public (bool IsCheck, bool IsMate) IsCheckOrMate(King king)
{
bool isInCheck = false;
foreach (var piece in this.Instance)
{
if (piece != null && piece.Type != PieceTypeEnum.King && piece.Color != king.Color)
{
var pieceMoves = piece.AvailableMoves(this);
if (pieceMoves.Contains(new KeyValuePair <int, int>(king.CurrentLocation_x, king.CurrentLocation_y)))
{
isInCheck = true;
// conditions for mate -
// 1 - all possible moves for king result in checks
// 2 - the piece putting king in check isn't capturable
// 3 - no piece can intercept the check path
// 1
var kingMoves = king.AvailableMoves(this);
foreach (var kingMove in kingMoves)
{
// simulate moves on a board copy to see if it results in check
var kingCopy = (King)this.DeepClone(king);
var boardCopy = (Board)this.DeepClone(this);
boardCopy.MovePiece(kingCopy, kingMove.Key, kingMove.Value);
if (!kingCopy.IsInCheck(boardCopy))
{
// has an available move, not a mate
return(true, false);
}
}
// 2/3
var checkPath = piece.GetCheckPath(this);
foreach (var defensePiece in this.Instance)
{
if (defensePiece != null && defensePiece.Color != piece.Color)
{
var defensePieceMoves = defensePiece.AvailableMoves(this);
// 2. see if a defense piece can capture the piece putting king in check
if (defensePieceMoves.Contains(new KeyValuePair <int, int>(piece.CurrentLocation_x, piece.CurrentLocation_y)))
{
// can capture piece
return(true, false);
}
// 3. see if any defenses piece can intercept the check path
if (defensePieceMoves.Any(x => checkPath.Any(e => e.Key == x.Key && e.Value == x.Value)))
{
// can intercept check
return(true, false);
}
}
}
}
}
}
return(isInCheck, true);
}