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[gnus] / lisp / message.el

;;; message.el --- composing mail and news messages
;; Copyright (C) 1996 Free Software Foundation, Inc.

;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
;; Keywords: mail, news

;; This file is part of GNU Emacs.

;; GNU Emacs 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.

;; GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; This mode provides mail-sending facilities from within Emacs.  It
;; consists mainly of large chunks of code from the sendmail.el,
;; gnus-msg.el and rnewspost.el files.

;;; Code:

(eval-when-compile 
  (require 'cl))
(require 'mail-header)
(require 'nnheader)
(require 'timezone)

;;;###autoload
(defvar message-fcc-handler-function 'rmail-output
  "*A function called to save outgoing articles.
This function will be called with the name of the file to store the
article in. The default function is `rmail-output' which saves in Unix
mailbox format.")

;;;###autoload
(defvar message-courtesy-message
  "The following message is a courtesy copy of an article\nthat has been posted as well.\n\n"
  "*This is inserted at the start of a mailed copy of a posted message.
If this variable is nil, no such courtesy message will be added.")

;;;###autoload
(defvar message-ignored-bounced-headers "^\\(Received\\):"
  "*Regexp that matches headers to be removed in resent bounced mail.")

;;;###autoload
(defvar message-from-style 'default
  "*Specifies how \"From\" headers look.

If `nil', they contain just the return address like:
        king@grassland.com
If `parens', they look like:
        king@grassland.com (Elvis Parsley)
If `angles', they look like:
        Elvis Parsley <king@grassland.com>

Otherwise, most addresses look like `angles', but they look like
`parens' if `angles' would need quoting and `parens' would not.")

;;;###autoload
(defvar message-syntax-checks
  '(subject-cmsg multiple-headers sendsys message-id from
                 long-lines control-chars size new-text
                 redirected-followup signature approved sender 
                 empty empty-headers message-id from subject)
  "In non-nil, message will attempt to run some checks on outgoing posts.
If this variable is t, message will check everything it can.  If it is
a list, then those elements in that list will be checked.")

;;;###autoload
(defvar message-required-news-headers
  '(From Date Newsgroups Subject Message-ID 
         (optional . Organization) Lines 
         (optional . X-Newsreader))
  "*Headers to be generated or prompted for when posting an article.
RFC977 and RFC1036 require From, Date, Newsgroups, Subject,
Message-ID.  Organization, Lines, In-Reply-To, Expires, and
X-Newsreader are optional.  If don't you want message to insert some
header, remove it from this list.")

;;;###autoload
(defvar message-required-mail-headers 
  '(From Date Subject (optional . In-Reply-To) Message-ID Lines
         (optional . X-Mailer))
  "*Headers to be generated or prompted for when mailing a message.
RFC822 required that From, Date, To, Subject and Message-ID be
included.  Organization, Lines and X-Mailer are optional.")

;;;###autoload
(defvar message-deletable-headers '(Message-ID Date)
  "*Headers to be deleted if they already exist and were generated by message previously.")

;;;###autoload
(defvar message-ignored-news-headers 
  "^NNTP-Posting-Host:\\|^Xref:\\|^Bcc:\\|^Gcc:\\|^Fcc:"
  "*Regexp of headers to be removed unconditionally before posting.")

;;;###autoload
(defvar message-ignored-mail-headers "^Gcc:\\|^Fcc:"
  "*Regexp of headers to be removed unconditionally before mailing.")

;;;###autoload
(defvar message-ignored-supersedes-headers
  "^Path:\\|^Date\\|^NNTP-Posting-Host:\\|^Xref:\\|^Lines:\\|^Received:\\|^X-From-Line:\\|Return-Path:"
  "*Header lines matching this regexp will be deleted before posting.
It's best to delete old Path and Date headers before posting to avoid
any confusion.")

;;;###autoload
(defvar message-signature-separator "^-- *$"
  "Regexp matching signature separator.")

;;;###autoload
(defvar message-interactive nil 
  "Non-nil means when sending a message wait for and display errors.
nil means let mailer mail back a message to report errors.")

(defvar gnus-local-organization)
;;;###autoload
(defvar message-user-organization 
  (or (and (boundp 'gnus-local-organization)
           gnus-local-organization)
      (getenv "ORGANIZATION")
      t)
  "*String to be used as an Organization header.
If t, use `message-user-organization-file'.")

;;;###autoload
(defvar message-user-organization-file "/usr/lib/news/organization"
  "*Local news organization file.")

;;;###autoload
(defvar message-autosave-directory "~/Mail/drafts/"
  "*Directory where message autosaves buffers.
If nil, message won't autosave.")

(defvar message-forward-start-separator 
  "------- Start of forwarded message -------\n"
  "*Delimiter inserted before forwarded messages.")

(defvar message-forward-end-separator
  "------- End of forwarded message -------\n"
  "*Delimiter inserted after forwarded messages.")

;;;###autoload
(defvar message-signature-before-forwarded-message t
  "*If non-nil, put the signature before any included forwarded message.")

;;;###autoload
(defvar message-included-forward-headers 
  "^From:\\|^Newsgroups:\\|^Subject:\\|^Date:\\|^Followup-To:\\|^Reply-To:\\|^Organization:\\|^Summary:\\|^Keywords:\\|^To:\\|^Cc:\\|^Posted-To:\\|^Mail-Copies-To:\\|^Apparently-To:\\|^Gnus-Warning:\\|^Resent-\\|^Message-ID:\\|^References:"
  "*Regexp matching headers to be included in forwarded messages.")

;;;###autoload
(defvar message-ignored-resent-headers "^Return-receipt"
  "*All headers that match this regexp will be deleted when resending a message.")

;;;###autoload
(defvar message-ignored-cited-headers "."
  "Delete these headers from the messages you yank.")

;; Useful to set in site-init.el
;;;###autoload
(defvar message-send-mail-function 'message-send-mail 
  "Function to call to send the current buffer as mail.
The headers should be delimited by a line whose contents match the
variable `mail-header-separator'.")

;;;###autoload
(defvar message-send-news-function 'message-send-news
  "Function to call to send the current buffer as news.
The headers should be delimited by a line whose contents match the
variable `message-header-separator'.")

;;;###autoload
(defvar message-reply-to-function nil
  "Function that should return a list of headers.")

;;;###autoload
(defvar message-wide-reply-to-function nil
  "Function that should return a list of headers.")

;;;###autoload
(defvar message-followup-to-function nil
  "Function that should return a list of headers.")

;;;###autoload
(defvar message-use-followup-to 'ask
  "*Specifies what to do with Followup-To header.
If nil, ignore the header. If it is t, use its value, but ignore
\"poster\".  If it is the symbol `ask', query the user whether to
ignore the \"poster\" value.  If it is the symbol `use', always use
the value.")

(defvar gnus-post-method)
(defvar gnus-select-method)
;;;###autoload
(defvar message-post-method 
  (cond ((boundp 'gnus-post-method)
         gnus-post-method)
        ((boundp 'gnus-select-method)
         gnus-select-method)
        (t '(nnspool "")))
  "Method used to post news.")

;;;###autoload
(defvar message-generate-headers-first nil
  "*If non-nil, generate all possible headers before composing.")

;;;###autoload
(defvar message-header-separator "--text follows this line--" 
  "*Line used to separate headers from text in messages being composed.")

;;;###autoload
(defvar message-alias-file nil
  "*If non-nil, the name of a file to use instead of `/usr/lib/aliases'.
This file defines aliases to be expanded by the mailer; this is a different
feature from that of defining aliases in `.mailrc' to be expanded in Emacs.
This variable has no effect unless your system uses sendmail as its mailer.")

;;;###autoload
(defvar message-personal-alias-file "~/.mailrc"
  "*If non-nil, the name of the user's personal mail alias file.
This file typically should be in same format as the `.mailrc' file used by
the `Mail' or `mailx' program.
This file need not actually exist.")

(defvar message-setup-hook nil
  "Normal hook, run each time a new outgoing message is initialized.
The function `message-setup' runs this hook.")

(defvar message-header-setup-hook nil
  "Hook called narrowed to the headers when setting up a message buffer.")

;;;###autoload
(defvar message-citation-line-function 'message-insert-citation-line
  "*Function called to insert the \"Whomever writes:\" line.")

