;;;; conditions.lisp -- MCIAS error condition hierarchy

(in-package #:mcias-client)

(define-condition mcias-error (error)
  ((status  :initarg :status  :reader mcias-error-status
            :documentation "HTTP status code (integer).")
   (message :initarg :message :reader mcias-error-message
            :documentation "Server error message string."))
  (:report (lambda (c s)
             (format s "MCIAS error ~A: ~A"
                     (mcias-error-status c)
                     (mcias-error-message c))))
  (:documentation "Base condition for all MCIAS API errors."))

(define-condition mcias-auth-error     (mcias-error) ()
  (:documentation "401 Unauthorized -- token missing, invalid, or expired."))
(define-condition mcias-forbidden-error (mcias-error) ()
  (:documentation "403 Forbidden -- insufficient role."))
(define-condition mcias-not-found-error (mcias-error) ()
  (:documentation "404 Not Found -- resource does not exist."))
(define-condition mcias-input-error    (mcias-error) ()
  (:documentation "400 Bad Request -- malformed request."))
(define-condition mcias-conflict-error (mcias-error) ()
  (:documentation "409 Conflict -- e.g. duplicate username."))
(define-condition mcias-server-error   (mcias-error) ()
  (:documentation "5xx -- unexpected server error."))

(defun signal-mcias-error (status message)
  "Signal the appropriate MCIAS condition for STATUS (integer) and MESSAGE (string)."
  (case status
    (401 (error 'mcias-auth-error      :status status :message message))
    (403 (error 'mcias-forbidden-error :status status :message message))
    (404 (error 'mcias-not-found-error :status status :message message))
    (400 (error 'mcias-input-error     :status status :message message))
    (409 (error 'mcias-conflict-error  :status status :message message))
    (t   (error 'mcias-server-error    :status status :message message))))