#!%GUILE% --no-auto-compile

-*- scheme -*-

!#

;;;; This file is part of Guile Netlink

;;;;

;;;; Copyright (C) 2025 Dale Mellor

;;;; 

;;;; This library 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 library 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 library.  If not, see <https://www.gnu.org/licenses/>.

(unless (getenv "NETLINK_UNINSTALLED")

  (set! %load-path (cons "%modsrcdir%" %load-path))

  (set! %load-compiled-path (cons "%modbuilddir%" %load-compiled-path)))

;; This is both an example of use of guile-netlinkʼs ACPI notifications

;; interface‒it being the simplest such application that we can think of‒, and

;; a useful diagnostic tool in its own right to help fathom the meaning of the

;; messages coming out of the Linux kernel, as these are not at all well

;; documented and depend critically on the nature of the physical computer

;; system and the kernel build configuration.

;;

;; There are no command-line arguments; the program will simply sit and listen

;; for kernel ACPI events to be broadcast, and then report the data returned

;; on the screen.  It is left as an exercise to the end user (hah!) to work

;; out the actual meanings of these data.

;; Use guile-netlinkʼs ACPI interface.  The use of a prefix is discretionary;

;; it is useful to have in example code.

(use-modules  ((netlink acpi) #:prefix ACPI::))

(define (event-action event)

  "Print the contents of the EVENT object in a line on the screen."

  ((@ (ice-9 format) format)

      #t

      "device: ~20a, bus ID: ~15a, type: ~8,'0x, data: ~8,'0x\n"

      (ACPI::event-device-class  event)

      (ACPI::event-bus-id        event)

      (ACPI::event-kind          event)

      (ACPI::event-data          event)))

;; Connect to the kernelʼs Netlink ACPI notifier and obtain the three control

;; procedures for this connection.

((@ (ice-9 receive) receive)

    (ACPI::read-selector  ACPI::process-events  ACPI::close-connection)

    (ACPI::connect-events)

    ;; In a tight loop use the first procedure in a (select _) call to wait

    ;; for data from the connection, then use the second procedure to actually

    ;; read and interpret those data and call the above event-action function

    ;; on any ACPI event data found there.

    (let loop ()

      (select (list (ACPI::read-selector)) '() '())

      (ACPI::process-events event-action)

      (loop))

    ;; We wonʼt ever get here, but if for some reason we did... use the third

    ;; procedure given us from the connection to shut that connection down.

    (ACPI::close-connection))