import java.applet.Applet;
import java.awt.*;
import java.lang.*;

public class Wrench extends Applet {

  WrenchPanel mainpanel;
  Button restartButton, componentsButton;
  Panel buttonpanel = new Panel();

  public void init() {
    mainpanel = new WrenchPanel();
    setLayout(new BorderLayout());
    add("Center",mainpanel);
    mainpanel.init();
    add("South",buttonpanel);
    buttonpanel.setLayout(new BorderLayout());
    restartButton = new Button("restart");
    buttonpanel.add("West",restartButton);
    componentsButton = new Button("components");
    buttonpanel.add("East",componentsButton);
  }


  public boolean action(Event e, Object o) {
    if (e.target.equals(restartButton)) mainpanel.init(); 
    if (e.target.equals(componentsButton)) mainpanel.components=!mainpanel.components;
    mainpanel.repaint();
    return true;
  }


  public class WrenchPanel extends Panel {
    int boltradius = 400/20;
    double to_radians = Math.atan(1)/45.0;
    Image back; Graphics bg; Dimension bsize = size();
    boolean components=false;
    int  centerx = 400/2, centery = 400/2;
    int wrench_ang, wrench_len, force_ang, force_len, arrow_head, unit_len;
    int wrench_x, wrench_y, epsilon, force_x,force_y, torque;
    int handlex[]={0,0,0,0};
    int handley[]={0,0,0,0};
    int mode = 0;
    boolean busy = false;
    Color tan_col = new Color(.9f,.8f,.6f);
    public void init() {
      wrench_len=400/4; wrench_ang=0; force_ang=90; force_len=wrench_len/2; arrow_head=force_len/10;
      epsilon=(int) wrench_len/7;
      wrench_x=(int) (centerx+wrench_len*Math.cos(((double)wrench_ang)*to_radians)); 
      wrench_y=(int) (centery+wrench_len*Math.sin(((double)wrench_ang)*to_radians));
      force_x=(int) (wrench_x+force_len*Math.cos(((double)(force_ang+180.))*to_radians));
      force_y=(int) (wrench_y+force_len*Math.sin(((double)(force_ang+180.))*to_radians));
      unit_len=wrench_len;    components=false; reset();
    }
  
    public void reset() {
      repaint();
    }
  
    public boolean mouseDown(Event e, int x, int y) {
      if (Math.abs(x-wrench_x)<=epsilon && Math.abs(y-wrench_y)<=epsilon) {
        wrench_x=x; wrench_y=y; 
        wrench_len=(int) (Math.sqrt((wrench_x-centerx)*(wrench_x-centerx)+(wrench_y-centery)*(wrench_y-centery)));
        wrench_ang=(int) (Math.atan(((double)(wrench_y-centery))/((double)(wrench_x-centerx)))/to_radians);
        if (wrench_x<centerx) wrench_ang = 180+wrench_ang;
        force_x=(int) (wrench_x+force_len*Math.cos(((double)(force_ang+180.))*to_radians));
        force_y=(int) (wrench_y+force_len*Math.sin(((double)(force_ang+180.))*to_radians));
      } else {
        force_x=x; force_y=y;
        force_len=(int) (Math.sqrt((wrench_x-force_x)*(wrench_x-force_x)+(wrench_y-force_y)*(wrench_y-force_y)));
        force_ang=(int) (Math.atan(((double)(wrench_y-force_y))/((double)(wrench_x-force_x)))/to_radians);
        if (wrench_x<force_x) force_ang = 180+force_ang;
      }
      repaint();
      return true;
    }
  
    public boolean mouseDrag(Event e, int x, int y) {
      if (Math.abs(x-wrench_x)<=epsilon && Math.abs(y-wrench_y)<=epsilon) {
        wrench_x=x; wrench_y=y; 
        wrench_len=(int) (Math.sqrt((wrench_x-centerx)*(wrench_x-centerx)+(wrench_y-centery)*(wrench_y-centery)));
        wrench_ang=(int) (Math.atan(((double)(wrench_y-centery))/((double)(wrench_x-centerx)))/to_radians);
        if (wrench_x<centerx) wrench_ang = 180+wrench_ang;
        force_x=(int) (wrench_x+force_len*Math.cos(((double)(force_ang+180.))*to_radians));
        force_y=(int) (wrench_y+force_len*Math.sin(((double)(force_ang+180.))*to_radians));
      } else {
        force_x=x; force_y=y;
        force_len=(int) (Math.sqrt((wrench_x-force_x)*(wrench_x-force_x)+(wrench_y-force_y)*(wrench_y-force_y)));
        force_ang=(int) (Math.atan(((double)(wrench_y-force_y))/((double)(wrench_x-force_x)))/to_radians);
        if (wrench_x<force_x) force_ang = 180+force_ang;
      }
      repaint();
      return true;
    }
  
    public void update(Graphics g) {
      if (!busy) {
        busy = true; 
        paint(g); 
      }
    }
  
    public void paint(Graphics g) {
      if (back == null || bsize.width!=size().width || bsize.height!=size().height) {
        back = createImage(size().width, size().height);
        bsize = size();
        bg = back.getGraphics();
      }
      if (back != null) {
        dopaint(bg);
        g.drawImage(back,0,0,this);
      } else {
        dopaint(g);
      }
      done();
    }
  
