import java.awt.*;
import java.awt.event.*;
import PositionPanel;

public class JavaEyes extends Frame implements Runnable{

    Panel my_p;
    Button quit_button;
    Point mouse_pos;
    
    /* This next line declares the variable my_thread of type Thread.
     * You will comment this line out during your lab to
     * Observe the compiler error you get.
     * Please do not comment it out until the lab asks you to.
     */
    Thread my_thread;

    Image offscreen_image;

    public JavaEyes() {

	/* Note: This is the constructor for the JavaEyes window.
	 *       You should NOT look into here for changes
	 */

	super("JavaEyes");
    
	my_p = new Panel();
	this.add("Center",my_p);

	// record the latest mouse position
        mouse_pos = new Point();
	my_p.addMouseMotionListener(new MouseMotionAdapter() {
	    public void mouseMoved(MouseEvent e) {
		JavaEyes.this.setMousePos(e.getX(),e.getY());
	    }
	});

	// set up a Quit button
	quit_button = new Button("Quit");
	this.add("North",quit_button);
	quit_button.addActionListener(new ActionListener() {
	    public void actionPerformed(ActionEvent e) {
		JavaEyes.this.dispose();
		System.exit(0);
	    }
	});

	// standard window stuff 
	this.pack();
	this.show();
	this.setSize(400,300);
	this.setLocation(1,1);

	// handle Window Closing events
        this.addWindowListener(new WindowAdapter() {
	    public void WindowClosed(WindowEvent e) {
	        JavaEyes.this.dispose();
		System.exit(0);
	    }
	});
	    
	my_thread= new Thread(this);
	my_thread.start();
    }

    public static void main(String argv[]) {
    
	new JavaEyes();
    
    }

    public synchronized void setMousePos(int x, int y) {
	mouse_pos.setLocation(x, y);
    }

    public synchronized Point getMousePos() {
	return mouse_pos.getLocation();
    }
    
    public void paintEyes(Graphics g) {
    
	/*
	 * Note: a lot of this is grungy math to position the eyes.
	 *        there are some interesting things that you can change, though.
	 */

	/* This paints onto a graphic that is only 200 by 80 pixels, but it is using the coordinates
	 * of the mouse in a much larger panel. Thus, we are going to be painting using coordinates
	 * within the (200,80) rectangle, but calculating the position of the pupils using greater
	 * coordinates
	 */

	// it's a 200 by 80 rectangle
	int g_width= 200;
	int g_height= 80;
	
	// Get the dimensions of the central Panel
	Dimension d= my_p.getSize();
	int w= d.width;
	int h= d.height;

	// The offset of the (200,80) rectangle in the Panel
	int x_offset= (w-g_width)/2;
	int y_offset= h-g_height;
	
	// Get the mouse position
	Point p= getMousePos();

	// Set the color to white, and draw the background rectangle for the eyes
	// POSSIBLE MODIFICATION: You can change the color of the background rectangle.
	g.setColor(Color.white);
	g.fillRect(0,0,g_width,g_height);

	// Set the color to black, to draw the eyes.
	// POSSIBLE MODIFICATION: You can change the color of the eyes.
	g.setColor(Color.black);

	// draw the outline of the eyes
	g.drawOval(35,20,50,50);
	g.drawOval(105,20,50,50);


	// the centers of the eyes, using the small rectangle coordinates
	int eye1_x= 55 ;
	int eye1_y= 40;
	int eye2_x= 125;
	int eye2_y= 40;

	// the centers of the eyes, with offsets, in the panel coordinates
	int eye1_offset_x= eye1_x + x_offset;
	int eye1_offset_y= eye1_y + y_offset;
	int eye2_offset_x= eye2_x + x_offset;
	int eye2_offset_y= eye2_y + y_offset;
	
	int x1,y1,x2,y2,dist;

	dist= (int)Math.sqrt((p.x-eye1_offset_x)*(p.x-eye1_offset_x)+(p.y-eye1_offset_y)*(p.y-eye1_offset_y));
	x1=(int) ((p.x-eye1_offset_x) * 16 / dist);
	y1=(int) ((p.y-eye1_offset_y) * 16 / dist);

	dist= (int)Math.sqrt((p.x-eye2_offset_x)*(p.x-eye2_offset_x)+(p.y-eye2_offset_y)*(p.y-eye2_offset_y));
	x2=(int) ((p.x-eye2_offset_x) * 16/dist);
	y2=(int) ((p.y-eye2_offset_y) * 16/dist);


	// draw the eyes!! 
	g.fillOval(eye1_x+x1,eye1_y+y1,12,12);
	g.fillOval(eye2_x+x2,eye2_y+y2,12,12);

    }

    public void updateEyes() {

	/* Note: This implements a graphical technique called Double Buffering.
	 *       You need not worry about what this does, although it will be
	 *       explained later on in the course
	 */
	
	// If no offscreen image has yet been created, create one.
	if (offscreen_image==null) {
	    offscreen_image= createImage(200,80);
	}

	paintEyes(offscreen_image.getGraphics());

	// paint the offscreen image onto the Panel
	Dimension d= my_p.getSize();
	my_p.getGraphics().drawImage(offscreen_image,d.width/2-100,d.height-80,this);
	repaint();
    }

    public void run() {

	/* Note: DON'T try to modify this.
	 */

	while(true) {
	    updateEyes();
	    try {
		Thread.sleep(100);
	    } catch (Throwable e) {
	    }
	    //Point p= getMousePos();
	}
    }
}