//Main method

public class pong{
  public static void main(String[] arg){
    Tennis tennisFönster = new Tennis();
    tennisFönster.setVisible(true);
    }
}





//Tennis

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Tennis extends JFrame{
  private Tennisbana bana = new Tennisbana();
  private JLabel poäng;
  private JPanel p;
  private JButton[] knapp  = new JButton[4];
  private String[] knapptext =
  {"Nytt spel" , "Paus" , "Fortsätt" , "Avsluta"};

  public Tennis(){
    super("Tennis");
    poäng = new JLabel(" 0", JLabel.RIGHT);
    poäng.setFont(new Font("Arial", Font.BOLD, 30));
    p = new JPanel();

    Lyssnare minLyssnare = new Lyssnare();

    for (int i=0; i < knapp.length; i++){
      knapp[i] = new JButton();
      knapp[i].setText(knapptext[i]);
      knapp[i].addActionListener(minLyssnare);
      p.add(knapp[i]);
    }
    Container c = getContentPane();
    c.add(poäng, "North");
    c.add(bana, "Center");
    c.add(p, "South");
    addWindowListener(new WindowAdapter(){
      public void windowsClosing(WindowEvent e){
        System.exit(0);
      }
    });
    
    pack();
    bana.start(poäng);
    }

    class Lyssnare implements ActionListener{
      public void actionPerformed(ActionEvent ae){
        bana.requestFocus();
        if (ae.getSource() == knapp[0]){
          bana.nyttSpel();
        }
        else if (ae.getSource() == knapp[2]){
          bana.startaSpel();
        }
        else{
          System.exit(0);
        }
       }
      }
    }




//Tennisbana

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

class Tennisbana extends JPanel implements ActionListener{
  private Timer klocka = new Timer (10, this);
  private JLabel visapoäng;
  private int poäng;
  private int xMax;
  private int yMax;
  private int radie;
  private int x;
  private int y;
  private int vx;
  private int vy;
  private int xSteg;
  private int ySteg;
  private int racket;
  private int racket1;
  private int längdR;
  private int stegR;

  public Tennisbana(){
    setPreferredSize(new Dimension(300, 400));
    setBackground(Color.white);
  }

  public void start (JLabel p){
    visapoäng = p;
    xMax = getSize().width;
    yMax = getSize().height;
    radie = 15;
    längdR = 40;
    stegR= 15;
    nollställ();

    //Första Racket
    addKeyListener (new KeyAdapter(){
      public void keyPressed(KeyEvent e){
        if (e.getKeyCode() == KeyEvent.VK_LEFT){
          racket = Math.max(0, racket-stegR);
        }
        else if (e.getKeyCode() == KeyEvent.VK_RIGHT){
          racket = Math.min(xMax-längdR, racket+stegR);
        }
      }
    });
      // Andra racket
    addKeyListener (new KeyAdapter(){
      public void keyPressed(KeyEvent e){
        if (e.getKeyCode() == KeyEvent.VK_A){
          racket1 = Math.max(0, racket1-stegR);
        }
        else if (e.getKeyCode() == KeyEvent.VK_S){
          racket1 = Math.min(xMax-längdR, racket1+stegR);
        }
      }
    });

    //Storleksändring
    addComponentListener(new ComponentAdapter(){
      public void componentResized(ComponentEvent e){
        xMax = e.getComponent().getSize().width;
        yMax = e.getComponent().getSize().height;
        e.getComponent().requestFocus();
        repaint();
      }
    });
    }
    private void nollställ(){
      poäng = 0;
      visapoäng.setText(" 0");
      xSteg = vx = 3;
      ySteg = vy = 3;
      x = xMax/2;
      y = radie+2;
      racket = xMax/2-längdR/2;
      racket1 = xMax/2-längdR/2;
    }
    
    public void startaSpel(){
      if (poäng < 10){
        klocka.start();
      }
    }
    public void stoppaSpel(){
      klocka.stop();
    }

    public void nyttSpel(){
      stoppaSpel();
      nollställ();
      startaSpel();
    }

    //anropas av timern
    public void actionPerformed(ActionEvent e){
      if ( y+radie >= yMax-4){
        if (x < racket || x > racket+längdR){
          Toolkit.getDefaultToolkit().beep();
          visapoäng.setText(String.valueOf(++poäng));
          if (poäng >= 10){
            stoppaSpel();
          }
        }
        else if (xSteg >0){
          xSteg++;
          vy++;
        }
        else{
          xSteg--;
          vy++;
        }
        ySteg = -vy;
      }
      else if (y-radie <= 0){
        ySteg = vy;
      }

      if (x-radie<=0 || x+radie>=xMax){
        xSteg = -xSteg;
      }
      
      x += xSteg;
      y += ySteg;
      if (y < radie){
        y = radie;
      }
      else if (x > xMax-radie){
        x = xMax-radie;

      }

      repaint();
    
    }

    // Boll och racket
    public void paintComponent(Graphics g) {
      super.paintComponent(g);
      g.setColor(Color.yellow);
      g.fillOval(x-radie, y-radie, 2*radie, 2*radie);
      g.setColor(Color.yellow);
      g.fillRect(racket, yMax-4,längdR, yMax);
      g.setColor(Color.red);
      g.fillRect(racket1, yMax-4,längdR, yMax);
    }
    }