Points for bbPress topic author when topic is favorited

add_filter( 'mycred_setup_hooks', 'register_my_bbp_fav_hook' );
function register_my_bbp_fav_hook( $installed )
{
    $installed['bbp_fav_topic'] = array(
        'title'       => __( 'bbPress Favorites', 'mytheme' ),
        'description' => __( 'Give points to topic author when topic is favorited.', 'mytheme' ),
        'callback'    => array( 'my_bbp_fav_hook' )
    );
    return $installed;
}

if ( !class_exists( 'my_bbp_fav_hook' ) ) {
    class my_bbp_fav_hook extends myCRED_Hook {

        function __construct( $hook_prefs ) {
            parent::__construct( array(
                'id'       => 'bbp_fav_topic',
                'defaults' => array(
                    'fav_topic' => array(
                        'creds'   => 1,
                        'log'     => '%plural% for someone favorited your forum topic'
                    )
                )
            ), $hook_prefs );
        }

        public function run() {
            add_action( 'bbp_add_user_favorite',  array( $this, 'fav_topic' ), 10, 2 );
        }

        /**
         * Check if the user qualifies for points
         */
        public function fav_topic( $user_id, $topic_id ) {
            // $user_id is loggedin_user, not author

            // get topic author
            $topic_author = get_post_field( 'post_author', $topic_id );

            // Check if user is excluded (required)
            if ( $this->core->exclude_user( $topic_author ) || $topic_author == $user_id  ) return;

            // Make sure this is a unique event
            if ( $this->has_entry( 'topic_favorited', $topic_id, $topic_author ) ) return;

            // Execute
            $this->core->add_creds(
                'topic_favorited',
                $topic_author,
                $this->prefs['fav_topic']['creds'],
                $this->prefs['fav_topic']['log'],
                $topic_id
            );

            // Clean up
            //unset( $this );
        }

        /**
         * Add Settings
         */
         public function preferences() {
            // Our settings are available under $this->prefs
            $prefs = $this->prefs; ?>

    <!-- First we set the amount -->
    <label class="subheader"><?php echo $this->core->plural(); ?></label>
    <ol>
        <li>
            <div class="h2"><input type="text" name="<?php echo $this->field_name( array( 'fav_topic' => 'creds' ) ); ?>" id="<?php echo $this->field_id( array( 'fav_topic' => 'creds' ) ); ?>" value="<?php echo $this->core->format_number( $prefs['fav_topic']['creds'] ); ?>" size="8" /></div>
        </li>
    </ol>
    <!-- Then the log template -->
    <label class="subheader"><?php _e( 'Log template', 'mycred' ); ?></label>
    <ol>
        <li>
            <div class="h2"><input type="text" name="<?php echo $this->field_name( array( 'fav_topic' => 'log' ) ); ?>" id="<?php echo $this->field_id( array( 'fav_topic' => 'log' ) ); ?>" value="<?php echo $prefs['fav_topic']['log']; ?>" class="long" /></div>
        </li>
    </ol>
    <?php
        }

        /**
         * Sanitize Preferences
         */
        public function sanitise_preferences( $data ) {
            $new_data = $data;

            // Apply defaults if any field is left empty
            $new_data['fav_topic']['creds'] = ( !empty( $data['fav_topic']['creds'] ) ) ? $data['fav_topic']['creds'] : $this->defaults['fav_topic']['creds'];
            $new_data['fav_topic']['log'] = ( !empty( $data['fav_topic']['log'] ) ) ? sanitize_text_field( $data['fav_topic']['log'] ) : $this->defaults['fav_topic']['log'];

            return $new_data;
        }
    }
}