public bool IsValidMove(CellId source, CellId target, IChessBoard board)
{
var sourceCell = board.GetCell(source);
var targetCell = board.GetCell(target);
return(IsValidMove(sourceCell, targetCell, board));
}
public void MovePiece(CellId source, CellId target)
{
if (!IsValidMove(source, target))
{
throw new InvalidOperationException("Invalid move!");
}
// Figure out if it is a castle operation.
//
var sourceCell = _chessboard.GetCell(source);
var targetCell = _chessboard.GetCell(target);
// We know it is a valid move. We just have to identify if it is a castle
// operation.
//
if (sourceCell.PieceType == EChessPieceType.King &&
targetCell.PieceType == EChessPieceType.Rook &&
sourceCell.PieceColor == targetCell.PieceColor)
{
_chessboard.SwapPiece(source, target);
}
else
{
_chessboard.MovePiece(source, target);
}
nextTurn();
}
public void SetPiece(CellId identifier, EChessPieceType piece, EChessPieceColor color)
{
EChessPieceType oldPiece = _cells[identifier].PieceType;
EChessPieceColor oldColor = _cells[identifier].PieceColor;
_cells[identifier].SetPiece(piece, color);
CellStatusChanged(this, new CellStatusChangedEventArgs(identifier, oldPiece, oldColor, piece, color));
}
private void SetValidMoveTargets(bool isValidMoveTarget, CellId sourceCell)
{
var validMoveTargets = _gameLogic.ValidMovesForCell(sourceCell);
foreach (var moveTarget in validMoveTargets)
{
GetCell(moveTarget).IsValidMoveTarget = isValidMoveTarget;
}
}
public CellStatusChangedEventArgs(CellId identifier, EChessPieceType oldPiece, EChessPieceColor oldColor,
EChessPieceType newPiece, EChessPieceColor newColor)
{
Identifier = identifier;
OldPiece = oldPiece;
NewPiece = newPiece;
OldColor = oldColor;
NewColor = newColor;
}
// We need this for castling and other things.
//
public bool HasMoved(CellId cell)
{
// Just look through the history and check if some piece has moved to this cell.
//
foreach (var move in _moveHistory)
{
if (move.Target.Equals(cell))
{
return(true);
}
}
return(false);
}
public void MovePiece(CellId source, CellId target)
{
if (!_gameRules.IsValidMove(source, target, this))
{
throw new InvalidOperationException("This is an invalid move.");
}
var pieceType = _cells[source].PieceType;
var pieceColor = _cells[source].PieceColor;
SetPiece(target, pieceType, pieceColor);
SetPiece(source, EChessPieceType.Empty, EChessPieceColor.Empty);
_moveHistory.AddMove(new Move(source, target));
}
public void SwapPiece(CellId source, CellId target)
{
if (!_gameRules.IsValidMove(source, target, this))
{
throw new InvalidOperationException("This is an invalid move.");
}
var pieceType1 = _cells[source].PieceType;
var pieceType2 = _cells[target].PieceType;
var pieceColor1 = _cells[source].PieceColor;
var pieceColor2 = _cells[target].PieceColor;
SetPiece(target, pieceType1, pieceColor1);
SetPiece(source, pieceType2, pieceColor2);
// Can we use this for castling??
//
_moveHistory.AddMove(new Move(source, target));
}
private void Cell_CellSelected(object sender, CellId selectedCellIdentifier)
{
// XXX: Implement the move logic here.
// Hint: Use the _gameLogic object to check for valid moves and for moving pieces.
// If a user selects a piece, we remember the selected piece using the _selectedPiece
// field. If a user then selects a valid field, we move the piece. If the user selects
// an invalid field, we reset the selection.