(defvar message-aliases t
  "Alist of mail address aliases.
If t, initialized from your mail aliases file.
\(The file's name is normally `~/.mailrc', but your MAILRC environment
variable can override that name.)
The alias definitions in the file have this form:
    alias ALIAS MEANING")

(defvar message-alias-modtime nil
  "The modification time of your mail alias file when it was last examined.")

;;;###autoload
(defvar message-yank-prefix "> "
  "*Prefix inserted on the lines of yanked messages.
nil means use indentation.")

(defvar message-indentation-spaces 3
  "*Number of spaces to insert at the beginning of each cited line.
Used by `message-yank-original' via `message-yank-cite'.")

;;;###autoload
(defvar message-cite-function 'message-cite-original
  "*Function for citing an original message.")

;;;###autoload
(defvar message-indent-citation-function 'message-indent-citation
  "*Function for modifying a citation just inserted in the mail buffer.
This can also be a list of functions.  Each function can find the
citation between (point) and (mark t).  And each function should leave
point and mark around the citation text as modified.")

(defvar message-abbrevs-loaded nil)

(autoload 'expand-mail-aliases "mailalias"
  "Expand all mail aliases in suitable header fields found between BEG and END.
Suitable header fields are `To', `Cc' and `Bcc' and their `Resent-' variants.
Optional second arg EXCLUDE may be a regular expression defining text to be
removed from alias expansions."
  nil)

;;;###autoload
(defvar message-signature t
  "*String to be inserted at the and the the message buffer.
If t, the `message-signature-file' file will be inserted instead.
If a function, the result from the function will be used instead.
If a form, the result from the form will be used instead.")

;;;###autoload
(defvar message-signature-file "~/.signature"
  "*File containing the text inserted at end of mail buffer.")

(defvar message-distribution-function nil
  "*Function called to return a Distribution header.")

(defvar message-expires 14
  "*Number of days before your article expires.")

(defvar message-user-path nil
  "If nil, use the NNTP server name in the Path header.
If stringp, use this; if non-nil, use no host name (user name only).")

(defvar message-reply-buffer nil)
(defvar message-reply-headers nil)
(defvar message-newsreader nil)
(defvar message-mailer nil)
(defvar message-sent-message-via nil)
(defvar message-checksum nil)
(defvar message-send-actions nil
  "A list of actions to be performed upon successful sending of a message.")

;;;###autoload
(defvar message-default-headers nil
  "*A string containing header lines to be inserted in outgoing messages.
It is inserted before you edit the message, so you can edit or delete
these lines.")

;;;###autoload
(defvar message-default-mail-headers nil
  "*A string of header lines to be inserted in outgoing mails.")

;;;###autoload
(defvar message-default-news-headers nil
  "*A string of header lines to be inserted in outgoing news articles.")

;; Note: could use /usr/ucb/mail instead of sendmail;
;; options -t, and -v if not interactive.
(defvar message-mailer-swallows-blank-line
  (if (and (string-match "sparc-sun-sunos\\(\\'\\|[^5]\\)" 
                         system-configuration)
           (file-readable-p "/etc/sendmail.cf")
           (let ((buffer (get-buffer-create " *temp*")))
             (unwind-protect
                 (save-excursion
                   (set-buffer buffer)
                   (insert-file-contents "/etc/sendmail.cf")
                   (goto-char (point-min))
                   (let ((case-fold-search nil))
                     (re-search-forward "^OR\\>" nil t)))
               (kill-buffer buffer))))
      ;; According to RFC822, "The field-name must be composed of printable
      ;; ASCII characters (i.e. characters that have decimal values between
      ;; 33 and 126, except colon)", i.e. any chars except ctl chars,
      ;; space, or colon.
      '(looking-at "[ \t]\\|[][!\"#$%&'()*+,-./0-9;<=>?@A-Z\\\\^_`a-z{|}~]+:"))
  "Set this non-nil if the system's mailer runs the header and body together.
\(This problem exists on Sunos 4 when sendmail is run in remote mode.)
The value should be an expression to test whether the problem will
actually occur.")

(defvar message-mode-syntax-table 
  (let ((table (copy-syntax-table text-mode-syntax-table)))
    (modify-syntax-entry ?% ". " table)
    table)
  "Syntax table used while in Message mode.")

(defvar message-font-lock-keywords
  (let* ((cite-prefix "A-Za-z") (cite-suffix (concat cite-prefix "0-9_.@-")))
    (list '("^To:" . font-lock-function-name-face)
          '("^B?CC:\\|^Reply-To:" . font-lock-keyword-face)
          '("^\\(Subject:\\)[ \t]*\\(.+\\)?"
            (1 font-lock-comment-face) (2 font-lock-type-face nil t))
          (list (concat "^\\(" (regexp-quote mail-header-separator) "\\)$")
                1 'font-lock-comment-face)
          (cons (concat "^[ \t]*"
                        "\\([" cite-prefix "]+[" cite-suffix "]*\\)?"
                        "[>|}].*")
                'font-lock-reference-face)
          '("^\\(X-[A-Za-z0-9-]+\\|In-reply-to\\):.*"
            . font-lock-string-face)))
  "Additional expressions to highlight in Message mode.")

(defvar message-face-alist
  '((bold . bold-region)
    (underline . underline-region)
    (default . (lambda (b e) 
                 (unbold-region b e)
                 (ununderline-region b e))))
  "Alist of mail and news faces for facemenu.
The cdr of ech entry is a function for applying the face to a region.")

(defvar message-send-hook nil
  "Hook run before sending messages.")

(defvar message-sent-hook nil
  "Hook run after sending messages.")

(defvar message-header-format-alist 
  `((Newsgroups)
    (To . message-fill-header) 
    (Cc . message-fill-header)
    (Subject)
    (In-Reply-To)
    (Fcc)
    (Bcc)
    (Date)
    (Organization)
    (Distribution)
    (Lines)
    (Expires)
    (Message-ID)
    (References . message-fill-header)
    (X-Mailer)
    (X-Newsreader))
  "Alist used for formatting headers.")

\f

;;; 
;;; Utility functions.
;;;

(defun message-point-at-bol ()
  "Return point at the beginning of the line."
  (let ((p (point)))
    (beginning-of-line)
    (prog1
        (point)
      (goto-char p))))

(defun message-point-at-eol ()
  "Return point at the end of the line."
  (let ((p (point)))
    (end-of-line)
    (prog1
        (point)
      (goto-char p))))

;; Delete the current line (and the next N lines.);
(defmacro message-delete-line (&optional n)
  `(delete-region (progn (beginning-of-line) (point))
                  (progn (forward-line ,(or n 1)) (point))))

(defun message-tokenize-header (header &optional separator)
  "Split HEADER into a list of header elements.
\",\" is used as the separator."
  (let* ((beg 0)
         (separator (or separator ","))
         (regexp
          (format "[ \t]*\\([^%s]+\\)?\\([%s]+\\|\\'\\)" separator separator))
         elems)
    (while (and (string-match regexp header beg)
                (< beg (length header)))
      (when (match-beginning 1)
        (push (match-string 1 header) elems))
      (setq beg (match-end 0)))
    (nreverse elems)))

(defun message-fetch-reply-field (header)
  "Fetch FIELD from the message we're replying to."
  (when (and message-reply-buffer
             (buffer-name message-reply-buffer))
    (save-excursion
      (set-buffer message-reply-buffer)
      (mail-fetch-field header))))

(defun message-set-work-buffer ()
  (if (get-buffer " *message work*")
      (progn
        (set-buffer " *message work*")
        (erase-buffer))
    (set-buffer (get-buffer-create " *message work*"))
    (kill-all-local-variables)
    (buffer-disable-undo (current-buffer))))

(defun message-functionp (form)
  "Return non-nil if FORM is funcallable."
  (or (and (symbolp form) (fboundp form))
      (and (listp form) (eq (car form) 'lambda))))

(defun message-strip-subject-re (subject)
  "Remove \"Re:\" from subject lines."
  (if (string-match "^[Rr][Ee]: *" subject)
      (substring subject (match-end 0))
    subject))

