;;; dumlaut.el --- Fix Broken Umlate from Kill Ring -*- lexical-binding: t; -*-

;; Copyright (C) 2022, 2023  Philip Kaludercic

;; Author: Philip Kaludercic <philip.kaludercic@fau.de>
;; Version: $Id: dumlaut.el,v 1.3 2023/05/04 09:36:10 oj14ozun Exp $
;; URL: https://wwwcip.cs.fau.de/~oj14ozun/src+etc/dumlate.el
;; Package-Version: 1
;; Keywords: convenience

;; 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:

;; Enable `dumlate-on-yank-mode' to fix broke umlaute when pasting
;; from PDFs.

;;; Code:

(defgroup dumlat ()
  "Fix Broken Umlate from Kill Ring."
  :group 'convenience)

(defcustom dumlaut-mapping
  '((" ̈a" . "ä")
    (" ̈u" . "ü")
    (" ̈o" . "ö"))
  "Alist of mappings, translating faulty input to the correct replacement."
  :type '(alist :key-type string :value-type string))

(defun dumlat-cleanup (str)
  "Fix broken umlaute in STR."
  (replace-regexp-in-string
   (rx " ̈" alpha)
   (lambda (str)
     (alist-get str 
		str nil #'string=))
   str))

(defun dumlate-advise-insert-for-yank (args)
  "Apply `dumlat-cleanup' to the first argument in ARGS."
  (list (dumlat-cleanup (car args))))

;;;###autoload
(define-minor-mode dumlate-on-yank-mode
  "Minor mode to advise `insert-for-yank'."
  :global t
  (if dumlate-on-yank-mode
      (advice-add
       'insert-for-yank
       :filter-args
       #'dumlate-advise-insert-for-yank)
    (advice-remove
     'insert-for-yank
     #'dumlate-advise-insert-for-yank)))

(provide 'dumlaut)
;;; dumlaut.el ends here