(in-package :wu)

;;; +=========================================================================+
;;; | Copyright (c) 2009, 2010  Mike Travers and CollabRx, Inc                |
;;; |                                                                         |
;;; | Released under the MIT Open Source License                              |
;;; |   http://www.opensource.org/licenses/mit-license.php                    |
;;; |                                                                         |
;;; | Permission is hereby granted, free of charge, to any person obtaining   |
;;; | a copy of this software and associated documentation files (the         |
;;; | "Software"), to deal in the Software without restriction, including     |
;;; | without limitation the rights to use, copy, modify, merge, publish,     |
;;; | distribute, sublicense, and/or sell copies of the Software, and to      |
;;; | permit persons to whom the Software is furnished to do so, subject to   |
;;; | the following conditions:                                               |
;;; |                                                                         |
;;; | The above copyright notice and this permission notice shall be included |
;;; | in all copies or substantial portions of the Software.                  |
;;; |                                                                         |
;;; | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,         |
;;; | EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF      |
;;; | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  |
;;; | IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY    |
;;; | CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,    |
;;; | TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE       |
;;; | SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                  |
;;; +=========================================================================+

;;; Author:  Mike Travers


(export '(async))

;;; Render a DIV with PRE-TEXT now, and replace it with the results of BODY when that completes.
;;; Note that the use of continuations replaces a ton of special-purpose machinery.

(defmacro async ((&key (pre-text "waiting...") spinner) &body body)
  `(let ((%id (gensym "async")))
     (html
      ((:div :id %id)
       (:princ ,pre-text)
       (when ,spinner
	 (html (image-tag "spinner.gif"))))
      ((:script :type "text/javascript")
       (:princ
	(remote-function 
	 (ajax-continuation ()
	   (render-update
	     (:update
	      %id
	      ,@body)))
	 :in-function? nil))))))