;;;; cl-oid-connect.lisp
 #|

 |Copyright (c) 2015 Edward Langley
 |All rights reserved.
 |
 |Redistribution and use in source and binary forms, with or without
 |modification, are permitted provided that the following conditions
 |are met:
 |
 |Redistributions of source code must retain the above copyright notice,
 |this list of conditions and the following disclaimer.
 |
 |Redistributions in binary form must reproduce the above copyright
 |notice, this list of conditions and the following disclaimer in the
 |documentation and/or other materials provided with the distribution.
 |
 |Neither the name of the project's author nor the names of its
 |contributors may be used to endorse or promote products derived from
 |this software without specific prior written permission.
 |
 |THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 |"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 |LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 |FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 |HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 |SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES  INCLUDING, BUT NOT LIMITED
 |TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 |PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 |LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 |NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 |SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 |
 |#

 
 (in-package :cl-oid-connect)

 ; Should this be here?
 (setf drakma:*text-content-types* (cons '("application" . "json") drakma:*text-content-types*))
 
 (sheeple:defproto =service-info= ()
                   ((client-id nil :accessor t)
                    (secret nil :accessor t)))
 
 (defvar *FBOOK-INFO* (sheeple:clone =service-info=))
 (defun load-facebook-info (loadfrom)
   (setf *FBOOK-INFO* 
         (with-open-file (fbook-info (truename loadfrom))
           (let* ((data (yason:parse fbook-info))
                  (client-id (gethash "client-id" data))
                  (secret (gethash "secret" data)))
             (sheeple:defobject (=service-info=)
                                ((client-id client-id)
                                 (secret secret)))))))
 
 (defvar *GOOG-INFO* (sheeple:clone =service-info=))
 (defun load-google-info (loadfrom)
   (setf *GOOG-INFO*
         (with-open-file (goog-info (truename loadfrom))
           (let* ((data (yason:parse goog-info))
                  (client-id (gethash "client-id" data))
                  (secret (gethash "secret" data)))
             (sheeple:defobject (=service-info=)
                                ((client-id client-id)
                                 (secret secret)))))))
 
 (load-facebook-info #p"facebook-secrets.json")
 (load-google-info #p"google-secrets.json")

 
 (defmacro string-assoc (key alist) `(assoc ,key ,alist :test #'equal))
 (defmacro assoc-cdr (key alist) `(cdr (assoc ,key ,alist)))
 

 (sheeple:defproto =endpoint-schema= ()
                   ((auth-endpoint nil :accessor t)
                    (token-endpoint nil :accessor t)
                    (redirect-uri nil :accessor t)))
 (sheeple:defmessage get-user-info (a b))
 (sheeple:defmessage get-access-token (a b))
 
 (sheeple:defreply get-user-info ((a =endpoint-schema=) (b sheeple:=string=)))
 (sheeple:defreply get-access-token ((a =endpoint-schema=) (b sheeple:=string=)))
 
 (defun discover-endpoints (service-info discovery-doc-url &key (gat nil gat-p) (gui nil gui-p))
   (let ((discovery-document (cl-json:decode-json-from-string (drakma:http-request discovery-doc-url)))
         (schema (sheeple:object :parents `(,=endpoint-schema= ,service-info))))
 
     (setf (auth-endpoint schema) (assoc-cdr :authorization--endpoint discovery-document))
     (setf (token-endpoint schema) (assoc-cdr :token--endpoint discovery-document))
 
     (if gui-p (sheeple:defreply get-user-info ((a schema)) (funcall gui a)))
     (if gat-p (sheeple:defreply get-access-token ((a schema) (b sheeple:=string=))
                 (funcall gat a b)))
 
     schema))
 
 ; This probably should eventually go?
 (defvar *endpoint-schema* nil)
 (defmacro with-endpoints (endpoint-schema  &body body)
   `(let* ((*endpoint-schema* ,endpoint-schema))
      ,@body))
 
