;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2016 Federico Beffa <beffa@fbengineering.ch>
;;; Copyright © 2016 Efraim Flashner <efraim@flashner.co.il>
;;; Copyright © 2017, 2019 Tobias Geerinckx-Rice <me@tobias.gr>
;;; Copyright © 2019 Brett Gilio <brettg@gnu.org>
;;; Copyright © 2020 Brendan Tildesley <mail@brendan.scot>
;;; Copyright © 2021, 2022 Philip McGrath <philip@philipmcgrath.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 packages chez-and-racket-bootstrap)
  #:use-module (guix packages)
  #:use-module (guix download)
  #:use-module (guix git-download)
  #:use-module (guix utils)
  #:use-module (guix gexp)
  #:use-module (ice-9 match)
  #:use-module (ice-9 regex)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:use-module (guix build-system gnu)
  #:use-module (gnu packages)
  #:use-module (gnu packages compression)
  #:use-module (gnu packages ghostscript)
  #:use-module (gnu packages linux)
  #:use-module (gnu packages ncurses)
  #:use-module (gnu packages netpbm)
  #:use-module (gnu packages tex)
  #:use-module (gnu packages xorg)
  #:use-module ((guix licenses)
                #:prefix license:))

;; Commentary:
;;
;; Alphabetically and chronologically, Chez comes before Racket.
;;
;; The bootstrapping paths for Chez Scheme and Racket are closely
;; entwined. Racket CS (the default Racket implementation) is based on (a fork
;; of) Chez Scheme. Racket's variant of Chez Scheme shares sources for
;; nanopass and stex with upstream Chez Scheme.
;;
;; Racket's variant of Chez Scheme can be bootstrapped by an older Racket
;; implementation, Racket BC, which can be bootstrapped from C. Porting that
;; code to work with upstream Chez Scheme (or finding an old version that
;; does) is our best hope for some day bootstrapping upstream Chez Scheme from
;; source.
;;
;; Putting the relevant definitions together in this module avoids having to
;; work around dependency cycles.
;;
;; Code:

(define (chez-machine->nonthreaded machine)
  "Given a string MACHINE naming a Chez Scheme machine type, returns a string
naming the nonthreaded machine type for the same architecture and OS as
MACHINE.  The returned string may share storage with MACHINE."
  ;; Chez Scheme documentation consistently uses "nonthreaded" rather than
  ;; e.g. "unthreaded"
  (if (eqv? #\t (string-ref machine 0))
      (substring machine 1)
      machine))
(define (chez-machine->threaded machine)
  "Like @code{chez-machine->nonthreaded}, but returns the threaded machine
type."
  (if (eqv? #\t (string-ref machine 0))
      machine
      (string-append "t" machine)))

;; Based on the implementation from raco-cross-lib/private/cross/platform.rkt
;; in https://github.com/racket/raco-cross.
;; For supported platforms, refer to release_notes/release_notes.stex in the
;; upstream Chez Scheme repository or to racket/src/ChezScheme/README.md
;; in https://github.com/racket/racket.
(define %nix-arch-to-chez-alist
  `(("x86_64" . "a6")
    ("i386" . "i3")
    ("aarch64" . "arm64")
    ("armhf" . "arm32") ;; Chez supports ARM v6+
    ("ppc" . "ppc32")))
(define %nix-os-to-chez-alist
  `(("w64-mingw32" . "nt")
    ("darwin" . "osx")
    ("linux" . "le")
    ("freebsd" . "fb")
    ("openbsd" . "ob")
    ("netbsd" . "nb")
    ("solaris" . "s2")))

(define (chez-machine->nix-system machine)
  "Return the Nix system type corresponding to the Chez Scheme machine type
MACHINE.  If MACHINE is not a string representing a known machine type, an
exception is raised.  This function does not distinguish between threaded and
nonthreaded variants of MACHINE.

Note that this function only handles Chez Scheme machine types in the
strictest sense, not other kinds of descriptors sometimes used in place of a
Chez Scheme machine type by Racket, such as @code{\"pb\"}, @code{#f}, or
@code{\"racket\"}.  (When using such extensions, the Chez Scheme machine type
for the host system is often still relevant.)"
  (let ((machine (chez-machine->nonthreaded machine)))
    (let find-arch ((alist %nix-arch-to-chez-alist))
      (match alist
        (((nix . chez) . alist)
         (if (string-prefix? chez machine)
             (string-append
              nix "-" (let ((machine-os
                             (substring machine (string-length chez))))
                        (let find-os ((alist %nix-os-to-chez-alist))
                          (match alist
                            (((nix . chez) . alist)
                             (if (equal? chez machine-os)
                                 nix
                                 (find-os alist)))))))
             (find-arch alist)))))))

(define* (nix-system->chez-machine #:optional
                                   (system (or (%current-target-system)
                                               (%current-system))))
  "Return the Chez Scheme machine type corresponding to the Nix system
identifier SYSTEM, or @code{#f} if the translation of SYSTEM to a Chez Scheme
machine type is undefined.

