/// <summary>
/// Draws the winner on the screen
/// </summary>
/// <param name="game">Game.</param>
public void DrawWinner(ChessGame game)
{
string toCheck = DetermineCheck(game);
if (toCheck == "Black checkmated")
{
SwinGame.DrawText("White wins", Color.Crimson, SwinGame.FontNamed("Chelsea"), 620, 400);
}
else if (toCheck == "White checkmated")
{
SwinGame.DrawText("Black wins", Color.Crimson, SwinGame.FontNamed("Chelsea"), 620, 400);
}
else
{
SwinGame.DrawText(game.PlayerInturn.Team + " 's turn", Color.Crimson, SwinGame.FontNamed("Chelsea"), 620, 400);
}
}
/// <summary>
/// Determines the checking condition of the game and return a string
/// </summary>
/// <returns>A string message</returns>
/// <param name="game">The game</param>
public string DetermineCheck(ChessGame game)
{
for (int i = 0; i < 2; i++)
{
if (game.Players[i].King == null || game.Players [i].King.isCheckmated(game.Players [(i + 1) % 2], game.Board))
{
return(game.Players [i].Team + " checkmated");
}
}
for (int i = 0; i < 2; i++)
{
if (game.Players [i].King.isChecked(game.Players [(i + 1) % 2], game.Board))
{
return(game.Players [i].Team + " in check");
}
}
return("In safety");
}
/// <summary>
/// Reverses the move.
/// </summary>
/// <param name="game">the Game</param>
/// <param name="isTurnChanged">If set to <c>true</c> the turn is swapped</param>
public void ReverseMove(ChessGame game, bool isTurnChanged)
{
if (_moves.Count == 0)
{
return;
}
Move lastMove = _moves [_moves.Count - 1];
MoveWithoutChecking(new Move(lastMove.PlayerMove, lastMove.PieceMove, null, lastMove.CellTo, lastMove.CellFrom), false);
if (lastMove.PieceCaptured != null)
{
lastMove.PlayerMove.Opponent.AddPiece(lastMove.PieceCaptured, lastMove.CellTo);
}
_moves.Remove(_moves [_moves.Count - 1]);
_moves.Remove(lastMove);
if (isTurnChanged)
{
game.ChangeTurn();
}
}
/// <summary>
/// Handle input and take a turn for Human Player
/// </summary>
/// <param name="point">usually the mouse position</param>
/// <param name="game">the game in play</param>
public virtual void TakeTurn(Point2D point, ChessGame game)
{
//if the player is selecting piece to move
if (game.State == GameState.Selecting)
{
Cell chosen = game.FetchCell(point);
//if the piece chosen is not null and belongs to the player
if (chosen != null && chosen.Piece != null && _pieces.Contains(chosen.Piece))
{
game.ChangeState(GameState.Moving);
chosen.Piece.Select();
game.SetChosenPiece(chosen.Piece);
}
}
//if the player is selecting a cell to move the piece
else if (game.State == GameState.Moving)
{
Cell chosen = game.FetchCell(point);
//if the chosen cell is the cell that contains the piece, deselect the piece
if (chosen.Piece != null && chosen.Piece.isSelected)
{
game.ChangeState(GameState.Selecting);
chosen.Piece.Deselect();
}
//if the chosen cell is in possible moves of the chosen piece
else if (chosen.isPossibleMoveOf(game.ChosenPiece, _board))
{
game.ChangeState(GameState.Moved);
_board.Move(new Move(this, game.ChosenPiece, chosen.Piece, game.ChosenPiece.Cell, chosen));
//if the king is moved, check if whether it is a castle
if (game.ChosenPiece.GetType() == typeof(King) && _board.timesKingMovedBefore(_color) == 1)
{
MoveRookInCastle(_color, chosen);
}
game.ChosenPiece.Deselect();
game.ChangeTurn();
Opponent.TakeTurn(point, game);
}
}
}
/// <summary>
/// Figure out the best move for the AI
/// </summary>
/// <returns>The Move</returns>
/// <param name="depth">Number of moves the AI can see ahead</param>
/// <param name="game">the chess game</param>
/// <param name="p">the player needing best move</param>
public Move BestMove(int depth, ChessGame game, Player p)
{
List <Move> newGameMoves = GeneratedMoves();
Console.WriteLine(newGameMoves.Count);
int bestValue = -9999;
Move bestMove = null;
for (int i = 0; i < newGameMoves.Count; i++)
{
Move newMove = newGameMoves [i];
game.Board.Move(newMove);
int moveValue = AlphaBetaMin(depth - 1, game, p.Opponent, -10000, 10000);
game.Board.ReverseMove(game, false);
if (moveValue >= bestValue)
{
bestValue = moveValue;
bestMove = newMove;
}
}
return(bestMove);
}
/// <summary>
/// Calculate the best move for the Human Player
/// </summary>
/// <returns>the smallest board value</returns>
/// <param name="depth">the number of moves the AI can look ahead</param>
/// <param name="game">the chess game</param>
/// <param name="minimising">The player trying to minimize the board value</param>
/// <param name="alpha">the minimum board value</param>
/// <param name="beta">the maximum board value</param>
public int AlphaBetaMin(int depth, ChessGame game, Player minimising, int alpha, int beta)
{
if (depth == 0)
{
Console.WriteLine(BoardValue());
return(BoardValue());
}
List <Move> newGameMoves = minimising.GeneratedMoves();
int bestValue = 9999;
for (int i = 0; i < newGameMoves.Count; i++)
{
game.Board.Move(newGameMoves [i]);
bestValue = Math.Min(bestValue, AlphaBetaMax(depth - 1, game, minimising.Opponent, alpha, beta));
beta = Math.Min(beta, bestValue);
game.Board.ReverseMove(game, false);
if (beta <= alpha)
{
return(bestValue);
}
}
return(bestValue);
}
/// <summary>
/// Draws the checking state on the screen
/// </summary>
/// <param name="game">the Game</param>
public void DrawCheckingState(ChessGame game)
{
SwinGame.DrawText(DetermineCheck(game), Color.Chocolate, SwinGame.FontNamed("Chelsea"), CHECKING_STATE_X, CHECKING_STATE_Y);
}
/// <summary>
/// Creates the new game.
/// </summary>
/// <param name="AI">Whether the player is human or AI</param>
public void CreateGame(bool AI)
{
_game = new ChessGame(AI);
}
