;;;; wh-engine/serialization.lisp
(in-package wh-engine)

(defstruct id-ref
  (scene 0 :type fixnum)
  (actor nil :type (or fixnum null))
  (component nil :type (or symbol null)))

(deftype pointer () '(or id-ref weak-pointer null))

(defun suspend-ptr (ptr)
  "Convert weak-pointer ptr to an id-ref."
  (declare (type weak-pointer ptr))

  (let (target (weak-pointer-value ptr))
  (cond
    ((typep target 'scene)
     (make-id-ref :scene [target id]))
    ((typep target 'actor)
     (make-id-ref :scene [target scene id]
                  :actor [target id]))
    ((typep target 'component)
     (make-id-ref :scene [target scene id]
                  :actor [target actor id]
                  :component (class-name (class-of target))))
    (t ptr))))

(defun resume-ptr (ref)
  "Convert id-ref ref to a weak-pointer."
  (declare (type id-ref ref))

  (let ((scene (get-scene (id-ref-scene ref))) actor component)
    (if (setf actor [scene (get-actor (id-ref-actor ref))])
        (if (setf component [actor (get-component (find-class (id-ref-component ref)))])
            (make-weak-pointer component)
            (make-weak-pointer actor))
        (make-weak-pointer scene))))

(defmacro suspend-setf (place)
  `(when (typep ,place 'weak-pointer)
     (setf ,place (suspend-ptr ,place))))
(defmacro resume-setf (place)
  `(when (typep ,place 'id-ref)
     (setf ,place (resume-ptr ,place))))