// this is the basics of gui stuff
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.*;

public class J07UserControl extends Component implements Runnable, MouseListener, MouseMotionListener
{
  private ArrayList<ColouredPoint> points;
  private JFrame mainFrame;

  // this is called a constructor (look up the term)
  public J07UserControl()
  {
    points = new ArrayList<ColouredPoint>();
    points.add(new ColouredPoint(5,5,new Color((float)Math.random(),(float)Math.random(),(float)Math.random())));
    points.add(new ColouredPoint(20,20,new Color((float)Math.random(),(float)Math.random(),(float)Math.random())));

    mainFrame = new JFrame();

    mainFrame.getContentPane().setLayout(new FlowLayout());
    mainFrame.getContentPane().add(this);
    mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    this.addMouseMotionListener(this);
    this.addMouseListener(this);
    
    mainFrame.pack();
    mainFrame.setVisible(true);
  }

  public static void main(String[] args)
  {
    J07UserControl j07 = new J07UserControl();
    Thread t = new Thread(j07);
    t.start();
  }	
  
  public void run()
  {
    while(mainFrame.isVisible())
    {
      try{
	this.repaint();
	Thread.sleep(50);
      }catch(Exception e){}
    }
  }

  public Dimension getPreferredSize() 
  {
    return new Dimension(400,400);
  }

  public void paint(Graphics g)
  {
    g.setColor(Color.BLACK);
    g.fillRect(0,0,400,400);
    
    for(int i=0;i<points.size()-1;i++)
    {
      g.setColor(points.get(i).myColour);
      g.drawLine(points.get(i).x,points.get(i).y,points.get(i+1).x,points.get(i+1).y);
    }

    g.setColor(Color.RED);
    // note the two types of loop
    for(Point p : points)
    {
      g.drawLine(p.x,p.y,p.x,p.y);
    }
  }

  // mouse interface functions
  public void mouseClicked(MouseEvent e){} //Invoked when the mouse button has been clicked (pressed and released) on a component.
  public void mouseEntered(MouseEvent e){} //Invoked when the mouse enters a component.
  public void mouseExited(MouseEvent e){} //Invoked when the mouse exits a component.

  public void mousePressed(MouseEvent e) //Invoked when a mouse button has been pressed on a component.
  {
    points.add(new ColouredPoint((int)e.getX(),(int)e.getY(),new Color((float)Math.random(),(float)Math.random(),(float)Math.random())));
  }

  public void mouseReleased(MouseEvent e){} // Invoked when a mouse button has been released on a component.

  public void mouseDragged(MouseEvent e){} //Invoked when a mouse button is pressed on a component and then dragged.
  public void mouseMoved(MouseEvent e) //Invoked when the mouse cursor has been moved onto a component but no buttons have been pushed.
  {
    points.get(points.size()-1).x = (int)e.getX();
    points.get(points.size()-1).y = (int)e.getY();
  }

  private class ColouredPoint extends Point
  {
    Color myColour;

    public ColouredPoint(int x,int y,Color c)
    {
      super(x,y);
      myColour = c;
    }
  }
}