//Tictactoe applet
//3rd assignment.  added computer player
import javax.swing.*;    
import java.awt.*;
import java.awt.event.*;
import java.util.StringTokenizer;

public class Tictactoe5 extends JApplet {

    final static int maxboard=6;
    final static int N=3;      //kludge  FIX
    private CustomPanel drawPanel;
    private JTextField owinsField, xwinsField, tiesField;
    private JTextField playField;
    private Timer gameOverTimer;
	
    char[][] B = new char [maxboard][maxboard];
    int moves;
    int numPlayers;
    char who;
    boolean gameOver;

    
    public void init() {
	JLabel oLabel, xLabel, tieLabel;
	JLabel playLabel;
	JPanel statusPanel;
	JPanel playPanel;
	JMenuBar bar;
	JMenu gameMenu;
	JMenuItem gameItem;
	JMenuItem matchItem;
	JMenuItem exitItem;

	Container container = getContentPane();
	container.setLayout( new BorderLayout(3,3) );


	playPanel = new JPanel();
	playPanel.setLayout( new FlowLayout() );

	playLabel = new JLabel( "Enter row column" );
	playPanel.add( playLabel );

	playField = new JTextField( "", 6 );
	playField.addActionListener( new PlayHandler() );
	playPanel.add( playField );
	container.add( playPanel, BorderLayout.NORTH );


	statusPanel = new JPanel();
	statusPanel.setLayout( new GridLayout( 1, 9 ) );

	oLabel = new JLabel( "O wins" );
	statusPanel.add( oLabel );

	owinsField = new JTextField( "0" );
	owinsField.setEditable( false );
	statusPanel.add( owinsField );

	xLabel = new JLabel( "X wins" );
	statusPanel.add( xLabel );

	xwinsField = new JTextField( "0" );
	xwinsField.setEditable( false );
	statusPanel.add( xwinsField );

	tieLabel = new JLabel( "Ties" );
	statusPanel.add( tieLabel );

	tiesField = new JTextField( "0" );
	tiesField.setEditable( false );
	statusPanel.add( tiesField );

	container.add( statusPanel, BorderLayout.SOUTH );


	drawPanel = new CustomPanel();
	container.add( drawPanel, BorderLayout.CENTER );

	bar = new JMenuBar();
	setJMenuBar( bar );

	gameMenu = new JMenu( "Game" );
	gameMenu.setMnemonic( 'G' );
	bar.add( gameMenu );

	gameItem = new JMenuItem( "New game" );
	gameItem.setMnemonic( 'n' );
	gameMenu.add( gameItem );
	gameItem.addActionListener(
	   new ActionListener() {
	       public void actionPerformed( ActionEvent event ) {
		   newGame();
	       }
	   }
	);

	matchItem = new JMenuItem( "New match" );
	matchItem.setMnemonic( 'm' );
	gameMenu.add( matchItem );
	matchItem.addActionListener(
	   new ActionListener() {
	       public void actionPerformed( ActionEvent event ) {
		   xwinsField.setText( "0" );
		   owinsField.setText( "0" );
		   tiesField.setText( "0" );
		   newMatch();
	       }
	   }
	);

	exitItem = new JMenuItem( "Exit" );
	exitItem.setMnemonic( 'x' );
	gameMenu.add( exitItem );
	exitItem.addActionListener(
	   new ActionListener() {
	       public void actionPerformed( ActionEvent event ) {
		   stop();
	       }
	   }
	);

	gameOverTimer = new Timer( 1000, new ActionListener() {
		public void actionPerformed( ActionEvent event ) {
		    if ( gameOver ) {
			gameOver = false;
			newGame();
		    }
		}
	    }
				   );


    }


    public void start() {
	newMatch();

    }


    void newMatch() {
	xwinsField.setText( "0" );
	owinsField.setText( "0" );
	tiesField.setText( "0" );

	String s = JOptionPane.showInputDialog( "2 people or 1? 2 or [1])" );
	if ( s.equals( "2" ) ) {
	    numPlayers = 2;
	    who = 'o';
	}
	else {
	    numPlayers = 1;
	    String first = JOptionPane.showInputDialog( "You are Oh.\n You play first? ([y]es or no)" );
	    if ( first.equals("") || first.charAt(0)=='y' )
		who = 'o';
	    else
		who = 'x';

