/**
 * File: ClickLife.java
 * Author: Brian Borowski
 * Date created: May 1999
 * Date last modified: November 7, 2008
 */
import java.applet.AudioClip;
import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JComponent;
import java.util.Random;

public class ClickLife extends JApplet implements MouseListener {
    private int width, height, distanceSqr;
    private JButton lifeButton;
    private Random generator;
    private Board board;

    public void init() {
        generator = new Random();
        final AudioClip audioClip =
            getAudioClip(getCodeBase(), "Audio/Surprise.au");
        lifeButton = new JButton("Click Me!");
        lifeButton.addMouseListener(this);
        lifeButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                audioClip.play();
            }
        });
        Board board = new Board(getColor(getParameter("border")),
                                getColor(getParameter("background")));
        board.setLayout(new FlowLayout());
        board.add(lifeButton);
        Container contentPane = getContentPane();
        contentPane.add(board);
        width = getSize().width;
        height = getSize().height;
        board.setSize(width, height);
        // In the next iteration, we want to move the button far enough away
        // from its current position.  1/2 the average of the width and
        // height of the JApplet seems to work well.
        int distanceAway = ((width + height) / 2) / 2;
        distanceSqr = distanceAway * distanceAway;
        setVisible(true);
        // Allow users to press the button with keystrokes, since they may
        // actually want to hear the audio clip.
        lifeButton.requestFocusInWindow();
    }

    public void mouseEntered(MouseEvent me) {
        int x, y, prevX, prevY, buttonWidth, buttonHeight;
        buttonWidth = lifeButton.getSize().width;
        buttonHeight = lifeButton.getSize().height;
        prevX = lifeButton.getX();
        prevY = lifeButton.getY();
        if (generator.nextDouble() < 0.5) {
            // Generate a random x half of the time.
            x = generator.nextInt(width - 2 - buttonWidth) + 1;
            int diff = x - prevX;
            // Solve for y.
            y = ((int)Math.sqrt(distanceSqr - diff * diff) + prevY) %
                (height - 2 - buttonHeight);
        } else {
            // Generate a random y the other half of the time.
            y = generator.nextInt(height - 2 - buttonHeight) + 1;
            int diff = y - prevY;
            // Solve for x.
            x = ((int)Math.sqrt(distanceSqr - diff * diff) + prevX) %
                (width - 2 - buttonWidth);
        }
        lifeButton.setLocation(x, y);
    }

    public void mouseExited(MouseEvent me) { }

    public void mousePressed(MouseEvent me) { }

    public void mouseClicked(MouseEvent me) { }

    public void mouseReleased(MouseEvent me) { }

    private Color getColor(String background) {
        if ((background == null) || (background.length() != 7) ||
            (background.charAt(0) != '#')) {
            return Color.white;
        } else {
            String hexcolor, red, green, blue;
            hexcolor = background.substring(1, background.length());
            red = hexcolor.substring(0, 2);
            green = hexcolor.substring(2, 4);
            blue = hexcolor.substring(4, 6);
            try {
                return new Color(Integer.parseInt(red, 16),
                                 Integer.parseInt(green, 16),
                                 Integer.parseInt(blue, 16));
            } catch (NumberFormatException nfe) {
                return Color.white;
            }
        }
    }
}

class Board extends JComponent {
    private Color borderColor, backgroundColor;

    public Board(Color borderColor, Color backgroundColor) {
        this.borderColor = borderColor;
        this.backgroundColor = backgroundColor;
        setDoubleBuffered(true);
    }

    public void paintComponent(Graphics g) {
        int canvasWidth = getSize().width,
            canvasHeight = getSize().height;
        g.setColor(backgroundColor);
        g.fillRect(0, 0, canvasWidth, canvasHeight);
        g.setColor(borderColor);
        g.drawRect(0, 0, canvasWidth - 1, canvasHeight - 1);
    }
}