Org-Mode Calendar Notifications

I was wondering if I could create notifications for my calendar entries in org-mode on Windows and Linux and it turns out, that the setup isn't that complex.

The appt module can display notifications for specific appointments, so we need to export org-mode entries as appointments:

(require 'appt)
(appt-activate t)

(defun fw/org-agenda-to-appt ()
  "Rebuild all appt reminders using org."
  (interactive)
  (setq appt-time-msg-list nil)
  (org-agenda-to-appt))

(fw/org-agenda-to-appt)
(add-hook 'org-agenda-finalize-hook 'fw/org-agenda-to-appt)

The above snippet will create appointments when Emacs boots up and every time when we open org-agenda. The appt notifications appear in a mini-buffer, which disappears after a few seconds. We can get persistent notifications by using a different "backend" such as the Windows 10 notifications area (via the PowerShell module BurntToast) or the Linux command line tool notify-send:

(defun fw/appt-disp-linux (min-to-app new-time msg)
  "A custom `appt-disp-window-function' which uses `notifications'."
  (require 'notifications)
  (notifications-notify :title msg :timeout 0))

(defun fw/appt-disp-windows (min-to-app new-time msg)
  "A custom `appt-disp-window-function' which uses the PowerShell module 'BurntToast'"
  (shell-command
   (concat "powershell.exe -Command \"New-BurntToastNotification -Text '" msg "'\"")))

(when (eq system-type 'gnu/linux)
  (progn
    (setq appt-display-format 'window)
    (setq appt-disp-window-function (function fw/appt-disp-linux))
    (setq appt-delete-window-function (lambda nil))))

(when (eq system-type 'windows-nt)
  (progn
    (setq appt-display-format 'window)
    (setq appt-disp-window-function (function fw/appt-disp-windows))
    (setq appt-delete-window-function (lambda nil))))