;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2014 David Thompson <davet@gnu.org>
;;; Copyright © 2015 Eric Bavier <bavier@member.fsf.org>
;;; Copyright © 2016 Jelle Licht <jlicht@fsfe.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/>.

(define-module (guix import utils)
  #:use-module (guix base32)
  #:use-module ((guix build download) #:prefix build:)
  #:use-module (guix hash)
  #:use-module ((guix licenses) #:prefix license:)
  #:use-module (guix utils)
  #:use-module (ice-9 match)
  #:use-module (ice-9 regex)
  #:use-module (json)
  #:use-module (srfi srfi-1)
  #:export (factorize-uri

            hash-table->alist
            flatten
            assoc-ref*

            url-fetch
            json-fetch
            guix-hash-url

            spdx-string->license
            license->symbol

            snake-case
            beautify-description))

(define (factorize-uri uri version)
  "Factorize URI, a package tarball URI as a string, such that any occurrences
of the string VERSION is replaced by the symbol 'version."
  (let ((version-rx (make-regexp (regexp-quote version))))
    (match (regexp-exec version-rx uri)
      (#f
       uri)
      (_
       (let ((indices (fold-matches version-rx uri
                                    '((0))
                                    (lambda (m result)
                                      (match result
                                        (((start) rest ...)
                                         `((,(match:end m))
                                           (,start . ,(match:start m))
                                           ,@rest)))))))
         (fold (lambda (index result)
                 (match index
                   ((start)
                    (cons (substring uri start)
                          result))
                   ((start . end)
                    (cons* (substring uri start end)
                           'version
                           result))))
               '()
               indices))))))

(define (hash-table->alist table)
  "Return an alist represenation of TABLE."
  (map (match-lambda
        ((key . (lst ...))
         (cons key
               (map (lambda (x)
                      (if (hash-table? x)
                          (hash-table->alist x)
                          x))
                    lst)))
        ((key . (? hash-table? table))
         (cons key (hash-table->alist table)))
        (pair pair))
       (hash-map->list cons table)))

(define (flatten lst)
  "Return a list that recursively concatenates all sub-lists of LST."
  (fold-right
   (match-lambda*
    (((sub-list ...) memo)
     (append (flatten sub-list) memo))
    ((elem memo)
     (cons elem memo)))
   '() lst))

(define (assoc-ref* alist key . rest)
  "Return the value for KEY from ALIST.  For each additional key specified,
recursively apply the procedure to the sub-list."
  (if (null? rest)
      (assoc-ref alist key)
      (apply assoc-ref* (assoc-ref alist key) rest)))

(define (url-fetch url file-name)
  "Save the contents of URL to FILE-NAME.  Return #f on failure."
  (parameterize ((current-output-port (current-error-port)))
    (build:url-fetch url file-name)))

(define (guix-hash-url filename)
  "Return the hash of FILENAME in nix-base32 format."
  (bytevector->nix-base32-string (file-sha256 filename)))

