;;; gadict.el --- major mode for editing gadict dictionary source files -*- lexical-binding: t -*-

;; 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

;; Version: 0.1

;; Keywords: dict, dictionary

;;; Commentary:

;;

;; Mode can be installed by:

;;

;;   (autoload 'gadict-mode "gadict")

;;

;; File association can be registered by:

;;

;;   (add-to-list 'auto-mode-alist (cons "\\.gadict$" 'gadict-mode))

;;; Code:

(defvar gadict-font-lock-keywords

  '( ("^\\(__\\)\n\n\\(\\w.*\\)$" (1 font-lock-function-name-face) (2 font-lock-keyword-face))

     ("^ .*\n\\(\\w.*\\)" (1 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\\|abbr\\|comp\\|super\\|Am\\|Br\\|Au\\)$" . font-lock-doc-face)

(defun gadict-setup-fontlock ()

  "Setup gadict 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-syntax ()

  "Setup gadict characters syntax."

  (modify-syntax-entry ?' "w"))

(defun gadict-setup-comment ()

  "Setup gadict comment commands."

  (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 ()

  "Setup gadict paragraph definition."

  (set (make-local-variable 'paragraph-separate)  "__$")

  (set (make-local-variable 'paragraph-start)  "__$") )

(defun gadict-setup-page ()

  "Setup gadict page definition."

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

(defvar gadict-indent-offset 2

  "Indent level.")

(defun gadict-indent-line ()

  "Indent line in gdict mode."

  (if (eq (current-indentation) gadict-indent-offset)

      (indent-line-to 0)

    (indent-line-to gadict-indent-offset)))

(defun gadict-setup-indent ()

  "Setup indenting for gdict mode."

  (set (make-local-variable 'indent-line-function) 'gadict-indent-line))

(defun gadict-mark-article ()

  "Mark current article."

  (end-of-line)

  (re-search-backward "^__$")

  (set-mark (point))

  (forward-line)

  (if (re-search-forward "^__$" nil t)

      (forward-line 0)

    (goto-char (point-max)))

  (exchange-point-and-mark))

(defvar er/try-expand-list)

(defun gadict-setup-expansions ()

  "Add `gadict-mode' specific expansions."

  (set (make-local-variable 'er/try-expand-list) (list #'gadict-mark-article)))

(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")

(put 'gadict-tr 'safe-local-variable 'string-or-null-p)

(defun gadict-insert-template (&optional headword)

  "Insert new article template after the current place."

  (interactive)

  (if (re-search-forward "^__" nil t)

      (beginning-of-line)

    (goto-char (point-max)))

  (while (eq (char-before) ?\n)

    (delete-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)

  (when headword

    (insert headword)

    (insert "\n  []")

    (backward-char)))

(defun gadict-search-floor (headword)

  "Move to HEADWORD definition or place on posiiton for new corresponding

definition. Check for headwords ordering during search.

Return `t' if definition found, `nil' if no such headword."

  (let ( prev curr )

    (catch 'exit

      (goto-char (point-min))

      (unless (re-search-forward "^__$" nil t)

        (throw 'exit nil))

      (forward-line 2)

      (setq prev (buffer-substring-no-properties (point) (line-end-position)))

      (when (string= headword prev)

        (throw 'exit t))

      (when (string< headword prev)

        (goto-char (point-min))

        (throw 'exit nil))

      (while t

        (unless (re-search-forward "^__$" nil t)

          (throw 'exit nil))

        (forward-line 2)

        (setq curr (buffer-substring-no-properties (point) (line-end-position)))

        (unless (string< prev curr)

          (error (format "%s < %s" curr prev)))

        (when (string= headword curr)

          (throw 'exit t))

        (when (string< headword curr)

          (forward-line -2)

          (re-search-backward "^__$")

          (forward-line 2)

          (throw 'exit nil))

        (setq prev curr)) )))

(defun gadict-search (headword)

  "Move to HEADWORD definition or place on posiiton for new corresponding

definition. Check for headwords ordering during search."

  (interactive (list (read-string "Headword: ")))

  (gadict-search-floor headword)

  (recenter))

(defun gadict-insert-template-in-order (headword)

  "Insert new article template with respect of headword order."

  (interactive (list (read-string "Headword: ")))

  (unless (gadict-search-floor headword)

    (gadict-insert-template headword))

  (recenter))

(defun gadict-setup-keymap ()

  "Setup gadict keymap."

  (define-key (current-local-map) [S-return] 'gadict-search)

  (define-key (current-local-map) [C-return] 'gadict-insert-template-in-order))

;;;###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)

  (gadict-setup-indent)

  (gadict-setup-expansions) )

(provide 'gadict)

;;; dict-mode.el ends here

(provide 'gadict)

;;; gadict.el ends here