(define-module (vkraus modules minetest)
  #:use-module (gnu services)
  #:use-module (gnu services shepherd)
  #:use-module (gnu services admin)
  #:use-module (gnu system shadow)
  #:use-module (guix gexp)
  #:use-module (guix modules)
  #:use-module (guix records)
  #:use-module (guix packages)
  #:use-module (guix build-system minetest)
  #:use-module (guix git-download)
  #:use-module (gnu packages bash)
  #:use-module (gnu packages minetest)
  #:use-module (gnu packages admin)
  #:use-module (srfi srfi-9)
  #:use-module (srfi srfi-26)
  #:use-module (ice-9 match)
  #:use-module (ice-9 optargs)
  #:use-module ((guix licenses) #:prefix license:)
  #:export
  (<minetest-server-configuration>
   make-minetest-server-configuration
   minetest-server-configuration?
   minetest-server-configuration-admin
   minetest-server-configuration-games
   minetest-server-configuration-mods
   minetest-shepherd-service
   minetest-service-type))

(define-record-type <minetest-server-configuration>
  (make-minetest-server-configuration admin games mods)
  minetest-server-configuration?
  (admin minetest-server-configuration-admin)
  (games minetest-server-configuration-games)
  (mods minetest-server-configuration-mods))

(define minetest-shepherd-service
  (match-lambda
    (($ <minetest-server-configuration> admin games mods)
     (let ((script-file
            (computed-file
             "minetest-with-log-files"
             #~(begin
                 (call-with-output-file #$output
                   (lambda (port)
                     (format port "#!~a/bin/bash

~a/bin/minetest \"$@\" >> /var/log/minetest/server.log 2>>/var/log/minetest/server.err
"
                             #$bash #$minetest)))
                 (chmod #$output #o755))))
           (game-pack
            (directory-union
             "minetest-game-pack"
             (map (cute file-append <> "/share/minetest/games")
                  games)))
           (mod-pack
            (directory-union
             "minetest-mod-pack"
             (map (cute file-append <> "/share/minetest/mods")
                  mods)))
           (config-file
            (plain-file "minetest.conf"
                        (format #f "bind_address = eno1
ipv6_server = true
name = ~a
default_privs = \"\"
"
                                admin))))
       (list
        (shepherd-service
         (provision '(minetest))
         (documentation "Run a sensible minetest server")
         (requirement '(user-processes))
         (modules '((gnu build shepherd)
                    (gnu system file-systems)))
         (start
          (with-imported-modules
           (source-module-closure
            '((gnu build shepherd)
              (gnu system file-systems)))
           #~(begin
               (let ((user (getpwnam "minetest")))
                 (for-each
                  (lambda (dir)
                    (mkdir-p dir)
                    (chown dir (passwd:uid user) (passwd:gid user))
                    (chmod dir #o700))
                  '("/var/log/minetest" "/var/lib/minetest"))
                 (chown "/etc/minetest/password" (passwd:uid user) (passwd:gid user))
                 (chmod "/etc/minetest/password" #o700)
                 (false-if-exception
                  (delete-file "/var/lib/minetest/home/.minetest/debug.txt"))
                 (make-forkexec-constructor
                  (list #$script-file
                        "--server"
                        "--password-file" "/etc/minetest/password"
                        "--world" "/var/lib/minetest/world"
                        "--config" #$config-file)
                  #:user "minetest"
                  #:group "minetest"
                  #:environment-variables
                  `(,(format #f "MINETEST_SUBGAME_PATH=~a" #$game-pack)
                    ,(format #f "MINETEST_MOD_PATH=~a" #$mod-pack)
                    "HOME=/var/lib/minetest/home"))))))
         (stop #~(make-kill-destructor))))))))

(define %minetest-accounts
  (list (user-group
         (name "minetest")
         (system? #t))
        (user-account
         (name "minetest")
         (group "minetest")
         (system? #t)
         (comment "The user that runs the minetest server.")
         (home-directory "/var/empty")
         (shell (file-append shadow "/sbin/nologin")))))

(define %minetest-rottlog
  `(,(log-rotation
      (frequency 'weekly)
      (files
       (list "/var/log/minetest/server.log"
             "/var/log/minetest/server.err"))
      (options '("sharedscripts" "storedir /var/log/minetest")))))

(define minetest-service-type
  (service-type
   (name 'minetest)
   (description "Run a minetest server")
   (extensions
    (list
     (service-extension account-service-type (const %minetest-accounts))
     (service-extension rottlog-service-type (const %minetest-rottlog))
     (service-extension shepherd-root-service-type minetest-shepherd-service)))))