org-fc-scheduler.el

;;; org-fc-scheduler.el --- Schedulers used for ordering items during review -*- lexical-binding: t; -*-

;; Copyright (C) 2020-2024  Leon Rische

;; Author: Leon Rische <emacs@leonrische.me>

;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:
;;
;;; Code:

(require 'eieio)

(require 'org-fc-core)

(defclass org-fc-scheduler ()
  ((positions
    :initarg :positions
    :initform nil)))

(defclass org-fc-scheduler-shuffled (org-fc-scheduler)
  ())

(cl-defmethod org-fc-scheduler-init ((scheduler org-fc-scheduler) cards)
  (oset
   scheduler
   positions
   (mapcan (lambda (card) (oref card positions)) cards)))

(cl-defmethod org-fc-scheduler-init ((scheduler org-fc-scheduler-shuffled)
				     cards)
  ;; 1. assign each position a random number
  ;; 2. flatten the list
  ;; 3. sort by the random number
  ;; 4. remove the random numbers from the result
  (let ((positions-with-random
	 (mapcan
	  (lambda (card)
	    (let ((positions (oref card positions)))
	      (org-fc-zip
	       (org-fc-sorted-random (length positions))
	       positions)))
	  cards)))
    (oset
     scheduler
     positions
     (mapcar
      #'cdr
      (sort positions-with-random (lambda (a b) (> (car a) (car b))))))))

(cl-defmethod org-fc-scheduler-next-position ((scheduler org-fc-scheduler))
  (pop (oref scheduler positions)))

(cl-defmethod org-fc-scheduler-push-position ((scheduler org-fc-scheduler) position)
  (with-slots (positions) scheduler
    (setf positions (append positions (list position)))))

(cl-defmethod org-fc-scheduler-remove-siblings ((scheduler org-fc-scheduler) position)
  "Given one POSITION, remove all other positions that belong to the same card."
  (let ((id (oref (oref position card) id)))
    (with-slots (positions) scheduler
      (setf positions
	    (cl-remove-if
	     (lambda (other) (string= (oref (oref other card) id) id))
	     positions)))))

;;; Footer

(provide 'org-fc-scheduler)

;;; org-fc-scheduler.el ends here