;; This is an operating system configuration file for a fairly minimal
;; "desktop" setup with i3 where the /home partition partition is
;; encrypted with LUKS.
;;
;; https://guix.gnu.org/manual/en/html_node/operating_002dsystem-Reference.html

(define-module (tw system frm)
  #:use-module (gnu)
  #:use-module (gnu bootloader grub)
  #:use-module (gnu system locale)
  #:use-module (gnu system nss)
  #:use-module (guix gexp)
  #:use-module (guix packages)
  #:use-module ((nongnu packages linux)
                #:prefix nongnu:)   ; don't interfere with (gnu packages linux)
  #:use-module ((nongnu system linux-initrd)
                #:prefix nongnu:)
  #:use-module (tw channels)
  #:use-module (tw packages scanner)
  #:use-module (tw services secrets)
  #:use-module (tw services wireguard)
  #:use-module (tw system))

(use-package-modules android certs cups disk docker file-systems gnome guile
                     kerberos linux mtools pulseaudio search shells tls wm xorg)

(use-service-modules admin authentication avahi base cups dbus desktop docker
                     kerberos linux mcron networking pm shepherd syncthing vpn xorg)

(define efi-system-partition          ; /dev/nvme0n1p1
  (uuid "D8C7-2624" 'fat))
(define root-partition                ; /dev/nvme0n1p2
  (uuid "62fb4710-33d1-4eaf-aaaa-43d16ab26a58" 'btrfs))

(define touchpad-xorg-config
  (@@ (tw system lap) touchpad-xorg-config))

(define set-timezone-script
  (@@ (tw system lap) set-timezone-script))

(define custom-xorg-config
  (xorg-configuration
   (keyboard-layout %british-keyboard)
   (extra-config (list touchpad-xorg-config))))

(define-public %frm-system
  (operating-system
    (host-name "frm.twilken.net")
    (timezone "Europe/Paris")
    (locale "en_GB.utf8")
    (locale-definitions
     (list (locale-definition (name "en_GB.utf8") (source "en_GB"))
           (locale-definition (name "en_US.utf8") (source "en_US"))
           (locale-definition (name "fr_FR.utf8") (source "fr_FR"))))

    ;; Allow resolution of '.local' host names with mDNS.
    (name-service-switch %mdns-host-lookup-nss)

    ;; Choose UK English X11 keyboard layout.
    (keyboard-layout %british-keyboard)

    ;; Use the UEFI variant of GRUB with the EFI System
    ;; Partition mounted on /boot/efi.
    (bootloader
     (bootloader-configuration
      (bootloader grub-efi-bootloader)
      (targets '("/boot/efi"))
      ;; Note: keyboard-layout is ignored by non-grub bootloaders.
      (keyboard-layout keyboard-layout)))

    ;; Use non-free kernel to load non-free firmware (e.g. for wifi).
    (kernel nongnu:linux)
    (initrd nongnu:microcode-initrd)
    (firmware (cons* nongnu:amdgpu-firmware  ; TODO: wifi firmware?
                     %base-firmware))

    (file-systems
     (cons* (file-system
              (device root-partition)
              (mount-point "/")
              (flags '(no-atime))
              (options (alist->file-system-options
                        '("ssd" ("compress" . "zstd"))))
              (type "btrfs"))
            (file-system
              (device efi-system-partition)
              (mount-point "/boot/efi")
              (flags '(no-atime))
              (type "vfat"))
            ;; Put /home in a subvolume for better accounting/snapshotting potential.
            (file-system
              (device root-partition)
              (mount-point "/home")
              (flags '(no-atime))
              (options (alist->file-system-options
                        '("ssd" ("compress" . "zstd")
                          ("subvol" . "home"))))
              (type "btrfs"))
            %base-file-systems))

    ;; Members of the wheel group are allowed to use sudo.
    (users (cons* (user-account
                   (name "timo")
                   (comment "Timo Wilken")
                   (group "users")
                   (supplementary-groups
                    '("wheel" "audio" "video" "docker" "adbusers"))
                   (shell (file-append zsh "/bin/zsh")))
                  %base-user-accounts))