//
var targetCell = GetCell(selectedCellIdentifier);
if (_selectedPiece == null)
{
if (!CanActivePlayerMove(targetCell.ChessPieceColor))
{
return;
}
_selectedPiece = targetCell;
_selectedPiece.IsCellSelected = true;
SetValidMoveTargets(true, _selectedPiece.Identifier);
return;
}
var sourceCell = _selectedPiece;
_selectedPiece.IsCellSelected = false;
_selectedPiece = null;
SetValidMoveTargets(false, sourceCell.Identifier);
bool isValidMove = _gameLogic
.IsValidMove(sourceCell.Identifier, targetCell.Identifier);
if (!isValidMove)
{
return;
}
_gameLogic.MovePiece(sourceCell.Identifier, targetCell.Identifier);
}
public IReadOnlyList <CellId> ValidMovesForCell(CellId cellId, IChessBoard board)
{
var validMoveList = new List <CellId>();
var source = board.GetCell(cellId);
for (int row = 0; row < board.NumRows; row++)
{
for (int col = 0; col < board.NumCols; col++)
{
// Figure out the status of the cell.
//
var target = board.GetCell(CellId.Create(row, col));
if (IsValidMove(source, target, board))
{
validMoveList.Add(CellId.Create(row, col));
}
}
}
return(validMoveList);
}
public void MovePiece(CellId source, CellId target)
{
if (!IsValidMove(source, target))
{
throw new InvalidOperationException("Invalid move!");
}
// Figure out if it is a castle operation.
//
var sourceCell = _chessboard.GetCell(source);
var targetCell = _chessboard.GetCell(target);
// We know it is a valid move. We just have to identify if it is a castle
// operation.
//
if (sourceCell.PieceType == EChessPieceType.King &&
targetCell.PieceType == EChessPieceType.Rook &&
sourceCell.PieceColor == targetCell.PieceColor)
{
_chessboard.SwapPiece(source, target);
}
else
{
if (targetCell.PieceColor != sourceCell.PieceColor) // The player captured a piece
{
PieceCaptured(this, new PieceCapturedEventArgs(targetCell.PieceType, targetCell.PieceColor));
// Check if the king was captured.
//
if (targetCell.PieceType == EChessPieceType.King)
{
GameFinished(this, new GameEndedEventArgs(ActivePlayer));
}
}
_chessboard.MovePiece(source, target);
}
nextTurn();
}
private void setupBlackBishopRules()
{
var blackBishopRules =
GameRule.Create().Filter(x => x.PieceColor == EChessPieceColor.Black && x.PieceType == EChessPieceType.Bishop);
blackBishopRules.InvalidMove((s, t, c) =>
{
// Can not move to a field occupied by a black piece.
//
return(t.PieceColor == EChessPieceColor.Black);
});
blackBishopRules.InvalidMove((s, t, c) =>
{
// Can not move past another piece.
//
int colDiff = s.ColIndex - t.ColIndex;
int rowDiff = s.RowIndex - t.RowIndex;
if (Math.Abs(colDiff) != Math.Abs(rowDiff))
{
return(false); // Check its a diagonal move
}
int stepRow = rowDiff > 0 ? -1 : 1;
int stepCol = colDiff > 0 ? -1 : 1;
// Check there is no piece on the way to the target.
//
for (int step = 1; t.ColIndex != s.ColIndex + stepCol * step; step++)
{
int row = s.RowIndex + stepRow * step;
int col = s.ColIndex + stepCol * step;
// We reached the target it is not an invalid move.
//
if (row == t.RowIndex || col == t.RowIndex)
{
return(false);
}
// We reached another piece, but it can not be the target of our move
// therefore this move is not valid.
//
var cell = c.GetCell(CellId.Create(row, col));
if (cell.PieceType != EChessPieceType.Empty)
{
return(true);
}
}
return(false);
});
blackBishopRules.ValidMove((s, t, c) =>
{
// Bishop can move diagonally to take any piece.
