;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2018 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 (gnu installer)
  #:use-module (guix packages)
  #:use-module (guix gexp)
  #:use-module (guix modules)
  #:use-module (guix utils)
  #:use-module (guix ui)
  #:use-module ((guix self) #:select (make-config.scm))
  #:use-module (gnu packages admin)
  #:use-module (gnu packages base)
  #:use-module (gnu packages bash)
  #:use-module (gnu packages connman)
  #:use-module (gnu packages guile)
  #:autoload   (gnu packages gnupg) (guile-gcrypt)
  #:use-module (gnu packages iso-codes)
  #:use-module (gnu packages linux)
  #:use-module (gnu packages ncurses)
  #:use-module (gnu packages package-management)
  #:use-module (gnu packages xorg)
  #:use-module (ice-9 match)
  #:use-module (srfi srfi-1)
  #:export (installer-program))

(define not-config?
  ;; Select (guix …) and (gnu …) modules, except (guix config).
  (match-lambda
    (('guix 'config) #f)
    (('guix rest ...) #t)
    (('gnu rest ...) #t)
    (rest #f)))

(define* (build-compiled-file name locale-builder)
  "Return a file-like object that evalutes the gexp LOCALE-BUILDER and store
its result in the scheme file NAME. The derivation will also build a compiled
version of this file."
  (define set-utf8-locale
    #~(begin
        (setenv "LOCPATH"
                #$(file-append glibc-utf8-locales "/lib/locale/"
                               (version-major+minor
                                (package-version glibc-utf8-locales))))
        (setlocale LC_ALL "en_US.utf8")))

  (define builder
    (with-extensions (list guile-json)
      (with-imported-modules (source-module-closure
                              '((gnu installer locale)))
        #~(begin
            (use-modules (gnu installer locale))

            ;; The locale files contain non-ASCII characters.
            #$set-utf8-locale

            (mkdir #$output)
            (let ((locale-file
                   (string-append #$output "/" #$name ".scm"))
                  (locale-compiled-file
                   (string-append #$output "/" #$name ".go")))
              (call-with-output-file locale-file
                (lambda (port)
                  (write #$locale-builder port)))
              (compile-file locale-file
                            #:output-file locale-compiled-file))))))
  (computed-file name builder))

(define apply-locale
  ;; Install the specified locale.
  #~(lambda (locale-name)
      (false-if-exception
       (setlocale LC_ALL locale-name))))

(define* (compute-locale-step #:key
                              locales-name
                              iso639-languages-name
                              iso3166-territories-name)
  "Return a gexp that run the locale-page of INSTALLER, and install the
selected locale. The list of locales, languages and territories passed to
locale-page are computed in derivations named respectively LOCALES-NAME,
ISO639-LANGUAGES-NAME and ISO3166-TERRITORIES-NAME. Those lists are compiled,
so that when the installer is run, all the lengthy operations have already
been performed at build time."
  (define (compiled-file-loader file name)
    #~(load-compiled
       (string-append #$file "/" #$name ".go")))

  (let* ((supported-locales #~(supported-locales->locales
                               #$(local-file "installer/aux-files/SUPPORTED")))
         (iso-codes #~(string-append #$iso-codes "/share/iso-codes/json/"))
         (iso639-3 #~(string-append #$iso-codes "iso_639-3.json"))
         (iso639-5 #~(string-append #$iso-codes "iso_639-5.json"))
         (iso3166 #~(string-append #$iso-codes "iso_3166-1.json"))
         (locales-file (build-compiled-file
                        locales-name
                        #~`(quote ,#$supported-locales)))
         (iso639-file (build-compiled-file
                       iso639-languages-name
                       #~`(quote ,(iso639->iso639-languages
                                   #$supported-locales
                                   #$iso639-3 #$iso639-5))))
         (iso3166-file (build-compiled-file
                        iso3166-territories-name
                        #~`(quote ,(iso3166->iso3166-territories #$iso3166))))
         (locales-loader (compiled-file-loader locales-file
                                               locales-name))
         (iso639-loader (compiled-file-loader iso639-file
                                              iso639-languages-name))
         (iso3166-loader (compiled-file-loader iso3166-file
                                               iso3166-territories-name)))
    #~(lambda (current-installer)
        (let ((result
               ((installer-locale-page current-installer)
                #:supported-locales #$locales-loader
                #:iso639-languages #$iso639-loader
                #:iso3166-territories #$iso3166-loader)))
          (#$apply-locale result)))))

(define apply-keymap
  ;; Apply the specified keymap.
  #~(match-lambda
      ((model layout variant)
       (kmscon-update-keymap model layout variant))))

(define* (compute-keymap-step)
  "Return a gexp that runs the keymap-page of INSTALLER and install the
selected keymap."
  #~(lambda (current-installer)
      (let ((result
             (call-with-values
                 (lambda ()
                   (xkb-rules->models+layouts
                    (string-append #$xkeyboard-config
                                   "/share/X11/xkb/rules/base.xml")))
               (lambda (models layouts)
                 ((installer-keymap-page current-installer)
                  #:models models
                  #:layouts layouts)))))
        (#$apply-keymap result))))

