bbPress auto tags

<?php
/***
    * Plugin Name:  bbPress AutoTagger
    * Plugin URI:   http://example.org/
    * Description:  --- description here --
    * Version:      1.0
    * Author:       Shmoo
    * Author URI:   http://example.org/
    * License:      Same as WordPress I guess.
***/

//add_action( 'bbp_new_topic',  'shmoo_auto_save_tags', 10, 5 );
//add_action( 'bbp_edit_topic', 'shmoo_auto_save_tags', 10, 5 );


function shmoo_auto_save_tags() {

// Topic Tags


    // Get all bbPress topic tags inside an array + strip them to plain text
    $bbp_topic_tags = wp_tag_cloud( array( 'format' => 'array', 'taxonomy' => 'topic-tag' ) );

        function tag_stripper( &$items, $format ) {

            $items = strip_tags( $items );

        }
        array_walk( $bbp_topic_tags, 'tag_stripper' );


// Topic Content


    // Get the topic content
    $bbp_topic_content = bbp_get_topic_content();


// Match Topics Tags against Topic Content


    // Check and echo matches
    $matches = array();

    $match_found = preg_match_all( "/\b(" . implode($bbp_topic_tags,"|") . ")\b/i", $bbp_topic_content, $matches );

    if ( $match_found ) {
        $words = array_unique( $matches[0] );
            foreach( $words as $word ) {
                echo $word . ", ";
            }
    }


}