public ChessGame MoveChessPiece(ChessGame game, Position startPosition, Position targetPosition)
{
var chessBoard = new ChessBoard(game.Board);
if (!chessBoard.IsValidPosition(startPosition))
{
var errorMessage = $"The starting position ({startPosition}) is not on the board";
throw new InvalidOperationException(errorMessage);
}
if (!chessBoard.IsValidPosition(targetPosition))
{
var errorMessage = $"The target position ({targetPosition}) is not on the board";
throw new InvalidOperationException(errorMessage);
}
if (startPosition.Equals(targetPosition))
{
var errorMessage = $"The starting position ({startPosition}) was the same as the target position ({targetPosition})";
throw new InvalidOperationException(errorMessage);
}
var pieceInSource = chessBoard.GetPiece(startPosition);
var pieceInTarget = chessBoard.GetPiece(targetPosition);
if (pieceInSource == null)
{
var errorMessage = $"There is no piece in the starting position ({startPosition})";
throw new InvalidOperationException(errorMessage);
}
var moveChecker = new MoveChecker();
var move = new Move(startPosition, targetPosition);
if (!moveChecker.IsValidMovement(chessBoard, pieceInSource, move))
{
var errorMessage = $"This move (Rows: {move.X}, Cols: {move.Y}) is not valid for this piece ({pieceInSource}).";
throw new InvalidOperationException(errorMessage);
}
if (moveChecker.MoveIsBlocked(chessBoard, pieceInSource, pieceInTarget, targetPosition, move))
{
var errorMessage = $"This move (Rows: {move.X}, Cols: {move.Y}) is blocked by another piece.";
throw new InvalidOperationException(errorMessage);
}
if (moveChecker.WouldLeaveInCheck())
{
var errorMessage = $"This move (Rows: {move.X}, Cols: {move.Y}) would leave the current player in check.";
throw new InvalidOperationException(errorMessage);
}
chessBoard.SetPosition(startPosition, null);
if (pieceInSource.Type == "Pawn")
{
switch (pieceInSource.Colour)
{
case Player.Black when targetPosition.Row == 7:
chessBoard.SetPosition(targetPosition, new Queen(Player.Black));
game.RemovedPieces.Add(pieceInSource);
break;
case Player.White when targetPosition.Row == 0:
chessBoard.SetPosition(targetPosition, new Queen(Player.White));
game.RemovedPieces.Add(pieceInSource);
break;
}
}
else
{
chessBoard.SetPosition(targetPosition, pieceInSource);
}
if (pieceInTarget != null)
{
game.RemovedPieces.Add(pieceInTarget);
}
return(new ChessGame
{
Board = new ChessBoard().GetBoard(),
ActivePlayer = game.ActivePlayer == Player.White ? Player.Black : Player.White,
GameState = "",
RemovedPieces = game.RemovedPieces
});
}