;; based on https://codeberg.org/squishypinkelephant/guix-random-junk

;; how to guix: / as tmpfs

;; /var/guix is REQUIRED to perform rollbacks
;; create the folders /gnu/persist/etc/ssh /gnu/persist/etc/wireguard and
;; the file /gnu/persist/etc/machine-id for dbus

(define-module (buer file-systems)
  #:use-module (gnu system file-systems)

  #:export (rootfs
            bootfs
            file-systems))

;;; reminder: Send a patch to guix to make file-system-options receive a
;;; list-of-strings

(define rootfs
  (file-system
       (device (file-system-label "root"))
       (mount-point "/")
       (type "tmpfs")
       (options "mode=755")))

(define bootfs
  (file-system
    (device (file-system-label "root")
     (type "btrfs")
     (mount-point "/boot")
     (dependencies (list rootfs))
     (flags '(no-atime))
     (options (format #f "compress=zstd:7,~
                          discard=async,~
                          ssd,~
                          subvol=@boot")))))

(define file-systems
  (cons* rootfs
         ;; /gnu/store
         (file-system
           (device (file-system-label "root"))
           (type "btrfs")
           (mount-point "/gnu/store")
           (needed-for-boot? #t)
           (dependencies (list rootfs))
           (flags '(read-only bind-mount no-atime))
           (options (format #f "compress=zstd:7,~
                                discard=async,~
                                ssd,~
                                subvol=@gnu/store")))
         ;; /gnu/persist
         (file-system
           (device (file-system-label "root"))
           (type "btrfs")
           (mount-point "/gnu/persist")
           (needed-for-boot? #t)
           (dependencies (list rootfs))
           (flags '(no-atime bind-mount))
           (options (format #f "discard=async,~
                                ssd,~
                                subvol=@gnu/persist")))
         ;; /home
         (file-system
           (device (file-system-label "root"))
           (type "btrfs")
           (mount-point "/home")
           (dependencies (list rootfs))
           (flags '(no-atime bind-mount))
           (options (format #f "compress=zstd:7,~
                                discard=async,~
                                ssd,~
                                subvol=@home")))
         ;; /var/guix
         (file-system
           (device (file-system-label "root"))
           (type "btrfs")
           (mount-point "/var/guix")
           (dependencies (list rootfs))
           (flags '(no-atime))
           (options (format #f "compress=zstd:7,~
                                discard=async,~
                                ssd,~
                                subvol=@var/guix")))
         ;; /var/log
         (file-system
           (device (file-system-label "root"))
           (type "btrfs")
           (mount-point "/var/log")
           (dependencies (list rootfs))
           (flags '(no-atime))
           (options (format #f "compress=zstd:7,~
                                discard=async,~
                                ssd,~
                                subvol=@var/log")))
         ;; /boot
         bootfs
         (file-system
          (device (file-system-label "esp"))
          (type "vfat")
          (dependencies (list bootfs))
          (mount-point "/boot/efi")
          (create-mount-point? #t))
         %base-file-systems))