;;;; cl-scopes/web/response - set up and render server response

(defpackage :scopes/web/response
  (:use :common-lisp)
  (:local-nicknames (:message :scopes/core/message))
  (:export #:setup
           #:render #:render-not-found))

(in-package :scopes/web/response)

(defclass plain-text-response ()
  ((context :initarg :context)
   (env :initarg :env)))

(defclass json-response (plain-text-response) ())

(defclass html-response (plain-text-response) ())

(defun setup (ctx env)
  (let* ((headers (getf env :headers))
         (resp-class (select-response-class (gethash "accept" headers))))
    (make-instance resp-class :context ctx :env env)))

(defun select-response-class (accept)
  (cond 
    ((null accept) 'html-response)
    ((str:containsp "html" accept) 'html-response)
    ((str:containsp "json" accept) 'json-response)
    ((str:containsp "plain" accept) 'plain-text-response)
    (t 'html-response)))

(defun render (resp msg)
  (let ((headers '(:content-type "text/plain"))
        (rcode 200)
        (content (getf (message:data msg) :info)))
    ; process special message heads, e.g. (:system :error ...)
    ;   => set status code, provide additional data elements
    ; (gethash "accept" (getf env :headers)) => select output format
    ; set headers, render body
    (list rcode headers (list content))))

(defun render-not-found(resp)
  (list 404 '(:content-type "text/plain") '("Not found")))