;; disfluid, implementation of the Solid specification
;; Copyright (C) 2020, 2021  Vivien Kraus

;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU Affero General Public License as
;; published by the Free Software Foundation, either version 3 of the
;; License, or (at your option) any later version.

;; This program 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 Affero General Public License for more details.

;; You should have received a copy of the GNU Affero General Public License
;; along with this program.  If not, see <https://www.gnu.org/licenses/>.

(define-module (webid-oidc token-endpoint)
  #:use-module (webid-oidc server endpoint identity-provider)
  #:use-module (webid-oidc errors)
  #:use-module (webid-oidc server endpoint)
  #:use-module (webid-oidc authorization-code)
  #:use-module (webid-oidc dpop-proof)
  #:use-module (webid-oidc jws)
  #:use-module (webid-oidc jwk)
  #:use-module (webid-oidc oidc-id-token)
  #:use-module (webid-oidc access-token)
  #:use-module (webid-oidc web-i18n)
  #:use-module ((webid-oidc parameters) #:prefix p:)
  #:use-module ((webid-oidc stubs) #:prefix stubs:)
  #:use-module ((webid-oidc refresh-token) #:prefix refresh:)
  #:use-module (web request)
  #:use-module (web response)
  #:use-module (web uri)
  #:use-module (ice-9 optargs)
  #:use-module (ice-9 receive)
  #:use-module (ice-9 control)
  #:use-module (ice-9 exceptions)
  #:use-module (srfi srfi-19)
  #:use-module (srfi srfi-26)
  #:use-module (rnrs bytevectors)
  #:use-module (sxml simple)
  #:use-module (sxml match)
  #:use-module (oop goops)
  #:duplicates (merge-generics)
  #:declarative? #t
  #:export
  (
   make-token-endpoint
   ))

(define (try-handle-web-failure thunk)
  (call/ec
   (lambda (return)
     (with-exception-handler
         (lambda (error)
           (unless (web-exception? error)
             (raise-exception error))
           (return
            (build-response
             #:code (web-exception-code error)
             #:reason-phrase (web-exception-reason-phrase error)
             #:headers `((content-type application/xhtml+xml)))
            (call-with-output-string
              (cute sxml->xml
                    `(*TOP*
                      (*PI* xml "version=\"1.0\" encoding=\"utf-8\"")
                      (html (@ (xmlns "http://www.w3.org/1999/xhtml")
                               (xml:lang ,(W_ "xml-lang|en")))
                            (body
                             ,(call-with-input-string
                                  (format #f (W_ "<h1>The token request failed</h1>"))
                                xml->sxml)
                             ,(if (user-message? error)
                                  (user-message-sxml error)
                                  (call-with-input-string
                                      (format #f (W_ "<p>No more information.</p>"))
                                    xml->sxml)))))
                    <>))))
       thunk))))

(define (make-token-endpoint token-endpoint-uri iss issuer-key-file)
  (define endpoint
    (make <token-endpoint>
      #:issuer iss
      #:key-file issuer-key-file))
  (lambda (request request-body)
    (when (bytevector? request-body)
      (set! request-body (utf8->string request-body)))
    (try-handle-web-failure
     (lambda ()
       (parameterize ((web-locale request))
         (receive (response response-body response-meta)
             (handle endpoint request request-body)
           (values response response-body)))))))