;;; create-license.el --- Conveniently create license files  -*- lexical-binding: t; -*-

;; Copyright (C) 2024  Tristan Riehs

;; Author: Tristan Riehs <tristan.riehs@bordeaux-inp.fr>
;; Keywords: convenience license
;; Maintainer: Tristan Riehs <tristan.riehs@bordeaux-inp.fr>
;; URL: https://tristanriehs.fr/git/create-license

;; 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:

;; This packages aims at providing a convenient way of creating license
;; files.  The core command is `create-license', which you can invoke
;; interactively using M-x `create-license'.

;; Before using this package, you have to download the licenses listed
;; in `create-license-common' using M-x
;; `create-license-download-common'.  The licenses are stored in the
;; directory `create-license-directory'.  When a license is copied, the
;; new file is named according to the content if
;; `create-license-file-name'.

;;; Code:

(defgroup create-license nil
  "Conveniently create license files."
  :group 'emacs
  :prefix "create-license-")

(defcustom create-license-file-name "COPYING"
  "The name of the license file."
  :group 'create-license
  :type 'string
  :safe 'stringp)

(defcustom create-license-directory
  (file-name-as-directory (expand-file-name "licenses" user-emacs-directory))
  "Directory where licenses are stored.

`create-license' ignores files in this directory whose name start by a
dot."
  :group 'create-license
  :type 'string)

(defun create-license--dired-update ()
  "Revert the current buffer if it is a `dired' buffer."
  (when (eq major-mode 'dired-mode)
    (revert-buffer)))

(defcustom create-license-hook '(create-license--dired-update)
  "Hook run after `create-license'.

Functions in this hook are called with no arguments."
  :group 'create-license
  :type 'hook)

(defcustom create-license-common
  '(("GPL3"	. "https://www.gnu.org/licenses/gpl-3.0.txt")
    ("GPL2"	. "https://www.gnu.org/licenses/old-licenses/gpl-2.0.txt")
    ("Apache2"	. "https://www.apache.org/licenses/LICENSE-2.0.txt")
    ("MPL2"	. "https://www.mozilla.org/media/MPL/2.0/index.f75d2927d3c1.txt")
    ("CC-BY"	. "https://creativecommons.org/licenses/by/4.0/legalcode.txt")
    ("CC-BY-SA" . "https://creativecommons.org/licenses/by-sa/4.0/legalcode.txt")
    ("FDL"	. "https://www.gnu.org/licenses/fdl-1.3.txt"))
  "Common known licenses.

Each member of this list is of the form (NAME . URL)."
  :group 'create-license
  :type '(list (cons string string)))

(defvar create-license--hist nil
  "History for `create-license'.")

;;;###autoload
(defun create-license (dir name)
  "Copy the license NAME in DIR.

The destination file name under DIR is given by
`create-license-file-name'."
  (interactive
   (list
    default-directory
    (let ((files (directory-files create-license-directory nil "^[^\\.].*")))
      (when files
	(completing-read "License: "
			 files
			 nil
			 'require-match
			 nil
			 'create-license--hist
			 (car create-license--hist))))))

  (if name
      (progn
	(copy-file (expand-file-name name create-license-directory)
		   (expand-file-name create-license-file-name dir))
	(run-hooks 'create-license-hook))
    (message "No license found in \"%s\", you may want to run \
`create-license-download-common'"
	     create-license-directory)))

;;;###autoload
(defun create-license-download-common ()
  "Download licenses listed in `create-license-common'."
  (interactive)
  (require 'url-handlers)
  (make-directory create-license-directory t)
  (dolist (license create-license-common)
    (url-copy-file (cdr license)
		   (expand-file-name (car license) create-license-directory))))

(provide 'create-license)
;;; create-license.el ends here