	}

	newGame();
    }


    private void newGame() {
	for (int i=0; i<N; i++)       //clear board
	    for (int j=0; j<N; j++)
		B[i][j] = ' ';

	moves = 0;

	gameOver = false;

	drawPanel.draw();

	if ( numPlayers==2 || (numPlayers==1 && who=='o') )
	    playField.requestFocusInWindow();  
	else
	    computerMakesMove();   //numPlayers==1 and who==x (computer)

	gameOverTimer.start();
    }


    //user inputs pair of numbers into play textfield
    class PlayHandler implements ActionListener {
	public void actionPerformed (ActionEvent event) {
	    
	    int i,j;
	    boolean err=false;
	    char inchar;
	    String row_col;
	    
	    row_col = playField.getText();
	    StringTokenizer two_ints = new StringTokenizer(row_col);
	    try {
		if ( ! two_ints.hasMoreTokens() )
		    i = j = 0;
		else {
		    i =  Integer.parseInt(two_ints.nextToken());
		    if ( ! two_ints.hasMoreTokens() )
			j = 0;
		    else
			j =  Integer.parseInt(two_ints.nextToken());
		}
	    }
	    catch (NumberFormatException e) {
		i = j =0;    //set to 0, get the Invalid JOptionPane
	    }
	    
	    if ( i<1 || i>N || j<1 || j>N ) {
		err = true;
		JOptionPane.showMessageDialog(Tictactoe5.this,"Invalid row column.  Re-enter.",
					      "Invalid input", JOptionPane.PLAIN_MESSAGE);	    
		playField.setText( "" );
	    }
	    else if ( B[i-1][j-1] != ' ' ) {
		err = true;
		JOptionPane.showMessageDialog(Tictactoe5.this,"Already played!  Re-enter.",
					      "Invalid input", JOptionPane.PLAIN_MESSAGE);	    
		playField.setText( "" );
	    }

	    else {	
		moves++;

		playField.setText( "" );
		
		B[i-1][j-1] = who;
		
		drawPanel.draw();
		
		gameOver = end_check();
		//this if needs to be atomic with the end_check...
		if (who == 'x') 
		    who = 'o';
		else 
		    who = 'x';
		if ( !gameOver && numPlayers==1 )
		    computerMakesMove();
		
	    }
	}
    }


    void computerMakesMove() {
	int row, col;
	char otherWho;

	playField.setEditable( false );   //for really slow computer ;)

	otherWho = who=='x' ? 'o' : 'x';

	//"strategy":
	//1. win if can
	int[] winning = new int[2];   //row and col of winning move
	if ( canWin( winning, who ) ) {
	    row = winning[0];
	    col = winning[1];
	}
	//2. don't lose
	else if ( canWin( winning, otherWho ) ) { //if human can win, take his position
	    row = winning[0];
	    col = winning[1];
	}

	//3. random unplayed one
	else 
	    do {
		row = (int)(Math.random() * 3);
		col = (int)(Math.random() * 3);
	    } while ( B[row][col] != ' ');


	moves++;
	
	B[row][col] = who;
	
	drawPanel.draw();
	
	gameOver = end_check();
	//this if needs to be atomic with the end_check...
	if (who == 'x') 
	    who = 'o';
	else 
	    who = 'x';

	playField.setEditable( true );
	playField.requestFocusInWindow();  
    }



    public boolean end_check() {

	String result;
    
	if (check_winner()) {
	    if (who == 'x') {
		result = "Winner is X";
		int xwins = Integer.parseInt(xwinsField.getText());
		xwins++;
		xwinsField.setText("" + xwins);
	    }
	    else {
		result = "Winner is O";
		int owins = Integer.parseInt(owinsField.getText());
		owins++;
		owinsField.setText("" + owins);
	    }

	    JOptionPane.showMessageDialog(this,result,"Game decision",
					  JOptionPane.PLAIN_MESSAGE);
	    return true; 
	}
	else  if (moves == N*N) {
	    result = "Draw";
	    JOptionPane.showMessageDialog(this,result,"Game decision",
					  JOptionPane.PLAIN_MESSAGE);
	    int ties = Integer.parseInt(tiesField.getText());
	    ties++;
	    tiesField.setText("" + ties);
	    return true; 
	}

	return false;
    }


    public boolean check_winner () {
	
	int inseq;
	
