/**
 * A tic-tac-toe game on the 3x3 board
 */
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class TicTacToe extends JFrame implements ActionListener
{
    
    private static final int BOARD_SIZE = 3;
    private String[][] board;
        
    private JButton squares[][];     
    private JButton newGameButton;
    private JLabel score;
    private int emptySquaresLeft;
    private String whoseTurn;
    

    /** 
     * Construct a TicTacToe game with a nice user interface
     */ 
    public TicTacToe()
    {       
        setUpInterface();
  
        board = new String[BOARD_SIZE][BOARD_SIZE];
        initializeBoard();
    }
    
    /*
     * Helper method to set up the user interface
     */
    private void setUpInterface()
    {
        // A large font for the buttons
        Font font = new Font(null, Font.BOLD, 32);

        setTitle("TicTacToe");
        setSize(400,400);
        
        // Get the content pane - 
        // all window components go there
        Container  contentPane = getContentPane();
        
        //Set the layout manager and background color
        contentPane.setLayout(new BorderLayout());
        contentPane.setBackground(Color.CYAN);
        
        // Create the button New Game and register it 
        // with the action listener 
        newGameButton = new JButton("New Game");
        newGameButton.addActionListener(this);
        
        JPanel topPanel = new JPanel();
        topPanel.add(newGameButton);
        
        contentPane.add(topPanel,"North");
        
        JPanel centerPanel = new JPanel();
        centerPanel.setLayout(new GridLayout(BOARD_SIZE,BOARD_SIZE));
        contentPane.add(centerPanel,"Center");
        
        score = new JLabel("X's turn", JLabel.CENTER);
        contentPane.add(score,"South");
        
        // create an array to hold references to 9 buttons
        squares = new JButton[BOARD_SIZE][BOARD_SIZE];   
        
        // Instantiate the buttons, store the references 
        // to them in the 2d array called squares,
        // register them with the listener, and add to panel 
        for (int i=0; i < BOARD_SIZE; i++)
        {
            for (int j=0; j < BOARD_SIZE; j++)
            {
                squares[i][j] = new JButton();
                squares[i][j].addActionListener(this);
                squares[i][j].setFont(font);
                centerPanel.add(squares[i][j]);
            }
        }
    }
    
    /*
     * Helper method to initialize the board for a new game
     */
    private void initializeBoard()
    {       
        for (int i=0; i < BOARD_SIZE; i++)
        {
            for (int j=0; j < BOARD_SIZE; j++)
            {
                board[i][j] = "";
                squares[i][j].setBackground(Color.YELLOW);
                squares[i][j].setEnabled(true);
                squares[i][j].setText("");
            }
        }    
        
        emptySquaresLeft = BOARD_SIZE*BOARD_SIZE;
        whoseTurn = "X";
        score.setText(whoseTurn + "'s turn");
        newGameButton.setEnabled(false);
    }
    
    /**
     * This method will process all action events
     * @param ActionEvent object
     */
    public void actionPerformed(ActionEvent e)
    {
        
        JButton theButton = (JButton) e.getSource();
        String winner = "";
        
        // Is this a New Game button?
        if (theButton == newGameButton)
        {
            initializeBoard();
            return;  // exit the method here
        }
       
        // Which square was clicked?
        for (int i=0; i < BOARD_SIZE; i++ )
        {
            for (int j=0; j < BOARD_SIZE; j++)
            {               
                if (theButton == squares[i][j])
                {                    
                    squares[i][j].setText(whoseTurn);
                    squares[i][j].setEnabled(false);
                    emptySquaresLeft--;
                    
                    board[i][j] = whoseTurn;
                    winner = lookForWinner();  
                    
                    if (winner.equals(""))
                    {
                        if (emptySquaresLeft == 0)
                        {
                            endTheGame();
                            score.setText("It's a tie!");
                        }
                        else
                        {
                            toggleTurn();
                        }
                    }
                    else
                    {
                        endTheGame();
                        score.setText(winner + " won!");
                    } 
                    return;
                }
            }
        }   
    }
    
    /*
     * Helper method to switch to the other player
     */
    private void toggleTurn()
    {
        if (whoseTurn.equals("X"))
        {
            whoseTurn = "O";
        }
        else
        {
            whoseTurn = "X";
        }
        score.setText(whoseTurn + "'s turn");
    }
    
    /*
     *  Helper method called after every move to see 
     *  if we have a winner. 
     *  It checks every row, column and diagonal to find 
     *  squares with the same label (other than blank)
     *  @return "X", "O", or "" (for no winner)     
     */
    private String lookForWinner()
    {

        /*********      TO DO      *********/
        
        // stub
        return "";
    }
    

    /*
     * Helper method to disable squares and enable New Game button
     */
    private void endTheGame()
    {
        for (int i=0; i<BOARD_SIZE; i++)
        {
            for (int j=0; j<BOARD_SIZE; j++)
            {
                squares[i][j].setEnabled(false);
            }
        }
        newGameButton.setEnabled(true);
    }
 
    
    public static void main(String[] args)
    {
        TicTacToe game = new TicTacToe();
        game.setVisible(true);
    }
}