;;; ol-man.el --- Links to man pages -*- lexical-binding: t; -*-
;;
;; Copyright (C) 2020-2022 Free Software Foundation, Inc.
;; Author: Carsten Dominik <carsten.dominik@gmail.com>
;; Maintainer: Bastien Guerry <bzg@gnu.org>
;; Keywords: outlines, hypermedia, calendar, wp
;; Homepage: https://orgmode.org
;;
;; This file is part of GNU Emacs.
;;
;; 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 GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;;; Commentary:

(require 'ol)

(org-link-set-parameters "man"
			 :follow #'org-man-open
			 :export #'org-man-export
			 :store #'org-man-store-link)

(defcustom org-man-command 'man
  "The Emacs command to be used to display a man page."
  :group 'org-link
  :type '(choice (const man) (const woman)))

(defun org-man-open (path _)
  "Visit the manpage on PATH.
PATH should be a topic that can be thrown at the man command.
If PATH contains extra ::STRING which will use `occur' to search
matched strings in man buffer."
  (string-match "\\(.*?\\)\\(?:::\\(.*\\)\\)?$" path)
  (let* ((command (match-string 1 path))
	 (search (match-string 2 path)))
    (funcall org-man-command command)
    (when search
      (with-current-buffer (concat "*Man " command "*")
	(goto-char (point-min))
	(search-forward search)))))

(defun org-man-store-link ()
  "Store a link to a README file."
  (when (memq major-mode '(Man-mode woman-mode))
    ;; This is a man page, we do make this link
    (let* ((page (org-man-get-page-name))
           (link (concat "man:" page))
           (description (format "Manpage for %s" page)))
      (org-link-store-props
       :type "man"
       :link link
       :description description))))

(defun org-man-get-page-name ()
  "Extract the page name from the buffer name."
  ;; This works for both `Man-mode' and `woman-mode'.
  (if (string-match " \\(\\S-+\\)\\*" (buffer-name))
      (match-string 1 (buffer-name))
    (error "Cannot create link to this man page")))

(defun org-man-export (link description format)
  "Export a man page link from Org files."
  (let ((path (format "http://man.he.net/?topic=%s&section=all" link))
	(desc (or description link)))
    (cond
     ((eq format 'html) (format "<a target=\"_blank\" href=\"%s\">%s</a>" path desc))
     ((eq format 'latex) (format "\\href{%s}{%s}" path desc))
     ((eq format 'texinfo) (format "@uref{%s,%s}" path desc))
     ((eq format 'ascii) (format "%s (%s)" desc path))
     ((eq format 'md) (format "[%s](%s)" desc path))
     (t path))))

(provide 'ol-man)

;;; ol-man.el ends here