 (defun goog-get-access-token (endpoint-schema code)
   (cl-json:decode-json-from-string
     (drakma:http-request (token-endpoint endpoint-schema)
                          :method :post
                          :redirect nil
                          :parameters `(("code" . ,code)
                                        ("client_id" . ,(client-id endpoint-schema))
                                        ("client_secret" . ,(secret endpoint-schema))
                                        ("redirect_uri" . ,(redirect-uri endpoint-schema))
                                        ("grant_type" . "authorization_code")))))
 
 ; goog is well behaved
 (defvar *goog-endpoint-schema*
   (discover-endpoints *GOOG-INFO* "https://accounts.google.com/.well-known/openid-configuration"
                       :gat #'goog-get-access-token))
 (setf (redirect-uri *goog-endpoint-schema*)   "http://srv2.elangley.org:9090/oidc_callback/google")
 
 
 ; fbook needs personal attention
 (defproto *fbook-endpoint-schema* (=endpoint-schema= *fbook-info*)
           ((auth-endpoint "https://www.facebook.com/dialog/oauth")
            (token-endpoint "https://graph.facebook.com/v2.3/oauth/access_token")
            (userinfo-endpoint "https://graph.facebook.com/v2.3/me" :accessor t)
            (redirect-uri  "http://srv2.elangley.org:9090/oidc_callback/facebook")))
 
 (sheeple:defreply get-access-token ((endpoint-schema *fbook-endpoint-schema*) (code sheeple:=string=))
   (cl-json:decode-json-from-string
     (drakma:http-request (token-endpoint endpoint-schema)
                          :method :post
                          :redirect nil
                          :parameters `(("code" . ,code)
                                        ("client_id" . ,(client-id endpoint-schema))
                                        ("app_id" . ,(client-id endpoint-schema))
                                        ("client_secret" . ,(secret endpoint-schema))
                                        ("redirect_uri" . ,(redirect-uri endpoint-schema))
                                        ("grant_type" . "authorization_code")
                                        ("")
                                        ))))
 
 (sheeple:defreply get-user-info ((endpoint-schema *fbook-endpoint-schema*) (access-token sheeple:=string=))
   (let ((endpoint (userinfo-endpoint endpoint-schema)))

     (cl-json:decode-json-from-string
       (drakma:http-request endpoint
                            :parameters `(("access_token" . ,access-token))))))
 
 (defvar *fbook-mw*
   (lambda (app)
     (lambda (env)
       (with-fbook-endpoints
         (format t "~a" *client-id*)
         (funcall app env)))))
 

 (defvar *goog-mw*
   (lambda (app)
     (lambda (env)
       (with-goog-endpoints
         (funcall app env)))))
 

 (defun do-auth-request (endpoint-schema state)
   (format t "~%client-id: ~a~%" (auth-endpoint endpoint-schema))
   (drakma:http-request (auth-endpoint endpoint-schema)

                        :redirect nil

                        :parameters `(("client_id" . ,(client-id endpoint-schema))
                                      ("app_id" . ,(client-id endpoint-schema))

                                      ("response_type" . "code")

                                      ("scope" . "email")

                                      ("redirect_uri" . ,(redirect-uri endpoint-schema))

                                      ("state" . ,state))))
 
 (defun gen-state (len)
   (with-output-to-string (stream)
     (let ((*print-base* 36))
       (loop repeat len
             do (princ (random 36) stream)))))
 

 (defvar *app* (make-instance 'ningle:<app>))

 (defmacro def-route (url args &body body)
   `(setf (ningle:route *app* ,url)
          #'(lambda ,args

              (declare (ignorable ,@args))

              ,@body)))
 
 (defmacro check-state (received-state then else)

   (alexandria:with-gensyms (saved-state session)
     `(let* ((,session (context :session))
             (,saved-state (gethash :state ,session)))

        (if (equal ,saved-state ,received-state)
          ,then
          ,else))))
 
