sound.lisp

;;; sound.lisp --- Set sound parameters and show them in OSD

;; Copyright © 2013–2016, 2022 Alex Kost <alezost@gmail.com>

;; This program 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.
;;
;; This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; This file provides a couple of commands to set sound parameters
;; (volume and muteness).  It looks mostly like a wrapper around
;; 'amixer' command, except that 'osd-sound' is called instead.
;;
;; This 'osd-sound' is a simple shell script that sends some Guile
;; expression to Guile-Daemon <https://github.com/alezost/guile-daemon>.
;; 2 things eventually happen: amixer is called and the sound value is
;; displayed in OSD.
;;
;; 'osd-sound' script can be found in my Guile-Daemon config:
;; <https://github.com/alezost/guile-daemon-config/blob/master/scripts/osd-sound>.

;;; Code:

(in-package :stumpwm)

(defvar al/sound-program "osd-sound"
  "Name of a program to be called with amixer arguments.")

(defvar al/sound-scontrols '("Master" "Line")
  "List of simple controls for managing.")

(defvar al/sound-current-scontrol-num 0
  "The number of the currently used simple control.")

(defvar al/sound-volume nil
  "Sound volume of the current simple control.
This variable should have (STRING . TIME) value, where STRING is the
latest value of the sound volume and TIME is the time (seconds since epoch)
of the latest update.")

(defun al/sound-get-current-scontrol ()
  "Return the current simple control from `al/sound-scontrols'."
  (nth al/sound-current-scontrol-num al/sound-scontrols))

(defun al/sound-get-next-scontrol ()
  "Return next simple control from `al/sound-scontrols'."
  (setq al/sound-current-scontrol-num
        (if (>= al/sound-current-scontrol-num
                (- (length al/sound-scontrols) 1))
            0
            (+ 1 al/sound-current-scontrol-num)))
  (al/sound-get-current-scontrol))

(defun al/sound-call (&rest args)
  "Execute `al/sound-program' using amixer ARGS."
  (run-prog al/sound-program
            :args args :wait nil :search t))

(defcommand al/sound-set-current-scontrol (&rest args) (:rest)
  "Set sound value for the current simple control.
ARGS are the rest amixer arguments after 'sset CONTROL'."
  (apply #'al/sound-call "sset" (al/sound-get-current-scontrol) args)
  (setf al/sound-volume (cons nil (get-universal-time))))

(defcommand al/sound-current-scontrol () ()
  "Show sound value of the current simple control."
  (al/sound-call "sget" (al/sound-get-current-scontrol)))

(defcommand al/sound-next-scontrol () ()
  "Switch simple control and show its sound value."
  (al/sound-call "sget" (al/sound-get-next-scontrol))
  (setf al/sound-volume (cons nil (get-universal-time))))

(defun al/sound-update-volume (&optional scontrol)
  "Update `al/sound-volume' with SCONTROL (\"Master\" by default)."
  (let* ((cmd (concat "amixer sget "
                      (or scontrol (al/sound-get-current-scontrol))
                      " | sed -rn '$s/[^[]+\\[([0-9]+)%.*/\\1/p'"))
         (output (run-shell-command cmd t))
         (res (first (split-string output '(#\newline)))))
    (setf al/sound-volume
          (cons res
                (if res
                    (get-universal-time)
                    ;; If sound volume is not available for some reason,
                    ;; do not update it for an hour.
                    (+ (get-universal-time) 3600))))))

;;; sound.lisp ends here