/** * @param BoardWalker $walker * @param MoveInterface $lastMove */ private function walkEnPassant(BoardWalker $walker, MoveInterface $lastMove = null) { $lastEnemyPiece = $lastMove ? $walker->getBoard()->getSquare($lastMove->getTo())->getPiece() : null; if ($lastMove === null || $lastEnemyPiece === null || $lastEnemyPiece->getType() !== PieceInterface::TYPE_PAWN) { return; } $leftToPosition = $walker->peek(BoardWalker::DIRECTION_LEFT, 1, null, true, false); $rightToPosition = $walker->peek(BoardWalker::DIRECTION_RIGHT, 1, null, true, false); if ($leftToPosition !== null) { if (abs(BoardHelper::getRowFromPosition($lastMove->getFrom()) - BoardHelper::getRowFromPosition($leftToPosition)) !== 2) { return; } if ($lastMove->getTo() === $leftToPosition) { // en passant left $walker->forwardLeft(1, false)->restart(); } } if ($rightToPosition !== null) { if (abs(BoardHelper::getRowFromPosition($lastMove->getFrom()) - BoardHelper::getRowFromPosition($rightToPosition)) !== 2) { return; } if ($lastMove->getTo() === $rightToPosition) { // en passant left $walker->forwardRight(1, false)->restart(); } } }