thread(this);
      th.start();
    }
  }

  public void stop() {
    if (th != null) th = null;
    if (d2d != null) d2d = null;
  }


  // ---------------------------------- event listener -----------

  public void itemStateChanged(ItemEvent ev){
    if (ev.getSource() == ch_view){
      dispMode = ch_view.getSelectedIndex();
    }
  }

  public void actionPerformed(ActionEvent ev){
    if(ev.getSource() == bt_reset){ 
      d2d.reset();
      thCount = 0;
    } else if (ev.getSource() == bt_startStop){
      if (d2d.getStartSW()==0) {
        d2d.setStartSW(1);
      } else {
        d2d.setStartSW(0);
      }
    } else if (ev.getSource() == bt_step){
      if (d2d.getStartSW()==0) {
        d2d.setStepSW();
      }
    }
  }

  public void adjustmentValueChanged(AdjustmentEvent ev){
    if (ev.getSource() == sc_vx0) { 
      d2d.setVx0( 1.0*(double)(sc_vx0.getValue())-100.0 );
    } else if (ev.getSource() == sc_scale) { 
      dsp.setScale( 0.01*(double)(sc_scale.getValue()) );
    }
  }

  public void mousePressed(MouseEvent ev){ }
  public void mouseReleased(MouseEvent ev){
    dgXb = 0; dgYb = 0;
    dgX = 0; dgY = 0;
  }
  public void mouseClicked(MouseEvent ev){ }
  public void mouseEntered(MouseEvent ev){ } 
  public void mouseExited (MouseEvent ev){ }

  public void mouseMoved  (MouseEvent ev){ }

  public void mouseDragged(MouseEvent ev){
    dgXb = dgX; dgYb = dgY;
    dgX=ev.getX();
    dgY=ev.getY();
    if (dgXb==0 && dgYb==0) {
      dgXb = dgX; dgYb = dgY;
    }
    dsp.setViewDelta( (dgX-dgXb), (dgY-dgYb) );
  }



  // ========================= run() - paint() loop ==============

  public void run() {
    while (th != null) {
      try {
        Thread.sleep(sleepTime);
      } catch (InterruptedException e) { }
      thCount += 1;
      offPaint();
      repaint();
    }
  }

  public void update(Graphics g) {
    paint(g);
  }

  public void paint(Graphics g) {
    g.drawImage(imgOff,0,0,this);
  }

  private void offPaint() {
    if (d2d != null) {
      dsp.plotGraph(gOff, d2d, dispMode, thCount);
    }
  }

}  



// ================================= display D2D class ===========

class DisplayD2D {

  Graphics gOff;
  AO2D d2d;

  private double xMax = 100.0*1.0e5;
  private double yMax = 100.0*1.0e5;

  private int Nmt = 0;

  private double dispWidth = 300.0;
  private double dispScale = (dispWidth/xMax);
  private double viewScale = 1.0;

  private double xShift = 0.0;
  private double yShift = 0.0;

  private int drawnCount = 0;


  DisplayD2D() {
  }

  public void plotGraph(Graphics gg, AO2D ad2d, int dispMode, int thCount) {
    int d2dCount, gx, gy, gbx;
    double sc;

    gOff = gg;
    d2d = ad2d;
    if (d2d==null) return;
    d2dCount = d2d.getCount();
    if (d2dCount==drawnCount) return;
    drawnCount = d2dCount;

    Nmt = d2d.getNmt();
    sc = dispScale*viewScale;
    gx = 30+(int)(sc*xShift);
    gy = 80+(int)(sc*yShift);

    gOff.setColor(Color.black);
    gOff.fillRect(0,0,630,460);


    drawWaku(gx,gy,sc);
    if (dispMode==0) {
      ballPlot(gx,gy,sc,0);

    } else if (dispMode==1) {
      ballPlot(gx,gy,sc,1);

    } else if (dispMode==2) {
      ballPlot(gx,gy,sc,0);
      velocityPlot(gx,gy,sc,0.2);

