;;; org-checklist.el --- org functions for checklist handling
;;
;; ©2008 James TD Smith
;;
;; Author: James TD Smith (@ ahktenzero (. mohorovi cc))
;; Version: 1.0
;; Keywords: org, checklists
;;
;; 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, 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, write to the Free Software
;; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
;;
;;; Commentary:
;; This file provides some functions for handing repeated tasks which involve
;; checking off a list of items. By setting the RESET_CHECK_BOXES property in an
;; item, when the TODO state is set to done all checkboxes under that item are
;; cleared. If the LIST_EXPORT_BASENAME property is set, a file will be created
;; using the value of that property plus a timestamp, containing all the items
;; in the list which are not checked. Additionally the user will be prompted to
;; print the list.
;;
;; I use this for to keep track of stores of various things (food stores,
;; components etc) which I check periodically and use the exported list of items
;; which are not present as a shopping list.
;;
;;; Usage:
;; (require 'org-checklist)
;;
;; Set the RESET_CHECK_BOXES and LIST_EXPORT_BASENAME properties in items as
;; needed.
;;
;;; Code:
(require 'org)

(defvar export-time-format "%Y%m%d%H%M"
  "format of timestamp appended to export file")
(defvar export-function 'org-export-as-ascii
  "function used to prepare the export file for printing")

(defun org-reset-checkbox-state-maybe ()
  "Reset all checkboxes in an entry if the `RESET_CHECK_BOXES' property is set"
  (interactive "*")
  (if (org-entry-get (point) "RESET_CHECK_BOXES")
      (save-restriction
	(save-excursion
	  (org-narrow-to-subtree)
	  (org-show-subtree)
	  (goto-char (point-min))
	  (let ((end (point-max)))
	    (while (< (point) end)
	      (when (org-at-item-checkbox-p)
		(replace-match "[ ]" t t))
	      (beginning-of-line 2))))
	(org-update-checkbox-count-maybe))))

(defun org-make-checklist-export ()
  "Produce a checklist containing all unchecked items from a list
of checkbox items"
  (interactive "*")
  (if (org-entry-get (point) "LIST_EXPORT_BASENAME")
      (let* ((export-file (concat (org-entry-get (point) "LIST_EXPORT_BASENAME")
				  "-" (format-time-string export-time-format)
				  ".org"))
	     exported-lines
	     title)
	(save-restriction
	  (save-excursion
	    (org-narrow-to-subtree)
	    (org-show-subtree)
	    (goto-char (point-min))
	    (if (looking-at org-complex-heading-regexp)
		(setq title (match-string 4)))
	    (goto-char (point-min))
	    (let ((end (point-max)))
	      (while (< (point) end)
		(when (and (org-at-item-checkbox-p)
			   (or (string= (match-string 0) "[ ]")
			       (string= (match-string 0) "[-]")))
		  (add-to-list 'exported-lines (thing-at-point 'line) t))
		(beginning-of-line 2)))
	    (set-buffer (get-buffer-create export-file))
	    (org-insert-heading)
	    (insert (or title export-file) "\n")
	    (dolist (entry exported-lines) (insert entry))
	    (org-update-checkbox-count-maybe)
	    (write-file export-file)
	    (if (y-or-n-p "Print list? ")
		((funcall export-function)
		 (a2ps-buffer))))))))

(defun org-checklist ()
  (if (member state org-done-keywords)
      (org-make-checklist-export))
  (org-reset-checkbox-state-maybe))

(add-hook 'org-after-todo-state-change-hook 'org-checklist)

(provide 'org-checklist)

;;; org-elisp-symbol.el ends here