It is unspecified whether the resulting string will name a threaded or a
nonthreaded machine type: when the distinction is relevant, use
@code{chez-machine->nonthreaded} or @code{chez-machine->threaded} to adjust
the result."
  (let* ((hyphen (string-index system #\-))
         (nix-arch (substring system 0 hyphen))
         (nix-os (substring system (+ 1 hyphen)))
         (chez-arch (assoc-ref %nix-arch-to-chez-alist nix-arch))
         (chez-os (assoc-ref %nix-os-to-chez-alist nix-os)))
    (and chez-arch chez-os (string-append chez-arch chez-os))))

(define* (chez-upstream-features-for-system #:optional
                                            (system
                                             (or (%current-target-system)
                                                 (%current-system))))
  "Return a list of symbols naming features supported by upstream Chez Scheme
for the Nix system identifier SYSTEM, or @code{#f} if upstream Chez Scheme
does not support SYSTEM at all.

If native threads are supported, the returned list will include
@code{'threads}.  Other feature symbols may be added in the future."
  (cond
   ((not (nix-system->chez-machine system))
    #f)
   ((target-aarch64? system)
    #f)
   ((target-arm32? system)
    (and (target-linux? system)
         '()))
   ((target-ppc32? system)
    (and (target-linux? system)
         '(threads)))
   (else
    '(threads))))

;;
;; Chez Scheme:
;;

(define-public nanopass
  (let ((version "1.9.2"))
    (origin
      (method git-fetch)
      (uri (git-reference
            (url "https://github.com/nanopass/nanopass-framework-scheme")
            (commit (string-append "v" version))))
      (sha256 (base32 "16vjsik9rrzbabbhbxbaha51ppi3f9n8rk59pc6zdyffs0vziy4i"))
      (file-name (git-file-name "nanopass" version)))))

(define-public stex
  ;; This commit includes a fix, which we would otherwise want to use as
  ;; patch.  Let's revert to tagged releases as soon as one becomes available.
  (let* ((commit "54051494434a197772bf6ca5b4e6cf6be55f39a5")
         (version "1.2.2")
         (version (git-version version "1" commit)))
    (origin
      (method git-fetch)
      (uri (git-reference
            (url "https://github.com/dybvig/stex")
            (commit commit)))
      (sha256 (base32 "01jnvw8qw33gnpzwrakwhsr05h6b609lm180jnspcrb7lds2p23d"))
      (file-name (git-file-name "stex" version)))))

