;;; +ispell.el --- Customizations for `ispell' -*- lexical-binding: t; -*-

;;; Commentary:

;;; Code:

(require 'cl-lib)
(require 'seq)

;; Utility function TODO: move elsewhere
(defun +ispell-append-removing-duplicates (&rest lists)
  "Append LISTS, removing duplicates from the result.
Any keyword arguments to `cl-remove-duplicates' should come
before the LISTS."
  (let (cl-remove-duplicates-args)
    (while (keywordp (car lists))
      (push (pop lists) cl-remove-duplicates-args)
      (push (pop lists) cl-remove-duplicates-args))
    (apply #'cl-remove-duplicates (apply #'append lists)
           (nreverse cl-remove-duplicates-args))))

;;; Ispell in .dir-locals

;; Let Emacs know a list of strings is safe
(defun +ispell-safe-local-p (list)
  (and (listp list)
       (seq-every-p #'stringp list)))

;; Can I instruct ispell to insert LocalWords in a different file?
;; https://emacs.stackexchange.com/q/31396/2264

;; How can I move all my file-local LocalWords to .dir-locals.el?
;; https://emacs.stackexchange.com/q/31419

;; Adapted from ispell.el:ispell-buffer-local-words
(defun +ispell-buffer-local-words-list ()
  (let (words)
    (or ispell-buffer-local-name
        (setq ispell-buffer-local-name (buffer-name)))
    (save-excursion
      (goto-char (point-min))
      (while (search-forward ispell-words-keyword nil t)
        (let ((end (point-at-eol))
              (ispell-casechars (ispell-get-casechars))
              string)
          (while (re-search-forward " *\\([^ ]+\\)" end t)
            (setq string (match-string-no-properties 1))
            (if (and (< 1 (length string))
                     (equal 0 (string-match ispell-casechars string)))
                (push string words))))))
    words))

;;;###autoload
(defun +ispell-move-buffer-words-to-dir-locals (&optional arg)
  "Move the current buffer-local words to .dir-locals.el.
This function prompts the user to save .dir-locals.el, unless
prefix ARG is non-nil; then it just saves them."
  (interactive "P")
  (unless (buffer-file-name)
    (user-error "Buffer not attached to file"))
  (hack-dir-local-variables)
  (let ((print-level nil)
        (print-length nil))
    (when-let ((new-words (cl-remove-if (lambda (el) (eq el '\.\.\.)) ; XXX: NO IDEA
                                        ; where this came from
                                        (+ispell-append-removing-duplicates
                                         :test #'string=
                                         ispell-buffer-session-localwords
                                         (alist-get 'ispell-buffer-session-localwords
                                                    dir-local-variables-alist)
                                         (alist-get 'ispell-buffer-session-localwords
                                                    file-local-variables-alist)
                                         (+ispell-buffer-local-words-list)))))
      (save-excursion
        (add-dir-local-variable
         major-mode
         'ispell-buffer-session-localwords
         (setq ispell-buffer-session-localwords
               new-words))
        (when (or arg
                  (y-or-n-p "Save .dir-locals.el?"))
          (save-buffer))
        (bury-buffer))
      (or ispell-buffer-local-name
          (setq ispell-buffer-local-name (buffer-name)))
      (save-excursion
        (goto-char (point-min))
        (while (search-forward ispell-words-keyword nil t)
          (delete-region (point-at-bol) (1+ (point-at-eol))))))))

;;;###autoload
(defun +ispell-move-buffer-words-to-dir-locals-hook ()
  "Convenience function for binding to a hook."
  (+ispell-move-buffer-words-to-dir-locals t))

(provide '+ispell)
;;; +ispell.el ends here