(define-module (system base-system)
  #:use-module (guix gexp)

  #:use-module (nongnu system linux-initrd)
  #:use-module (nongnu packages linux)

  #:use-module (gnu bootloader)
  #:use-module (gnu bootloader grub)
  #:use-module (gnu system accounts)
  #:use-module (gnu system shadow)
  #:use-module (gnu system setuid)
  #:use-module (gnu services configuration)
  #:use-module (gnu system file-systems)
  #:use-module (gnu system)
  #:use-module (gnu system nss)
  #:use-module (gnu services kerberos)
  #:use-module (gnu services sssd)
  #:use-module (gnu services base)
  #:use-module (gnu services)
  #:use-module (gnu services desktop)
  #:use-module (gnu services networking)
  #:use-module (gnu services ssh)
  #:use-module (gnu services vpn)
  #:use-module (gnu system pam)
  #:use-module (gnu services dbus)
  #:use-module (gnu system keyboard)
  #:use-module (gnu packages admin)

  #:use-module (gnu packages slapd)
  #:use-module (gnu packages linux)

  #:use-module (gnu packages shells)
  #:use-module (gnu packages gnome)
  #:use-module (gnu packages ssh)
  #:use-module (gnu packages dns)
  #:use-module (gnu packages version-control)
  #:use-module (gnu packages vim)
  #:use-module (gnu packages certs)
  #:use-module (gnu packages kerberos)
  #:use-module (gnu packages vpn)
  #:use-module (gnu packages wm)
  #:use-module (gnu packages suckless)
  #:use-module (gnu packages terminals)
  #:use-module (gnu packages gnuzilla)

  #:export (%metznet-base-user-accounts)
  #:export (%metznet-base-groups)

  #:export (%metznet-desktop-packages)
  #:export (%metznet-base-packages)

  #:export (%kvm-udev-rule)
  #:export (%usb-udev-rule)
  #:export (%tun-udev-rule)

  #:export (%metznet-desktop-services)
  #:export (%metznet-server-services)

  #:export (%metznet-base-server-system)
  #:export (%metznet-base-desktop-system))

(define %domain-realm
  "METZNET.CA")

(define %domain-name
  "metznet.ca")

(define %domain-kadmin
  (string-append "kerberos." %domain-name))

(define %domain-kdc
  (string-append "kerberos." %domain-name))

(define %metznet-base-user-accounts
  (append (list (user-account
                  (name "root")
                  (group "root")
                  (uid 0)
                  (password (crypt (or (getenv "GUIX_ROOT_PW")"root") "$6$salt"))
                  (shell (file-append zsh "/bin/zsh")))) %base-user-accounts))

(define %metznet-base-groups
  (append (list (user-group
                  (system? #t)
                  (name "realtime"))
                (user-group
                  (system? #t)
                  (name "usb"))) %base-groups))

(define %metznet-base-packages
  (append (list openssh

                openldap-slapd
                strace

                git
                neovim
                zsh
                le-certs
                nss-certs
                mit-krb5) %base-packages))

(define %metznet-desktop-packages
  (append (list i3-wm i3status dmenu kitty icecat) %metznet-base-packages))

(define %desktop-setuid-programs
  (append (list (setuid-program
                  (program #~(string-append #$openvpn "/sbin/openvpn")))
                (setuid-program
                  (program #~(string-append #$openresolv "/sbin/resolvconf"))))
          %setuid-programs))

(define %metznet-krb5-config
  (krb5-configuration (default-realm %domain-realm)
                      (allow-weak-crypto? #t)
                      (rdns? #f)
                      (realms (list (krb5-realm (name %domain-realm)
                                                (admin-server %domain-kadmin)
                                                (kdc %domain-kdc))))))

(define %default-keyboard-layout
  (keyboard-layout "us"))

(define %kvm-udev-rule
  (udev-rule "65-kvm.rules"
             "KERNEL==\"KVM\", GROUP=\"libvirt\", MODE=\"0660\""))

(define %usb-udev-rule
  (udev-rule "51-usb.rules"
             (string-append "SUBSYSTEM==\"usb\", GROUP=\"usb\"\n"
                            "SUBSYSTEM==\"usbmisc\", GROUP=\"usb\"")))

(define %tun-udev-rule
  (udev-rule "90-tun.rules"
   "KERNEL==\"tun\", GROUP=\"netdev\", MODE=\"0660\", OPTIONS+=\"static_node=net/tun\""))

(define %backlight-udev-rule
  (udev-rule "55-backlight.rules"
   "RUN+=\"/bin/chgrp video /sys/class/backlight/intel_backlight/brightness\""))

(define %metznet-name-service-switch
  (let ((services (list (name-service (name "sss"))
                        (name-service (name "files")))))
    (name-service-switch (password services)
                         (shadow services)
                         (group services))))

(define list-of-strings? (list-of string?))

