;;; helm-man.el --- Man and woman UI -*- lexical-binding: t -*-

;; Copyright (C) 2012 ~ 2014 Thierry Volpiatto <thierry.volpiatto@gmail.com>

;; 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 <http://www.gnu.org/licenses/>.

;;; Code:

(require 'cl-lib)
(require 'helm)

(declare-function woman-file-name-all-completions "woman.el" (topic))
(declare-function Man-getpage-in-background "man.el" (topic))
(declare-function helm-generic-sort-fn "helm-utils.el" (S1 S2))

(defgroup helm-man nil
  "Man and Woman applications for helm."
  :group 'helm)

(defcustom helm-man-or-woman-function 'Man-getpage-in-background
  "Default command to display a man page."
  :group 'helm-man
  :type '(radio :tag "Preferred command to display a man page"
          (const :tag "Man" Man-getpage-in-background)
          (const :tag "Woman" woman)))

;; Internal
(defvar helm-man-pages nil
  "All man pages on system.
Will be calculated the first time you invoke helm with this
source.")

(defun helm-man-default-action (candidate)
  "Default action for jumping to a woman or man page from helm."
  (let ((wfiles (mapcar
                 'car (woman-file-name-all-completions candidate))))
    (condition-case nil
        (if (> (length wfiles) 1)
            (let ((file (helm-comp-read
                         "ManFile: " wfiles :must-match t)))
              (if (eq helm-man-or-woman-function 'Man-getpage-in-background)
                  (manual-entry (format "-l %s" file))
                (woman-find-file file)))
          (funcall helm-man-or-woman-function candidate))
      ;; If woman is unable to format correctly
      ;; use man instead.
      (error (kill-buffer)              ; Kill woman buffer.
             (Man-getpage-in-background candidate)))))

(defvar helm-source-man-pages
  '((name . "Manual Pages")
    (init . (lambda ()
              (require 'woman)
              (require 'helm-utils)
              (unless helm-man-pages
                (setq helm-man-pages
                      (ignore-errors
                        (woman-file-name "" t)
                        (sort (mapcar 'car woman-topic-all-completions)
                              'string-lessp))))
              (helm-init-candidates-in-buffer 'global helm-man-pages)))
    (candidates-in-buffer)
    (persistent-action . ignore)
    (filtered-candidate-transformer
     . (lambda (candidates _source)
         (sort candidates #'helm-generic-sort-fn)))
    (action  . (("Display Man page" . helm-man-default-action)))
    ;; Woman does not work OS X
    ;; http://xahlee.org/emacs/modernization_man_page.html
    (action-transformer . (lambda (actions candidate)
                            (if (eq system-type 'darwin)
                                '(("Display Man page" . man))
                              actions)))))

;;;###autoload
(defun helm-man-woman (arg)
  "Preconfigured `helm' for Man and Woman pages.
With a prefix arg reinitialize the cache."
  (interactive "P")
  (when arg (setq helm-man-pages nil))
  (helm-other-buffer 'helm-source-man-pages "*Helm man woman*"))

(provide 'helm-man)

;; Local Variables:
;; byte-compile-warnings: (not cl-functions obsolete)
;; coding: utf-8
;; indent-tabs-mode: nil
;; End:

;;; helm-man.el ends here