(define (installer-steps)
  (let ((locale-step (compute-locale-step
                      #:locales-name "locales"
                      #:iso639-languages-name "iso639-languages"
                      #:iso3166-territories-name "iso3166-territories"))
        (keymap-step (compute-keymap-step))
        (timezone-data #~(string-append #$tzdata
                                        "/share/zoneinfo/zone.tab")))
    #~(lambda (current-installer)
        (list
         ;; Welcome the user and ask him to choose between manual installation
         ;; and graphical install.
         (installer-step
          (id 'welcome)
          (compute (lambda _
                     ((installer-welcome-page current-installer)
                      #$(local-file "installer/aux-files/logo.txt")))))

         ;; Ask the user to choose a locale among those supported by the glibc.
         ;; Install the selected locale right away, so that the user may
         ;; benefit from any available translation for the installer messages.
         (installer-step
          (id 'locale)
          (description (G_ "Locale selection"))
          (compute (lambda _
                     (#$locale-step current-installer))))

         ;; Ask the user to select a timezone under glibc format.
         (installer-step
          (id 'timezone)
          (description (G_ "Timezone selection"))
          (compute (lambda _
                     ((installer-timezone-page current-installer)
                      #$timezone-data))))

         ;; The installer runs in a kmscon virtual terminal where loadkeys
         ;; won't work. kmscon uses libxkbcommon as a backend for keyboard
         ;; input. It is possible to update kmscon current keymap by sending it
         ;; a keyboard model, layout and variant, in a somehow similar way as
         ;; what is done with setxkbmap utility.
         ;;
         ;; So ask for a keyboard model, layout and variant to update the
         ;; current kmscon keymap.
         (installer-step
          (id 'keymap)
          (description (G_ "Keyboard mapping selection"))
          (compute (lambda _
                     (#$keymap-step current-installer))))

         ;; Ask the user to input a hostname for the system.
         (installer-step
          (id 'hostname)
          (description (G_ "Hostname selection"))
          (compute (lambda _
                     ((installer-hostname-page current-installer)))))

         ;; Provide an interface above connmanctl, so that the user can select
         ;; a network susceptible to acces Internet.
         (installer-step
          (id 'network)
          (description (G_ "Network selection"))
          (compute (lambda _
                     ((installer-network-page current-installer)))))

         ;; Prompt for users (name, group and home directory).
         (installer-step
          (id 'hostname)
          (description (G_ "User selection"))
          (compute (lambda _
                     ((installer-user-page current-installer)))))))))

(define (installer-program)
  "Return a file-like object that runs the given INSTALLER."
  (define init-gettext
    ;; Initialize gettext support, so that installer messages can be
    ;; translated.
    #~(begin
        (bindtextdomain "guix" (string-append #$guix "/share/locale"))
        (textdomain "guix")))

  (define set-installer-path
    ;; Add the specified binary to PATH for later use by the installer.
    #~(let* ((inputs
              '#$(append (list bash connman shadow)
                         (map canonical-package (list coreutils)))))
        (with-output-to-port (%make-void-port "w")
          (lambda ()
            (set-path-environment-variable "PATH" '("bin" "sbin") inputs)))))

  (define steps (installer-steps))

  (define installer-builder
    (with-extensions (list guile-gcrypt guile-newt guile-json)
      (with-imported-modules `(,@(source-module-closure
                                  '((gnu installer newt)
                                    (guix build utils))
                                  #:select? not-config?)
                               ((guix config) => ,(make-config.scm)))
        #~(begin
            (use-modules (gnu installer record)
                         (gnu installer keymap)
                         (gnu installer steps)
                         (gnu installer locale)
                         (gnu installer newt)
                         (guix i18n)
                         (guix build utils)
                         (ice-9 match))

            ;; Set the default locale to install unicode support.
            (setlocale LC_ALL "en_US.utf8")

            ;; Initialize gettext support so that installers can use
            ;; (guix i18n) module.
            #$init-gettext

            ;; Add some binaries used by the installers to PATH.
            #$set-installer-path

            (let ((current-installer newt-installer))
              ((installer-init current-installer))

              (catch #t
                (lambda ()
                  (run-installer-steps
                   #:rewind-strategy 'menu
                   #:menu-proc (installer-menu-page current-installer)
                   #:steps (#$steps current-installer)))
                (const #f)
                (lambda (key . args)
                  ((installer-exit-error current-installer) key args)

                  ;; Be sure to call newt-finish, to restore the terminal into
                  ;; its original state before printing the error report.
                  (call-with-output-file "/tmp/error"
                    (lambda (port)
                      (display-backtrace (make-stack #t) port)
                      (print-exception port
                                       (stack-ref (make-stack #t) 1)
                                       key args)))
                  (primitive-exit 1))))
            ((installer-exit current-installer))))))

  (program-file "installer" installer-builder))