(defun message-remove-header (header &optional is-regexp first reverse)
  "Remove HEADER in the narrowed buffer.
If REGEXP, HEADER is a regular expression.
If FIRST, only remove the first instance of the header.
Return the number of headers removed."
  (goto-char (point-min))
  (let ((regexp (if is-regexp header (concat "^" header ":")))
        (number 0)
        (case-fold-search t)
        last)
    (while (and (not (eobp))
                (not last))
      (if (if reverse
              (not (looking-at regexp))
            (looking-at regexp))
          (progn
            (incf number)
            (when first
              (setq last t))
            (delete-region
             (point)
             ;; There might be a continuation header, so we have to search
             ;; until we find a new non-continuation line.
             (progn
               (forward-line 1)
               (if (re-search-forward "^[^ \t]" nil t)
                   (goto-char (match-beginning 0))
                 (point-max)))))
        (forward-line 1)
        (if (re-search-forward "^[^ \t]" nil t)
            (goto-char (match-beginning 0))
          (point-max))))
    number))

(defun message-narrow-to-headers ()
  "Narrow the buffer to the head of the message."
  (widen)
  (narrow-to-region
   (goto-char (point-min))
   (if (re-search-forward
        (concat "^" (regexp-quote mail-header-separator) "\n") nil t)
       (match-beginning 0)
     (point-max)))
  (goto-char (point-min)))

(defun message-narrow-to-head ()
  "Narrow the buffer to the head of the message."
  (widen)
  (narrow-to-region
   (goto-char (point-min))
   (if (search-forward "\n\n" nil 1)
       (1- (point))
     (point-max)))
  (goto-char (point-min)))

(defun message-news-p ()
  "Say whether the current buffer contains a news message."
  (save-excursion
    (save-restriction
      (message-narrow-to-headers)
      (mail-fetch-field "newsgroups"))))

(defun message-mail-p ()
  "Say whether the current buffer contains a mail message."
  (save-excursion
    (save-restriction
      (message-narrow-to-headers)
      (or (mail-fetch-field "to")
          (mail-fetch-field "cc")
          (mail-fetch-field "bcc")))))
    
\f

;;;
;;; Message mode
;;;

;;; Set up keymap.

(defvar message-mode-map nil)

(unless message-mode-map
  (setq message-mode-map (copy-keymap text-mode-map))
  (define-key message-mode-map "\C-c?" 'describe-mode)

  (define-key message-mode-map "\C-c\C-f\C-t" 'message-goto-to)
  (define-key message-mode-map "\C-c\C-f\C-b" 'message-goto-bcc)
  (define-key message-mode-map "\C-c\C-f\C-f" 'message-goto-fcc)
  (define-key message-mode-map "\C-c\C-f\C-c" 'message-goto-cc)
  (define-key message-mode-map "\C-c\C-f\C-s" 'message-goto-subject)
  (define-key message-mode-map "\C-c\C-f\C-r" 'message-goto-reply-to)
  (define-key message-mode-map "\C-c\C-f\C-n" 'message-goto-newsgroups)
  (define-key message-mode-map "\C-c\C-f\C-d" 'message-goto-distribution)
  (define-key message-mode-map "\C-c\C-f\C-o" 'message-goto-followup-to)
  (define-key message-mode-map "\C-c\C-f\C-k" 'message-goto-keywords)
  (define-key message-mode-map "\C-c\C-f\C-u" 'message-goto-summary)
  (define-key message-mode-map "\C-c\C-b" 'message-goto-body)
  (define-key message-mode-map "\C-c\C-i" 'message-goto-signature)

  (define-key message-mode-map "\C-c\C-t" 'message-insert-to)
  (define-key message-mode-map "\C-c\C-n" 'message-insert-newsgroups)
  
  (define-key message-mode-map "\C-c\C-y" 'message-yank-original)
  (define-key message-mode-map "\C-c\C-q" 'message-fill-yanked-message)
  (define-key message-mode-map "\C-c\C-w" 'message-insert-signature)
  (define-key message-mode-map "\C-c\C-r" 'message-caesar-buffer-body)

  (define-key message-mode-map "\C-c\C-c" 'message-send-and-exit)
  (define-key message-mode-map "\C-c\C-s" 'message-send))

(defun message-make-menu-bar ()
  (unless (boundp 'message-menu)
    (easy-menu-define
     message-menu message-mode-map ""
     '("Message"
       ["Fill Citation" message-fill-yanked-message t]))))

;;;###autoload
(defun message-mode ()
  "Major mode for editing mail and news to be sent.
Like Text Mode but with these additional commands:
C-c C-s  message-send (send the message)    C-c C-c  message-send-and-exit
C-c C-f  move to a header field (and create it if there isn't):
         C-c C-f C-t  move to To        C-c C-f C-s  move to Subject
         C-c C-f C-c  move to Cc        C-c C-f C-b  move to Bcc
         C-c C-f C-f  move to Fcc       C-c C-f C-r  move to Reply-To
         C-c C-f C-u  move to Summary   C-c C-f C-n  move to Newsgroups
         C-c C-f C-k  move to Keywords  C-c C-f C-d  move to Distribution
         C-c C-f C-o  move to Followup-To
C-c C-t  message-insert-to (add a To header to a news followup)
C-c C-n  message-insert-newsgroups (add a Newsgroup header to a news reply)
C-c C-b  message-goto-body (move to beginning of message text).
C-c C-i  message-goto-signature (move to the beginning of the signature).
C-c C-w  message-insert-signature (insert `message-signature-file' file).
C-c C-y  message-yank-original (insert current message, if any).
C-c C-q  message-fill-yanked-message (fill what was yanked).
C-c C-r  message-ceasar-buffer-body (rot13 the message body)."
  (interactive)
  (kill-all-local-variables)
  (make-local-variable 'message-reply-buffer)
  (setq message-reply-buffer nil)
  (make-local-variable 'message-send-actions)
  (set-syntax-table message-mode-syntax-table)
  (use-local-map message-mode-map)
  (setq local-abbrev-table text-mode-abbrev-table)
  (setq major-mode 'message-mode)
  (setq mode-name "Message")
  (setq buffer-offer-save t)
  (make-local-variable 'font-lock-defaults)
  (setq font-lock-defaults '(message-font-lock-keywords t))
  (make-local-variable 'facemenu-add-face-function)
  (make-local-variable 'facemenu-remove-face-function)
  (setq facemenu-add-face-function
        (lambda (face end)
          (let ((face-fun (cdr (assq face message-face-alist))))
            (if face-fun
                (funcall face-fun (point) end)
              (error "Face %s not configured for %s mode" face mode-name)))
          "")
        facemenu-remove-face-function t)
  (make-local-variable 'paragraph-separate)
  (make-local-variable 'paragraph-start)
  (setq paragraph-start (concat (regexp-quote mail-header-separator)
                                "$\\|[ \t]*[-_][-_][-_]+$\\|"
                                paragraph-start))
  (setq paragraph-separate (concat (regexp-quote mail-header-separator)
                                   "$\\|[ \t]*[-_][-_][-_]+$\\|"
                                   paragraph-separate))
  (make-local-variable 'message-reply-headers)
  (setq message-reply-headers nil)
  (make-local-variable 'message-newsreader)
  (make-local-variable 'message-mailer)
  (make-local-variable 'message-post-method)
  (make-local-variable 'message-sent-message-via)
  (setq message-sent-message-via nil)
  (make-local-variable 'message-checksum)
  (setq message-checksum nil)
  (run-hooks 'text-mode-hook 'message-mode-hook))

\f

;;;
;;; Message mode commands
;;;

;;; Movement commands

(defun message-goto-to ()
  "Move point to the To header."
  (interactive)
  (message-position-on-field "To"))

(defun message-goto-subject ()
  "Move point to the Subject header."
  (interactive)
  (message-position-on-field "Subject"))

(defun message-goto-cc ()
  "Move point to the Cc header."
  (interactive)
  (message-position-on-field "Cc" "To"))

(defun message-goto-bcc ()
  "Move point to the Bcc  header."
  (interactive)
  (message-position-on-field "Bcc" "Cc" "To"))

(defun message-goto-fcc ()
  "Move point to the Fcc header."
  (interactive)
  (message-position-on-field "Fcc" "To" "Newsgroups"))

(defun message-goto-reply-to ()
  "Move point to the Reply-To header."
  (interactive)
  (message-position-on-field "Reply-To" "Subject"))

(defun message-goto-newsgroups ()
  "Move point to the Newsgroups header."
  (interactive)
  (message-position-on-field "Newsgroups"))

(defun message-goto-distribution ()
  "Move point to the Distribution header."
  (interactive)
  (message-position-on-field "Distribution"))