(define-public chez-scheme
  (package
    (name "chez-scheme")
    ;; The version should match `(scheme-version-number)`.
    ;; See s/cmacros.ss c. line 360.
    (version "9.5.6")
    (source (origin
              (method git-fetch)
              (uri (git-reference
                    (url "https://github.com/cisco/ChezScheme")
                    (commit (string-append "v" version))))
              (sha256
               (base32
                "07s433hn1z2slfc026sidrpzxv3a8narcd40qqr1xrpb9012xdky"))
              (file-name (git-file-name name version))
              (snippet #~(begin
                           (use-modules (guix build utils))
                           (for-each (lambda (dir)
                                       (when (directory-exists? dir)
                                         (delete-file-recursively dir)))
                                     '("stex"
                                       "nanopass"
                                       "lz4"
                                       "zlib"))))))
    (build-system gnu-build-system)
    (inputs
     (list
      `(,util-linux "lib") ;<-- libuuid
      zlib
      lz4
      ncurses ;<-- for expeditor
      ;; for X11 clipboard support in expeditor:
      ;; https://github.com/cisco/ChezScheme/issues/9#issuecomment-222057232
      libx11))
    (native-inputs
     (list nanopass ; source only
           ;; for docs
           stex
           xorg-rgb
           (texlive-updmap.cfg (list texlive-dvips-l3backend
                                     texlive-epsf
                                     texlive-fonts-ec
                                     texlive-oberdiek))
           ghostscript
           netpbm))
    (native-search-paths
     (list (search-path-specification
            (variable "CHEZSCHEMELIBDIRS")
            (files (list (string-append "lib/chez-scheme"))))))
    (outputs '("out" "doc"))
    (arguments
     (list
      #:modules
      '((guix build gnu-build-system)
        (guix build utils)
        (ice-9 ftw)
        (ice-9 match))
      #:test-target "test"
      ;; TODO when we fix armhf, it may not support --threads
      #:configure-flags #~'("--threads")
      #:phases
      #~(modify-phases %standard-phases
          (add-after 'unpack 'unpack-nanopass+stex
            (lambda args
              (copy-recursively #$nanopass
                                "nanopass"
                                #:keep-mtime? #t)
              (copy-recursively #$stex
                                "stex"
                                #:keep-mtime? #t)))
          ;; NOTE: the custom Chez 'configure' script doesn't allow
          ;; unrecognized flags, such as those automatically added
          ;; by `gnu-build-system`.
          (replace 'configure
            (lambda* (#:key inputs (configure-flags '()) #:allow-other-keys)
              ;; add flags which are always required:
              (let ((flags (cons* (string-append "--installprefix=" #$output)
                                  "ZLIB=-lz"
                                  "LZ4=-llz4"
                                  "--libkernel"
                                  ;; Guix will do compress-man-pages,
                                  ;; and letting Chez try causes an error
                                  "--nogzip-man-pages"
                                  configure-flags)))
                (format #t "configure flags: ~s~%" flags)
                ;; Some makefiles (for tests) don't seem to propagate CC
                ;; properly, so we take it out of their hands:
                (setenv "CC" #$(cc-for-target))
                (setenv "HOME" "/tmp")
                (apply invoke "./configure" flags))))
          ;; The binary file name is called "scheme" as is the one from
          ;; MIT/GNU Scheme.  We add a symlink to use in case both are
          ;; installed.
          (add-after 'install 'install-symlink
            (lambda* (#:key outputs #:allow-other-keys)
              (let* ((scheme (search-input-file outputs "/bin/scheme"))
                     (bin-dir (dirname scheme)))
                (symlink scheme
                         (string-append bin-dir "/chez-scheme"))
                (match (find-files (string-append bin-dir "/../lib")
                                   "scheme.boot")
                  ((scheme.boot)
                   (symlink scheme.boot
                            (string-append (dirname scheme.boot)
                                           "/chez-scheme.boot")))))))
          ;; Building explicitly lets us avoid using substitute*
          ;; to re-write makefiles.
          (add-after 'install-symlink 'prepare-stex
            (lambda* (#:key native-inputs inputs outputs #:allow-other-keys)
              ;; Eventually we want to install stex as a real
              ;; package so it's reusable. For now:
              (let* ((stex-output "/tmp")
                     (doc-dir (string-append stex-output "/share/doc/stex")))
                (with-directory-excursion "stex"
                  (invoke "make"
                          "install"
                          (string-append "LIB="
                                         stex-output
                                         "/lib/stex")
                          (string-append "Scheme="
                                         (search-input-file outputs
                                                            "/bin/scheme")))
                  (for-each (lambda (pth)
                              (install-file pth doc-dir))
                            '("ReadMe" ; includes the license
                              "doc/stex.html"
                              "doc/stex.css"
                              "doc/stex.pdf"))))))
          ;; Building the documentation requires stex and a running scheme.
          ;; FIXME: this is probably wrong for cross-compilation
          (add-after 'prepare-stex 'install-doc
            (lambda* (#:key native-inputs inputs outputs #:allow-other-keys)
              (match (assoc-ref outputs "doc")
                (#f
                 (format #t "not installing docs~%"))
                (doc-prefix
                 (let* ((chez+version (strip-store-file-name #$output))
                        (scheme (search-input-file outputs "/bin/scheme"))
                        (stexlib "/tmp/lib/stex")
                        (doc-dir (string-append doc-prefix
                                                "/share/doc/"
                                                chez+version)))
                   (define* (stex-make #:optional (suffix ""))
                     (invoke "make" "install"
                             (string-append "Scheme=" scheme)
                             (string-append "STEXLIB=" stexlib)
                             (string-append "installdir=" doc-dir suffix)))
                   (with-directory-excursion "csug"
                     (stex-make "/csug"))
                   (with-directory-excursion "release_notes"
                     (stex-make "/release_notes"))
                   (with-directory-excursion doc-dir
                     (symlink "release_notes/release_notes.pdf"
                              "release_notes.pdf")
                     (symlink "csug/csug9_5.pdf"
                              "csug.pdf"))))))))))
    ;; Chez Scheme does not have a  MIPS backend.
    ;; FIXME: Debian backports patches to get armhf working.
    ;; We should too. It is the Chez machine type arm32le
    ;; (no threaded version upstream yet, though there is in
    ;; Racket's fork), more specifically (per the release notes) ARMv6.
    (supported-systems
     (delete
      "armhf-linux" ;; <-- should work, but reportedly broken
      (filter chez-upstream-features-for-system
              %supported-systems)))
    (home-page "https://cisco.github.io/ChezScheme/")
    (synopsis "R6RS Scheme compiler and run-time")
    (description
     "Chez Scheme is a compiler and run-time system for the language of the
Revised^6 Report on Scheme (R6RS), with numerous extensions.  The compiler
generates native code for each target processor, with support for x86, x86_64,
and 32-bit PowerPC architectures.")
    (license license:asl2.0)))