(in-package :cl-tty.slot)

(defvar *slots* (make-hash-table :test #'equal)
  "Hash table mapping slot name (string) -> list of (order . render-fn) pairs.")

(defun defslot (name &key (order 0) render-fn)
  (let* ((key (string name))
         (entries (gethash key *slots*)))
    (if (null entries)
        (setf (gethash key *slots*) (list (cons order render-fn)))
        (setf (gethash key *slots*)
              (sort (cons (cons order render-fn) entries) #'< :key #'car))))
  render-fn)

(defun slot-render (slot-name &rest args)
  (let ((entries (gethash (string slot-name) *slots*)))
    (when entries
      (mapcar (lambda (entry) (apply (cdr entry) args)) entries))))

(defun slot-p (slot-name)
  (nth-value 1 (gethash (string slot-name) *slots*)))

(defun clear-slot (slot-name)
  (remhash (string slot-name) *slots*))

(defun list-slots ()
  (loop for key being the hash-keys of *slots* collect key))