// comment 
function convert_external_links_comment($comment_text) {
	$outlink_options = get_option('external-link-options');
	$enable = $outlink_options['enable-outlink'];
	if (!$enable) {
		return $comment_text;
	}

	if (!is_string($comment_text)) {
		return $comment_text;
	}

	$domain_ignore = [];
	if (isset($outlink_options['ignore-domain']) && !empty($outlink_options['ignore-domain'])) {
		$domain_ignore = explode("\r\n", $outlink_options['ignore-domain']);
	}

	libxml_use_internal_errors(true);
	$dom = new DOMDocument('1.0', 'UTF-8');
	$dom->loadHTML('<?xml encoding="UTF-8">' . $comment_text, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
	libxml_clear_errors();

	$links = $dom->getElementsByTagName('a');
	$replacements = [];

	foreach ($links as $link) {
		$href = $link->getAttribute('href');
		if (strpos($href, home_url()) !== 0 && strpos($href, 'http') === 0) {
			$parsed_url = parse_url($href);
			$domain = $parsed_url['host'];
			if (!in_array($domain, $domain_ignore)) {
				$link->removeAttribute('href');
				$replacement = $dom->createElement('span', $link->nodeValue);
				foreach ($link->attributes as $attribute) {
					$replacement->setAttribute($attribute->name, $attribute->value);
				}
				$replacements[] = ['original' => $link, 'replacement' => $replacement];
			}
		}
	}

	foreach ($replacements as $replacement) {
		$replacement['original']->parentNode->replaceChild($replacement['replacement'], $replacement['original']);
	}

	return $dom->saveHTML($dom->documentElement);
}

add_filter('comment_text', 'convert_external_links_comment');