	//each row
	for (int i=0; i<N; i++) {
	    inseq = 0;
	    for (int j=0; j<N; j++)
		if (B[i][j] == who)
		    inseq++;
	    if (inseq == N)
		return true;
	}
	//each column
	for (int i=0; i<N; i++) {
	    inseq = 0;
	    for (int j=0; j<N; j++)
		if (B[j][i] == who)
		    inseq++;
	    if (inseq == N)
		return true;
	}
	//main diagonal
	inseq = 0;
	for (int i=0; i<N; i++) {
	    if (B[i][i] == who)
		inseq++;
	}
	if (inseq == N)
	    return true;
	//other diagonal
	inseq = 0;
	for (int i=0; i<N; i++) {
	    if (B[i][N-i-1] == who)
		inseq++;
	}
	if (inseq == N)
	    return true;
	
	return false;
    }


    //true if arg has 2 on any of the 8 rows, columns, diagonals and the other is free
    //total of 24 possiblities.    just go with the brute force enumeration? NO
    //use the loops as below
    public boolean canWin( int[] winning, char w ) {
	
	int wCount;
	int free;
	int freeCol=-1;

	//3 rows
	for (int i=0; i<3; i++) {
	    wCount = 0;
	    free = 0;
	    for (int j=0; j<3; j++)
	       	if ( B[i][j] == w )
		    wCount++;
		else if  ( B[i][j] == ' ' ) {
		    freeCol = j;
		    free++;
		}
	    if ( wCount==2 && free==1 ) {
		winning[0] = i;
		winning[1] = freeCol;
		return true;
	    }
	}

	//3 columns.  same code as above, swapping i rows and j cols
	for (int i=0; i<3; i++) {  //these are the columns
	    wCount = 0;
	    free = 0;
	    for (int j=0; j<3; j++)
	       	if ( B[j][i] == w )
		    wCount++;
		else if  ( B[j][i] == ' ' ) {
		    freeCol = j;  //should be named freeRow...
		    free++;
		}
	    if ( wCount==2 && free==1 ) {
		winning[0] = freeCol;
		winning[1] = i;
		return true;
	    }
	}

	//main diagonal
	wCount = 0;
	free = 0;
	for (int i=0; i<3; i++) {
	    if ( B[i][i] == w )
		wCount++;
	    else if  ( B[i][i] == ' ' ) {
		freeCol = i;
		free++;
	    }
	}
	if ( wCount==2 && free==1 ) {
	    winning[0] = freeCol;
	    winning[1] = freeCol;
	    return true;
	}

	//other diagonal: i:012  j:210 (2-i)
	wCount = 0;
	free = 0;
	for (int i=0; i<3; i++)
	    if ( B[i][2-i] == w )
		wCount++;
	    else if  ( B[i][2-i] == ' ' ) {
		freeCol = i;    //should be named free spot I
		free++;
	    }
	if ( wCount==2 && free==1 ) {
	    winning[0] = freeCol;
	    winning[1] = 2-freeCol;
	    return true;
	}

	//no possible winning move
	return false;


    }


// A customized JPanel nested class.

class CustomPanel extends JPanel {


    public void paintComponent( Graphics g )
    {
	super.paintComponent( g );
	
	g.drawRect(0,0,getWidth()-1,getHeight()-1);
	g.drawLine(getWidth()/3,0,getWidth()/3,getHeight());
	g.drawLine(2*getWidth()/3,0,2*getWidth()/3,getHeight());
	g.drawLine(0,getHeight()/3,getWidth(),getHeight()/3);
	g.drawLine(0,2*getHeight()/3,getWidth(),2*getHeight()/3);
	
	for (int i=0; i<3; i++)
	    for (int j=0; j<3; j++)
		switch (B[i][j]) {
		case ' ': break;
		case 'x': 
		    g.fillPolygon(new int[] 
			              {j*getWidth()/3+3, j*getWidth()/3+7,
				       (j+1)*getWidth()/3-3, (j+1)*getWidth()/3-7},
		                  new int[] 
                                      {i*getHeight()/3+7, i*getHeight()/3+3,
				       (i+1)*getHeight()/3-7, (i+1)*getHeight()/3-3},
			          4);
		    g.fillPolygon(new int[] 
			              {(j+1)*getWidth()/3-3, (j+1)*getWidth()/3-7,
				       j*getWidth()/3+3, j*getWidth()/3+7},
		                  new int[] 
                                      {i*getHeight()/3+7, i*getHeight()/3+3,
				       (i+1)*getHeight()/3-7, (i+1)*getHeight()/3-3},
			          4);
		    break;
		case 'o':
		    g.fillOval(j*getWidth()/3+2, i*getHeight()/3+2,
			       getWidth()/3-4, getHeight()/3-4);
		    break;
		}
    }
    

    public void draw( )
    {
	repaint();
    }
    
}







 

}