BBP_BuddyPress_Activity::group_forum_topic_activity_action_callback( $action,  $activity )

	public function group_forum_topic_activity_action_callback( $action, $activity ) {
		$user_id  = $activity->user_id;
		$topic_id = $activity->secondary_item_id;
		$forum_id = bbp_get_topic_forum_id( $topic_id );

		// User
		$user_link = bbp_get_user_profile_link( $user_id );

		// Topic
		$topic_permalink = bbp_get_topic_permalink( $topic_id );
		$topic_title     = get_post_field( 'post_title', $topic_id, 'raw' );
		$topic_link      = '<a href="' . $topic_permalink . '">' . $topic_title . '</a>';

		// Group
		$group_id   = current( bbp_get_forum_group_ids( $forum_id ) );
		$group      = groups_get_group( $group_id );
		$group_link = bp_get_group_link( $group );

		return sprintf(
			esc_html__( '%1$s started the discussion %2$s in the forum %3$s', 'buddyboss' ),
			$user_link,
			$topic_link,
			$group_link
		);
	}