/**
* Add castling moves if available
*
* @return array the squares where the king can go
**/
protected function addCastlingSquares(King $king, array $squares)
{
$player = $king->getPlayer();
$rooks = PieceFilter::filterNotMoved(PieceFilter::filterClass(PieceFilter::filterAlive($player->getPieces()), 'Rook'));
if (empty($rooks)) {
return $squares;
}
$opponentControlledKeys = $this->getPlayerControlledKeys($player->getOpponent(), true);
foreach ($rooks as $rook) {
$kingX = $king->getX();
$kingY = $king->getY();
$dx = $kingX > $rook->getX() ? -1 : 1;
$possible = true;
foreach (array($kingX + $dx, $kingX + 2 * $dx) as $_x) {
$key = Board::postoKey($_x, $kingY);
if ($this->board->hasPieceByKey($key) || in_array($key, $opponentControlledKeys)) {
$possible = false;
break;
}
}
if ($possible) {
if (-1 === $dx && $this->board->hasPieceByKey(Board::postoKey($kingX - 3, $kingY))) {
} else {
$squares[] = $this->board->getSquareByKey($key);
}
}
}
return $squares;
}