(define-configuration/no-serialization
  metznet-system-configuration
  (certs (file-like le-certs) "certificate package")
  (pam-services (list-of-strings (list "su" "gdm-password" "login" "sshd" "passwd")) "list of pam services to configure"))

(define (pam-mkhomedir-service configuration)
  (lambda (pam)
    (if (member (pam-service-name pam) (metznet-system-configuration-pam-services configuration))
        (let ((required (pam-entry (control "required")
                                   (module "pam_mkhomedir.so"))))
          (pam-service (inherit pam)
                       (session (cons required
                                      (pam-service-account pam))))) pam)))

(define (pam-mkhomedir-services configuration)
  (list (pam-mkhomedir-service configuration)))

(define (metznet-activation configuration)
  #~(if (access? "/bin/zsh" F_OK)
        (display "zsh already linked")
        (begin
          (display "linking zsh")
          (symlink (string-append #$zsh "/bin/zsh") "/bin/zsh"))))

(define (metznet-etc-service configuration)
  '(("/etc/openvpn/ta.key" (local-file "ta.key"))
    ("/etc/openvpn/ca.crt" (local-file "ca.crt"))
    ("/etc/openvpn/client.crt" (local-file "client.crt"))
    ("/etc/openvpn/client.key" (local-file "client.key"))))

(define metznet-service-type
  (service-type (name 'metznet-service)
                (description "MetzNet Services")
                (extensions (list (service-extension activation-service-type
                                                     metznet-activation)
                                  (service-extension profile-service-type
                                                     (compose list metznet-system-configuration-certs))
                                  (service-extension etc-service-type
                                                     metznet-etc-service)
                                  (service-extension pam-root-service-type
                                                     pam-mkhomedir-services)))
                (default-value (metznet-system-configuration))))

(define %metznet-services
  (list (service openssh-service-type
                 (openssh-configuration (extra-content
                                         "KerberosAuthentication yes")))
        (service krb5-service-type %metznet-krb5-config)
        (service pam-krb5-service-type
                 (pam-krb5-configuration (pam-krb5 pam-krb5)
                                         (minimum-uid 1000)))
        (service sssd-service-type
                 (sssd-configuration (pam-services (list "su" "gdm-password" "login" "sshd" "passwd"))))
        (service metznet-service-type)))

(define %metznet-nscd-configuration
  (nscd-configuration (caches (append (list (nscd-cache (database 'passwd)
                                                        (positive-time-to-live
                                                         (* 3600 12))
                                                        (negative-time-to-live
                                                         20)
                                                        (persistent? #t))
                                            (nscd-cache (database 'group)
                                                        (positive-time-to-live
                                                         (* 3600 12))
                                                        (negative-time-to-live
                                                         20)
                                                        (persistent? #t)))
                                      %nscd-default-caches))))

(define %metznet-desktop-services
  (append %metznet-services
          (modify-services %desktop-services
            (nscd-service-type config => %metznet-nscd-configuration)
            (guix-service-type config =>
                               (guix-configuration (inherit config)
                                                   (substitute-urls (append (list
                                                                             "https://substitutes.nonguix.org")
                                                                     %default-substitute-urls))
                                                   (authorized-keys (append (list
                                                                             (plain-file
                                                                              "nonguix.pub"
                                                                              "(public-key\n                                                       (ecc\n                                                         (curve Ed25519)\n                                                         (q #C1FD53E5D4CE971933EC50C9F307AE2171A2D3B52C804642A7A35F84F3A4EA98#)))"))
                                                                     %default-authorized-guix-keys))))
            (udev-service-type config =>
                               (udev-configuration (inherit config)
                                                   (rules (append (list
                                                                   %tun-udev-rule
                                                                   %backlight-udev-rule)
                                                                  (udev-configuration-rules
                                                                   config)))))
            (network-manager-service-type config =>
                                          (network-manager-configuration (inherit
                                                                          config)
                                                                         (vpn-plugins
                                                                          (list
                                                                           network-manager-openvpn)))))))

(define %metznet-server-services
  (append %metznet-services
          (list (dbus-service)
                (service dhcp-client-service-type)
                (openvpn-client-service #:config (openvpn-client-configuration
                                                  (openvpn openvpn)
                                                  (pid-file
                                                   "/var/run/openvpn/client.pid")
                                                  (persist-key? #f)
                                                  (remote (list (openvpn-remote-configuration
                                                              (name "vpn.metznet.ca"))))
                                                  (tls-auth
                                                   "/etc/openvpn/ta.key"))))
          (modify-services %base-services
            (nscd-service-type config => %metznet-nscd-configuration))))

(define %metznet-base-operating-system
  (operating-system
    ;; Hostname and localization information
    (host-name "base")
    (timezone "America/Edmonton")
    (locale "en_CA.utf8")
    (keyboard-layout %default-keyboard-layout)
    (name-service-switch %metznet-name-service-switch)
    ;; Kernel and firmware definitions
    (kernel linux)
    (kernel-arguments (append '("console=ttyS0") %default-kernel-arguments))
    (firmware (list linux-firmware))
    (initrd microcode-initrd)
    ;; Grub UEFI Bootloader installed to /boot/efi
    (bootloader (bootloader-configuration
                  (bootloader grub-efi-bootloader)
                  (targets '("/boot/efi"))
                  (keyboard-layout keyboard-layout)))
    (file-systems (cons* (file-system
                           (mount-point "/boot/efi")
                           (device "/dev/vda1")
                           (type "vfat")
                           (check? #f))
                         (file-system
                           (mount-point "/")
                           (device "/dev/vda3")
                           (type "xfs")
                           (check? #f)) %base-file-systems))
    (users %metznet-base-user-accounts)
    (groups %metznet-base-groups)
    (packages %metznet-base-packages)
    (services
     (append %metznet-services %base-services))))

(define %metznet-base-server-system
  (operating-system
    (inherit %metznet-base-operating-system)
    (host-name "metznet-base-server")
    (packages %metznet-base-packages)
    (services
     %metznet-server-services)))

(define %metznet-base-desktop-system
  (operating-system
    (inherit %metznet-base-operating-system)
    (host-name "metznet-base-desktop")
    (setuid-programs %desktop-setuid-programs)
    (packages %metznet-desktop-packages)
    (services
     %metznet-desktop-services)))