/* Copyright (C) 2002 J. M. Spivey */

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

/** GUI class for the Lights Out board.
 * 
 * The board responds to mouse clicks by making moves in the game.
 */
public class LightsBoard extends Canvas {
    private int mode = PLAY;
    public static final int PLAY = 1, SETUP = 2;
    private Label messageLabel;
    private int count[][] = new int[5][5];
    private int hint[][] = new int[5][5];
    private boolean sflag = false;
    private int i0, j0;
    
    public LightsBoard(Label messageLabel) {
        this.messageLabel = messageLabel;
        
        setBackground(Color.lightGray);
        
        this.addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                click(e.getX(), e.getY(), true);
            }
            public void mouseReleased(MouseEvent e) {
                click(e.getX(), e.getY(), false);
            }
        });
        
        setRandom(5);
    }
    
    /** Respond to a mouse click */
    private void click(int x, int y, boolean down) {
        message("");
        
        // Compute which square the click is in
        int i = x / u, j = y / u;
    
        // Return if we are not actually inside the square
        if (! (x >= i*u+d && x < (i+1)*u-d 
	       && y >= j*u+d && y < (j+1)*u-d)) return;
        
        if (down) {
            // Record where the mouse button goes down
            i0 = i; j0 = j;
        } else {
            // Perform action if the button comes up in the same square
            if (i == i0 && j == j0) {
                if (mode == PLAY)
                    toggle(i, j, -1);
                else {
                    sflag = false;
                    increment(i, j, 1);
                }
                repaint();
            }
            i0 = j0 = -1;
        }
    }
    
    /** Display a message in the message area */
    private void message(String text) {
        if (messageLabel != null)
            messageLabel.setText(text);
    }
     
    /** Set the mode to PLAY or SETUP */
    public void setMode(int mode) {
        this.mode = mode;
    }
    
    /** Increment a specified square */
    private void increment(int i, int j, int inc) {
        if (i < 0 || i >= 5 || j < 0 || j >= 5) return;
        count[i][j] = (count[i][j] + inc + 3) % 3;
    }
    
    /** Carry out a move in a specified square */
    private void toggle(int i, int j, int inc) {
        increment(i, j, inc);
        increment(i+1, j, inc);
        increment(i, j+1, inc);
        increment(i-1, j, inc);
        increment(i, j-1, inc);
        
        // Update the hint if the solution is being shown
        if (sflag) hint[i][j] = (hint[i][j] - 1 + 3) % 3;
    }
    
    /** Choose a random integer from 1 to n-1 */
    private static int randChoice(int n) {
        return (int) (n * Math.random());
    }
    
    /** Set up n random moves */
    public void setRandom(int n) { 
        setBlank();
        for (int k = 0; k < n; k++)
            toggle(randChoice(5), randChoice(5), 1);
    }

    /** Blank out the board */
    public void setBlank() { 
        for (int i = 0; i < 5; i++)
            for (int j = 0; j < 5; j++)
                count[i][j] = 0;
        
        message("");
        sflag = false;
        repaint();
    }

    /** Compute and display the solution */
    public void showSolution() { 
        int y[] = new int[25];
        
        for (int i = 0; i < 5; i++)
            for (int j = 0; j < 5; j++)
                y[5*i+j] = count[i][j];
        
        int x[] = LightsSolver.solve(y);
        if (x == null) {
            sflag = false;
            message("Impossible");
            return;
        }
        
        for (int i = 0; i < 5; i++)
            for (int j = 0; j < 5; j++)
                hint[i][j] = x[5*i+j];

        sflag = true;
        repaint();
    }
    
    final int u = 60, d = 2, r = 20;
    final Color[] colours = 
	new Color[] { Color.white, Color.green, Color.red };

    public void paint(Graphics g) {
        for (int i = 0; i < 5; i++)
            for (int j = 0; j < 5; j++) {
                g.setColor(colours[count[i][j]]);
                g.fillRoundRect(i*u+d, j*u+d, u-2*d, u-2*d, r, r);
                g.setColor(Color.black);
                g.drawRoundRect(i*u+d, j*u+d, u-2*d, u-2*d, r, r);
                if (sflag && hint[i][j] > 0)
                    g.drawString(Integer.toString(hint[i][j]), 
				 i*u+d+r/2, (j+1)*u-d-r/2);
            }
    }
    
    public void update(Graphics g) { paint(g); }
    
    public Dimension getPreferredSize() {
        return new Dimension(5*u+1, 5*u+1);
    }
}