Selezione parole con offset

function getWords(string $string, int $words, int $offset = 0): string
{
    $ret = '';

    $insideTag = FALSE;
    $wCount = 0;
    $lastChar = NULL;
    $offset = max($offset, 0);

    for ($i = 0; ($i < \mb_strlen($string)) && ($wCount < ($words + $offset)); $i++)
    {
        $char = \mb_substr($string, $i, 1);

        if ($char === '<')
        {
            $insideTag = TRUE;

            if (\ctype_alnum($lastChar))
            {
                $wCount++;
            }
        }
        else if ($char === '>')
        {
            $insideTag = FALSE;
        }
        else if (!\ctype_alnum($char))
        {
            if (!$insideTag && \ctype_alnum($lastChar))
            {
                $wCount++;
            }
        }

        $lastChar = $char;

        if (!$insideTag && ($char !== '>') && ($wCount >= $offset))
        {
            $ret .= $char;
        }
    }

    $ret = trim($ret);

    while (!\ctype_alnum(\mb_substr($ret, 0, 1)))
    {
        $ret = \mb_substr($ret, 1);
    }

    return $ret;
}