//
int colDiff = Math.Abs(s.ColIndex - t.ColIndex);
int rowDiff = Math.Abs(s.RowIndex - t.RowIndex);
if (colDiff != rowDiff)
{
return(false);
}
return(true);
});
_gameRules.Add(blackBishopRules);
}
private CellId keyFor(int row, int col)
{
return(CellId.Create(row, col));
}
public bool IsValidMove(CellId source, CellId target)
{
return(_gameRules.IsValidMove(source, target, this));
}
private CellStatusViewModel GetCell(CellId cellId)
{
return(Cells[cellId.Row][cellId.Col]);
}
public bool IsValidMove(CellId source, CellId target)
{
return(_gameRules.IsValidMove(source, target, _chessboard));
}
private void Cell_CellSelected(object sender, CellId selectedCellIdentifier)
{
if (_isGameFinished)
{
return;
}
// If an empty cell or a cell of the opponent color was selected
// unselect the previous cell.
//
var cell = fetchCell(selectedCellIdentifier);
if (_isPieceSelected == true) // The user previously selected a valid piece.
{
if (_gameLogic.IsValidMove(_selectedPiece.Identifier, selectedCellIdentifier))
{
_gameLogic.MovePiece(_selectedPiece.Identifier, selectedCellIdentifier);
unselectAllCells();
clearValidMoves();
_isPieceSelected = false;
ActivePlayer = _gameLogic.ActivePlayer;
}
else
{
// It is not a valid move. If another valid piece was selected change the selection.
//
if (!cell.IsEmpty)
{
if (ActivePlayer == EActivePlayer.Black && cell.ChessPieceColor == EChessPieceColor.Black ||
ActivePlayer == EActivePlayer.White && cell.ChessPieceColor == EChessPieceColor.White)
{
unselectAllCells();
clearValidMoves();
_selectedPiece = cell;
_selectedPiece.IsCellSelected = true;
displayValidMovesForPiece(_selectedPiece);
}
}
}
}
if (_isPieceSelected == false) // We have no selected piece.
{
if (cell.IsEmpty) // Nothing to do here
{
return;
}
// Check the user selected a valid piece.
//
if (_gameLogic.ActivePlayer == EActivePlayer.White && cell.ChessPieceColor == EChessPieceColor.White ||
_gameLogic.ActivePlayer == EActivePlayer.Black && cell.ChessPieceColor == EChessPieceColor.Black)
{
_selectedPiece = cell;
_selectedPiece.IsCellSelected = true;
_isPieceSelected = true;
displayValidMovesForPiece(_selectedPiece);
}
// User selected a an invalid piece.
//
else
{
return;
}
}
}
private void setupQueenRules()
{
var queenRules =
GameRule.Create().Filter(x =>
x.PieceType == EChessPieceType.Queen);
queenRules.InvalidMove((s, t, c) =>
{
// Can not move to our own position. This would cause an indexing issue.
//
if (s.ColIndex == t.ColIndex && s.RowIndex == t.RowIndex)
{
return(true);
}
// Can not move past another piece.
//
int colDiff = s.ColIndex - t.ColIndex;
int rowDiff = s.RowIndex - t.RowIndex;
int stepRow = rowDiff > 0 ? -1 : 1;
int stepCol = colDiff > 0 ? -1 : 1;
if (colDiff == 0)
{
stepCol = 0;
}
if (rowDiff == 0)
{
stepRow = 0;
}
// Check there is no piece on the way to the target.
//
for (int step = 1; ; step++)
{
int row = s.RowIndex + stepRow * step;
int col = s.ColIndex + stepCol * step;
if (row < 0 || row >= c.NumRows || col < 0 || col >= c.NumCols)
{
return(true);
}
// We reached the target it is not an invalid move.
//
if (row == t.RowIndex && col == t.ColIndex)
{
return(false);
}
if (row == c.NumCols - 1 && col == c.NumRows - 1)
{
return(true);
}
// We reached another piece, but it can not be the target of our move
// therefore this move is not valid.
//
var cell = c.GetCell(CellId.Create(row, col));
if (cell.PieceType != EChessPieceType.Empty)
{
return(true);
}
}
});
queenRules.InvalidMove((s, t, c) =>
{
// Can not move to our own position. This would cause an indexing issue.
//
if (s.ColIndex == t.ColIndex && s.RowIndex == t.RowIndex)
{
return(true);
}
// Can not move past another piece.
