tag pointing to its /peptides/ page.
* Skips text that is already inside an existing tag to avoid nested links.
*
* Triggered by: PRAutoBlogger_Publisher::create_post() (before wp_insert_post).
* Dependencies: PR Core plugin (pr_peptide CPT). Gracefully no-ops if PR Core is inactive.
*
* @see core/class-publisher.php — Calls inject_links() on post_content.
* @see peptide-repo-core/includes/cpt/class-pr-core-peptide-cpt.php — Peptide CPT.
*/
class PRAutoBlogger_Peptide_Linker {
/**
* Inject peptide hyperlinks into HTML content.
*
* Every occurrence of a known peptide name is wrapped in a link to its
* database page, except when the text is already inside an tag.
*
* @param string $html Article HTML content.
* @return string HTML with peptide names hyperlinked.
*/
public static function inject_links( string $html ): string {
if ( ! post_type_exists( 'pr_peptide' ) ) {
return $html;
}
$link_map = self::build_link_map();
if ( empty( $link_map ) ) {
return $html;
}
// Build a single regex alternation of all peptide names, longest first
// so "BPC-157" matches before a hypothetical "BPC" would.
$names = array_keys( $link_map );
usort( $names, static function ( string $a, string $b ): int {
return strlen( $b ) - strlen( $a );
} );
$escaped = array_map( static function ( string $name ): string {
return preg_quote( $name, '/' );
}, $names );
// Word-boundary match, case-insensitive.
$pattern = '/\b(' . implode( '|', $escaped ) . ')\b/iu';
// Split HTML into segments: inside … tags vs. outside.
// Only replace in segments that are NOT inside an anchor tag.
return self::replace_outside_links( $html, $pattern, $link_map );
}
/**
* Build a map of peptide display names → permalink URLs.
*
* Includes the canonical title and common aliases (e.g., "BPC-157" and
* "BPC 157") so both hyphenated and space-separated forms get linked.
*
* @return array Name → URL pairs, case-preserved keys.
*/
private static function build_link_map(): array {
$peptides = get_posts( [
'post_type' => 'pr_peptide',
'post_status' => 'publish',
'posts_per_page' => 200,
'orderby' => 'title',
'order' => 'ASC',
'fields' => 'ids',
] );
$map = [];
foreach ( $peptides as $peptide_id ) {
$title = get_the_title( $peptide_id );
$url = get_permalink( $peptide_id );
if ( ! $title || ! $url ) {
continue;
}
// Canonical name (e.g., "BPC-157").
$map[ $title ] = $url;
// If the name contains hyphens, also match the space-separated
// variant (e.g., "BPC 157" → same URL as "BPC-157").
if ( strpos( $title, '-' ) !== false ) {
$space_variant = str_replace( '-', ' ', $title );
$map[ $space_variant ] = $url;
}
}
return $map;
}
/**
* Replace peptide names with links, but only outside existing tags.
*
* Splits HTML into chunks by … boundaries. Replacement only
* runs on chunks that are outside anchors, preventing nested tags.
*
* @param string $html Full HTML content.
* @param string $pattern Regex pattern matching peptide names.
* @param array $link_map Name → URL map (case-preserved keys).
* @return string HTML with replacements applied.
*/
private static function replace_outside_links( string $html, string $pattern, array $link_map ): string {
// Split on anchor tags, keeping the delimiters.
// This regex captures full … blocks as array elements.
$parts = preg_split( '/(]*>.*?<\/a>)/is', $html, -1, PREG_SPLIT_DELIM_CAPTURE );
if ( false === $parts ) {
return $html;
}
// Build a lowercase → URL lookup for case-insensitive matching.
$lower_map = [];
foreach ( $link_map as $name => $url ) {
$lower_map[ mb_strtolower( $name ) ] = $url;
}
$result = '';
foreach ( $parts as $part ) {
// If this chunk is an anchor tag, pass it through untouched.
if ( preg_match( '/^' . esc_html( $matched_text ) . '';
},
$part
);
}
return $result;
}
}