 (defmacro require-login (&body body)

   (alexandria:with-gensyms (session)
     `(let ((,session (context :session)))
        (if (not (eql nil (gethash :userinfo ,session)))
          (progn
            ,@body)

          (progn
            (setf (gethash :next-page session) (lack.request:request-path-info *request*))
            '(302 (:location "/login")))))))

 
 (defmacro with-session ((var) &body body)
   `(let ((,var (context :session)))
      ,@body))
 

 (def-route "/login/google" (params)
   (with-session (session)
     (let ((state (gen-state 36)))
       (setf (gethash :state session) state)

       (with-endpoints *goog-endpoint-schema*
         (setf (gethash :endpoint-schema session) *goog-endpoint-schema*)
         (multiple-value-bind (content rcode headers) (do-auth-request *goog-endpoint-schema* state)

           (if (< rcode 400)
             `(302 (:location ,(cdr (assoc :location headers))))
             content))))))
 
 
 (def-route "/login/facebook" (params)
   (with-session (session)
     (let ((state (gen-state 36)))
       (setf (gethash :state session) state)

       (with-endpoints *fbook-endpoint-schema*
         (setf (gethash :endpoint-schema session) *fbook-endpoint-schema*)
         (multiple-value-bind (content rcode headers uri) (do-auth-request *fbook-endpoint-schema* state)

           (if (< rcode 400)
             `(302 (:location ,(format nil "~a" uri)))
             content))))))
 
 (def-route "/oidc_callback/google" (params)

   (let ((received-state (cdr (string-assoc "state" params)))
         (code (cdr (string-assoc "code" params))))
     (check-state received-state

                  (with-session (session)

                    (with-endpoints *goog-endpoint-schema*
                      (let* ((a-t (get-access-token *goog-endpoint-schema* code))
                             (id-token (assoc-cdr :id--token a-t))

                             (decoded (cljwt:decode id-token :fail-if-unsupported nil)))
                        (setf (gethash :userinfo session) decoded)
                        '(302 (:location "/")))))

                  '(403 '() "Out, vile imposter!"))))
 

 
 (def-route "/oidc_callback/facebook" (params)
   (let ((received-state (cdr (string-assoc "state" params)))
         (code (cdr (string-assoc "code" params))))

     (with-endpoints *fbook-endpoint-schema*

       (check-state received-state
                    (with-session (session)

                      (let* ((a-t (get-access-token *fbook-endpoint-schema* code))

                             (id-token (assoc-cdr :access--token a-t)))

                        (setf (gethash :userinfo session) (get-user-info *fbook-endpoint-schema* id-token))

                        '(302 (:location "/"))))
                    '(403 '() "Out, vile imposter!")))))
 
 (def-route "/userinfo.json" (params)
   (with-session (session)
     (require-login 

       (with-endpoints  (gethash :endpoint-schema session)

         (cl-json:encode-json-to-string (gethash :userinfo session))))))
 
 (def-route "/logout" (params)
   (with-session (session)
     (setf (gethash :userinfo session) nil)
     '(302 (:location "/"))))
 

 (def-route "/login" (params)
   (cl-who:with-html-output-to-string (s)
     (:html
       (:head
         (:title "Login"))
       (:body
         (:div (:a :href "/login/facebook" "Facebook"))
         (:div (:a :href "/login/google" "Google")))))) 
 

 (def-route "/" (params)

   (with-session (session)

     (if (not (null (gethash :next-page session)))
       `(302 (:location ,(gethash :next-page session)))
       (require-login 
         (anaphora:sunless (gethash :counter session) (setf anaphora:it 0))
         (format nil "~Ath visit<br/>~a<br/><br/>~S<br/>"
                 (gethash :counter session)
                 (alexandria:hash-table-alist session)
                 (alexandria:hash-table-alist (context :session)))))))

 (setf *handler* (clack:clackup (lack.builder:builder :session *app*) :port 9090))