//
int colDiff = s.ColIndex - t.ColIndex;
int rowDiff = s.RowIndex - t.RowIndex;
if (Math.Abs(colDiff) != Math.Abs(rowDiff))
{
return(false); // Check its a diagonal move
}
int stepRow = rowDiff > 0 ? -1 : 1;
int stepCol = colDiff > 0 ? -1 : 1;
// Check there is no piece on the way to the target.
//
for (int step = 1; t.ColIndex != s.ColIndex + stepCol * step; step++)
{
int row = s.RowIndex + stepRow * step;
int col = s.ColIndex + stepCol * step;
// We reached the target it is not an invalid move.
//
if (row == t.RowIndex || col == t.ColIndex)
{
return(false);
}
if (row == c.NumCols - 1 && col == c.NumRows - 1)
{
return(true);
}
// We reached another piece, but it can not be the target of our move
// therefore this move is not valid.
//
var cell = c.GetCell(CellId.Create(row, col));
if (cell.PieceType != EChessPieceType.Empty)
{
return(true);
}
}
return(false);
});
queenRules.ValidMove((s, t, c) =>
{
// Rook can move diagonally or vertically.
//
int colDiff = Math.Abs(s.ColIndex - t.ColIndex);
int rowDiff = Math.Abs(s.RowIndex - t.RowIndex);
if (colDiff == 0 || rowDiff == 0)
{
return(true);
}
return(false);
});
queenRules.ValidMove((s, t, c) =>
{
// Bishop can move diagonally to take any piece.
//
int colDiff = Math.Abs(s.ColIndex - t.ColIndex);
int rowDiff = Math.Abs(s.RowIndex - t.RowIndex);
if (colDiff != rowDiff)
{
return(false);
}
return(true);
});
_gameRules.Add(queenRules);
}
private void setupKingRules()
{
var kingRules =
GameRule.Create().Filter(x =>
x.PieceType == EChessPieceType.King);
kingRules.InvalidMove((s, t, c) =>
{
if (t.PieceColor != s.PieceColor)
{
return(false);
}
// Can not move to a piece of the same color unless it is a rook.
// Some more castle rules are checked below.
//
if (t.PieceColor == s.PieceColor && t.PieceType == EChessPieceType.Rook)
{
return(false);
}
return(true);
});
kingRules.ValidMove((s, t, c) =>
{
int colDiff = Math.Abs(s.ColIndex - t.ColIndex);
int rowDiff = Math.Abs(s.RowIndex - t.RowIndex);
return(colDiff <= 1 && rowDiff <= 1);
});
// Setup up the castle, it is only possible if the king and the rook have not been moved before and
// there is no piece between the king and the rook.
//
kingRules.ValidMove((s, t, c) =>
{
// Check the target is a friendly rook.
//
if (t.PieceType != EChessPieceType.Rook || s.PieceColor != t.PieceColor)
{
return(false);
}
// Check the rook and the king have not been moved.
//
if (c.HasMoved(s.Identifier) || c.HasMoved(t.Identifier))
{
return(false);
}
// Check there is no piece between the king and the rook.
//
int colDiff = s.ColIndex - t.ColIndex;
int colStep = colDiff > 0 ? -1 : 1;
for (int step = 1; s.ColIndex + step * colStep != t.ColIndex; step++)
{
int col = s.ColIndex + step * colStep;
var cell = c.GetCell(CellId.Create(s.RowIndex, col));
if (cell.PieceType != EChessPieceType.Empty)
{
return(false);
}
}
return(true);
});
_gameRules.Add(kingRules);
}
private CellStatusViewModel fetchCell(CellId identifier)
{
return(Cells[identifier.Row][identifier.Col]);
}
public IReadOnlyList <CellId> ValidMovesForCell(CellId source)
{
return(_gameRules.ValidMovesForCell(source, _chessboard));
}
public Move(CellId source, CellId target)
{
Source = source;
Target = target;
}
public ChessCellModel GetCell(CellId cellId)
{
return(_cells[cellId]);
}