;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2022 pukkamustard <pukkamustard@posteo.net>
;;;
;;; 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 eris http)
  #:use-module (eris utils base32)
  #:use-module (web uri)

  #:use-module (srfi srfi-2)

  #:export (make-blake2b-urn-query-ref))

(define blake2b-uri-path-regexp
  (make-regexp "^blake2b:" regexp/icase))

(define (make-blake2b-urn-query-ref block-ref)
  (lambda (query)
    (and-let* ((_ query) ; ensure query is not false
               (urn (string->uri query))
               (_ (uri? urn))
               (_ (eqv? (uri-scheme urn) 'urn))
               (_ (regexp-exec blake2b-uri-path-regexp
                               (uri-path urn)))
               (blake2b-ref (base32-decode
                             (string-drop (uri-path urn) 8))))
      (block-ref blake2b-ref))))