;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2023 Janneke Nieuwenhuizen <janneke@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix 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 Guix 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 Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (gnu home services shepherd-xyz)
  #:use-module (srfi srfi-26)

  #:use-module (ice-9 match)

  #:use-module (shepherd support)

  #:use-module (gnu home services)
  #:use-module (gnu home services shepherd)
  #:use-module (gnu packages version-control)
  #:use-module (gnu services configuration)
  #:use-module (gnu services shepherd)
  #:use-module (guix records)
  #:use-module (guix gexp)

  #:export (home-git-daemon-configuration
            home-git-daemon-service-type))

;;; Commentary:
;;
;; Home Services for the Shepherd.
;;
;; Example configurations.
;;
;; Git daemon: use $HOME/src as the base directory.
;;
;; (service home-git-service-type
;;          (home-git-configuration
;;           (root (string-append (getenv "HOME") "/src"))))
;;
;;; Code:

;;;
;;; Directories.
;;;
(define %user-data-home
  ;; Default cache directory if shepherd is run as a normal user.
  (string-append (or (getenv "XDG_DATA_HOME")
                     (string-append user-homedir "/.local/share"))))

(define %user-log-dir
  ;; Default log directory if shepherd is run as a normal user.
  (string-append (or (getenv "XDG_DATA_HOME")
                     (string-append user-homedir "/.local/var/log"))))


;;;
;;; Git daemon.
;;;
(define-record-type* <home-git-daemon-configuration>
  home-git-daemon-configuration make-home-git-daemon-configuration
  home-git-daemon-configuration?
  (git           home-git-daemon-git                     ;file-like
                 (default git))
  (root          home-git-daemon-root                    ;string
                 (default (string-append %user-data-home
                                         "/git-daemon")))
  (export-all?   home-git-daemon-export-all?             ;boolean
                 (default #f))
  (listen        home-git-daemon-configuration-listen    ;list of string
                 (default '()))
  (port          home-git-daemon-configuration-port      ;number | #f
                 (default #f))
  (whitelist     home-git-daemon-configuration-whitelist ;list of string
                 (default '()))
  (extra-options home-git-daemon-extra-options           ;list of string
                 (default '())))

(define (home-git-daemon-services config)
  "Return a <shepherd-service> for a git daemon with CONFIG."
  (match config
    (($ <home-git-daemon-configuration>
        git root export-all? listen port whitelist extra-options)
     (let* ((git (file-append git "/bin/git"))
            (command `(,git
                       "daemon"
                       ,(string-append "--base-path=" root)
                       ,@(if export-all?
                             '("--export-all")
                             '())
                       ,@(map (cute string-append "--listen=" <>) listen)
                       ,@(if port
                             `(,(string-append
                                 "--port=" (number->string port)))
                             '())
                       ,@extra-options
                       ,@whitelist))
            (log-file (string-append %user-log-dir "/git-daemon.log")))
       (list (shepherd-service
              (documentation "Run the git daemon.")
              (provision '(git-daemon))
              (start #~(make-forkexec-constructor '#$command
                                                  #:log-file #$log-file))
              (stop #~(make-kill-destructor))))))))

(define home-git-daemon-service-type
  (service-type
   (name 'home-git-daemon)
   (default-value (home-git-daemon-configuration))
   (extensions
    (list (service-extension home-shepherd-service-type
                             home-git-daemon-services)))
   (description
    "Install and configure the git-daemon as a shepherd service.")))