class StringInput

class StringInput extends ArgvInput {
    public const REGEX_UNQUOTED_STRING = '([^\\s\\\\]+?)';
    public const REGEX_QUOTED_STRING = '(?:"([^"\\\\]*(?:\\\\.[^"\\\\]*)*)"|\'([^\'\\\\]*(?:\\\\.[^\'\\\\]*)*)\')';
    
    /**
     * @param string $input A string representing the parameters from the CLI
     */
    public function __construct(string $input) {
        parent::__construct([]);
        $this->setTokens($this->tokenize($input));
    }
    
    /**
     * Tokenizes a string.
     *
     * @return list<string>
     *
     * @throws InvalidArgumentException When unable to parse input (should never happen)
     */
    private function tokenize(string $input) : array {
        $tokens = [];
        $length = \strlen($input);
        $cursor = 0;
        $token = null;
        while ($cursor < $length) {
            if ('\\' === $input[$cursor]) {
                $token .= $input[++$cursor] ?? '';
                ++$cursor;
                continue;
            }
            if (preg_match('/\\s+/A', $input, $match, 0, $cursor)) {
                if (null !== $token) {
                    $tokens[] = $token;
                    $token = null;
                }
            }
            elseif (preg_match('/([^="\'\\s]+?)(=?)(' . self::REGEX_QUOTED_STRING . '+)/A', $input, $match, 0, $cursor)) {
                $token .= $match[1] . $match[2] . stripcslashes(str_replace([
                    '"\'',
                    '\'"',
                    '\'\'',
                    '""',
                ], '', substr($match[3], 1, -1)));
            }
            elseif (preg_match('/' . self::REGEX_QUOTED_STRING . '/A', $input, $match, 0, $cursor)) {
                $token .= stripcslashes(substr($match[0], 1, -1));
            }
            elseif (preg_match('/' . self::REGEX_UNQUOTED_STRING . '/A', $input, $match, 0, $cursor)) {
                $token .= $match[1];
            }
            else {
                // should never happen
                throw new InvalidArgumentException(\sprintf('Unable to parse input near "... %s ...".', substr($input, $cursor, 10)));
            }
            $cursor += \strlen($match[0]);
        }
        if (null !== $token) {
            $tokens[] = $token;
        }
        return $tokens;
    }

}