// Rocket_flight.java
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;

public class Rocket_flight extends Frame
{
  double Ft[] = new double[20]; // thrust force in newtons
  double s = 0.0;               // altitude in meters
  double v = 0.0;               // velocity in meters per second
  double a = 0.0;               // acceleration in meters per second squared
  double m = 0.0;               // mass in kilograms
  double m_body = 0.0340;       // mass of body in kilograms
  double m_engine = 0.0242;     // initial engine mass
  double t = 0.0;               // time in seconds
  double dt = 0.1;              // delta time step in seconds
  double Fd = 0.0;              // drag force in newtons
  double Fg = 0.0;              // fource due to gravity in newtons
  double F = 0.0;               // total force in newtons
  double gr = 9.80665;          // acceleration due to gravity
  double Rho = 1.293;           // kilograms per cubic meter
  double Cd_body = 0.45;        // coefficient of drag for nose cone and body
  double A_body = 0.000506;     // cross section area of body in square meter
  double Cd_fins = 0.01;        // coefficient of drag for fins
  double A_fins = 0.00496;      // surface area of fins in square meters
  double sum = 0.0;             // sum of thrust for checking
  int step = 0;                 // step number for thrust, max=19
  int width = 800;
  int height = 700;
  int x, y, b;
  ImageIcon imageRocket = new ImageIcon(" "); // set below 
  ImageIcon imageThrust = new ImageIcon(" "); // set below 
  Dimension dimActive;

  public Rocket_flight()
  {  
    System.out.println("Rocket_flight.java launching"); 
    setTitle("Rocket_flight");
    setSize(width,height);
    setBackground(Color.white);
    setForeground(Color.black);
    addWindowListener(new WindowAdapter()
    {
      public void windowClosing(WindowEvent e)
      {
        System.exit(0);
      }
    });
    setVisible(true);
    this.addMouseListener (new mousePressHandler());

    Ft[0] = 0.0; // actually unused, initial condition
    Ft[1] = 6.0;
    Ft[2] = 14.1;
    Ft[3] = 5.01;
    for(int i=4; i<19; i++) Ft[i] = 4.326;
    Ft[19] = 0.0;
    imageRocket = new ImageIcon("rocket.jpg");
    dimActive = new Dimension(imageRocket.getIconWidth(),
			      imageRocket.getIconHeight());
    System.out.println("rocket.jpg dimension = "+dimActive);
    imageThrust = new ImageIcon("thrust.jpg");
    dimActive = new Dimension(imageThrust.getIconWidth(),
			      imageThrust.getIconHeight());
    System.out.println("thrust.jpg dimension = "+dimActive);

    requestFocus();
    repaint();
  }

  double drag(double Cd, double Rho, double Area, double velocity)
  {
    return Cd*Rho*Area*velocity*velocity/2.0;
  }

  class mousePressHandler extends MouseAdapter
  {
    public void mousePressed (MouseEvent e)
    {
      x = e.getX();
      y = e.getY();
      b = e.getButton();
      System.exit(0);

      requestFocus();
      repaint();
    }
  }

  public void paint(Graphics g)
  {
    int ti=0;

    // draw a boundary
    setForeground(Color.black);
    g.drawRect(20, 40, width-40, height-60);
    g.drawString("Estes Alpha III", 200, 70);
    g.drawString("meter", 30, 50);
    g.drawString("time seconds", 100, 50);
    // <img src="images/c6thrust.jpg">
    imageThrust.paintIcon( this, g, 120, 380);
    // <img src="images/rocket.jpg"
    imageRocket.paintIcon( this, g, width-180, 50);
    g.drawString("Length      12.25  inches =  0.311 meters", 150, 90);
    g.drawString("Diameter     0.95  inches =  0.0241 meters", 150, 110);
    g.drawString("Body area    0.506E-3  square meters cross section", 150, 130);
    g.drawString("Cd of body   0.45  dimensionless", 150, 150);
    g.drawString("Fins area    0.00496  square meters total for 3 fins", 150, 170);
    g.drawString("Cd of fins   0.01  dimensionless", 150, 190);
    g.drawString("Weight/mass  0.0340 kilogram without engine", 150, 210);
    g.drawString("Engine       0.0242 kilogram initial engine mass", 150, 230);
    g.drawString("Engine       0.0094 kilogram final engine mass", 150, 250);
    g.drawString("Fd = Cd*Rho*A*v^2 /2  body and fins", 150, 270);
    g.drawString("Fg = m*g", 150, 290);
    g.drawString("F = Ft - (Fd body + Fd fins + Fg)", 150, 310);
    g.drawString("a = F/m", 150, 330);
    g.drawString("v = v + a*dt", 150, 350);
    g.drawString("s = s + v*dt", 150, 370);
    g.drawString("000", 30, height-30);
    g.drawString("100", 30, height-200);
    g.drawString("200", 30, height-370);
    g.drawString("300", 30, height-540);

    step = 0; // incremented for first time
    t = 0.0;
    s = 0.0;
    v = 0.0;
    m = m_body + m_engine;
    while(v>=0.0)
    {
      // System.out.println("t="+t+", s="+s+", v="+v+", a="+a+
      //                    ", F="+F+", m="+m);
      t = t + dt;
      ti = (int)(t*10.0+0.0000001);
      t = (double)ti/10.0; // remove trailing
      if(step<19) step++;
      Fg = m * gr;
      m = m - Ft[step]*0.0001648;
      Fd = drag(Cd_body, Rho, A_body, v) +
           drag(Cd_fins, Rho, A_fins, v);
      F = Ft[step] - Fg - Fd;
      a = F/m;
      v = v + a * dt;
      s = s + v * dt;
      if(v>=0.0)
      {
        setForeground(Color.red);
        // g.fillOval(70, height-(int)(1.68*s)-25 , 6, 6);
        g.drawLine(70, height-(int)(1.68*s)-25 ,80, height-(int)(1.68*s)-25);
        g.drawString(" "+t+" ", 90, height-(int)(1.68*s)-25);
      }
      try
      {
	// physicsComputation();
        Thread.sleep(100); // 100 millisec  0.1 sec
      }
      catch(InterruptedException e)
      {
	System.out.println("interruptedException"+e);
      }
    }
    setForeground(Color.black);
    g.drawString(" "+t+" ", 200, 50);
    g.drawString("height "+s+" ", 300, 50);
  } // end paint

  
  public static void main (String[] args)
  {
    new Rocket_flight();
  }
} // end Rocket_flight.java