;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2015 Federico Beffa <beffa@fbengineering.ch>
;;; Copyright © 2020 Morgan Smith <Morgan.J.Smith@outlook.com>
;;; Copyright © 2024 Liliana Marie Prikler <liliana.prikler@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 build-system emacs)
  #:use-module ((guix build emacs-build-system)
                #:select (%default-include %default-exclude))
  #:use-module (guix store)
  #:use-module (guix utils)
  #:use-module (guix packages)
  #:use-module (guix gexp)
  #:use-module (guix monads)
  #:use-module (guix search-paths)
  #:use-module (guix build-system)
  #:use-module (guix build-system gnu)
  #:export (%emacs-build-system-modules
            emacs-build
            emacs-build-system
            package-with-explicit-emacs
            ;; Common variants.
            package-with-emacs-minimal
            package-with-emacs-next
            package-with-emacs-no-x-toolkit
            package-with-emacs-pgtk)
  #:re-export (%default-include         ;for convenience
               %default-exclude))


;; Commentary:
;;
;; Standard build procedure for Emacs packages.  This is implemented as an
;; extension of 'gnu-build-system'.
;;
;; Code:

(define %emacs-build-system-modules
  ;; Build-side modules imported by default.
  `((guix build emacs-build-system)
    (guix build emacs-utils)
    ,@%gnu-build-system-modules))

(define* (resolve-emacs name)
  "Lazily resolve the emacs package by variable NAME."
  ;; Lazily resolve the binding to avoid a circular dependency.
  (let ((emacs-mod (resolve-interface '(gnu packages emacs))))
    (module-ref emacs-mod name)))

(define (default-emacs) (resolve-emacs 'emacs))

(define* (lower name
                #:key source inputs native-inputs outputs system target
                (emacs (default-emacs))
                #:allow-other-keys
                #:rest arguments)
  "Return a bag for NAME."
  (define private-keywords
    '(#:target #:emacs #:inputs #:native-inputs))

  (and (not target)                               ;XXX: no cross-compilation
       (bag
         (name name)
         (system system)
         (host-inputs `(,@(if source
                              `(("source" ,source))
                              '())
                        ,@inputs

                        ;; Keep the standard inputs of 'gnu-build-system'.
                        ,@(standard-packages)))
         (build-inputs `(("emacs" ,emacs)
                         ,@native-inputs))
         (outputs outputs)
         (build emacs-build)
         (arguments (strip-keyword-arguments private-keywords arguments)))))

(define* (emacs-build name inputs
                      #:key source
                      (tests? #f)
                      (parallel-tests? #t)
                      (test-command ''("make" "check"))
                      (phases '%standard-phases)
                      (outputs '("out"))
                      (include (quote %default-include))
                      (exclude (quote %default-exclude))
                      (search-paths '())
                      (system (%current-system))
                      (guile #f)
                      (imported-modules %emacs-build-system-modules)
                      (modules '((guix build emacs-build-system)
                                 (guix build utils)
                                 (guix build emacs-utils))))
  "Build SOURCE using EMACS, and with INPUTS."
  (define builder
    (with-imported-modules imported-modules
      #~(begin
          (use-modules #$@(sexp->gexp modules))
          (emacs-build #:name #$name
                       #:source #+source
                       #:system #$system
                       #:test-command #$test-command
                       #:tests? #$tests?
                       #:parallel-tests? #$parallel-tests?
                       #:phases #$phases
                       #:outputs #$(outputs->gexp outputs)
                       #:include #$include
                       #:exclude #$exclude
                       #:search-paths '#$(sexp->gexp
                                          (map search-path-specification->sexp
                                               search-paths))
                       #:inputs #$(input-tuples->gexp inputs)))))

  (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
                                                  system #:graft? #f)))
    (gexp->derivation name builder
                      #:system system
                      #:guile-for-build guile)))

(define emacs-build-system
  (build-system
    (name 'emacs)
    (description "The build system for Emacs packages")
    (lower lower)))

(define* (package-with-explicit-emacs emacs old-prefix new-prefix
                                      #:key variant-property)
  "Return a procedure of one argument, P.  The procedure creates a package with
the same fields as P, which is assumed to use EMACS-BUILD-SYSTEM, such that
it is compiled with EMACS instead.  The inputs are changed recursively
accordingly.  If the name of P starts with OLD-PREFIX, this is replaced by
NEW-PREFIX; otherwise, NEW-PREFIX is prepended to the name.

When VARIANT-PROPERTY is present, it is used as a key to search for
pre-defined variants of this transformation recorded in the 'properties' field
of packages.  The property value must be the promise of a package.  This is a
convenient way for package writers to force the transformation to use
pre-defined variants."
  (define package-variant
    (if variant-property
        (lambda (package)
          (assq-ref (package-properties package)
                    variant-property))
        (const #f)))

  (define (transform pkg)
    (cond
     ;; If VARIANT-PROPERTY is present, use that.
     ((package-variant pkg)
      => force)

     ;; Otherwise build the new package object graph.
     ((eq? (package-build-system pkg) emacs-build-system)
      (package/inherit pkg
        (location (package-location pkg))
        (name (let ((name (package-name pkg)))
                (string-append new-prefix
                               (if (string-prefix? old-prefix name)
                                   (substring name
                                              (string-length old-prefix))
                                   name))))
        (arguments
         (let ((emacs (if (promise? emacs)
                          (force emacs)
                          emacs)))
           (ensure-keyword-arguments (package-arguments pkg)
                                     `(#:emacs ,emacs))))))
     (else pkg)))

  (define (cut? pkg)
    (or (not (eq? (package-build-system pkg) emacs-build-system))
        (package-variant pkg)))

  (package-mapping transform cut?))

(define package-with-emacs-minimal
  (package-with-explicit-emacs (delay (resolve-emacs 'emacs-minimal))
                               "emacs-" "emacs-minimal-"
                               #:variant-property 'emacs-minimal-variant))

(define package-with-emacs-next
  (package-with-explicit-emacs (delay (resolve-emacs 'emacs-next))
                               "emacs-" "emacs-next-"
                               #:variant-property 'emacs-next-variant))

;; We prefer emacs-minimal, but sometimes the "minimal" variant still needs
;; X support.
(define package-with-emacs-no-x-toolkit
  (package-with-explicit-emacs (delay (resolve-emacs 'emacs-no-x-toolkit))
                               "emacs-" "emacs-no-x-toolkit-"))

(define package-with-emacs-pgtk
  (package-with-explicit-emacs (delay (resolve-emacs 'emacs-pgtk))
                               "emacs-" "emacs-pgtk-"
                               #:variant-property 'emacs-pgtk-variant))

;;; emacs.scm ends here