/// <summary>
/// Called when the user clicks a square button in the game board visual area
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void square_clicked(object sender, EventArgs e)
{
Button squareClicked = (Button)sender;
if (squareClicked.Enabled && gameActive != null)
{
Square squareObject = null;
for (int iX = 0; iX < 3; iX++)
{
for (int iY = 0; iY < 3; iY++)
{
if (squareButtons[iX,iY] == squareClicked)
{
squareObject = gameActive.Board.Squares[iX, iY];
break;
}
}
}
if (squareObject != null)
{
Move move = new Move(gameActive.ActivePlayer, squareObject);
gameActive.PlayMove(move);
}
}
}
/// <summary>
/// Method called when the game passes control to this player
/// </summary>
/// <param name="game">Game object that this player belongs to</param>
public override void PromptForMove(Game game)
{
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
Square bestSquare = null;
float bestValue = float.MinValue;
_playerOpponent = game.Players[0];
if (_playerOpponent == this)
{
_playerOpponent = game.Players[1];
}
Random rand = new Random();
int equalSquares = 0;
foreach (Square square in game.Board.Squares)
{
if (square.Owner == null)
{
square.Owner = this;
float curValue = AlphaBetaPrune(game, int.MinValue, int.MaxValue, false);
square.Owner = null;
if (bestSquare == null || curValue > bestValue)
{
bestValue = curValue;
bestSquare = square;
equalSquares = 0;
}
else if (curValue == bestValue)
{
equalSquares++;
if (rand.Next(0,equalSquares + 1) == 0)
{
bestValue = curValue;
bestSquare = square;
}
}
}
}
int curTurnTime = (int)stopwatch.ElapsedMilliseconds;
int turnTimeDiff = _minTurnTime - curTurnTime;
Move move = new Move(this, bestSquare);
Action playMove = () => game.PlayMove(move);
int sleepMs = Math.Max(0, turnTimeDiff);
// Ensure that the AI waits at least the minTurnTime before playing a move,
// making the AI seem more human-like in that it won't make all of its moves near instantaniously.
_timer = new Timer(PlayMoveAfterDelayCallback, playMove, sleepMs, Timeout.Infinite);
}
/// <summary>
/// Attempt to play the given move
/// </summary>
/// <param name="move">Move to try and play</param>
public void PlayMove(Move move)
{
if (move == null)
{
throw new InvalidMoveException("Cannot play null move.");
}
if (move.Player != ActivePlayer)
{
throw new InvalidMoveException("It is not this player's [" + move.Player.ToString() + "] turn.");
}
if (move.Square.Owner != null)
{
throw new InvalidMoveException("Board square [" + move.Square.ToString() + "] already has an owner.");
}
move.Square.Owner = move.Player;
OnGameUpdate();
AdvanceTurn();
if (GetGameState().IsCompleted == false)
{
ActivePlayer.PromptForMove(this);
}
}
/// <summary>
/// Assigns arbitrary weights to a move. Used for computing a winner.
/// </summary>
/// <param name="move">
/// The move whose weight to get.
/// </param>
/// <returns>
/// An integer value weight for the move.
/// </returns>
private int GetWeightForMove(Move move)
{
int value = 0;
switch (move)
{
case Move.X:
value = 1;
break;
case Move.O:
value = -1;
break;
case Move.Undefined:
value = 0;
break;
}
return value;
}
/// <summary>
/// Sets the target row and column in the board to the passed in move.
/// </summary>
/// <param name="slot">
/// The slot to place the move in.
/// </param>
/// <param name="move">
/// The move to make. X or O.
/// </param>
public void MakeMove(int slot, Move move)
{
if (slot < 1 || slot > 9)
{
throw new IndexOutOfRangeException("Slot numbers must be between 1 and 9");
}
var index = slot - 1;
if (moves[index] == Move.Undefined)
{
this.moves[index] = move;
this.winner = this.CheckForWinner();
}
else
{
throw new ArgumentException("Someone already moved there!");
}
}
/// <summary>
/// Swaps X's to O's and O's to X's. Allows for alternating moves.
/// </summary>
/// <param name="currentPlayer">
/// The current move to be made by a player. X or O.
/// </param>
/// <returns>
/// If X, then O. If O, then X.
/// </returns>
private Move FlipCurrentPlayer(Move currentPlayer)
{
return currentPlayer == Move.X ? Move.O : Move.X;
}
/// <summary>
/// Prints out a move.
/// </summary>
/// <param name="move">
/// The move to print.
/// </param>
/// <returns>
/// Prints the symbol for the move.
/// </returns>
private string PrintMove(Move move)
{
return move == Move.X ? "X" : "O";
}
/// <summary>
/// Sets the target row and column in the board to the passed in move.
/// </summary>
/// <param name="slot">
/// The slot to place the move in.
/// </param>
/// <param name="move">
/// The move to make. X or O.
/// </param>
public void MakeMove(int slot, Move move)
{
throw new NotImplementedException();
}