BP_Group_Member_Query::get_gm_ids_ordered_by_activity( BP_User_Query $query, array $gm_ids = array() )

	public function get_gm_ids_ordered_by_activity( $query, $gm_ids = array() ) {
		global $wpdb;

		if ( empty( $gm_ids ) ) {
			return $gm_ids;
		}

		if ( ! bp_is_active( 'activity' ) ) {
			return $gm_ids;
		}

		$activity_table = buddypress()->activity->table_name;

		$sql = array(
			'select'  => "SELECT user_id, max( date_recorded ) as date_recorded FROM {$activity_table}",
			'where'   => array(),
			'groupby' => 'GROUP BY user_id',
			'orderby' => 'ORDER BY date_recorded',
			'order'   => 'DESC',
		);

		$sql['where'] = array(
			'user_id IN (' . implode( ',', wp_parse_id_list( $gm_ids ) ) . ')',
			'item_id = ' . absint( $query->query_vars['group_id'] ),
			$wpdb->prepare( "component = %s", buddypress()->groups->id ),
		);

		$sql['where'] = 'WHERE ' . implode( ' AND ', $sql['where'] );

		$group_user_ids = $wpdb->get_results( "{$sql['select']} {$sql['where']} {$sql['groupby']} {$sql['orderby']} {$sql['order']}" );

		return wp_list_pluck( $group_user_ids, 'user_id' );
	}