;;; Consfigurator -- Lisp declarative configuration management system

;;; Copyright (C) 2021  Sean Whitton <spwhitton@spwhitton.name>

;;; This file 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, or (at your option)
;;; any later version.

;;; This file 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 this program.  If not, see <http://www.gnu.org/licenses/>.

(in-package :consfigurator.property.installer)
(named-readtables:in-readtable :consfigurator)

;;;; Bootloaders

(defgeneric install-bootloader-propspec
    (bootloader-type volume running-on-target &key)
  (:documentation
   "Return a propspec expression which installs bootloader of type
BOOTLOADER-TYPE to VOLUME.
The propapp yielded by the propspec may be of type :POSIX or of type :LISP.

RUNNING-ON-TARGET indicates whether the host to which we are connected is the
host the bootloader will boot.  For example, it is NIL when building disk
images, and T when installing a host from a live environment.  Bootloader
installation might behave differently when RUNNING-ON-TARGET is NIL, or error
out."))

(defgeneric install-bootloader-binaries-propspec (bootloader-type volume &key)
  (:documentation
   "Return a propspec expression evaluating to a :POSIX propapp which
fetches/installs whatever binaries/packages need to be available to install
BOOTLOADER-TYPE to VOLUME."))

(defun get-propspecs (volumes running-on-target)
  (loop for volume in (mapcan #'all-subvolumes volumes)
        when (slot-boundp volume 'volume-bootloader)
          collect (destructuring-bind (type . args) (volume-bootloader volume)
                    (apply #'install-bootloader-propspec
                           type volume running-on-target args))))

;; At :HOSTATTRS time we don't have the OPENED-VOLUME values required by the
;; :APPLY subroutines which actually install the bootloaders.  So we call
;; GET-PROPSPECS twice: (in CHROOT-INSTALLED-TO-VOLUMES) at :HOSTATTRS time to
;; generate propspecs for the sake of running :HOSTATTRS subroutines, and then
;; at :APPLY time where we can get at the OPENED-VOLUME values, we ignore the
;; previously generated propspecs and call GET-PROPSPECS again.  This approach
;; should work for any sensible VOLUME<->OPENED-VOLUME pairs.
(define-function-property-combinator
    %install-bootloaders (running-on-target &rest propapps)
  (:retprop
   :type :lisp
   :hostattrs (lambda () (mapc #'propappattrs propapps))
   :apply
   (lambda ()
     (mapc #'consfigure
           (get-propspecs (get-connattr :opened-volumes) running-on-target))
     (mrun "sync"))))


;;;; Properties

(defprop %update-target-from-chroot :posix (chroot target)
  (:desc #?"Updated ${target} from ${chroot}")
  (:apply
   (assert-euid-root)
   (run "rsync" "-PSavx" "--delete"
        (loop for volume
                in (mapcan (curry #'subvolumes-of-type 'mounted-filesystem)
                           (get-connattr :opened-volumes))
              collect (strcat "--exclude="
                              (unix-namestring (mount-point volume))))
        (strcat (unix-namestring chroot) "/")
        (strcat (unix-namestring target) "/"))))

(defpropspec chroot-installed-to-volumes :lisp
    (host chroot volumes &key running-on-target)
  "Where CHROOT contains the root filesystem of HOST and VOLUMES is a list of
volumes, recursively open the volumes and rsync in the contents of CHROOT.
Also update the fstab and crypttab, and try to install bootloader(s)."
  (:desc #?"${chroot} installed to volumes")
  (let ((target
          (ensure-directory-pathname
           (strcat
            (drop-trailing-slash
             (unix-namestring (ensure-directory-pathname chroot)))
            ".target"))))
    `(with-these-open-volumes (,volumes :mount-below ,target)
       (%update-target-from-chroot ,chroot ,target)
       (chroot:deploys-these
        ,target ,host
        ,(make-propspec
          :propspec
          `(eseqprops
            ,(propapp
              (os:etypecase
                  (debianlike
                   (file:lacks-lines
                    "/etc/fstab" "# UNCONFIGURED FSTAB FOR BASE SYSTEM")
                   ;; These will overwrite any custom mount options, etc.,
                   ;; with values from VOLUMES.  Possibly it would be better
                   ;; to use properties which only update the fs-spec/source
                   ;; fields.  However, given that VOLUMES ultimately comes
                   ;; from the volumes the user has declared for the host, it
                   ;; is unlikely there are other properties setting mount
                   ;; options etc. which are in conflict with VOLUMES.
                   (fstab:entries-for-opened-volumes)
                   (crypttab:entries-for-opened-volumes))))
            (%install-bootloaders
             ,running-on-target
             ,@(get-propspecs (get-hostattrs :volumes) running-on-target))))))))

(defpropspec bootloader-binaries-installed :posix ()
  "Install whatever binaries/packages need to be available to install the host's
bootloaders to its volumes from within that host.  For example, this might
install a package providing /usr/sbin/grub-install, but it won't execute it."
  (:desc "Bootloader binaries installed")
  (loop
    for volume in (mapcan #'all-subvolumes (get-hostattrs :volumes))
    when (slot-boundp volume 'volume-bootloader)
      collect (destructuring-bind (type . args) (volume-bootloader volume)
                (apply #'install-bootloader-binaries-propspec type volume args))
        into propspecs
    finally
       (setq propspecs (delete-duplicates propspecs :test #'tree-equal))
       (return
         (if (cdr propspecs) (cons 'eseqprops propspecs) (car propspecs)))))