;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2018 Mark H Weaver <mhw@netris.org>
;;;
;;; 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/>.


;;; This is very preliminary work.

(use-modules (guix)
             (guix derivations)
             (gnu)
             (ice-9 match)
             (srfi srfi-1))

(define proc-returns-t?
  (match-lambda
    (((or 'lambda
          'lambda*)
      formals bodies ... last)
     (returns-t? last))
    (((or 'let
          'let*
          'letrec
          'letrec*
          'with-fluids)
      (bindings ...) bodies ... last)
     (proc-returns-t? last))
    (('begin exprs ... last)
     (proc-returns-t? last))
    (('const expr)
     (returns-t? expr))
    ('invoke #t)
    (_ #f)))

(define returns-t?
  (match-lambda
    (#t #t)
    (('begin exprs ... last)
     (returns-t? last))
    (((or 'let
          'let*
          'letrec
          'letrec*
          'with-fluids)
      (bindings ...) bodies ... last)
     (returns-t? last))
    (('match expr (pattern bodies ... last) ...)
     (every returns-t? last))
    (('with-directory-excursion dir bodies ... last)
     (returns-t? last))
    (((or 'call-with-input-file
          'call-with-output-file
          'with-input-to-file
          'with-output-to-file
          'with-atomic-file-replacement)
      file-name proc)
     (proc-returns-t? proc))
    (('apply proc args ... tail)
     (proc-returns-t? proc))
    ((proc args ...)
     (proc-returns-t? proc))
    (_ #f)))

(define mod-spec-returns-t?
  (match-lambda
    (((or 'add-before 'add-after) _ _ proc)
     (proc-returns-t? proc))
    (('replace _ proc)
     (proc-returns-t? proc))
    (('delete _)
     #t)))

(define phases-return-t?
  (match-lambda
    (#f #t)
    ('%standard-phases #t)
    (('modify-phases orig mod-specs ...)
     (and (every mod-spec-returns-t? mod-specs)
          (phases-return-t? orig)))
    (((or 'alist-cons-before 'alist-cons-after) _ _ proc orig)
     (and (proc-returns-t? proc)
          (phases-return-t? orig)))
    (('alist-replace _ proc orig)
     (and (proc-returns-t? proc)
          (phases-return-t? orig)))
    (('alist-delete _ orig)
     (phases-return-t? orig))
    (_ #f)))

(define (package-snippet pkg)
  (and=> (package-source pkg)
         origin-snippet))

(define (snippet-returns-t? snippet)
  (or (not snippet)
      (returns-t? snippet)))

(define (possible-snippet-problem-pkgs)
  (fold-packages cons '() #:select? (negate (compose snippet-returns-t?
                                                     package-snippet))))

(define (arguments->phases arguments)
  (apply (lambda* (#:key phases #:allow-other-keys)
                    phases)
                  arguments))

(define (package-phases pkg)
  (and=> (package-arguments pkg)
         arguments->phases))

(define (possible-phase-problem-pkgs)
  (fold-packages cons '() #:select? (negate (compose phases-return-t?
                                                     package-phases))))

(define (arguments->builder arguments)
  (apply (lambda* (#:key builder #:allow-other-keys)
           builder)
         arguments))

(define (package-builder pkg)
  (and=> (package-arguments pkg)
         arguments->builder))

(define (builder-returns-t? builder)
  (or (not builder)
      (returns-t? builder)))

(define (possible-builder-problem-pkgs)
  (fold-packages cons '() #:select? (negate (compose builder-returns-t?
                                                     package-builder))))

(define (package-name<? a b)
  (string<? (package-name a) (package-name b)))

;; (sort probs package-name<?)


(define (possible-phase-problem-pkgs-from-drvs drv-files)
  (filter (lambda (drv-file)
            (and (file-exists? drv-file)
                 (let ((drv (read-derivation-from-file drv-file)))
                   (match (derivation-builder-arguments drv)
                     ((_ ... file)
                      (and (string-suffix? "-guile-builder" file)
                           (let ((builder (call-with-input-file file
                                            (lambda (p) (read p) (read p)))))
                             (match builder
                               (('exit ('begin ('gnu-build . arguments)))
                                (let ((phases (arguments->phases arguments)))
                                  (not (phases-return-t? phases))))
                               (_ #f)))))
                     (_ #f)))))
          drv-files))