    } else if (dispMode==3) {
      ;

    }

    gbx = 630/6;
    gOff.setColor(Color.yellow);
    gOff.drawString("t="+(int)(d2d.getTime()*10.0+0.5)/10.0+" s",gbx*0+10,40);
    if (d2d.getStartSW()==1) {
      gOff.drawString("started",630/6*1+10,40);
    } else {
      gOff.drawString("stop",630/6*1+10,40);
    }
    gOff.drawString("vx0="+(float)(d2d.getVx0())+"m/s",gbx*2+10,40);

    gOff.drawString("scale="+(int)(viewScale*100.0+0.5)+"%",gbx*4+10,40);
    gOff.drawString("view",gbx*5+10,40);

    gOff.setColor(Color.yellow);
    gOff.drawString("Box="+(int)(xMax/100.0+0.5)/10.0+" x "+(int)(yMax/100.0+0.5)/10.0+" km",430,60);

  }


  // ------------------------------------ plot methods -----------

  private void ballPlot(int gx, int gy, double sc, int mode) {
    int i,ix,iy,ir;
    double tm;

    for (i=0; i<Nmt; i++) {
      ix = (int)(sc*d2d.getxx(i))+gx;
      iy = (int)(sc*d2d.getyy(i))+gy;
      ir = (int)(sc*1.0*d2d.getr0(i)+1);
      gOff.setColor(Color.getHSBColor(d2d.getColorOf(i),0.8f,0.8f));
      if (mode==0) {
        gOff.fillOval(ix-ir/2,iy-ir/2, ir, ir);
      } else if (mode==1) {
        gOff.drawOval(ix-ir/2,iy-ir/2, ir, ir);
      }
    }
  }

  private void ovalPlot(int gx, int gy, double sc) {
    int i,ix,iy,ir;
    double tm;

    for (i=0; i<Nmt; i++) {
      ix = (int)(sc*d2d.getxx(i))+gx;
      iy = (int)(sc*d2d.getyy(i))+gy;
      ir = (int)(sc*1.0*d2d.getr0(i)+1);
      gOff.setColor(Color.getHSBColor(d2d.getColorOf(i),0.8f,0.8f));
      gOff.drawOval(ix-ir/2,iy-ir/2, ir, ir);
    }
  }

  private void velocityPlot(int gx, int gy, double sc, double vmag) {
    int i,ix,iy,ir,ix2,iy2;
    double vx;

    for (i=0; i<Nmt; i++) {
      ix = (int)(sc*d2d.getxx(i))+gx;
      iy = (int)(sc*d2d.getyy(i))+gy;
      vx = d2d.getvx(i);
      ix2 = ix+(int)(vmag*viewScale*vx);
      iy2 = iy+(int)(vmag*viewScale*d2d.getvy(i));
      if (vx>0) {
        gOff.setColor(Color.blue);
      } else {
        gOff.setColor(Color.red);
      }
      gOff.drawLine(ix,iy, ix2,iy2);
    }

  }

  private void drawWaku(int gx, int gy, double sc) {
    int ix,iy,gball,idx,idy;

    gball = (int)(3.0*viewScale);
    gOff.setColor(Color.darkGray); 
    ix = (int)(sc*xMax);
    iy = (int)(sc*yMax);
    idx = ix+2*gball;
    idy = iy+2*gball;
    gOff.drawRect(gx-gball,gy-gball,idx,idy);
  }


