/* Used when a new chess position is created. The property copies are made
and then this constructor is called with the copies. */
public ChessPosition(int size,
Tile[,] board,
Player player,
Dictionary<char, bool> castle,
Tuple<int, int> enPassantSq,
int halfmoveClock,
List<EGamePieces> piecesCapd)
{
this.Size = size;
this.Board = board;
this.Player = player;
this.Castle = castle;
this.EnPassantSq = enPassantSq;
this.HalfMoveClock = halfmoveClock;
this.PiecesCapd = piecesCapd;
}
/* Takes a move object and a chess board object and returns true if
the piece on the B position of the move belongs to the other player.
TODO: replace with alternate call to previous functions*/
private bool IsMoveBPieceOtherPlayer(FormedMove move, ChessPosition cpm, ref Tile tileB)
{
bool result = false;
tileB = cpm.Board[move.PosB.Item1, move.PosB.Item2];
if (!tileB.IsEmpty())
if (!cpm.Player.Owns(tileB.piece))
result = true;
return result;
}
/* Takes a move object and a chess board object and returns true if
the tile on the B position of the move is empty. */
private bool IsMoveBEmpty(FormedMove move, ChessPosition cpm, ref Tile tileB)
{
tileB = cpm.Board[move.PosB.Item1, move.PosB.Item2];
return tileB.IsEmpty();
}
/* Takes a move object and a chess board object and returns true if
the piece on the A position of the move belongs to the current player. */
private bool IsMoveAPieceCurPlayer(FormedMove move, ChessPosition cpm, ref Tile tileA)
{
bool result = false;
tileA = cpm.Board[move.PosA.Item1, move.PosA.Item2];
if (!tileA.IsEmpty())
if (cpm.Player.Owns(tileA.piece))
result = true;
return result;
}
/* Take a valid-format move object and check if it may be legally
applied to the current chess game. It must pass the following checks:
-the locations are distinct and
-the A tile contains a piece of the current player
Also one of the following:
-the B tile contains a piece of the current player (further castle checks) or
-the B tile contains a piece of the opponent player (further capture checks) or
-the B tile is empty:
-(further en passant checks)
-(further movement checks)
Finally it must check, if the move were to be applied, that it does not leave the
current player's king in check.*/
public bool IsValidMove(ref FormedMove move, ChessPositionModel cpm, ref List<Tuple<int, int>> kingCheckedBy)
{
bool validMove = false;
Tile tileA = new Tile();
Tile tileB = new Tile();
if (IsMovePositionsDistinct(move))
{
if (IsMoveAPieceCurPlayer(move, cpm, ref tileA))
{
// check if its a castling
if (IsMoveBPieceCurPlayer(move, cpm, ref tileB))
{
validMove = false; // IsLegalCastle? - this involves calls to isKingInCheck
move.MoveType = EChessMoveTypes.Castle;
}
// check if its a capture
else if (IsMoveBPieceOtherPlayer(move, cpm, ref tileB))
{
validMove = IsCaptureLegal(move, cpm);
move.MoveType = EChessMoveTypes.Capture;
}
// check if its a movement
else if (IsMoveBEmpty(move, cpm, ref tileB))
{
if (validMove = IsPieceMovementLegal(move, cpm))
{
move.MoveType = EChessMoveTypes.Movement;
}
else if (validMove = IsEnPassantCaptureLegal(move, cpm))
{
move.MoveType = EChessMoveTypes.EpMovement;
}
}
}
}
// if its a valid move so far, check if there is a pawn promotion,
// then apply the move to a copy of the chess position and
// finally check it passes a check test
if (validMove)
{
// if there is a pawn promotion the player is prompted for the promotion piece and it is added to the move object
MoveIncludesPawnPromotion(ref move, cpm);
// a copy of the chess position is made so that the move may
// be applied in order for the king-check to be checked without
// causing the chess position to update the display
ChessPosition cpCopy = cpm.getChessPositionCopy();
cpCopy.applyMove(move);
// after this application of the move
if (IsKingInCheck(cpCopy, ref kingCheckedBy))
validMove = false;
}
return validMove;
}
/* Returns a ChessPosition object which is a deep copy of this one. Since this method is
also inherited by the ChessPositionModel, if the CPM produces this object it will be a
deep copy of the ChessPositionModel object as if it were a ChessPosition. (CPM minus handlers etc).
This function will be used during evaluation in the king check phase, and will also be used during
the move search of the ai function. */
public ChessPosition getChessPositionCopy()
{
int dimCopy = Size;
// deep copy the board manually //
Tile[,] boardCopy = new Tile[dimCopy, dimCopy];
for (int j = 0; j < dimCopy; j ++)
{
for (int k = 0; k < dimCopy; k ++)
{
Tile tileCopy = new Tile();
if (!Board[j,k].IsEmpty())
{
Piece piece = Board[j, k].piece;
EGamePieces val = piece.Val;
bool mv = piece.MovedOnce;
Piece pieceCopy = new Piece(val);
pieceCopy.MovedOnce = mv;
tileCopy.piece = pieceCopy;
}
boardCopy[j, k] = tileCopy;
}
}
// copy rest of ChessPosition properties
Player playerCopy = new Player(this.Player.PlayerValue);
Dictionary<char, bool> castleCopy = new Dictionary<char, bool>(Castle);
Tuple<int, int> enPassantSqCopy = (EnPassantSq == null) ? null : Tuple.Create(EnPassantSq.Item1, EnPassantSq.Item2);
int halfmoveClockCopy = HalfMoveClock;
List<EGamePieces> piecesCapdCopy = new List<EGamePieces>(PiecesCapd);
// create and return the copy
ChessPosition cpCopy = new ChessPosition(dimCopy, boardCopy, playerCopy, castleCopy, enPassantSqCopy, halfmoveClockCopy, piecesCapdCopy);
return cpCopy;
}
