;;;; cl-scopes/web/dom - "Data Output Model" = simple and dedicated HTML generator

(defpackage :scopes/web/dom
  (:use :common-lisp)
  (:local-nicknames (:util :scopes/util)
                    (:alx :alexandria))
  (:export #:render #:text
           #:dl #:link))

(in-package :scopes/web/dom)

;;;; basic / common stuff

(defvar *output* (make-string-output-stream))

(defmacro render (&body body)
  `(let ((*output* (make-string-output-stream)))
     ,@body
     (get-output-stream-string *output*)))

(defmacro put-string (s)
  `(write-string ,s *output*))

(defmacro put-char (c)
  `(write-char ,c *output*))

(defmacro element (tag attrs &body body)
  `(progn
     (start ,tag ,attrs)
     ,@body
     (end ,tag)))

(defun put-attrs (plist)
  (loop for (key val . r) on plist by #'cddr do
     (put-char #\Space)
     (when val
       (put-string (string-downcase key))
       (when (not (eq val t))
         (put-string "=\"")
         (put-string (attr-str key val))
         (put-char #\")))))

(defun attr-str (key val)
  (case key 
    ((:id :class) (util:to-string val))
    (t (string val))))

(defun start (tag &optional attrs)
  (put-char #\<)
  (put-string tag)
  (put-attrs attrs)
  (put-char #\>))

(defun end (tag)
  (put-string "</")
  (put-string tag)
  (put-char #\>))

(defun text (s)
  (put-string (string s)))

(defun newline ()
  (put-char #\Newline))

;;;; tag-specific renderers

(defun dl (attrs plist)
  (element "dl" attrs
    (loop for (key val . r) on plist by #'cddr do
      (element "dt" nil (put-string (string-downcase key)))
      (dd nil val))))

(defun dd (attrs v)
  (if (atom v)
    (setf v (list v)))
  (dolist (el v)
    (element "dd" attrs (text el))))

(defmacro link (attrs &body body)
  `(element "a" ,attrs ,@body))