(defun message-goto-followup-to ()
  "Move point to the Followup-To header."
  (interactive)
  (message-position-on-field "Followup-To" "Newsgroups"))

(defun message-goto-keywords ()
  "Move point to the Keywords header."
  (interactive)
  (message-position-on-field "Keywords" "Subject"))

(defun message-goto-summary ()
  "Move point to the Summary header."
  (interactive)
  (message-position-on-field "Summary" "Subject"))

(defun message-goto-body ()
  "Move point to the beginning of the message body."
  (interactive)
  (goto-char (point-min))
  (search-forward (concat "\n" mail-header-separator "\n") nil t))

(defun message-goto-signature ()
  "Move point to the beginning of the message signature."
  (interactive)
  (goto-char (point-min))
  (or (re-search-forward message-signature-separator nil t)
      (goto-char (point-max))))

\f

(defun message-insert-to ()
  "Insert a To header that points to the author of the article being replied to."
  (interactive)
  (message-position-on-field "To")
  (insert (or (message-fetch-reply-field "reply-to")
              (message-fetch-reply-field "from") "")))

(defun message-insert-newsgroups ()
  "Insert the Newsgroups header from the article being replied to."
  (interactive)
  (message-position-on-field "Newsgroups")
  (insert (or (message-fetch-reply-field "newsgroups") "")))

\f

;;; Various commands

(defun message-insert-signature (&optional force)
  "Insert a signature.  See documentation for the `message-signature' variable."
  (interactive (list t))
  (let* ((signature 
          (cond ((and (null message-signature)
                      force)
                 t)
                ((message-functionp message-signature)
                 (funcall message-signature))
                ((listp message-signature)
                 (eval message-signature))
                (t message-signature)))
         (signature
          (cond ((stringp signature)
                 signature)
                ((and (eq t signature)
                      message-signature-file
                      (file-exists-p message-signature-file))
                 signature))))
    (when signature
      ;; Remove blank lines at the end of the message.
      (goto-char (point-max))
      (skip-chars-backward " \t\n")
      (end-of-line)
      (delete-region (point) (point-max))
      ;; Insert the signature.
      (insert "\n\n-- \n")
      (if (eq signature t)
          (insert-file-contents message-signature-file)
        (insert signature))
      (goto-char (point-max))
      (or (bolp) (insert "\n")))))

(defvar message-caesar-translation-table nil)

(defun message-caesar-region (b e &optional n)
  "Caesar rotation of region by N, default 13, for decrypting netnews."
  (interactive
   (list
    (min (point) (or (mark t) (point)))
    (max (point) (or (mark t) (point)))
    (when current-prefix-arg
      (prefix-numeric-value current-prefix-arg))))

  (setq n (if (numberp n) (mod n 26) 13)) ;canonize N
  (unless (or (zerop n)                 ; no action needed for a rot of 0
              (= b e))                  ; no region to rotate
    ;; We build the table, if necessary.
    (when (or (not message-caesar-translation-table)
              (/= (aref message-caesar-translation-table ?a) (+ ?a n)))
      (let ((i -1) 
            (table (make-string 256 0)))
        (while (< (incf i) 256)
          (aset table i i))
        (setq table
              (concat
               (substring table 0 ?A)
               (substring table (+ ?A n) (+ ?A n (- 26 n)))
               (substring table ?A (+ ?A n))
               (substring table (+ ?A 26) ?a)
               (substring table (+ ?a n) (+ ?a n (- 26 n)))
               (substring table ?a (+ ?a n))
               (substring table (+ ?a 26) 255)))
        (setq message-caesar-translation-table table)))
    ;; Then we translate the region.  Do it this way to retain 
    ;; text properties.
    (while (< b e)
      (subst-char-in-region 
       b (1+ b) (char-after b)
       (aref message-caesar-translation-table (char-after b)))
      (incf b))))

(defun message-caesar-buffer-body (&optional rotnum)
  "Caesar rotates all letters in the current buffer by 13 places.
Used to encode/decode possibly offensive messages (commonly in net.jokes).
With prefix arg, specifies the number of places to rotate each letter forward.
Mail and USENET news headers are not rotated."
  (interactive (if current-prefix-arg
                   (list (prefix-numeric-value current-prefix-arg))
                 (list nil)))
  (save-excursion
    (save-restriction
      (when (message-goto-body)
        (narrow-to-region (point) (point-max)))
      (message-caesar-region (point-min) (point-max) rotnum))))

(defun message-fill-yanked-message (&optional justifyp)
  "Fill the paragraphs of a message yanked into this one.
Numeric argument means justify as well."
  (interactive "P")
  (save-excursion
    (goto-char (point-min))
    (search-forward (concat "\n" mail-header-separator "\n") nil t)
    (fill-individual-paragraphs (point)
                                (point-max)
                                justifyp
                                t)))

(defun message-indent-citation ()
  "Modify text just inserted from a message to be cited.
The inserted text should be the region.
When this function returns, the region is again around the modified text.

Normally, indent each nonblank line `message-indentation-spaces' spaces.
However, if `message-yank-prefix' is non-nil, insert that prefix on each line."
  (let ((start (point)))
    ;; Remove unwanted headers.
    (when message-ignored-cited-headers
      (save-restriction
        (narrow-to-region 
         (goto-char start)
         (if (search-forward "\n\n" nil t)
             (1- (point))
           (point)))
        (message-remove-header message-ignored-cited-headers t)))
    ;; Do the indentation.
    (if (null message-yank-prefix)
        (indent-rigidly start (mark t) message-indentation-spaces)
      (save-excursion
        (goto-char start)
        (while (< (point) (mark t))
          (insert message-yank-prefix)
          (forward-line 1)))
      (goto-char start))))

(defun message-yank-original (&optional arg)
  "Insert the message being replied to, if any.
Puts point before the text and mark after.
Normally indents each nonblank line ARG spaces (default 3).  However,
if `message-yank-prefix' is non-nil, insert that prefix on each line.

Just \\[universal-argument] as argument means don't indent, insert no
prefix, and don't delete any headers."
  (interactive "P")
  (let ((modified (buffer-modified-p)))
    (when (and message-reply-buffer
               message-cite-function)
      (delete-windows-on message-reply-buffer t)
      (insert-buffer message-reply-buffer)
      (funcall message-cite-function)
      (exchange-point-and-mark)
      (unless (bolp)
        (insert ?\n))
      (unless modified
        (setq message-checksum (message-checksum))))))

(defun message-cite-original ()    
  (let ((start (point))
        (functions 
         (when message-indent-citation-function
           (if (listp message-indent-citation-function)
               message-indent-citation-function
             (list message-indent-citation-function)))))
    (goto-char start)
    (while functions
      (funcall (pop functions)))
    (when message-citation-line-function
      (unless (bolp)
        (insert "\n"))
      (funcall message-citation-line-function))))

(defun message-insert-citation-line ()
  "Function that inserts a simple citation line."
  (when message-reply-headers
    (insert (mail-header-from message-reply-headers) " writes:\n\n")))

(defun message-position-on-field (header &rest afters)
  (let ((case-fold-search t))
    (save-restriction
      (narrow-to-region
       (goto-char (point-min))
       (progn
         (re-search-forward 
          (concat "^" (regexp-quote mail-header-separator) "$"))
         (match-beginning 0)))
      (goto-char (point-min))
      (if (re-search-forward (concat "^" (regexp-quote header) ":") nil t)
          (progn
            (re-search-forward "^[^ \t]" nil 'move)
            (beginning-of-line)
            (skip-chars-backward "\n")
            t)
        (while (and afters
                    (not (re-search-forward 
                          (concat "^" (regexp-quote (car afters)) ":")
                          nil t)))
          (pop afters))
        (when afters
          (re-search-forward "^[^ \t]" nil 'move)
          (beginning-of-line))
        (insert header ": \n")
        (forward-char -1)
        nil))))

(defun message-remove-signature ()
  "Remove the signature from the text between point and mark.
The text will also be indented the normal way."
  (save-excursion
    (let ((start (point))
          mark)
    (if (not (re-search-forward message-signature-separator (mark t) t))
        ;; No signature here, so we just indent the cited text.
        (message-indent-citation)
      ;; Find the last non-empty line.
      (forward-line -1)
      (while (looking-at "[ \t]*$")
        (forward-line -1))
      (forward-line 1)
      (setq mark (set-marker (make-marker) (point)))
      (goto-char start)
      (message-indent-citation)
      ;; Enable undoing the deletion.
      (undo-boundary)
      (delete-region mark (mark t))
      (set-marker mark nil)))))

