;;; gnus-dbus.el --- DBUS integration for Gnus       -*- lexical-binding: t; -*-

;; Copyright (C) 2020-2023 Free Software Foundation, Inc.

;; Author: Eric Abrahamsen <eric@ericabrahamsen.net>

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; This library contains some Gnus integration for systems using DBUS.
;; At present it registers a signal to close all Gnus servers before
;; system sleep or hibernation.

;;; Code:

(require 'gnus)
(require 'dbus)
(declare-function gnus-close-all-servers "gnus-start")

(defcustom gnus-dbus-close-on-sleep nil
  "When non-nil, close Gnus servers on system sleep."
  :group 'gnus-dbus
  :type 'boolean)

(defvar gnus-dbus-sleep-registration-object nil
  "Object returned from `dbus-register-signal'.
Used to unregister the signal.")

(defun gnus-dbus-register-sleep-signal ()
  "Use `dbus-register-signal' to close servers on sleep."
  (when (featurep 'dbusbind)
    (setq gnus-dbus-sleep-registration-object
	  (dbus-register-signal :system
				"org.freedesktop.login1"
				"/org/freedesktop/login1"
				"org.freedesktop.login1.Manager"
				"PrepareForSleep"
				#'gnus-dbus-sleep-handler))
    (gnus-add-shutdown #'gnus-dbus-unregister-sleep-signal 'gnus)))

(defun gnus-dbus-sleep-handler (sleep-start)
  ;; Sleep-start is t before sleeping.
  (when (and sleep-start
	     (gnus-alive-p))
    (condition-case nil
	(gnus-close-all-servers)
      (error nil))))

(defun gnus-dbus-unregister-sleep-signal ()
  (condition-case nil
      (dbus-unregister-object
       gnus-dbus-sleep-registration-object)
    (wrong-type-argument nil)))

(provide 'gnus-dbus)
;;; gnus-dbus.el ends here
