;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix 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 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix 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 GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (guix scripts user)
  #:use-module (gnu services)
  #:use-module (gnu services shepherd)
  #:use-module (gnu system)
  #:use-module (guix derivations)
  #:use-module (guix records)
  #:use-module (guix scripts)
  #:use-module (guix scripts build)
  #:use-module (guix store)
  #:use-module (guix monads)
  #:use-module (guix gexp)
  #:use-module (guix ui)
  #:use-module (guix utils)
  #:use-module (ice-9 match)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-37)
  #:export (guix-user))


;;;
;;; Command-line options.
;;;

(define %options
  ;; Specifications of the command-line options.
  (cons* (option '(#\h "help") #f #f
                 (lambda args
                   (show-help)
                   (exit 0)))
         (option '(#\r "reconfigure") #t #f
                 (lambda (opt name arg result)
                   (alist-cons 'action `(reconfigure . ,arg) result)))
         (option '(#\V "version") #f #f
                 (lambda args
                   (show-version-and-exit "guix user")))
         %standard-build-options))

(define %default-options
  `((system . ,(%current-system))
    (substitutes? . #t)
    (graft? . #t)
    (max-silent-time . 3600)
    (verbosity . 0)))

(define (show-help)
  (display (G_ "Usage: guix user [OPTION]...
Create a bundle of PACKAGE.\n"))
  (display (G_ "
  -r, --reconfigure-services=FILE  reconfigure services described in FILE"))
  (newline)
  (display (G_ "
  -h, --help                       display this help and exit"))
  (display (G_ "
  -V, --version                    display version information and exit"))
  (newline)
  (show-bug-report-information))


;;;
;;; User services.
;;;

(define (fold-user-services services)
  (fold-services (cons* (service user-service-type #f)
                        %shepherd-user-root-service
                        services)
                 #:target-type shepherd-user-service-type))

(define (generate-sheperd-configuration services opts)
  (mlet* %store-monad ((services -> (fold-user-services services))
                       (shepherd-conf.drv (service-value services))
                       (shepherd-launch (gexp->script "shepherd" shepherd-conf.drv))
                       (drvs -> (list shepherd-launch)))
    (mbegin %store-monad
      (show-what-to-build* drvs
                           #:use-substitutes?
                           (assoc-ref opts 'substitutes?))
      (built-derivations drvs)
      (return (derivation->output-path shepherd-launch)))))


;;;
;;; Entry point.
;;;

(define %user-module
  ;; Module in which the user configuration file is loaded.
  (make-user-module '((gnu system)
                      (gnu services))))

(define (process-action store opts)
  (let ((action (assoc-ref opts 'action)))
    (match action
      (('reconfigure . file)
       (let* ((user-conf
               (if file
                   (load* file %user-module)
                   (leave (G_ "no user configuration file specified~%"))))
              (services (user-configuration-services user-conf)))
         (format #t "~a\n" (run-with-store store
                             (generate-sheperd-configuration services opts))))))))

(define (guix-user . args)
  (with-error-handling
    (let ((opts  (parse-command-line args %options (list %default-options)))
          (store (open-connection)))
      (process-action store opts))))