;;;; 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:
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|Redistributions of source code must retain the above copyright notice,
|this list of conditions and the following disclaimer.
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|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.
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|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
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|SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|#

(in-package :cl-oid-connect)
; Should this be here?
(defparameter *oid* (make-instance 'ningle:<app>))
(setf drakma:*text-content-types* (cons '("application" . "json") drakma:*text-content-types*))

(setf =service-info= (object :parents '()
                             :properties '((client-id nil :accessor client-id)
                                           (secret nil :accessor secret))))

(setf =endpoint-schema= (object :parents '()
                                :properties '((auth-endpoint nil :accessor auth-endpoint)
                                              (token-endpoint nil :accessor token-endpoint)
                                              (userinfo-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=)))

(defparameter *FBOOK-INFO* (sheeple:clone =service-info=))
(defparameter *GOOG-INFO* (sheeple:clone =service-info=))
(defparameter *endpoint-schema* nil)
; goog is well behaved
(defparameter *goog-endpoint-schema* (defobject (=endpoint-schema= *goog-info*)))

(defun get-base-url (request) (format nil "~a//~a/oidc_callback"
                                      (lack.request:request-query-parameters)
                                      ))

; 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")
           (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))))))

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

(defun discover-endpoints (schema 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))))

    (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?
(defmacro with-endpoints (endpoint-schema  &body body)
  `(let* ((*endpoint-schema* ,endpoint-schema))
     ,@body))

(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)))))


(defmacro def-route ((url args &key (app *oid*)) &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)
  `(progn
     (format t "The session var is: ~a it contains: ~a~%"  ,(symbol-name var) ,var)
     (let ((,var (context :session)))
       (format t "The session var is: ~a it now contains: ~a~%"  ,(symbol-name var) ,var)
       ,@body)))

(defun load-facebook-info (loadfrom)
  (with-open-file (fbook-info (truename loadfrom))
    (let* ((data (yason:parse fbook-info))
           (client-id (gethash "client-id" data))
           (secret (gethash "secret" data)))
      (setf (client-id *FBOOK-INFO*) client-id) 
      (setf (secret *FBOOK-INFO*) secret))))

(defun load-google-info (loadfrom)
  (with-open-file (goog-info (truename loadfrom))
    (let* ((data (yason:parse goog-info))
           (client-id (gethash "client-id" data))
           (secret (gethash "secret" data)))
      (setf (client-id *GOOG-INFO*) client-id)
      (setf (secret *GOOG-INFO*) secret))))

(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")))))

(defun load-goog-endpoint-schema ()
  (discover-endpoints *goog-endpoint-schema*
                      "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"))


(defun oauth2-login-middleware (&key google-info facebook-info)
  (let ((clack-env nil))
    (lambda (app)
      (in-package :cl-oid-connect)
      (load-facebook-info facebook-info)
      (load-goog-endpoint-schema)
      (load-google-info google-info)

    (def-route ("/login/google" (params) :app app)
      (with-context-variables (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) :app app)
      (let ((session (ningle:context :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)
              (declare (ignore headers))
              (if (< rcode 400)
                `(302 (:location ,(format nil "~a" uri)))
                content))))))

    (def-route ("/oidc_callback/google" (params) :app app)
      (let ((received-state (cdr (string-assoc "state" params)))
            (code (cdr (string-assoc "code" params))))
        (check-state received-state
                     (with-context-variables (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) :app app)
      (let ((received-state (cdr (string-assoc "state" params)))
            (code (cdr (string-assoc "code" params))))
        (with-endpoints *fbook-endpoint-schema*
          (check-state received-state
                       (with-context-variables (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) :app app)
      (with-context-variables (session)
        (require-login 
          (with-endpoints  (gethash :endpoint-schema session)
            (cl-json:encode-json-to-string (gethash :userinfo session))))))

    (def-route ("/logout" (params) :app app)
      (with-context-variables (session)
        (setf (gethash :userinfo session) nil)
        '(302 (:location "/"))))

    app)))


(defmacro redirect-if-necessary (sessionvar &body body)
  (with-gensyms (session)
    `(let* ((,session ,sessionvar)
            (next-page (gethash :next-page ,session)))
       (if (and (not (null next-page))
                (not (string= next-page (lack.request:request-path-info *request*))))
         (progn
           (setf (gethash :next-page ,session) nil)
           `(302 (:location ,next-page)))
         ,@body))))

(export '(redirect-if-necessary def-route require-login))
(export '(oauth2-login-middleware with-session))