    (sudoers-file
     (plain-file "sudoers"
       (string-append
        ;; We need to preserve $TERMINFO so that programs under sudo can
        ;; find kitty's terminfo files. This is possibly unsafe; sudo
        ;; explicitly deletes this variable by default.
        "Defaults env_keep += \"TERMINFO\"\n"
        (plain-file-content %sudoers-specification)
        ;; In addition to the default rules, allow admins to power off
        ;; the computer. They'll have to use the system binaries, not
        ;; those from their user profile, as /etc/sudoers requires
        ;; absolute paths to commands.
        "%wheel ALL=(ALL) NOPASSWD: "
        "/run/current-system/profile/sbin/halt, "
        "/run/current-system/profile/sbin/reboot, "
        "/run/current-system/profile/sbin/shutdown\n")))

    ;; This is where we specify system-wide packages.
    (packages
     (cons*
      ;; System stuff
      cups docker mit-krb5
      ;; File systems
      dosfstools mtools ntfs-3g
      ;; Desktop and drivers
      ;; FIXME: lightdm depends on python-2, but the build throws an
      ;; error that python2 is not supported.
      ;; TODO: Does lightdm have a service I need to enable?
      ;;lightdm lightdm-gtk-greeter
      pulseaudio xf86-video-amdgpu
      ;; Adds /sys/class/backlight entries for external monitors.
      ;; Not needed for laptop display.
      ;; ddcci-driver-linux
      i3-gaps  ; install i3 here so gdm can see its xsession file
      i3lock   ; we need a system service to make i3lock setuid root
      ;; We need to install gnome-keyring here so its PAM module is
      ;; enabled properly (by its service; see below).
      ;; nheko needs gnome-keyring to store secrets (kwallet doesn't do dbus).
      gnome-keyring
      ;; It's probably easiest to install geoclue system-wide, so it
      ;; gets added to `%desktop-services' and redshift can access the
      ;; location.
      geoclue
      ;; Base packages
      %base-system-packages))

    ;; Use the "desktop" services, which include the X11
    ;; log-in service, networking with NetworkManager, and more.
    ;; See info '(guix)Services' for useful services.
    (services
     (cons*
      (service syncthing-service-type
        (syncthing-configuration
         (user "timo")))

      (service cups-service-type
        (cups-configuration
         (web-interface? #t)
         (default-shared? #f)
         ;; See info '(guix)Printing Services' for more extensions.
         (extensions
          (list cups-filters foomatic-filters brlaser))))

      (service bluetooth-service-type)

      (service tw-wireguard-service-type
        (tw-wireguard-configuration
         (this-host host-name)))

      (service docker-service-type
        (docker-configuration))

      (service krb5-service-type
        (krb5-configuration
         (default-realm "CERN.CH")
         (rdns? #f)
         (realms (list (krb5-realm
                        (name "CERN.CH")
                        (default-domain "cern.ch")
                        (kdc "cerndc.cern.ch"))))))

      (service tlp-service-type
        (tlp-configuration))   ; TODO: configure properly

      (service thermald-service-type
        (thermald-configuration
         (adaptive? #t)))

      (service earlyoom-service-type
        (earlyoom-configuration))  ; TODO: configure at least `avoid-regexp'

      (service fprintd-service-type)

      ;; Install i3lock as a setuid binary, so it can talk to PAM.
      (service screen-locker-service-type
        (screen-locker-configuration
         (name "i3lock")
         (program (file-append i3lock "/bin/i3lock"))))

      ;; gnome-keyring is not in `%desktop-services' by default,
      ;; but needs to be there to add itself to /etc/pam.d/.
      ;; If using a DM other than GDM, add it to `pam-services' in
      ;; `gnome-keyring-configuration' (see its docs).
      (service gnome-keyring-service-type
        (gnome-keyring-configuration))

      (udev-rules-service 'android android-udev-rules #:groups '("adbusers"))

      (set-xorg-configuration custom-xorg-config)

      (service unattended-upgrade-service-type
        (unattended-upgrade-configuration
         (schedule "0 21 * * *")       ; every night at 21:00, when the laptop is turned on
         (maximum-duration (* 40 60))  ; 40 minutes to allow for slow downloads
         (channels %system-channels)
         (operating-system-expression
          #~(@ (tw system frm) %frm-system))
         (services-to-restart
          ;; Anything that won't cause disruption when restarting.
          '(syncthing-timo earlyoom thermald tlp wireguard-wg0 mcron))))