\f

;;;
;;; Sending messages
;;;

(defun message-send-and-exit (&optional arg)
  "Send message like `message-send', then, if no errors, exit from mail buffer."
  (interactive "P")
  (let ((buf (current-buffer)))
    (when (and (message-send arg)
               (buffer-name buf))
      (bury-buffer buf)
      (when (eq buf (current-buffer))
        (message-bury buf)))))

(defun message-dont-send ()
  "Don't send the message you have been editing."
  (interactive)
  (message-bury (current-buffer)))

(defun message-bury (buffer)
  "Bury this mail buffer."
  (let ((newbuf (other-buffer buffer)))
    (bury-buffer buffer)
    (if (and (fboundp 'frame-parameters)
             (cdr (assq 'dedicated (frame-parameters)))
             (not (null (delq (selected-frame) (visible-frame-list)))))
        (delete-frame (selected-frame))
      (switch-to-buffer newbuf))))

(defun message-send (&optional arg)
  "Send the message in the current buffer.
If `message-interactive' is non-nil, wait for success indication
or error messages, and inform user.
Otherwise any failure is reported in a message back to
the user from the mailer."
  (interactive "P")
  (when (if buffer-file-name
            (y-or-n-p (format "Send buffer contents as %s message? "
                              (if (message-mail-p)
                                  (if (message-news-p) "mail and news" "mail")
                                "news")))
          (or (buffer-modified-p)
              (y-or-n-p "No changes in the buffer; really send? ")))
    ;; Make it possible to undo the coming changes.
    (undo-boundary)
    (run-hooks 'message-send-hook)
    (message "Sending...")
    (when (and (or (not (message-news-p))
                   (and (or (not (memq 'news message-sent-message-via))
                            (y-or-n-p
                             "Already sent message via news; resend? "))
                        (funcall message-send-news-function arg)))
               (or (not (message-mail-p))
                   (and (or (not (memq 'mail message-sent-message-via))
                            (y-or-n-p
                             "Already sent message via mail; resend? "))
                        (funcall message-send-mail-function arg))))
      (message-do-fcc)
      (run-hooks 'message-sent-hook)
      (message "Sending...done")
      ;; If buffer has no file, mark it as unmodified and delete autosave.
      (unless buffer-file-name
        (set-buffer-modified-p nil)
        (delete-auto-save-file-if-necessary t))
      ;; Now perform actions on successful sending.
      (let ((actions message-send-actions))
        (while actions
          (condition-case nil
              (apply (caar actions) (cdar actions))
            (error))
          (pop actions)))
      ;; Return success.
      t)))

(defun message-send-mail (&optional arg)
  (require 'mail-utils)
  (let ((errbuf (if message-interactive
                    (generate-new-buffer " sendmail errors")
                  0))
        (tembuf (generate-new-buffer " message temp"))
        (case-fold-search nil)
        (news (message-news-p))
        (resend-to-addresses (mail-fetch-field "resent-to"))
        delimline
        (mailbuf (current-buffer)))
    (save-restriction
      (message-narrow-to-headers)
      ;; Insert some headers.
      (message-generate-headers message-required-mail-headers)
      ;; Let the user do all of the above.
      (run-hooks 'message-header-hook))
    (unwind-protect
        (save-excursion
          (set-buffer tembuf)
          (erase-buffer)
          (insert-buffer-substring mailbuf)
          ;; Remove some headers.
          (save-restriction
            (message-narrow-to-headers)
            ;; Remove some headers.
            (message-remove-header message-ignored-mail-headers t))
          (goto-char (point-max))
          ;; require one newline at the end.
          (or (= (preceding-char) ?\n)
              (insert ?\n))
          (when (and news
                     (or (mail-fetch-field "cc")
                         (mail-fetch-field "to")))
            (message-insert-courtesy-copy))
          (let ((case-fold-search t))
            ;; Change header-delimiter to be what sendmail expects.
            (goto-char (point-min))
            (re-search-forward
             (concat "^" (regexp-quote mail-header-separator) "\n"))
            (replace-match "\n")
            (backward-char 1)
            (setq delimline (point-marker))
            ;; Insert an extra newline if we need it to work around
            ;; Sun's bug that swallows newlines.
            (goto-char (1+ delimline))
            (when (eval message-mailer-swallows-blank-line)
              (newline))
            (when message-interactive
              (save-excursion
                (set-buffer errbuf)
                (erase-buffer))))
          (let ((default-directory "/"))
            (apply 'call-process-region
                   (append (list (point-min) (point-max)
                                 (if (boundp 'sendmail-program)
                                     sendmail-program
                                   "/usr/lib/sendmail")
                                 nil errbuf nil "-oi")
                           ;; Always specify who from,
                           ;; since some systems have broken sendmails.
                           (list "-f" (user-login-name))
                           (and message-alias-file
                                (list (concat "-oA" message-alias-file)))
                           ;; These mean "report errors by mail"
                           ;; and "deliver in background".
                           (if (null message-interactive) '("-oem" "-odb"))
                           ;; Get the addresses from the message
                           ;; unless this is a resend.
                           ;; We must not do that for a resend
                           ;; because we would find the original addresses.
                           ;; For a resend, include the specific addresses.
                           (or resend-to-addresses
                               '("-t")))))
          (when message-interactive
            (save-excursion
              (set-buffer errbuf)
              (goto-char (point-min))
              (while (re-search-forward "\n\n* *" nil t)
                (replace-match "; "))
              (if (not (zerop (buffer-size)))
                  (error "Sending...failed to %s"
                         (buffer-substring (point-min) (point-max)))))))
      (kill-buffer tembuf)
      (when (bufferp errbuf)
        (kill-buffer errbuf)))
    (set-buffer mailbuf)
    (push 'mail message-sent-message-via)))

(defun message-send-news (&optional arg)
  (let ((tembuf (generate-new-buffer " *message temp*"))
        (case-fold-search nil)
        (method (if (message-functionp message-post-method)
                    (funcall message-post-method arg)
                  message-post-method))
        (messbuf (current-buffer)))
    (save-restriction
      (message-narrow-to-headers)
      ;; Insert some headers.
      (message-generate-headers message-required-news-headers)
      ;; Let the user do all of the above.
      (run-hooks 'message-header-hook))
    (when (message-check-news-syntax)
      (unwind-protect
          (save-excursion
            (set-buffer tembuf)
            (buffer-disable-undo (current-buffer))
            (erase-buffer) 
            (insert-buffer-substring messbuf)
            ;; Remove some headers.
            (save-restriction
              (message-narrow-to-headers)
              ;; Remove some headers.
              (message-remove-header message-ignored-news-headers t))
            (goto-char (point-max))
            ;; require one newline at the end.
            (or (= (preceding-char) ?\n)
                (insert ?\n))
            (let ((case-fold-search t))
              ;; Remove the delimeter.
              (goto-char (point-min))
              (re-search-forward
               (concat "^" (regexp-quote mail-header-separator) "\n"))
              (replace-match "\n")
              (backward-char 1))
            (require (car method))
            (funcall (intern (format "%s-open-server" (car method)))
                     (cadr method) (cddr method))
            (funcall (intern (format "%s-request-post"
                                     (car method)))))
        (kill-buffer tembuf))
      (set-buffer messbuf)
      (push 'news message-sent-message-via))))

;;;
;;; Header generation & syntax checking.
;;;

