private function extractSearchTerms(string $query): array
    {
        $search_terms = [];

        // Words in double quotes stay together
        while (preg_match('/"([^"]+)"/', $query, $match)) {
            $search_terms[] = trim($match[1]);
            $query          = str_replace($match[0], '', $query);
        }

        // Other words get treated separately
        while (preg_match('/[\S]+/', $query, $match)) {
            $search_terms[] = trim($match[0]);
            $query          = str_replace($match[0], '', $query);
        }

        return $search_terms;
    }