BP_Media_Extractor::extract_mentions( string $richtext, string $plaintext, array $extra_args = array() )

	protected function extract_mentions( $richtext, $plaintext, $extra_args = array() ) {
		$data     = array( 'has' => array( 'mentions' => 0 ), 'mentions' => array() );
		$mentions = array();

		// If the Activity component is active, use it to parse @mentions.
		if ( bp_is_active( 'activity' ) ) {
			$mentions = bp_activity_find_mentions( $plaintext );
			if ( ! $mentions ) {
				$mentions = array();
			}

		// If the Activity component is disabled, instead do a basic parse.
		} else {
			if ( strpos( $plaintext, '@' ) !== false ) {
				preg_match_all( '/[@]+([A-Za-z0-9-_\.@]+)\b/', $plaintext, $matches );

				if ( ! empty( $matches[1] ) ) {
					$mentions = array_unique( array_map( 'strtolower', $matches[1] ) );
				}
			}
		}

		// Build results.
		foreach ( $mentions as $user_id => $mention_name ) {
			$mention = array( 'name' => strtolower( $mention_name ) );

			// If the Activity component is active, store the User ID, too.
			if ( bp_is_active( 'activity' ) ) {
				$mention['user_id'] = (int) $user_id;
			}

			$data['mentions'][] = $mention;
		}

		$data['has']['mentions'] = count( $data['mentions'] );

		/**
		 * Filters @mentions extracted from text.
		 *
		 * @since BuddyPress 2.3.0
		 *
		 * @param array  $data       Extracted @mentions. See {@link BP_Media_Extractor::extract_mentions()} for format.
		 * @param string $richtext   Content to parse.
		 * @param string $plaintext  Copy of $richtext without any markup.
		 * @param array  $extra_args Bespoke data for a particular extractor (optional).
		 */
		return apply_filters( 'bp_media_extractor_mentions', $data, $richtext, $plaintext, $extra_args );
	}