#!/usr/bin/env -S guix repl --
!#   ;-*- mode: scheme; -*-
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2025 Maxim Cournoyer <maxim.cournoyer@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/>.

;;; Commentary:
;;;
;;; This is a wrapper of 'guix refresh' that refreshes all the GNOME core
;;; packages listed in their release engineering (releng) list to their stable
;;; version.  Set the PARTIAL_VERSIONS environment variable to update to
;;; compatible versions instead of exact ones.  The GNOME_RELENG_VERSIONS_URI
;;; environment variable can also point to a different URL or file, for
;;; example to update to a past GNOME version.  The script can be invoked as:
;;;
;;; $ ./pre-inst-env etc/teams/gnome/gnome-core-refresh --update
;;; or
;;; $ ./pre-inst-env env PARTIAL_VERSIONS=1 etc/teams/gnome/gnome-core-refresh -u
;;;
;;; Code:

(use-modules (gnu packages)
             (guix diagnostics)
             (guix http-client)
             (guix scripts refresh)
             (guix utils)
             (ice-9 format)
             (ice-9 exceptions)
             (ice-9 match)
             (ice-9 peg)
             (ice-9 textual-ports)
             (srfi srfi-1))

(define %gnome-releng-versions-uri
  (make-parameter
   (or (getenv "GNOME_RELENG_VERSIONS_URI")
       "https://gitlab.gnome.org/GNOME/releng/-/raw/master/\
tools/versions-stable")))

(define (fetch-releng-content)
  "Return an input port to the %GNOME-RELENG-VERSIONS-URI file."
  (call-with-port (http-fetch/cached (%gnome-releng-versions-uri))
    get-string-all))

(define-exception-type &releng-parser-error &error
  make-releng-parser-error releng-parser-error?)

(define-peg-string-patterns "\
releng <-- (comment / entry)* !.
entry <-- suite C name C version C subdir NL
suite <-- text
name <-- text
version <-- text
subdir <-- text?
text <- (!NL !C  .)*
comment < '#' (!NL .)* NL
C < ':'
NL < '\n'")

(define %names
  '(("adwaita-fonts" . "font-adwaita")))

(define (parse-releng data)
  "Return DATA, a string representing the content of a GNOME releng file, and
return the complete parse tree."
  (let ((tree (peg:tree (match-pattern releng data))))
    (match tree
      (#f (raise-exception (make-releng-parser-error)))
      (_ tree))))

(define (check-package-name name)
  "Return #t if a package corresponding to NAME exists, else #f."
  (catch 'quit
    (lambda ()
      (parameterize ((guix-warning-port (%make-void-port "w")))
        (specification->package name)
        #t))
    (lambda _
      (format (current-error-port) "TODO: package ~a~%" name)
      #f)))

(define* (releng-tree->update-specs tree #:key (partial-versions?
                                                (getenv "PARTIAL_VERSIONS")))
  "Take TREE and return a list of package specifications.  If
PARTIAL-VERSIONS? is true, the least significant digit in version is
stripped and the version is prefixed with the '~' character, so that 'guix
refresh' can automatically find the newest compatible version."
  (match tree
    (('releng ('entry ('suite "core") ('name name) ('version version) _) ...)
     (filter-map (lambda (name version)
                   (let ((name (or (assoc-ref %names name) name)))
                     (and (check-package-name name)
                          (if partial-versions?
                              (let* ((parts (string-split version #\.))
                                     (num-parts (length parts)))
                                (if (> num-parts 1)
                                    (format #f "~a=~~~a" name
                                            (version-prefix version
                                                            (1- num-parts)))
                                    (format #f "~a=~a" name version)))
                              (format #f "~a=~a" name version)))))
                 name version))))

(apply guix-refresh (append (cdr (command-line))
                            (releng-tree->update-specs
                             (parse-releng (fetch-releng-content)))))