;;; gadict-mode.el --- major mode for editing gadict dictionary source files

;; Copyright (C) 2016 by Oleksandr Gavenko <gavenkoa@gmail.com>

;; You can do anything with this file without any warranty.

;; Author: Oleksandr Gavenko <gavenkoa@gmail.com>
;; Maintainer: Oleksandr Gavenko <gavenkoa@gmail.com>
;; Created: 2016
;; Keywords: dict, dictionary

;;; Commentary:
;;
;; File association can be registered by:
;;
;;   (add-to-list 'auto-mode-alist (cons "\\.gadict$" 'gadict-mode))

;;; Code:

(defvar gadict-font-lock-keywords
  '( ("^\\(_\\{2\\}\\)\n\n\\(\\w.*\\)$" (1 font-lock-function-name-face) (2 font-lock-keyword-face))
     ("^#.*" . font-lock-comment-face)
     ("^ +\\[[^]\n]+]" . font-lock-type-face)
     ("^\\(?:en\\|ru\\|uk\\|la\\): " . font-lock-type-face)
     ("^\\(?:en\\|ru\\|uk\\|la\\)> " . font-lock-doc-face)
     ("^\\(?:topic\\|ant\\|syn\\): " . font-lock-doc-face)
     ("^ +\\(?:v1\\|v2\\|v3\\|s\\|pl\\|male\\|female\\)$" . font-lock-doc-face)
     ("^\\(?:n\\|v\\|phr\\.v\\|adj\\|adv\\|pron\\|prep\\|num\\|conj\\|int\\)$" . font-lock-type-face) ))

(defun gadict-setup-fontlock ()
  (setq font-lock-defaults
        '(gadict-font-lock-keywords
          t nil nil nil
          (font-lock-multiline . t) ))
  (add-hook 'font-lock-extend-region-functions 'gadict-font-lock-extend-region t) )

(defun gadict-setup-comment ()
  (set (make-local-variable 'comment-start)  "#")
  (set (make-local-variable 'comment-continue)  nil)
  (set (make-local-variable 'comment-end)  "")
  (set (make-local-variable 'comment-end-skip)  nil)
  (set (make-local-variable 'comment-multi-line)  nil)
  (set (make-local-variable 'comment-use-syntax)  nil) )

(defun gadict-setup-paragraph ()
  (set (make-local-variable 'paragraph-separate)  "__$")
  (set (make-local-variable 'paragraph-start)  "__$") )

(defun gadict-setup-page ()
  (set (make-local-variable 'page-delimiter)  "__$") )

(defun gadict-setup-syntax ()
  (modify-syntax-entry ?' "w"))

(eval-when-compile
  (defvar font-lock-beg)
  (defvar font-lock-end))

(defun gadict-font-lock-extend-region ()
  "Look for '__' expression and extend `font-lock-beg' and `font-lock-end'."
  ;; (message "%d:%d, %d lines" font-lock-beg font-lock-end (count-lines font-lock-beg font-lock-end))
  (cond
   ((and
     (< (count-lines font-lock-beg font-lock-end) 5)
     (not (and (<= (point-max) font-lock-end) (<= font-lock-beg (point-min)) )))
    (save-excursion
      (goto-char font-lock-beg)
      (forward-line -2)
      (setq font-lock-beg (point))
      (goto-char font-lock-end)
      (forward-line 3)
      (setq font-lock-end (point))
      )
    t)
   (t nil) ))

(defvar-local gadict-tr nil
  "Translation markers as string separated by comma. Define own
  values in .dir-local.el or as -*- gadict-tr: \"...\" -*- file prelude")

(defun gadict-new-entry ()
  "Insert new entry template."
  (interactive)
  (if (re-search-forward "^__" nil t)
      (beginning-of-line)
    (goto-char (point-max)))
  (while (eq (char-before) ?\n)
    (delete-backward-char 1))
  (insert-char ?\n)
  (insert-char ?_ 2)
  (insert-char ?\n 3)
  (when (stringp gadict-tr)
    (mapc (lambda (tr)
            (insert-char ?\n)
            (insert tr)
            (insert ": "))
          (split-string gadict-tr ","))
    (insert-char ?\n)
    (re-search-backward "^$"))
  (backward-char))

(defun gadict-setup-keymap ()
  (define-key gadict-mode-map [C-return] 'gadict-new-entry))

;;;###autoload
(define-derived-mode gadict-mode fundamental-mode "gadict"
  "Derived mode for editing gadict dictionary source files."
  (gadict-setup-fontlock)
  (gadict-setup-keymap)
  (gadict-setup-syntax)
  (gadict-setup-paragraph)
  (gadict-setup-page)
  (gadict-setup-comment) )

(provide 'gadict)

;;; dict-mode.el ends here