/**
* {@inheritdoc}
*/
public function possibleCapturesFrom($position, BoardInterface $board)
{
$moves = [];
$fromPiece = $board->getSquare($position)->getPiece();
foreach ($this->possibleMovesFrom($position, $board) as $possibleMove) {
$toPiece = $board->getSquare($possibleMove->getTo())->getPiece();
if ($toPiece !== null && $toPiece->getColor() !== $fromPiece->getColor()) {
$moves[] = $possibleMove;
}
}
return $moves;
}
/**
* @param int $direction The direction to step into
* @param int $jumps The number of jumps to make in this direction
* @param int|null $startingPosition
* @param bool $ignoreCapture
*
* @return int|null The expected position, or null if the move is not possible
*
* @throws \InvalidArgumentException
*/
public function peek($direction, $jumps = 1, $startingPosition = null, $ignoreCapture = false, $requireAttack = false)
{
$newPosition = null;
if ($startingPosition !== null) {
$column = BoardHelper::getColumnFromPosition($startingPosition);
$row = BoardHelper::getRowFromPosition($startingPosition);
} else {
$column = $this->getColumn();
$row = $this->getRow();
}
switch ($direction) {
case self::DIRECTION_FORWARD:
if ($this->color === Color::WHITE) {
$newRow = $this->formatNumber($row + $jumps);
} else {
$newRow = $this->formatNumber($row - $jumps);
}
if ($newRow !== null) {
$newPosition = intval($column . $newRow);
}
break;
case self::DIRECTION_FORWARDRIGHT:
if ($this->color === Color::WHITE) {
$newColumn = $this->formatNumber($column + $jumps);
$newRow = $this->formatNumber($row + $jumps);
} else {
$newColumn = $this->formatNumber($column - $jumps);
$newRow = $this->formatNumber($row - $jumps);
}
if ($newColumn !== null && $newRow !== null) {
$newPosition = intval($newColumn . $newRow);
}
break;
case self::DIRECTION_RIGHT:
if ($this->color === Color::WHITE) {
$newColumn = $this->formatNumber($column + $jumps);
} else {
$newColumn = $this->formatNumber($column - $jumps);
}
if ($newColumn !== null) {
$newPosition = intval($newColumn . $row);
}
break;
case self::DIRECTION_BACKWARDRIGHT:
if ($this->color === Color::WHITE) {
$newColumn = $this->formatNumber($column + $jumps);
$newRow = $this->formatNumber($row - $jumps);
} else {
$newColumn = $this->formatNumber($column - $jumps);
$newRow = $this->formatNumber($row + $jumps);
}
if ($newColumn !== null && $newRow !== null) {
$newPosition = intval($newColumn . $newRow);
}
break;
case self::DIRECTION_BACKWARD:
if ($this->color === Color::WHITE) {
$newRow = $this->formatNumber($row - $jumps);
} else {
$newRow = $this->formatNumber($row + $jumps);
}
if ($newRow !== null) {
$newPosition = intval($column . $newRow);
}
break;
case self::DIRECTION_BACKWARDLEFT:
if ($this->color === Color::WHITE) {
$newColumn = $this->formatNumber($column - $jumps);
$newRow = $this->formatNumber($row - $jumps);
} else {
$newColumn = $this->formatNumber($column + $jumps);
$newRow = $this->formatNumber($row + $jumps);
}
if ($newColumn !== null && $newRow !== null) {
$newPosition = intval($newColumn . $newRow);
}
break;
case self::DIRECTION_LEFT:
if ($this->color === Color::WHITE) {
$newColumn = $this->formatNumber($column - $jumps);
} else {
$newColumn = $this->formatNumber($column + $jumps);
}
if ($newColumn !== null) {
$newPosition = intval($newColumn . $row);
}
break;
case self::DIRECTION_FORWARDLEFT:
if ($this->color === Color::WHITE) {
$newColumn = $this->formatNumber($column - $jumps);
$newRow = $this->formatNumber($row + $jumps);
} else {
$newColumn = $this->formatNumber($column + $jumps);
$newRow = $this->formatNumber($row - $jumps);
}
if ($newColumn !== null && $newRow !== null) {
$newPosition = intval($newColumn . $newRow);
}
break;
default:
throw new \InvalidArgumentException(sprintf('Unknown direction to calculate: %s', $direction));
}
if ($ignoreCapture !== true && $newPosition !== null) {
$toPiece = $this->board->getSquare($newPosition)->getPiece();
if (null !== $toPiece) {
if ($toPiece->getColor() === $this->getColor()) {
// own piece, can't capture
return null;
}
} elseif ($requireAttack === true) {
return null;
}
}
return $newPosition;
}