    public void dopaint(Graphics g) {
      g.setColor(Color.white);
      g.fillRect(0,0,size().width,size().height);
      int x0=(int) (centerx + boltradius * Math.cos((wrench_ang-45)*to_radians));
      int y0=(int) (centery + boltradius * Math.sin((wrench_ang-45)*to_radians));
      int x1=(int) (centerx + wrench_len * Math.cos(wrench_ang*to_radians));
      int y1=(int) (centery + wrench_len * Math.sin(wrench_ang*to_radians));
      int x2=(int) (centerx + boltradius * Math.cos((wrench_ang+45)*to_radians));
      int y2=(int) (centery + boltradius * Math.sin((wrench_ang+45)*to_radians));
      int x3=(int) (unit_len * Math.cos(wrench_ang*to_radians));
      int y3=(int) (unit_len * Math.sin(wrench_ang*to_radians));
      handlex[0]=x0; handlex[1]=x1; handlex[2]=x2; 
      handley[0]=y0; handley[1]=y1; handley[2]=y2; 
      g.setColor(Color.black);
      g.drawLine(centerx,centery,centerx+x3,centery+y3);  //connector
      g.setColor(tan_col);
      g.fillOval(centerx-boltradius,centery-boltradius,boltradius*2,boltradius*2);
      g.fillPolygon(handlex,handley,3);
      g.setColor(Color.black);
	g.drawRect(0,0,399,399); //boxit
      //make unit ticks:
      x0=(int) (boltradius/2 * Math.cos((wrench_ang+90)*to_radians));
      y0=(int) (boltradius/2 * Math.sin((wrench_ang+90)*to_radians));
      g.drawLine(centerx+x0,centery+y0,centerx-x0,centery-y0);
      g.drawLine(centerx+x0+x3,centery+y0+y3,centerx-x0+x3,centery-y0+y3);
      int tipx=handlex[1]; int tipy=handley[1];
      //draw torque meter next
      torque=Math.abs((centerx-wrench_x)*(wrench_y-force_y)-(centery-wrench_y)*(wrench_x-force_x));
      x0=(int) (centerx + boltradius/4 * Math.cos((wrench_ang+90)*to_radians));
      y0=(int) (centerx + boltradius/4 * Math.sin((wrench_ang+90)*to_radians));
      x3=(int) (centerx + boltradius/4 * Math.cos((wrench_ang-90)*to_radians));
      y3=(int) (centerx + boltradius/4 * Math.sin((wrench_ang-90)*to_radians));
      x1=x0+(int)(((double)torque/10000*unit_len)*Math.cos((wrench_ang)*to_radians));
      y1=y0+(int)(((double)torque/10000*unit_len)*Math.sin((wrench_ang)*to_radians));
      x2=x3+x1-x0;
      y2=y3+y1-y0;
      handlex[0]=x0; handlex[1]=x1; handlex[2]=x2; handlex[3]=x3;  //not really handle, but torque
      handley[0]=y0; handley[1]=y1; handley[2]=y2; handley[3]=y3;
      g.setColor(Color.green);
      g.fillPolygon(handlex,handley,4);
      //force vector next
      x0=(int) (tipx + force_len * Math.cos((force_ang+180)*to_radians));
      y0=(int) (tipy + force_len * Math.sin((force_ang+180)*to_radians));
      x1=(int) (tipx + force_len/7.0 * Math.cos((force_ang+180+20)*to_radians));
      y1=(int) (tipy + force_len/7.0 * Math.sin((force_ang+180+20)*to_radians));
      x2=(int) (tipx + force_len/7.0 * Math.cos((force_ang+180-20)*to_radians));
      y2=(int) (tipy + force_len/7.0 * Math.sin((force_ang+180-20)*to_radians));
      g.setColor(Color.red);
      g.drawLine(tipx,tipy,x0,y0);
      g.drawLine(tipx,tipy,x1,y1);
      g.drawLine(tipx,tipy,x2,y2);
      double magn2=0.0;
      if (components) {
        magn2 = (double) ((tipx-centerx)*(tipx-centerx)+(tipy-centery)*(tipy-centery));
        x1=tipx-(int)(((double)(((tipx-x0)*(tipx-centerx)+(tipy-y0)*(tipy-centery))*(tipx-centerx)))/magn2);
        y1=tipy-(int)(((double)(((tipx-x0)*(tipx-centerx)+(tipy-y0)*(tipy-centery))*(tipy-centery)))/magn2);
        g.drawLine(x0,y0,x1,y1); g.drawLine(tipx,tipy,x1,y1);
      }
      g.setColor(Color.black);
      g.setFont(new Font("Dialog",0,16));
      String s = "Wrench length = " + String.valueOf(((double)(wrench_len))/100);
      g.drawString(s,10,20);
      if (wrench_ang>180) wrench_ang-=360;
      s = "Wrench angle = " + String.valueOf(-wrench_ang) + '\u00B0';
      g.drawString(s,10,40);
      s = "Torque magnitude = " + String.valueOf(((double)(torque/100))/100.);
      g.drawString(s,220,60);
      s = "Force length = " + String.valueOf(((double)(force_len))/100);
      g.drawString(s,220,20);
      if (force_ang>180) force_ang-=360;
      s = "Force angle = " + String.valueOf(-force_ang) + '\u00B0';
      g.drawString(s,220,40);
      if (components)  s = "Components on"; 
      else s = "Components off";
      g.drawString(s,10,60);
    }
  
    private synchronized void done() {
      busy = false;
      notifyAll();
    }
  }
}