/** This file implements the TicTacToe class.  We have a constructor
 * that initializes the board, a set() function that puts an X or O token
 * on the board, a toString() function that allows us to display the board
 * for the players, and a findWinner() function that sees if the game is over.
 */

public class TicTacToe
{
  private char[][] board;
  private int numTokens;

  /** Create an empty game board.
   */
  public TicTacToe()
  {
    board = new char[3][3];

    for (int i = 0; i < 3; ++i)
      for (int j = 0; j < 3; ++j)
        board[i][j] = ' ';

    numTokens = 0;
  }

  /** The row and column numbers come in as 1-3, so we need to subtract
   * 1 from each when literally entering a value into the board.
   */
  public boolean set(int i, int j, char player)
  {
    if (board[i-1][j-1] != ' ')
    {
      System.out.println("You should not cheat :(");
      return false;
    }
    else
    {
      board[i-1][j-1] = player;
      ++numTokens;
      return true;
    }
  }

  /** Create string representation of the board.
   */
  public String toString()
  {
    String display = "";
    for (int i = 0; i < 3; ++i)
    {
      display += "|";
      for (int j = 0; j < 3; ++j)
      {
        display += board[i][j];
      }
      display += "|\n";
    }
    return display;
  }

  /** This function will determine if there is a winner, X or O.  If there
   * is no winner yet, we return ' '.  If the board is full and it's a tie,
   * return 'T'.
   */
  public char findWinner()
  {
    // let's add a print statement for debugging...
    System.out.println("entering findWinner() with numTokens = " + numTokens);

    // need to make sure that we don't declare "blank" the winner!
    // try the 3 rows
    if (board[0][0] == board[0][1] && board[0][1] == board[0][2])
      return board[0][0];
    else if (board[1][0] == board[1][1] && board[1][1] == board[1][2])
      return board[1][0];
    else if (board[2][0] == board[2][1] && board[2][1] == board[2][2])
      return board[2][0];

    // try the 3 columns
    else if (board[0][0] == board[1][0] && board[1][0] == board[2][0])
      return board[0][0];
    else if (board[0][1] == board[1][1] && board[1][1] == board[2][1])
      return board[0][1];
    else if (board[0][2] == board[1][2] && board[1][2] == board[2][2])
      return board[0][2];

    // try the diagonals
    else if (board[0][0] == board[1][1] && board[1][1] == board[2][2])
      return board[0][0];
    else if (board[0][2] == board[1][1] && board[1][1] == board[2][0])
      return board[0][2];

    // is board full?  
    else if (numTokens == 9)
      return 'T';

    // if there is no match, say there is no winner yet
    else
      return ' ';
  }
}