(define (spdx-string->license str)
  "Convert STR, a SPDX formatted license identifier, to a license object.
   Return #f if STR does not match any known identifiers."
  (match str
    ("AGPL-1.0"                    'license:AGPL-1.0)
    ("AGPL-3.0"                    'license:AGPL-3.0)
    ("Apache-1.1"                  'license:asl1.1)
    ("Apache-2.0"                  'license:asl2.0)
    ("BSL-1.0"                     'license:boost1.0)
    ("BSD-2-Clause-FreeBSD"        'license:bsd-2)
    ("BSD-3-Clause"                'license:bsd-3)
    ("BSD-4-Clause"                'license:bsd-4)
    ("CC0-1.0"                     'license:cc0)
    ("CC-BY-SA-4.0"                'license:cc-by-sa4.0)
    ("CC-BY-SA-3.0"                'license:cc-by-sa3.0)
    ("CC-BY-3.0"                   'license:cc-by3.0)
    ("CC-BY-2.0"                   'license:cc-by2.0)
    ("CDDL-1.0"                    'license:cddl1.0)
    ("CECILL-C"                    'license:cecill-c)
    ("Artistic-2.0"                'license:artistic2.0)
    ("ClArtistic"                  'license:clarified-artistic)
    ("CPL-1.0"                     'license:cpl1.0)
    ("EPL-1.0"                     'license:epl1.0)
    ("MIT"                         'license:expat)
    ("FTL"                         'license:freetype)
    ("Giftware"                    'license:giftware)
    ("GPL-1.0"                     'license:gpl1)
    ("GPL-1.0+"                    'license:gpl1+)
    ("GPL-2.0"                     'license:gpl2)
    ("GPL-2.0+"                    'license:gpl2+)
    ("GPL-3.0"                     'license:gpl3)
    ("GPL-3.0+"                    'license:gpl3+)
    ("ISC"                         'license:isc)
    ("IJG"                         'license:ijg)
    ("Imlib2"                      'license:imlib2)
    ("IPA"                         'license:ipa)
    ("LGPL-2.0"                    'license:lgpl2.0)
    ("LGPL-2.0+"                   'license:lgpl2.0+)
    ("LGPL-2.1"                    'license:lgpl2.1)
    ("LGPL-2.1+"                   'license:lgpl2.1+)
    ("LGPL-3.0"                    'license:lgpl3.0)
    ("MPL-1.0"                     'license:mpl1.0)
    ("MPL-1.1"                     'license:mpl1.1)
    ("MPL-2.0"                     'license:mpl2.0)
    ("MS-PL"                       'license:ms-pl)
    ("NCSA"                        'license:ncsa)
    ("OpenSSL"                     'license:openssl)
    ("OLDAP-2.8"                   'license:openldap2.8)
    ("QPL-1.0"                     'license:qpl)
    ("Ruby"                        'license:ruby)
    ("SGI-B-2.0"                   'license:sgifreeb2.0)
    ("OFL-1.1"                     'license:silofl1.1)
    ("Sleepycat"                   'license:sleepycat)
    ("TCL"                         'license:tcl/tk)
    ("Vim"                         'license:vim)
    ("Unlicense"                   'license:unlicense)
    ("X11"                         'license:x11)
    ("ZPL-2.1"                     'license:zpl2.1)
    ("Zlib"                        'license:zlib)
    (_ #f)))

(define (license->symbol license)
  "Convert license to a symbol representing the variable the object is bound
to in the (guix licenses) module, or #f if there is no such known license."
  ;; TODO: Traverse list public variables in (guix licenses) instead so we
  ;; don't have to maintain a list manualy.
  (assoc-ref `((,license:lgpl2.0 . license:lgpl2.0)
               (,license:gpl3 . license:gpl3)
               (,license:bsd-3 . license:bsd-3)
               (,license:expat . license:expat)
               (,license:public-domain . license:public-domain)
               (,license:asl2.0 . license:asl2.0))
             license))

(define (snake-case str)
  "Return a downcased version of the string STR where underscores are replaced
with dashes."
  (string-join (string-split (string-downcase str) #\_) "-"))

(define (beautify-description description)
  "Improve the package DESCRIPTION by turning a beginning sentence fragment
into a proper sentence and by using two spaces between sentences."
  (let ((cleaned (if (string-prefix? "A " description)
                     (string-append "This package provides a"
                                    (substring description 1))
                     description)))
    ;; Use double spacing between sentences
    (regexp-substitute/global #f "\\. \\b"
                              cleaned 'pre ".  " 'post)))

(define (json-fetch url)
  "Return an alist representation of the JSON resource URL, or #f on failure."
  (call-with-temporary-output-file
   (lambda (temp port)
     (and (url-fetch url temp)
          (hash-table->alist
           (call-with-input-file temp json->scm))))))