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

/**
 * <code>Gomoku</code> - a simple GUI for playing basic Gomoku. See
 * http://en.wikipedia.org/wiki/Gomoku
 *
 * Usage: java Gomoku [<grid size>]
 * @author Todd W. Neller
 * @version 1.0
 */
public class Gomoku extends JFrame
{
    private GomokuState state;
    Stack<GomokuState> stateStack = new Stack<GomokuState>();

    public Gomoku(int size) 
    {
	final int FRAME_WIDTH = 600;
	final int FRAME_HEIGHT = 650;
	setSize(FRAME_WIDTH, FRAME_HEIGHT);
	setTitle("Gomoku");
	setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

	GomokuPanel panel = new GomokuPanel(size);
	add(panel);
	addKeyListener(new UndoListener());
	setVisible(true);
    }

    /**
     * <code>main</code> - Create the JFrame and start a new embedded
     * Gomoku game.  The grid size is 19 by default, but may be
     * supplied in the first command line argument.
     *
     * @param args a <code>String[]</code> value - command line
     * arguments
     */
    public static void main(String[] args) {
	int size = 19;
	if (args.length > 0)
	    size = Integer.parseInt(args[0]);	
	new Gomoku(size);
    }

    class GomokuPanel extends JPanel
    {
	private final int MARGIN = 5;
	private final double PIECE_FRAC = 0.9;

	private int size = 19;
    
	public GomokuPanel() 
	{
	    this(19);
	}

	public GomokuPanel(int size) 
	{
	    super();
	    this.size = size;
	    state = new GomokuState(size);
	    addMouseListener(new GomokuListener());
	}

	class GomokuListener extends MouseAdapter 
	{
	    public void mouseReleased(MouseEvent e) 
	    {
		double panelWidth = getWidth();
		double panelHeight = getHeight();
		double boardWidth = Math.min(panelWidth, panelHeight) - 2 * MARGIN;
		double squareWidth = boardWidth / size;
		double pieceDiameter = PIECE_FRAC * squareWidth;
		double xLeft = (panelWidth - boardWidth) / 2 + MARGIN;
		double yTop = (panelHeight - boardWidth) / 2 + MARGIN;
		int col = (int) Math.round((e.getX() - xLeft) / squareWidth - 0.5);
		int row = (int) Math.round((e.getY() - yTop) / squareWidth - 0.5);
		if (row >= 0 && row < size && col >= 0 && col < size
		    && state.getPiece(row, col) == GomokuState.NONE
		    && state.getWinner() == GomokuState.NONE) {
		    stateStack.push((GomokuState) state.clone());
		    state.playPiece(row, col);
		    repaint();
		    int winner = state.getWinner();
		    if (winner != GomokuState.NONE)
			JOptionPane.showMessageDialog(null,
						      (winner == GomokuState.BLACK) ? "Black wins!" 
						      : "White wins!");
		}
	    }    
	}
    
    
	public void paintComponent(Graphics g) 
	{
	    Graphics2D g2 = (Graphics2D) g;
	    g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
				RenderingHints.VALUE_ANTIALIAS_ON);
	
	    double panelWidth = getWidth();
	    double panelHeight = getHeight();

	    g2.setColor(new Color(0.925f, 0.670f, 0.34f)); // light wood
	    g2.fill(new Rectangle2D.Double(0, 0, panelWidth, panelHeight));

	
	    double boardWidth = Math.min(panelWidth, panelHeight) - 2 * MARGIN;
	    double squareWidth = boardWidth / size;
	    double gridWidth = (size - 1) * squareWidth;
	    double pieceDiameter = PIECE_FRAC * squareWidth;
	    boardWidth -= pieceDiameter;
	    double xLeft = (panelWidth - boardWidth) / 2 + MARGIN;
	    double yTop = (panelHeight - boardWidth) / 2 + MARGIN;

	    g2.setColor(Color.BLACK);
	    for (int i = 0; i < size; i++) {
		double offset = i * squareWidth;
		g2.draw(new Line2D.Double(xLeft, yTop + offset, 
					  xLeft + gridWidth, yTop + offset));
		g2.draw(new Line2D.Double(xLeft + offset, yTop,
					  xLeft + offset, yTop + gridWidth));
	    }
	
	    for (int row = 0; row < size; row++) 
		for (int col = 0; col < size; col++) {
		    int piece = state.getPiece(row, col);
		    if (piece != GomokuState.NONE) {
			Color c = (piece == GomokuState.BLACK) ? Color.BLACK : Color.WHITE;
			g2.setColor(c);
			double xCenter = xLeft + col * squareWidth;
			double yCenter = yTop + row * squareWidth;
			Ellipse2D.Double circle
			    = new Ellipse2D.Double(xCenter - pieceDiameter / 2,
						   yCenter - pieceDiameter / 2,
						   pieceDiameter,
						   pieceDiameter);
			g2.fill(circle);
			g2.setColor(Color.black);
			g2.draw(circle);
		    }
		}
	}
    }
    
    class UndoListener extends KeyAdapter
    {
	public void keyTyped(KeyEvent e) 
	{
	    if (e.getKeyChar() == 'u') {
		if (stateStack.isEmpty())
		    JOptionPane.showMessageDialog(null, "Cannot undo.");
		else {
		    state = stateStack.pop();
		    repaint();
		}
	    }
	}
    }
}