  // ------------------------------------- I/O methods -----------

  public void setViewDelta(double xDisplacement, double yDisplacement) {
    xShift += (1.0/viewScale/dispScale)*xDisplacement;
    yShift += (1.0/viewScale/dispScale)*yDisplacement;
  }

  public void setScale(double sc) { viewScale = sc; };
}



// ============================= astro object 2D class ===========

class AO2D extends Thread {

  private double t = 0.0;
  private double dt = 20.0;

  private int Nmt = 1000;

  private double gg = 6.673e-11; // m^3kg^-1s-2
  private int incRate = 10;
  private double vx0 = 35.0; 

  private double AU = 1.0e18; // kg
  private double AA = 1.0e5; // m
  private double AD = 1.0e10; // dump

  private double aObject[][] = {
  // 0:mass(AU) 1:r0(AA) 2:dump 3:color
    {  1.0*AU, 0.8*AA, 2.0*AD, 0.85 }, // fixed ball
    {  1.0*AU, 0.8*AA, 1.0*AD, 0.01 }, // 1 A
    {  5.0*AU, 0.8*AA, 2.0*AD, 0.10 }, // 2 B
    { 10.0*AU, 0.8*AA, 1.0*AD, 0.20 }  // 3 C
  };

  private String materialStr[] = {
    "fixed" ,"A" ,"B","C"
  };
  private int NmatKind = 4;

  private int NN = Nmt + 1;
  private int kind[] = new int[NN];
  private double xx[] = new double[NN];
  private double yy[] = new double[NN];
  private double vx[] = new double[NN];
  private double vy[] = new double[NN];
  private double ffx[] = new double[NN];
  private double ffy[] = new double[NN];

  private int resetSW = 0;
  private int startSW = 1;
  private int stepSW = 0;
  private int sleepTime = 1;
  private int stopSleepTime = 100;
  private int count = 0;


  // ------------------------------- class constructor -----------

  AO2D() {
    setInitialCondition();
  }


  // -------------------------------------- thread run -----------

  public void run() {
    while (true) {
      count += 1;
      timeEvolution();
      if (sleepTime>0) {
        try {
          Thread.sleep(sleepTime);
        } catch (InterruptedException e) { }
      }
    }
  }


  // --------------------------- set initial condition -----------

  private void setInitialCondition() {
    int i; 

    t = 0.0;
    count = 0;

    i = 0;
    i = setNNCloud(i,10, 3.0e6, 0.0, vx0, 0.0, 2);
    i = setNNCloud(i,10, 3.0e6, 5.0e6, -vx0, 0.0, 2);
	i = setNNMeteor(i,5, 13.0e6, 2.5e6, 0.0, 0.0, 2.0e-4, 2);
    Nmt = i;

  }

  private int setNNCloud(int ii,int nn, double xPos, double yPos, double vvx0, double vvy0, int mat) {
    int i,ix,iy;
    double a;

    i = ii;

    a = 3.0e5;
    for (ix=0; ix<nn; ix++) {
      for (iy=0; iy<nn; iy++) {
        kind[i] = mat;
        xx[i] = a*ix + xPos;
        yy[i] = a*iy + yPos;
        vx[i] = 1.0*(Math.random()-0.5) + vvx0;
        vy[i] = 1.0*(Math.random()-0.5) + vvy0;
        ffx[i] = 0.0;
        ffy[i] = 0.0;

        i += 1;
      }
    }
    return ( i );
  }

  private int setNNMeteor(int ii,int nn, double xPos, double yPos, double vvx0, double vvy0, double omega, int mat) {
    int i,ir,ith,nth;
    double a,r,th;

    i = ii;

    kind[i] = mat;
    xx[i] = xPos;
    yy[i] = yPos;
    vx[i] = 1.0*(Math.random()-0.5) + vvx0;
    vy[i] = 1.0*(Math.random()-0.5) + vvy0;
    ffx[i] = 0.0;
    ffy[i] = 0.0;
    i += 1;

    a = 1.277*aObject[mat][1];
    for (ir=1; ir<nn; ir++) {
	  r = a*ir;
	  nth = (int)(2.0*Math.PI*r/a);
      for (ith=0; ith<nth; ith++) {
	    th = (2.0*Math.PI*ith)/nth;
        kind[i] = mat;
        xx[i] = r*Math.cos(th) + xPos;
        yy[i] = r*Math.sin(th) + yPos;
        vx[i] = 1.0*(Math.random()-0.5) + r*omega*Math.cos(th+Math.PI/2.0);
        vy[i] = 1.0*(Math.random()-0.5) + r*omega*Math.sin(th+Math.PI/2.0);
        ffx[i] = 0.0;
        ffy[i] = 0.0;

        i += 1;
      }
    }
    return ( i );
  }


  // ---------------------------------- time evolution -----------

  private void timeEvolution(){

    if (resetSW==1) {
      setInitialCondition();
      resetSW = 0;
      startSW = 1;
    }

    if (startSW==1) {
      timeStep();

