import java.util.Scanner;

/**
 * Represents the state of a game of Chips.
 * Comments describing the game are in Chips.java
 * 
 * Based on earlier versions written by Scot Drysdale and THC.
 * 
 * @author Scot Drysdale
 */

public class Game 
{
	// Instance variables.
	private int chips; // Number of chips left
	private int maxMove; // Max number of chips in next legal move
	private Player playerToMove; // Player whose turn it is to move
	private Player otherPlayer; // Player who does not move next

	/**
	 * Initialize the state of the game:
	 * @param numChips the number of chips in the pile
	 * @param player1 the first player
	 * @param player2 the second player
	 */
	public Game(int numChips, Player player1, Player player2) 
	{
		chips = numChips;
		maxMove = chips / 2;
		playerToMove = player1;
		otherPlayer = player2;
	}

	/**
	 * Return current number of chips in the pile
	 * @return number of chips in the pile
	 */
	public int getNumChips() 
	{
		return chips;
	}

	/**
	 * Return which player's move it is
	 * @return the play whose move it is
	 */
	public Player getPlayerToMove() 
	{
		return playerToMove;
	}

	/**
	 * Return other player
	 * @return the player not on move
	 */
	public Player getOtherPlayer() 
	{
		return otherPlayer;
	}

	/**
	 * Return the maximum number of chips that the current player can take
	 * @return the maximum number of chips that can be taken this move
	 */
	public int getMaxMove() 
	{
		return maxMove;
	}

	/**
	 * Is the game is over?
	 * @return true if the game is over
	 */
	public boolean isOver() 
	{
		return chips == 0;
	}

	/**
	 * Update the state of the game based on a move.
	 * Assumes that move is legal.
	 * @param move the move to make
	 */
	public void makeMove(int move) 
	{
		chips -= move; // Remove the chips taken from the pile
		playerToMove.addChips(move); // and update player's pile

		// Change whose move it is. 
		Player temp = playerToMove;
		playerToMove = otherPlayer;
		otherPlayer = temp;

		// And update the max legal move for the next turn.
		maxMove = Math.min(chips, 2 * move);
	}

	/**
	 * Which player won the game?
	 * @return the winning player
	 */
	public Player getWinner() 
	{
		// The winner is the player with an even number of chips.
		if (playerToMove.getChips() % 2 == 0)
			return playerToMove;
		else
			return otherPlayer;
	}

	/**
	 * Input a valid number of chips for the initial pile.
	 * It is static so that it can be called before the game object exists.
	 * @return the number of chips chosen
	 */
	public static int inputInitChips() 
	{
		final int MIN_CHIPS = 3; // Have to start with at least 3 chips
		Scanner input = new Scanner(System.in);

		System.out.print("How many chips does the initial pile contain? ");
		int chips = input.nextInt();
		while (chips < MIN_CHIPS || chips % 2 == 0) 
		{
			if (chips < MIN_CHIPS)
				System.out.print("You have to start with at least " + MIN_CHIPS
						+ " chips.  Choose another number: ");
			else
				System.out.print("You have to start with an odd number of chips.  "
						+ "Choose another number: ");
			chips = input.nextInt();
		}
		return chips;
	}
	
	/**
	 * Return a copy of the game, but with 2 computer players
	 * @return a copy of the game
	 */
  public Game makeCopy()
  {
    Game copy = new Game(chips, playerToMove.makeCopy(), 
    		                        otherPlayer.makeCopy());
    copy.maxMove = maxMove;
    return copy;   
  }
}