class PrefetchedResult

class PrefetchedResult extends ResultBase {
    use FetchModeTrait;
    
    /**
     * The column names.
     */
    public readonly array $columnNames;
    
    /**
     * The current row index in the result set.
     */
    protected ?int $currentRowIndex = NULL;
    
    /**
     * Constructor.
     *
     * @param \Drupal\Core\Database\Statement\FetchAs $fetchMode
     *   The fetch mode.
     * @param array{class: class-string, constructor_args: list<mixed>, column: int, cursor_orientation?: int, cursor_offset?: int} $fetchOptions
     *   The fetch options.
     * @param array $data
     *   The prefetched data, in FetchAs::Associative format.
     * @param int|null $rowCount
     *   The row count.
     */
    public function __construct(FetchAs $fetchMode, array $fetchOptions, array $data, ?int $rowCount) {
        parent::__construct($fetchMode, $fetchOptions);
        $this->columnNames = isset($this->data[0]) ? array_keys($this->data[0]) : [];
        $this->currentRowIndex = -1;
    }
    
    /**
     * {@inheritdoc}
     */
    public function rowCount() : ?int {
        return $this->rowCount;
    }
    
    /**
     * {@inheritdoc}
     */
    public function setFetchMode(FetchAs $mode, array $fetchOptions) : bool {
        // We do not really need to do anything here, since calls to any of this
        // class' methods require an explicit fetch mode to be passed in, and we
        // have no longer an active client statement to which we may want to pass
        // the default fetch mode. Just return TRUE.
        return TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function fetch(FetchAs $mode, array $fetchOptions) : array|object|int|float|string|bool|null {
        $this->currentRowIndex++;
        if (!isset($this->data[$this->currentRowIndex])) {
            $this->currentRowIndex = NULL;
            return FALSE;
        }
        $rowAssoc = $this->data[$this->currentRowIndex];
        unset($this->data[$this->currentRowIndex]);
        return $this->assocToFetchMode($rowAssoc, $mode, $fetchOptions);
    }
    
    /**
     * {@inheritdoc}
     */
    public function fetchAllKeyed(int $keyIndex = 0, int $valueIndex = 1) : array {
        if (!isset($this->columnNames[$keyIndex]) || !isset($this->columnNames[$valueIndex])) {
            return [];
        }
        $key = $this->columnNames[$keyIndex];
        $value = $this->columnNames[$valueIndex];
        $result = [];
        while ($row = $this->fetch(FetchAs::Associative, $this->fetchOptions)) {
            $result[$row[$key]] = $row[$value];
        }
        return $result;
    }

}