(defun message-check-news-syntax ()
  "Check the syntax of the message."
  (or
   (not message-syntax-checks)
   (and 
    ;; We narrow to the headers and check them first.
    (save-excursion
      (save-restriction
        (message-narrow-to-headers)
        (and 
         ;; Check for commands in Subject.
         (or 
          (message-check-element 'subject-cmsg)
          (save-excursion
            (if (string-match "^cmsg " (mail-fetch-field "subject"))
                (y-or-n-p
                 "The control code \"cmsg \" is in the subject. Really post? ")
              t)))
         ;; Check for multiple identical headers.
         (or (message-check-element 'multiple-headers)
             (save-excursion
               (let (found)
                 (while (and (not found) 
                             (re-search-forward "^[^ \t:]+: " nil t))
                   (save-excursion
                     (or (re-search-forward 
                          (concat "^" (setq found
                                            (buffer-substring 
                                             (match-beginning 0) 
                                             (- (match-end 0) 2))))
                          nil t)
                         (setq found nil))))
                 (if found
                     (y-or-n-p 
                      (format "Multiple %s headers. Really post? " found))
                   t))))
         ;; Check for Version and Sendsys.
         (or (message-check-element 'sendsys)
             (save-excursion
               (if (re-search-forward "^Sendsys:\\|^Version:" nil t)
                   (y-or-n-p
                    (format "The article contains a %s command. Really post? "
                            (buffer-substring (match-beginning 0) 
                                              (1- (match-end 0)))))
                 t)))
         ;; See whether we can shorten Followup-To.
         (or (message-check-element 'shorten-followup-to)
             (let ((newsgroups (mail-fetch-field "newsgroups"))
                   (followup-to (mail-fetch-field "followup-to"))
                   to)
               (when (and newsgroups (string-match "," newsgroups)
                          (not followup-to)
                          (not
                           (zerop
                            (length
                             (setq to (completing-read 
                                       "Followups to: (default all groups) " 
                                       (mapcar (lambda (g) (list g))
                                               (cons "poster" 
                                                     (message-tokenize-header 
                                                      newsgroups)))))))))
                 (goto-char (point-min))
                 (insert "Followup-To: " to "\n"))))

         ;; Check for Approved.
         (or (message-check-element 'approved)
             (save-excursion
               (if (re-search-forward "^Approved:" nil t)
                   (y-or-n-p
                    "The article contains an Approved header. Really post? ")
                 t)))
         ;; Check the Message-Id header.
         (or (message-check-element 'message-id)
             (save-excursion
               (let* ((case-fold-search t)
                      (message-id (mail-fetch-field "message-id")))
                 (or (not message-id)
                     (and (string-match "@" message-id)
                          (string-match "@[^\\.]*\\." message-id))
                     (y-or-n-p
                      (format 
                       "The Message-ID looks strange: \"%s\". Really post? "
                       message-id))))))
         ;; Check the Subject header.
         (or 
          (message-check-element 'subject)
          (save-excursion
            (let* ((case-fold-search t)
                   (subject (mail-fetch-field "subject")))
              (or
               (and subject
                    (not (string-match "\\`[ \t]*\\'" subject)))
               (progn
                 (message 
                  "The subject field is empty or missing.  Posting is denied.")
                 nil)))))
         ;; Check the From header.
         (or (message-check-element 'from)
             (save-excursion
               (let* ((case-fold-search t)
                      (from (mail-fetch-field "from")))
                 (cond
                  ((not from)
                   (message "There is no From line.  Posting is denied.")
                   nil)
                  ((not (string-match "@[^\\.]*\\." from))
                   (message
                    "Denied posting -- the From looks strange: \"%s\"." from)
                   nil)
                  ((string-match "@[^@]*@" from)
                   (message 
                    "Denied posting -- two \"@\"'s in the From header: %s."
                    from)
                   nil)
                  ((string-match "(.*).*(.*)" from)
                   (message
                    "Denied posting -- the From header looks strange: \"%s\"." 
                    from)
                   nil)
                  (t t))))))))
    ;; Check for long lines.
    (or (message-check-element 'long-lines)
        (save-excursion
          (goto-char (point-min))
          (re-search-forward
           (concat "^" (regexp-quote mail-header-separator) "$"))
          (while (and
                  (progn
                    (end-of-line)
                    (< (current-column) 80))
                  (zerop (forward-line 1))))
          (or (bolp)
              (eobp)
              (y-or-n-p
               "You have lines longer than 79 characters.  Really post? "))))
    ;; Check whether the article is empty.
    (or (message-check-element 'empty)
        (save-excursion
          (goto-char (point-min))
          (re-search-forward
           (concat "^" (regexp-quote mail-header-separator) "$"))
          (forward-line 1)
          (or (re-search-forward "[^ \n\t]" nil t)
              (y-or-n-p "Empty article.  Really post?"))))
    ;; Check for control characters.
    (or (message-check-element 'control-chars)
        (save-excursion
          (if (re-search-forward "[\000-\007\013\015-\037\200-\237]" nil t)
              (y-or-n-p 
               "The article contains control characters. Really post? ")
            t)))
    ;; Check excessive size.
    (or (message-check-element 'size)
        (if (> (buffer-size) 60000)
            (y-or-n-p
             (format "The article is %d octets long. Really post? "
                     (buffer-size)))
          t))
    ;; Check whether any new text has been added.
    (or (message-check-element 'new-text)
        (not message-checksum)
        (not (eq (message-checksum) message-checksum))
        (y-or-n-p
         "It looks like no new text has been added.  Really post? "))
    ;; Check the length of the signature.
    (or (message-check-element 'signature)
        (progn
          (goto-char (point-max))
          (if (not (re-search-backward "^-- $" nil t))
              t
            (if (> (count-lines (point) (point-max)) 5)
                (y-or-n-p
                 (format
                  "Your .sig is %d lines; it should be max 4.  Really post? "
                  (count-lines (point) (point-max))))
              t)))))))

;; Returns non-nil if this type is not to be checked.
(defun message-check-element (type)
  (not 
   (or (not message-syntax-checks)
       (if (listp message-syntax-checks)
           (memq type message-syntax-checks)
         t))))

(defun message-checksum ()
  "Return a \"checksum\" for the current buffer."
  (let ((sum 0))
    (save-excursion
      (while (not (eobp))
        (setq sum (logxor sum (following-char)))
        (forward-char 1)))
    sum))

(defun message-do-fcc ()
  "Process Fcc headers in the current buffer."
  (let ((case-fold-search t)
        list file)
    (save-excursion
      (save-restriction
        (message-narrow-to-headers)
        (while (setq file (mail-fetch-field "fcc"))
          (push file list)
          (message-remove-header "fcc" nil t))
        ;; Process FCC operations.
        (widen)
        (while list
          (setq file (pop list))
          (if (string-match "^[ \t]*|[ \t]*\\(.*\\)[ \t]*$" file)
              ;; Pipe the article to the program in question.
              (call-process-region (point-min) (point-max) shell-file-name
                                   nil nil nil "-c" (match-string 1 file))
            ;; Save the article.
            (setq file (expand-file-name file))
            (unless (file-exists-p (file-name-directory file))
              (make-directory (file-name-directory file) t))
            (if (and message-fcc-handler-function
                     (not (eq message-fcc-handler-function 'rmail-output)))
                (funcall message-fcc-handler-function file)
              (if (and (file-readable-p file) (mail-file-babyl-p file))
                  (rmail-output file 1)
                (let ((mail-use-rfc822 t))
                  (rmail-output file 1 t t))))))))))

(defun message-cleanup-headers ()
  "Do various automatic cleanups of the headers."
  ;; Remove empty lines in the header.
  (save-restriction
    (message-narrow-to-headers)
    (while (re-search-forward "^[ \t]*\n" nil t)
      (replace-match "" t t)))

  ;; Correct Newsgroups and Followup-To headers: change sequence of
  ;; spaces to comma and eliminate spaces around commas.  Eliminate
  ;; embedded line breaks.
  (goto-char (point-min))
  (while (re-search-forward "^\\(Newsgroups\\|Followup-To\\): +" nil t)
    (save-restriction
      (narrow-to-region
       (point)
       (if (re-search-forward "^[^ \t]" nil t)
           (match-beginning 0)
         (forward-line 1)
         (point)))
      (goto-char (point-min))
      (while (re-search-forward "\n[ \t]+" nil t)
        (replace-match " " t t))        ;No line breaks (too confusing)
      (goto-char (point-min))
      (while (re-search-forward "[ \t\n]*,[ \t\n]*\\|[ \t]+" nil t)
        (replace-match "," t t))
      (goto-char (point-min))
      ;; Remove trailing commas.
      (when (re-search-forward ",+$" nil t)
        (replace-match "" t t)))))

(defun message-make-date ()
  "Make a valid data header."
  (let ((now (current-time)))
    (timezone-make-date-arpa-standard 
     (current-time-string now) (current-time-zone now))))

