;;; cape-jinx-completion.el --- Completion At Point Extensions using Jinx spell checking -*- lexical-binding: t -*-

;; Copyright (C) 2021-2023 Adam Kruszewski

;; Author: Adam Kruszewski <adam@kruszewski.name>
;; Maintainer: Adam Kruszewski <adam@kruszewski.name>
;; Created: 2023
;; Version: 1.0
;; Package-Requires: ((emacs "28.1") (compat "29.1.4.0") (cape "0.15") (jinx "0.5"))
;; Homepage: https://code.bsdgeek.org/adam/cape-jinx-completion
;; Keywords: convenience, completion, spell-check

;; This file is not 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 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:
;; Additional completion backend in the form of Capfs
;; (completion-at-point-functions), using underlying C module provided
;; by Jinx just-in-time spell-checking package
;; (see https://github.com/minad/jinx ).
;;
;; It doesn't need Jinx enabled, but it uses its configuration
;; and C module bridge to enchant library.
;;
;; Having jinx and cape configured you just need to add:
;;  (add-to-list 'completion-at-point-functions #'cape-jinx-completion)
;; cape-jinx-completion to your completions-at-point-functions.

;;; Code:

(require 'cape)
(require 'jinx)
(eval-when-compile
  (require 'cl-lib)
  (require 'jinx))

;; jinx.el version 0.5 is required
(defun cape-jinx-completion-suggest-for-word (word)
  "Return suggestions as a list for `WORD'."
  (when (not jinx--dicts)
    (when (not (fboundp 'jinx--mod-dict))
      (jinx--load-module))
    (jinx--load-dicts))
  (if (fboundp 'jinx--mod-suggest)
  (let* ((result '()))
    (dolist (dict jinx--dicts)
      (dolist (el (jinx--mod-suggest dict word))
        (when (string-prefix-p word el)
          (cl-pushnew el result))))
    (delete-dups result))
  ;; this should never happen, as jinx--load-module will bind jinx--mod-suggest as well.
  '()))

;; cape-jinx-completion (based on cape-dict)
(defgroup cape-jinx-completion nil
  "Completion At Point extensions using Jinx spell checking."
  :prefix "cape-jinx-completion"
  :group 'cape-jinx-completion)

(defcustom cape-jinx-completion-case-replace 'case-replace
  "Preserve case of input.
See `dabbrev-case-replace' for details."
  :type '(choice (const :tag "off" nil)
                 (const :tag "use `case-replace'" case-replace)
                 (other :tag "on" t)))

(defcustom cape-jinx-completion-case-fold 'case-fold-search
  "Case fold search during search.
See `dabbrev-case-fold-search' for details."
  :type '(choice (const :tag "off" nil)
                 (const :tag "use `case-fold-search'" case-fold-search)
                 (other :tag "on" t)))

(defvar cape-jinx-completion--properties
  (list :annotation-function (lambda (_) " Jinx")
        :company-kind (lambda (_) 'text)
        :exclusive 'no)
  "Completion extra properties for `cape-jinx-completion'.")

(defun cape-jinx-completion--list (input)
  "Return all words from Jinx spell checking mechanism matching INPUT."
  (unless (equal input "")
    (cape--case-replace-list
     cape-jinx-completion-case-replace input
     (cape-jinx-completion-suggest-for-word input))))

;;;###autoload
(defun cape-jinx-completion (&optional interactive)
  "Complete word from Jinx spell checking at point.
If INTERACTIVE is nil the function acts like a Capf."
  (interactive (list t))
  (if interactive
      (cape-interactive #'cape-jinx-completion)
    (pcase-let ((`(,beg . ,end) (cape--bounds 'word)))
      `(,beg ,end
             ,(cape--table-with-properties
               (completion-table-case-fold
                (cape--cached-table beg end #'cape-jinx-completion--list #'string-search)
                (not (cape--case-fold-p cape-jinx-completion-case-fold)))
               :category 'cape-jinx-completion)
             ,@cape-jinx-completion--properties))))

(provide 'cape-jinx-completion)
;;; cape-jinx-completion.el ends here