      (simple-service 'disk-maintenance mcron-service-type
        ;; I don't think jobs run on boot if they would have run when the
        ;; computer was turned off, so choose a time when the computer is
        ;; probably turned on.
        (list #~(job "45 21 * * *" "guix gc -d 2w -F 25G")  ; after unattended-upgrade
              #~(job "0 22 * * *"  ; after guix gc
                     (string-append #$(file-append util-linux "/sbin/fstrim")
                                    " --fstab --verbose"))))

      (extra-special-file "/etc/NetworkManager/dispatcher.d/09-set-timezone"
        (program-file "set-timezone" set-timezone-script))

      (simple-service 'scanning-services shepherd-root-service-type
        (list
         (shepherd-service
          (documentation "Expose USB scanners over IPP.")
          (provision '(ipp-usb))
          (requirement '(networking))   ; only on localhost, though
          (start #~(make-forkexec-constructor
                    (list #$(file-append ipp-usb "/bin/ipp-usb") "standalone")))
          (stop #~(make-kill-destructor)))))

      ;; Since Guix 953c65ffdd4, build-machines can be directly specified in
      ;; `guix-configuration'. However, this doesn't allow the dynamic
      ;; selection of build machines as is done here.
      (extra-special-file "/etc/guix/machines.scm"
        (scheme-file "machines.scm"
          #~(let ((lud (build-machine
                        (name "lud.twilken.net")
                        (systems '("x86_64-linux"))
                        (port '#$(assoc-ref %ssh-ports "lud.twilken.net"))
                        (host-key "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGqXbxv3a2bZyGjnEirVCMtRBeLKW/ha8ULSR9Xye4Z1")
                        (user "timo")
                        (private-key "/home/timo/.local/share/ssh-keys/id_rsa")
                        (speed 1/3)))   ; 4 cores, 16 GB RAM
                  (vin (build-machine
                        (name "vin.twilken.net")
                        (systems '("x86_64-linux"))
                        (port '#$(assoc-ref %ssh-ports "vin.twilken.net"))
                        (host-key "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIEEpdfKxzoCwg53TKPF5YxgUwhGF+bELAyBGdxagQroJ")
                        (user "timo")
                        (private-key "/home/timo/.local/share/ssh-keys/id_rsa")
                        (speed 2/3))))  ; 8 cores, 16 GB RAM
              (use-modules (ice-9 popen)
                           (ice-9 textual-ports)
                           (ice-9 regex))
              (let* ((regexp (make-regexp "^GENERAL\\.CONNECTION:[[:space:]]+TLAN$" regexp/newline))
                     (pipe (open-pipe* OPEN_READ #$(file-append network-manager "/bin/nmcli")
                                       "device" "show" "wlp3s0"))
                     (at-home? (regexp-exec regexp (get-string-all pipe))))
                (close-pipe pipe)
                ;; Only offload to vin when at home, as the network connection is too bad otherwise.
                (if at-home?
                    (list vin)
                    (list lud))))))

      ;; Set up a secrets config for WireGuard to extend.
      (service secrets-service-type
        (secrets-configuration
         (host-key "/etc/secrets.key")))  ; we have no SSH host keys, so use a custom key

      (modify-services (append %system-channel-services %desktop-services)
        ;; Let sane find the airscan backend. ipp-usb needs to be running separately.
        (sane-service-type _ => sane-backends/airscan)

        (gdm-service-type
         config =>
         (gdm-configuration
          (inherit config)
          (auto-login? #f)
          (default-user "timo")
          (xorg-configuration custom-xorg-config)))

        (geoclue-service-type
         config =>
         (geoclue-configuration
          (inherit config)
          (applications
           (cons* (geoclue-application "redshift" #:system? #f)
                  %standard-geoclue-applications))))

        (login-service-type
         config =>
         (login-configuration
          (inherit config)
          (motd (plain-file "no-motd" ""))
          (allow-empty-passwords? #f))))))))

%frm-system