(defun message-make-message-id ()
  "Make a unique Message-ID."
  (concat "<" (message-unique-id) 
          (let ((psubject (save-excursion (mail-fetch-field "subject"))))
            (if (and message-reply-headers
                     (mail-header-references message-reply-headers)
                     (mail-header-subject message-reply-headers)
                     psubject
                     (mail-header-subject message-reply-headers)
                     (not (string= 
                           (message-strip-subject-re
                            (mail-header-subject message-reply-headers))
                           (message-strip-subject-re psubject))))
                "_-_" ""))
          "@" (message-make-fqdm) ">"))

(defvar message-unique-id-char nil)

;; If you ever change this function, make sure the new version
;; cannot generate IDs that the old version could.
;; You might for example insert a "." somewhere (not next to another dot
;; or string boundary), or modify the "fsf" string.
(defun message-unique-id ()
  ;; Don't use microseconds from (current-time), they may be unsupported.
  ;; Instead we use this randomly inited counter.
  (setq message-unique-id-char
        (% (1+ (or message-unique-id-char (logand (random t) (1- (lsh 1 20)))))
           ;; (current-time) returns 16-bit ints,
           ;; and 2^16*25 just fits into 4 digits i base 36.
           (* 25 25)))
  (let ((tm (current-time)))
    (concat
     (if (memq system-type '(ms-dos emx vax-vms))
         (let ((user (downcase (user-login-name))))
           (while (string-match "[^a-z0-9_]" user)
             (aset user (match-beginning 0) ?_))
           user)
       (message-number-base36 (user-uid) -1))
     (message-number-base36 (+ (car   tm) 
                               (lsh (% message-unique-id-char 25) 16)) 4)
     (message-number-base36 (+ (nth 1 tm)
                               (lsh (/ message-unique-id-char 25) 16)) 4)
     ;; Append the newsreader name, because while the generated
     ;; ID is unique to this newsreader, other newsreaders might
     ;; otherwise generate the same ID via another algorithm.
     ".fsf")))

(defun message-number-base36 (num len)
  (if (if (< len 0) (<= num 0) (= len 0))
      ""
    (concat (message-number-base36 (/ num 36) (1- len))
            (char-to-string (aref "zyxwvutsrqponmlkjihgfedcba9876543210"
                                  (% num 36))))))

(defun message-make-organization ()
  "Make an Organization header."
  (let* ((organization 
          (or (getenv "ORGANIZATION")
              (when message-user-organization
                (if (message-functionp message-user-organization)
                    (funcall message-user-organization)
                  message-user-organization)))))
    (save-excursion
      (message-set-work-buffer)
      (cond ((stringp message-user-organization)
             (insert message-user-organization))
            ((and (eq t message-user-organization)
                  message-user-organization-file
                  (file-exists-p message-user-organization-file))
             (insert-file-contents message-user-organization-file)))
      (goto-char (point-min))
      (when (re-search-forward "[ \t\n]*" nil t)
        (replace-match "" t t))
      (unless (zerop (buffer-size))
        (buffer-string)))))

(defun message-make-lines ()
  "Count the number of lines and return numeric string."
  (save-excursion
    (save-restriction
      (widen)
      (goto-char (point-min))
      (re-search-forward 
       (concat "^" (regexp-quote mail-header-separator) "$"))
      (forward-line 1)
      (int-to-string (count-lines (point) (point-max))))))

(defun message-make-in-reply-to ()
  "Return the In-Reply-To header for this message."
  (when message-reply-headers
    (let ((from (mail-header-from message-reply-headers))
          (date (mail-header-date message-reply-headers)))
      (when from
        (let ((stop-pos 
               (string-match "  *at \\|  *@ \\| *(\\| *<" from)))
          (concat (if stop-pos (substring from 0 stop-pos) from)
                  "'s message of " 
                  (if (or (not date) (string= date ""))
                      "(unknown date)" date)))))))

(defun message-make-distribution ()
  "Make a Distribution header."
  (let ((orig-distribution (message-fetch-reply-field "distribution")))
    (cond ((message-functionp message-distribution-function)
           (funcall message-distribution-function))
          (t orig-distribution))))

(defun message-make-expires ()
  "Return an Expires header based on `message-expires'."
  (let ((current (current-time))
        (future (* 1.0 message-expires 60 60 24)))
    ;; Add the future to current.
    (setcar current (+ (car current) (round (/ future (expt 2 16)))))
    (setcar (cdr current) (+ (nth 1 current) (% (round future) (expt 2 16))))
    ;; Return the date in the future in UT.
    (timezone-make-date-arpa-standard 
     (current-time-string current) (current-time-zone current) '(0 "UT"))))

(defun message-make-path ()
  "Return uucp path."
  (let ((login-name (user-login-name)))
    (cond ((null message-user-path)
           (concat (system-name) "!" login-name))
          ((stringp message-user-path)
           ;; Support GENERICPATH.  Suggested by vixie@decwrl.dec.com.
           (concat message-user-path "!" login-name))
          (t login-name))))

(defun message-make-from ()
  "Make a From header."
  (let* ((login (message-make-address))
         (fullname (user-full-name)))
    (when (string= fullname "&")
      (setq fullname (user-login-name)))
    (save-excursion
      (message-set-work-buffer)
      (cond 
       ((or (null message-from-style)
            (equal fullname ""))
        (insert login))
       ((or (eq message-from-style 'angles)
            (and (not (eq message-from-style 'parens))
                 ;; Use angles if no quoting is needed, or if parens would
                 ;; need quoting too.
                 (or (not (string-match "[^- !#-'*+/-9=?A-Z^-~]" fullname))
                     (let ((tmp (concat fullname nil)))
                       (while (string-match "([^()]*)" tmp)
                         (aset tmp (match-beginning 0) ?-)
                         (aset tmp (1- (match-end 0)) ?-))
                       (string-match "[\\()]" tmp)))))
        (insert fullname)
        (goto-char (point-min))
        ;; Look for a character that cannot appear unquoted
        ;; according to RFC 822.
        (when (re-search-forward "[^- !#-'*+/-9=?A-Z^-~]" nil 1)
          ;; Quote fullname, escaping specials.
          (goto-char (point-min))
          (insert "\"")
          (while (re-search-forward "[\"\\]" nil 1)
            (replace-match "\\\\\\&" t))
          (insert "\""))
        (insert " <" login ">"))
       (t                               ; 'parens or default
        (insert login " (")
        (let ((fullname-start (point)))
          (insert fullname)
          (goto-char fullname-start)
          ;; RFC 822 says \ and nonmatching parentheses
          ;; must be escaped in comments.
          ;; Escape every instance of ()\ ...
          (while (re-search-forward "[()\\]" nil 1)
            (replace-match "\\\\\\&" t))
          ;; ... then undo escaping of matching parentheses,
          ;; including matching nested parentheses.
          (goto-char fullname-start)
          (while (re-search-forward 
                  "\\(\\=\\|[^\\]\\(\\\\\\\\\\)*\\)\\\\(\\(\\([^\\]\\|\\\\\\\\\\)*\\)\\\\)"
                    nil 1)
            (replace-match "\\1(\\3)" t)
            (goto-char fullname-start)))
        (insert ")")))
      (buffer-string))))

(defun message-make-sender ()
  "Return the \"real\" user address.
This function tries to ignore all user modifications, and 
give as trustworthy answer as possible."
  (concat (user-login-name) "@" (system-name)))

(defun message-make-address ()
  "Make the address of the user."
  (or (message-user-mail-address)
      (concat (user-login-name) "@" (message-make-domain))))

(defun message-user-mail-address ()
  "Return the pertinent part of `user-mail-address'."
  (when (string-match
         "\\(\\`\\|[ \t]\\)\\([^ \t@]+@[^ \t]+\\)\\(\\'\\|[ \t]\\)" 
         user-mail-address)
    (match-string 2 user-mail-address)))

(defun message-make-fqdm ()
  "Return user's fully qualified domain name."
  (let ((system-name (system-name)))
    (cond 
     ((string-match "[^.]\\.[^.]" system-name)
      ;; `system-name' returned the right result.
      system-name)
     ;; We try `user-mail-address' as a backup.
     ((string-match "@\\([^\\s-]+\\)\\(\\'\\|\\W\\)" user-mail-address)
      (match-string 1 user-mail-address))
     ;; Try `mail-host-address'.
     ((and (boundp 'mail-host-address)
           mail-host-address)
      mail-host-address)
     ;; Default to this bogus thing.
     (t
      (concat system-name ".i-have-a-misconfigured-system-so-shoot-me")))))

