chamilo / chamilo-lms

	 * @param 	int $id The identifier of the announcement that should be

	 * @return	bool	True on success, false on failure

	 */

	public static function delete_announcement($id)

    {

		$db_table = Database :: get_main_table(TABLE_MAIN_SYSTEM_ANNOUNCEMENTS);

		$id = intval($id);

		$sql = "DELETE FROM ".$db_table." WHERE id =".$id;

		$res = Database::query($sql);

		if ($res === false) {

			return false;

		}

		return true;

	}

	/**

	 * Gets an announcement

     * Get the new messages for the current user from the database.

     * @return int

     */

    public static function get_new_messages()

    {

        $table = Database::get_main_table(TABLE_MESSAGE);

        if (!api_get_user_id()) {

            return false;

        }

        $sql = "SELECT * FROM $table

                WHERE

                    user_receiver_id=".api_get_user_id()." AND

                    msg_status=".MESSAGE_STATUS_UNREAD;

        $result = Database::query($sql);

        $i = Database::num_rows($result);

        return $i;

    }

    /**

     * Get the list of user_ids of users who are online.