;;; as-external.el --- Emacs as an external editor to other apps
;;
;; Author: Lennart Borgman (lennart O borgman A gmail O com)
;; Created: Mon Jun 25 19:02:49 2007
(defconst as-external:version "0.6") ;;Version:
;; Last-Updated: 2009-08-04 Tue
;; URL:
;; Keywords:
;; Compatibility:
;;
;; Features that might be required by this library:
;;
;;   None
;;
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;;
;;; Commentary:
;;
;;  This little library should make it easier to use Emacs as an
;;  external editor in certain cases. One such case is when want to
;;  use Emacs as the external editor with the Firefox add-on "It's All
;;  Text".
;;
;;  See variable `as-external-mode' for more information.
;;
;;
;;; A note on the implementation:
;;
;; You may wonder why this does not use `auto-mode-alist' since it
;; checks the file name in nearly the same way? It is perhaps possible
;; to use that, but there are two things to be aware of:
;;
;; 1. The choice made must override other possible choices.
;;
;; 2. Beside the file name the implementation here also checks if the
;;    buffer has clients waiting. That makes the check more reliable.
;;
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;;
;;; Change log:
;;
;;
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;;
;; 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 2, 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; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth
;; Floor, Boston, MA 02110-1301, USA.
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;;; Code:

(eval-when-compile (require 'cl))
(eval-when-compile (require 'html-write nil t))
(eval-when-compile (require 'mlinks nil t))
(eval-when-compile (require 'mumamo nil t))
(eval-when-compile (require 'nxhtml-mode nil t))
(eval-when-compile (require 'ourcomments-util nil t))
(eval-when-compile (require 'pause nil t))
(eval-when-compile (require 'server))
(eval-when-compile (require 'wikipedia-mode nil t))
(eval-and-compile  (require 'wrap-to-fill nil t))

;;;###autoload
(defgroup as-external nil
  "Settings related to Emacs as external editor."
  :group 'nxhtml
  :group 'external)

(defcustom as-external-its-all-text-regexp "/itsalltext/"
  "Regular expression matching It's All Text buffer's file."
  :type 'regexp
  :group 'as-external)

(defcustom as-external-alist
  '(
    ("/itsalltext/.*wiki" as-external-for-wiki)
    ("/itsalltext/.*mail" as-external-for-mail-mode)
    ("/itsalltext/"       as-external-for-xhtml)
   )
  "List to determine setup if Emacs is used as an external Editor.
Element in this list should have the form

  \(FILE-REGEXP BUFFER-SETUP)

where FILE-REGEXP should be a regular expression to match
`buffer-file-name'. If it matches then BUFFER-SETUP should be
called in the buffer.

* Tip when using Firefox's add-on It's All Text: It looks like
  the file name used will be constructed from the host url. For
  example if your are editing something on
  http://www.emacswiki.org/ the file name may be something like
  'www.emacswiki.org.283b1y212e.html'.


The list is processed by `as-external-setup'. Note that the first
match is used!

The default entries in this list supports for Firefox addon It's
All Text:

- `as-external-for-xhtml'.  For text areas on web pages where you
  can enter some XHTML code, for example blog comment fields.

- `as-external-for-mail-mode', for editing web mail messages.

- `as-external-for-wiki', for mediawiki.

See also `as-external-mode'."
  :type '(repeat
          (list (choice (variable :tag "Regexp variable")
                        regexp)
                command))
  :group 'as-external)

(defcustom as-external-its-all-text-coding 'utf-8
  "Coding system to use for It's All Text buffers.
See also `as-external-for-xhtml'."
  :type '(choice (const :tag "No special coding system" nil)
                 coding-system)
  :group 'as-external)

(defun as-external-fall-back (msg)
  "Fallback to text-mode if necessary."
  (text-mode)
  (lwarn t :warning "%s. Using text-mode" msg))

;;;###autoload
(defun as-external-for-xhtml ()
  "Setup for Firefox addon It's All Text to edit XHTML.
It's All Text is a Firefox add-on for editing textareas with an
external editor.
See URL `https://addons.mozilla.org/en-US/firefox/addon/4125'.

In this case Emacs is used to edit textarea fields on a web page.
The text will most often be part of a web page later, like on a
blog.  Therefore turn on these:

- `nxhtml-mode' since some XHTML tags may be allowed.
- `nxhtml-validation-header-mode' since it is not a full page.
- `wrap-to-fill-column-mode' to see what you are writing.
- `html-write-mode' to see it even better.

Also bypass the question for line end conversion when using
emacsw32-eol."
  (interactive)
  (if (not (fboundp 'nxhtml-mode))
      (as-external-fall-back "Can't find nXhtml")
    (nxhtml-mode)
    (nxhtml-validation-header-mode 1)
    (set (make-local-variable 'wrap-to-fill-left-marg-modes)
         '(nxhtml-mode fundamental-mode))
    (wrap-to-fill-column-mode 1)
    ;;(visible-point-mode 1)
    (when (fboundp 'html-write-mode) (html-write-mode 1))
    (when (boundp 'emacsw32-eol-ask-before-save)
      (make-local-variable 'emacsw32-eol-ask-before-save)
      (setq emacsw32-eol-ask-before-save nil))))


(defvar as-external-mail-mode-comment-pattern "^>.*$"
  "Regular expression for a comment line.")