    } else {
      if (stepSW==1) {
        timeStep();
        stepSW = 0;
      }
      try {
        Thread.sleep(stopSleepTime);
      } catch (InterruptedException e) { }
    }
  }

  private void timeStep() {
    int i;

    for (i=0; i<incRate; i++) {
      timeStep1();
    }
  }

  private void timeStep1() {
    int i; 
    double dtv2, a2, rr;

    t += dt;

    dtv2 = dt/2.0;
    for (i=0; i<Nmt; i++) {
      if (kind[i]>0) {
        a2 = dtv2/aObject[kind[i]][0];
        vx[i] += a2*ffx[i];
        vy[i] += a2*ffy[i];
        xx[i] += vx[i]*dt;
        yy[i] += vy[i]*dt;
      }
    }
    forceCalc();
    for (i=0; i<Nmt; i++) {
      if (kind[i]>0) {
        a2 = dtv2/aObject[kind[i]][0];
        vx[i] += a2*ffx[i];
        vy[i] += a2*ffy[i];
      }
    }

  }

  private void forceCalc() {
    int i,j,k, ki,kj;
    double xij,yij;
    double r2,rij,f,fxij,fyij;

    for(i=0;i<Nmt;i++) {
      ffx[i] = 0.0;
      ffy[i] = 0.0;
    }

    for(i=0;i<Nmt;i++) {
      for(j=i+1;j<Nmt;j++) {
        xij = xx[i]-xx[j]; yij = yy[i]-yy[j];  
        r2 = xij*xij+yij*yij;
        rij = Math.sqrt(r2);
		ki = kind[i]; kj = kind[j];
        f = force(rij,ki,kj);
		if (rij<0.638*(aObject[ki][1]+aObject[kj][1])) {
          f += -0.5*(aObject[ki][2]+aObject[kj][2])*(xij*(vx[i]-vx[j])+yij*(vy[i]-vy[j]));
        }
        fxij = f*xij/rij;
        fyij = f*yij/rij;

        ffx[i] +=  fxij;
        ffy[i] +=  fyij;

        ffx[j] += -fxij;
        ffy[j] += -fyij;
      }
    }

  }

  private double force(double r, int ki, int kj) {
    double r0,gmm,s,s4;

    r0 = 0.5*(aObject[ki][1]+aObject[kj][1]);
    gmm = gg*aObject[ki][0]*aObject[kj][0];
    s = (r0/r); s4 = s*s*s*s;
    return (gmm/r0)*(s/r)*(9*s4*s4-1.0);
  }


  // ------------------------------------- I/O methods -----------

  // control
  public void reset() { resetSW = 1; }
  public void setStartSW(int sw) { startSW = sw; }
  public int getStartSW() { return startSW; }
  public void setStepSW() { stepSW = 1; }
  public int getCount() { return count; }

  public void setVx0(double v) { vx0 = v; }
  public double getVx0() { return vx0; }

  // get data
  public int getNmt() { return Nmt; }
  public double getTime() { return t; }

  public double getxx(int i) { return xx[i]; }
  public double getyy(int i) { return yy[i]; }
  public double getvx(int i) { return vx[i]; }
  public double getvy(int i) { return vy[i]; }
  public double getffx(int i) { return ffx[i]; }
  public double getffy(int i) { return ffy[i]; }
  public double getr0(int i) { return 1.277*aObject[kind[i]][1]; }
  public float getColorOf(int i) { return (float)(aObject[kind[i]][3]); }

}