BuddyPress.org

I’d like to create a topic with his name at user registration.

What’s wrong with this code：

function bp_user_fst_topic (){

    // get user name	
    $user_data = get_user_by( 'id', bp_loggedin_user_id() )->data;
    $user_nicename = = $user_data->user_nicename;

    // create slug
    $new_slug = 'first-topic-' . $user_nicename;

    // create topic
    $post_value = array(
        'post_name' => $new_slug,
        'post_type' => 'topic',
        'post_author' => $userid,
        'post_title' => 'first topic',
        'post_content' => 'This topic was created when you registered.',
        'post_category' => array(1,5), 
        'tags_input' => array('tag1','tag2'), 
        'post_status' => 'publish' 
    );
    wp_insert_post($post_value);

}
add_filter( 'bp_core_activated_user', 'bp_user_fst_topic',1 );

Could you tell me how to do this..?