(defvar as-external-mail-mode-email-pattern
  (concat "[a-z0-9$%(*-=?[_][^<>\")!;:,{}]*"
          "\@"
          "\\(?:[a-z0-9\-]+\.\\)+[a-z0-9]\\{2,4\\}")
  "Regular expression for a mail address.")

(defvar as-external-mail-mode-font-lock-keywords
  (list
   (list as-external-mail-mode-comment-pattern
         '(0 font-lock-comment-face))
   ;; (list as-external-mail-mode-email-pattern
   ;;       '(0 font-lock-keyword-face))
   ))

;;;###autoload
(define-derived-mode as-external-for-mail-mode text-mode "ExtMail "
  "Setup for Firefox addon It's All Text to edit mail.
Set normal mail comment markers in column 1 (ie >).

Set `fill-column' to 90 and enable `wrap-to-fill-column-mode' so
that it will look similar to how it will look in the sent plain
text mail.

See also `as-external-mode'."
  ;; To-do: Look at http://globs.org/articles.php?lng=en&pg=2
  (set (make-local-variable 'comment-column) 0)
  (set (make-local-variable 'comment-start) ">")
  (set (make-local-variable 'comment-end)   "")
  (set (make-local-variable 'font-lock-defaults)
       '((as-external-mail-mode-font-lock-keywords) nil))
  (setq fill-column 90)
  (mlinks-mode 1)
  (wrap-to-fill-column-mode 1))

;;;###autoload
(defun as-external-for-wiki ()
  "Setup for Firefox addon It's All Text to edit MediaWikis."
  (interactive)
  (require 'wikipedia-mode nil t)
  (if (not (featurep 'wikipedia-mode))
      (as-external-fall-back "Can't find file wikipedia-mode.el")
    (wikipedia-mode)))


;;;###autoload
(define-minor-mode as-external-mode
  "If non-nil check if Emacs is called as external editor.
When Emacs is called as an external editor for example to edit
text areas on a web page viewed with Firefox this library tries
to help to setup the buffer in a useful way. It may for example
set major and minor modes for the buffer.

This can for example be useful when blogging or writing comments
on blogs.

See `as-external-alist' for more information."
  :global t
  :group 'as-external
  ;;(modify-coding-system-alist 'file "/itsalltext/" as-external-its-all-text-coding)
  (let ((coding-entry
         (cons
          as-external-its-all-text-regexp
          (cons as-external-its-all-text-coding
                as-external-its-all-text-coding))))
    ;;(message "as-external-mode=%s" as-external-mode)
    (if as-external-mode
        (progn
          (add-to-list 'file-coding-system-alist coding-entry)
          (add-hook 'server-visit-hook 'as-external-setup t))
      (setq file-coding-system-alist
            (delq coding-entry file-coding-system-alist))
      (remove-hook 'server-visit-hook 'as-external-setup))))

(defun as-external-setup ()
  "Check if Emacs is used as an external editor.
If so then turn on useful major and minor modes.
This is done by checking `as-external-alist'."
  (condition-case err
      (as-external-setup-1)
    (error (message "as-external-setup error: %s" err))))

(defvar as-external-my-frame nil)
(make-variable-buffer-local 'as-external-my-frame)

(defvar as-external-last-buffer nil)

(defun as-external-server-window-fix-frames ()
  (condition-case err
      (with-current-buffer as-external-last-buffer
        (unless (buffer-live-p pause-buffer)
          (remove-hook 'pause-break-exit-hook 'as-external-server-window-fix-frames)
          (setq as-external-my-frame (or as-external-my-frame
                                         (make-frame)))
          (dolist (f (frame-list))
            (unless (eq f as-external-my-frame)
              (lower-frame f)))
          (raise-frame as-external-my-frame)))
    (error (message "%s" (error-message-string err)))))

(defun as-external-server-window (buffer)
  (setq server-window nil)
  (with-current-buffer buffer
    (setq as-external-last-buffer (current-buffer))
    (run-with-idle-timer 2 nil 'as-external-server-window-fix-frames)
    (add-hook 'pause-break-exit-hook 'as-external-server-window-fix-frames)
    (add-hook 'kill-buffer-hook 'as-external-delete-my-frame nil t)))

(defun as-external-delete-my-frame ()
  (let ((win (and (frame-live-p as-external-my-frame)
                  (get-buffer-window nil as-external-my-frame))))
    (when (and win
               (= 1 (length (window-list as-external-my-frame 'no-mini))))
      (delete-frame as-external-my-frame)
      (lower-frame))))

(defun as-external-setup-1 ()
  ;; Fix-me: How does one know if the file names are case sensitive?
  (unless (when (boundp 'nowait) nowait) ;; dynamically bound in `server-visit-files'
    (unless server-window
      ;; `server-goto-toplevel' has been done here.
      ;; Setup to use a new frame
      (setq server-window 'as-external-server-window))
    (catch 'done
      (dolist (rec as-external-alist)
        (let ((file-regexp (car rec))
              (setup-fun   (cadr rec)))
          (when (symbolp file-regexp)
            (setq file-regexp (symbol-value file-regexp)))
          (when (string-match file-regexp (buffer-file-name))
            (funcall setup-fun)
            (throw 'done t)))))))

(provide 'as-external)
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;;; as-external.el ends here