// this is to add a fake component to BuddyPress. A registered component is needed to add notifications
function custom_filter_notifications_get_registered_components( $component_names = array() ) {
    // Force $component_names to be an array
    if ( ! is_array( $component_names ) ) {
        $component_names = array();
    }
    // Add 'custom' component to registered components array
    $component_names[] = 'kleo_likes';
    // Return component's with 'custom' appended
    return $component_names;
}
add_filter( 'bp_notifications_get_registered_components', 'custom_filter_notifications_get_registered_components' );

// this gets the saved item id, compiles some data and then displays the notification
function custom_format_buddypress_notifications( $content, $post_id, $secondary_item_id, $total_items, $format = 'string', $action ) {
    // New custom notifications

    if ( 'kleo_likes_action' === $action ) {

        $post = get_post( $post_id );
        if($secondary_item_id > 0) {
            $user_data_info = get_userdata( $secondary_item_id );
            $liker_name = $user_data_info->user_nicename;
        }else {
            $liker_name = 'Guest';
        }
        $custom_title = $post->post_title;
        $custom_link  = get_permalink($post->ID);
        $custom_text = $liker_name . __(' liked your post ', 'kleo_framework') . get_the_title( $post->ID );

        // WordPress Toolbar
        if ( 'string' === $format ) {
            $return = apply_filters( 'custom_filter', '<a href="' . esc_url( $custom_link ) . '" title="' . esc_attr( $custom_title ) . '">' . esc_html( $custom_text ) . '</a>', $custom_text, $custom_link );
            // Deprecated BuddyBar
        } else {
            $return = apply_filters( 'custom_filter', array(
                'text' => $custom_text,
                'link' => $custom_link
            ), $custom_link, (int) $total_items, $custom_text, $custom_title );
        }

        return $return;

    }

    return $content;

}
bp_notifications_get_notifications_for_user();
add_filter( 'bp_notifications_get_notifications_for_user', 'custom_format_buddypress_notifications', 10, 6 );
// this hooks to comment creation and saves the comment id
function bp_custom_add_notification( $post_id ) {
    $post = get_post( $post_id );
    $author_id = $post->post_author;

        bp_notifications_add_notification( array(
            'user_id'           => $author_id,
            'item_id'           => $post_id,
            'secondary_item_id' => get_current_user_id(),
            'component_name'    => 'kleo_likes',
            'component_action'  => 'kleo_likes_action',
            'date_notified'     => bp_core_current_time(),
            'is_new'            => 1,
    ) );

}
add_action( 'after_kleo_posts_like', 'bp_custom_add_notification', 99 );