/**
 * An interface for the game state of the Connect 4 game.
 * 
 * @author Scot Drysdale
 */
public interface Connect4State {
  public final static int ROWS = 6;            // Board height
  public final static int COLS = 7;            // Board width
  public final static char EMPTY = '.';        // Indicate empty place
  public final static char CHECKER0 = 'X';     // Indicate the first player's checker
  public final static char CHECKER1 = 'O';     // Indicate second player's checker
  public final static char [] CHECKERS = {CHECKER0, CHECKER1};
  
  /**
   * Gets a 2-D array representing the board.
   * The first subscript is the row number and the second the column number.
   * The bottom of the board is row 0 and the top is row ROWS-1.
   * The left side of the board is column 0 and the right side is column COLS-1.
   * @return the board
   */
  public char [][] getBoard();
  
  /**
   * Gets an array holding 2 Player objects
   * @return the players
   */
  public Player [] getPlayers();
  
  /**
   * Gets the number of the player whose move it is
   * @return the number of the player whose move it is
   */
  public int getPlayerNum ();
  
  /**
   * Gets the Player whose turn it is to move
   * @return the Player whose turn it is to move
   */
  public Player getPlayerToMove();

  /**
   * Is this move valid?
   * @param col column where we want to move
   * @return true if the move is valid
   */
  public boolean isValidMove(int col);
  
  /**
   * Make a move, dropping a checker in the given column
   * @param col the column to get the new checker
   */
  public void makeMove(int col);
  
 
  /**
   * Is the board full?
   * @return true if the board is full
   */
  public boolean isFull();

  /**
   * Decides if the game is over
   * @return true iff the game is over
   */
  public boolean gameIsOver();
}