private bool AttemptMove(Square destination)
{
if (_selectedSquare == null)
{
throw new NullReferenceException("selected square null while attempting move!");
}
Piece selectedPiece = _selectedSquare.piece;
int rowChange = destination.row - _selectedSquare.row;
int columnChange = destination.column - _selectedSquare.column;
bool moveLegal = false;
bool castle = false;
switch (selectedPiece.type)
{
case "Pawn": {
int movementDirection = selectedPiece.color == "White" ? 1 : -1;
if (rowChange == 2 * movementDirection && columnChange == 0 && selectedPiece.movesMade == 0 &&
(_squares[destination.row - movementDirection][destination.column].piece == null))
{
//this allows first step of size 2
}
else if (rowChange != movementDirection)
{
Debug.Log("Invalid move, pawn can only move forwards, by 1 or at first 2 squares!");
return(false);
}
if (columnChange == 0)
{
//Move pawn forwards
if (destination.piece == null)
{
moveLegal = true;
break;
}
Debug.Log("Invalid move, a piece is blocking your way!");
return(false);
}
if (columnChange == 1 || columnChange == -1)
{
//move diagonally only on top of other pieces!
if (destination.piece != null && destination.piece.color != _turn)
{
moveLegal = true;
break;
}
Debug.Log("Invalid move, no pieces to attack here!");
return(false);
}
Debug.Log("Pawn can only move 1 square diagonally!");
return(false);
}
case "Rook": {
if (rowChange != 0 && columnChange != 0)
{
Debug.Log("Rook can only move up, down, left, and right!");
return(false);
}
if (rowChange == 0)
{
int row = _selectedSquare.row;
int sign = Math.Sign(columnChange);
for (int column = _selectedSquare.column + sign;
Math.Abs(column - _selectedSquare.column) < Math.Abs(columnChange); column += sign)
{
if (_squares[row][column].piece == null)
{
continue;
}
Debug.Log("Pieces in the way, cannot go over them!" + row + ", " + column);
return(false);
}
}
if (columnChange == 0)
{
int column = _selectedSquare.column;
int sign = Math.Sign(rowChange);
for (int row = _selectedSquare.row + sign; Math.Abs(row - _selectedSquare.row) < Math.Abs(rowChange); row += sign)
{
if (_squares[row][column].piece == null)
{
continue;
}
Debug.Log("Pieces in the way of rook!" + row + ", " + column);
return(false);
}
}
//Move is legal
moveLegal = true;
break;
}
case "Bishop": {
if (Math.Abs(rowChange) != Math.Abs(columnChange))
{
Debug.Log("Bishops can only move diagonally!");
return(false);
}
int rowSign = Math.Sign(rowChange);
int columnSign = Math.Sign(columnChange);
for (int inc = 1; inc < Math.Abs(rowChange); inc++)
{
if (_squares[_selectedSquare.row + rowSign * inc][_selectedSquare.column + columnSign * inc].piece == null)
{
continue;
}
return(false);
}
//Move legal
moveLegal = true;
break;
}
case "Knight": {
if (!((Math.Abs(rowChange) == 2 && Math.Abs(columnChange) == 1) ||
(Math.Abs(rowChange) == 1 && Math.Abs(columnChange) == 2)))
{
Debug.Log("Knight can only move in an L patter!");
return(false);
}
moveLegal = true;
break;
}
case "Queen": {
if (!((Math.Abs(rowChange) == Math.Abs(columnChange)) || rowChange == 0 || columnChange == 0))
{
Debug.Log("Queen can only move in the 8 main directions!");
return(false);
}
int rowSign = Math.Sign(rowChange);
int columnSign = Math.Sign(columnChange);
for (int inc = 1; inc < Math.Abs(rowChange); inc++)
{
if (_squares[_selectedSquare.row + rowSign * inc][_selectedSquare.column + columnSign * inc].piece == null)
{
continue;
}
Debug.Log("Pieces in the way of Queen!");
return(false);
}
moveLegal = true;
break;
}
case "King": {
if (Math.Abs(rowChange) > 1 || Math.Abs(columnChange) > 1)
{
if (rowChange == 0 && Math.Abs(columnChange) == 2 && _selectedSquare.row % 7 == 0 && selectedPiece.movesMade == 0)
{
//Allow castling
int rookColumn = columnChange == 2 ? 7 : 0;
Square rookSquare = _squares[_selectedSquare.row][rookColumn];
if (rookSquare.piece != null && rookSquare.piece.type.Equals("Rook") && rookSquare.piece.movesMade == 0)
{
//King and rook both there
for (int col = _selectedSquare.column + Math.Sign(columnChange);
col == 1 || col == 6; col += Math.Sign(columnChange))
{
if (_squares[_selectedSquare.row][col].piece == null)
{
continue;
}
Debug.Log("Pieces in the way, cannot castle!");
return(false);
}
//If this is reached the move is legal, do castle;
castle = true;
}
else
{
Debug.Log("King cannot castle without rook!");
return(false);
}
}
else
{
Debug.Log("King can only move 1 square in each direction!");
return(false);
}
}
for (int i = -1; i < 2; i++)
{
for (int j = -1; j < 2; j++)
{
int rowIndex = Mathf.Clamp(destination.row + i, 0, 7);
int columnIndex = Mathf.Clamp(destination.column + j, 0, 7);
Piece temp = _squares[rowIndex][columnIndex].piece;
if (temp == null || temp.type != "King" || temp.color == _turn)
{
continue;
}
Debug.Log("King can't move close to the opposing king!");
return(false);
}
}
moveLegal = true;
if (castle)
{
DoMove(_selectedSquare.row, columnChange == 2 ? 7 : 0,
_selectedSquare.row, destination.column - Math.Sign(columnChange),
false, true);
}
break;
}
default:
Debug.Log("This should never happen!");
break;
}
//return false if this move is not legal
if (!moveLegal)
{
return(false);
}
selectedPiece.movesMade++;
string destroyedPieceType = "None";
string destroyedPieceColor = "None";
if (destination.piece != null)
{
if (destination.piece.color == _turn)
{
Debug.Log("Cannot destroy own piece!");
return(false);
}
destroyedPieceType = destination.piece.type;
destroyedPieceColor = destination.piece.color;
if (destination.piece.type.Equals("King"))
{
_gameOver = true;
}
StartCoroutine(DestroyPiece(destination.piece.gameObject));
}
destination.piece = selectedPiece;
_selectedSquare.piece = null;
Transform destinationTransform = destination.transform;
Transform selectedPieceTransform = selectedPiece.transform;
selectedPieceTransform.parent = destinationTransform;
Vector3 destinationPosition = destinationTransform.position;
Vector3 startSquarePosition = _selectedSquare.transform.position;
_replayManager.DoMove(_selectedSquare.row, _selectedSquare.column,
destination.row, destination.column, destroyedPieceType, destroyedPieceColor, castle);
StartCoroutine(MovePiece(selectedPieceTransform,
new Vector2(destinationPosition.x, destinationPosition.z),
new Vector2(startSquarePosition.x, startSquarePosition.z)));
return(true);
}