(defun message-make-host-name ()
  "Return the name of the host."
  (let ((fqdm (message-make-fqdm)))
    (string-match "^[^.]+\\." fqdm)
    (substring fqdm 0 (1- (match-end 0)))))

(defun message-make-domain ()
  "Return the domain name."
  (or mail-host-address
      (message-make-fqdm)))

(defun message-generate-headers (headers)
  "Prepare article HEADERS.
Headers already prepared in the buffer are not modified."
  (save-restriction
    (message-narrow-to-headers)
    (let* ((Date (message-make-date))
           (Message-ID (message-make-message-id))
           (Organization (message-make-organization))
           (From (message-make-from))
           (Path (message-make-path))
           (Subject nil)
           (Newsgroups nil)
           (In-Reply-To (message-make-in-reply-to))
           (To nil)
           (Distribution (message-make-distribution))
           (Lines (message-make-lines))
           (X-Newsreader message-newsreader)
           (X-Mailer (and (not (mail-fetch-field "X-Newsreader"))
                          message-mailer))
           (Expires (message-make-expires))
           (case-fold-search t)
           header value elem)
      ;; First we remove any old generated headers.
      (let ((headers message-deletable-headers))
        (while headers
          (goto-char (point-min))
          (and (re-search-forward 
                (concat "^" (symbol-name (car headers)) ": *") nil t)
               (get-text-property (1+ (match-beginning 0)) 'message-deletable)
               (message-delete-line))
          (pop headers)))
      ;; Go through all the required headers and see if they are in the
      ;; articles already. If they are not, or are empty, they are
      ;; inserted automatically - except for Subject, Newsgroups and
      ;; Distribution. 
      (while headers
        (goto-char (point-min))
        (setq elem (pop headers))
        (if (consp elem)
            (if (eq (car elem) 'optional)
                (setq header (cdr elem))
              (setq header (car elem)))
          (setq header elem))
        (when (or (not (re-search-forward 
                        (concat "^" (downcase (symbol-name header)) ":") 
                        nil t))
                  (progn
                    ;; The header was found. We insert a space after the
                    ;; colon, if there is none.
                    (if (/= (following-char) ? ) (insert " ") (forward-char 1))
                    ;; Find out whether the header is empty...
                    (looking-at "[ \t]*$")))
          ;; So we find out what value we should insert.
          (setq value
                (cond 
                 ((and (consp elem) (eq (car elem) 'optional))
                  ;; This is an optional header.  If the cdr of this
                  ;; is something that is nil, then we do not insert
                  ;; this header.
                  (setq header (cdr elem))
                  (or (and (fboundp (cdr elem)) (funcall (cdr elem)))
                      (and (boundp (cdr elem)) (symbol-value (cdr elem)))))
                 ((consp elem)
                  ;; The element is a cons.  Either the cdr is a
                  ;; string to be inserted verbatim, or it is a
                  ;; function, and we insert the value returned from
                  ;; this function.
                  (or (and (stringp (cdr elem)) (cdr elem))
                      (and (fboundp (cdr elem)) (funcall (cdr elem)))))
                 ((and (boundp header) (symbol-value header))
                  ;; The element is a symbol.  We insert the value
                  ;; of this symbol, if any.
                  (symbol-value header))
                 (t
                  ;; We couldn't generate a value for this header,
                  ;; so we just ask the user.
                  (read-from-minibuffer
                   (format "Empty header for %s; enter value: " header)))))
          ;; Finally insert the header.
          (when (and value 
                     (not (equal value "")))
            (save-excursion
              (if (bolp)
                  (progn
                    ;; This header didn't exist, so we insert it.
                    (goto-char (point-max))
                    (insert (symbol-name header) ": " value "\n")
                    (forward-line -1))
                ;; The value of this header was empty, so we clear
                ;; totally and insert the new value.
                (delete-region (point) (message-point-at-eol))
                (insert value))
              ;; Add the deletable property to the headers that require it.
              (and (memq header message-deletable-headers)
                   (progn (beginning-of-line) (looking-at "[^:]+: "))
                   (add-text-properties 
                    (point) (match-end 0)
                    '(message-deletable t face italic) (current-buffer)))))))
      ;; Insert new Sender if the From is strange. 
      (let ((from (mail-fetch-field "from"))
            (sender (mail-fetch-field "sender"))
            (secure-sender (message-make-sender)))
        (when (and from 
                   (not (message-check-element 'sender))
                   (not (string=
                         (downcase
                          (cadr (mail-extract-address-components from)))
                         (downcase secure-sender)))
                   (or (null sender)
                       (not 
                        (string=
                         (downcase
                          (cadr (mail-extract-address-components sender)))
                         (downcase secure-sender)))))
          (goto-char (point-min))    
          ;; Rename any old Sender headers to Original-Sender.
          (when (re-search-forward "^Sender:" nil t)
            (beginning-of-line)
            (insert "Original-")
            (beginning-of-line))
          (insert "Sender: " secure-sender "\n"))))))

(defun message-insert-courtesy-copy ()
  "Insert a courtesy message in mail copies of combined messages."
  (save-excursion
    (save-restriction
      (message-narrow-to-headers)
      (let ((newsgroups (mail-fetch-field "newsgroups")))
        (when newsgroups
          (goto-char (point-max))
          (insert "Posted-To: " newsgroups "\n"))))
    (forward-line 1)
    (insert message-courtesy-message)))
    
;;;
;;; Setting up a message buffer
;;;

(defun message-fill-header (header value)
  (let ((begin (point))
        (fill-column 78)
        (fill-prefix "\t")
        end)
    (insert (capitalize (symbol-name header))
            ": "
            (if (consp value) (car value) value)
            "\n")
    (save-restriction
      (narrow-to-region begin (point))
      (fill-region-as-paragraph begin (point))
      ;; Tapdance around looong Message-IDs.
      (forward-line -1)
      (when (looking-at "[ \t]*$")
        (message-delete-line))
      (goto-char begin)
      (re-search-forward ":" nil t)
      (when (looking-at "\n[ \t]+")
        (replace-match " " t t))
      (goto-char (point-max)))))

(defun sendmail-synch-aliases ()
  (let ((modtime (nth 5 (file-attributes message-personal-alias-file))))
    (or (equal message-alias-modtime modtime)
        (setq message-alias-modtime modtime
              message-aliases t))))

(defun message-position-point ()
  "Move point to where the user probably wants to find it."
  (message-narrow-to-headers)
  (cond 
   ((re-search-forward "^[^:]+:[ \t]*$" nil t)
    (search-backward ":" )
    (widen)
    (forward-char 1)
    (if (= (following-char) ? )
        (forward-char 1)
      (insert " ")))
   (t
    (goto-char (point-max))
    (widen)
    (forward-line 1)
    (unless (looking-at "$")
      (forward-line 2)))
   (sit-for 0)))

(defun message-pop-to-buffer (name)
  "Pop to buffer NAME, and warn if it already exists and is modified."
  (let ((buffer (get-buffer name)))
    (if (and buffer
             (buffer-name buffer))
        (progn
          (set-buffer (pop-to-buffer buffer))
          (when (and (buffer-modified-p)
                     (not (y-or-n-p
                           "Message already being composed; erase? ")))
            (error "Message being composed")))
      (set-buffer (pop-to-buffer name)))
    (erase-buffer)
    (message-mode)))

(defun message-setup (headers &optional replybuffer actions)
  (setq message-send-actions actions)
  (setq message-reply-buffer replybuffer)
  (goto-char (point-min))
  ;; Insert all the headers.
  (mail-header-format 
   (let ((h headers)
         (alist message-header-format-alist))
     (while h
       (unless (assq (caar h) message-header-format-alist)
         (push (list (caar h)) alist))
       (pop h))
     alist)
   headers)
  (forward-line -1)
  (when message-default-headers
    (insert message-default-headers))
  (insert mail-header-separator "\n")
  (forward-line -1)
  (when (and (message-news-p)
             message-default-news-headers)
    (when message-generate-headers-first
      (message-generate-headers message-required-news-headers))
    (insert message-default-news-headers))
  (when (and (message-mail-p)
             message-default-mail-headers)
    (when message-generate-headers-first
      (message-generate-headers message-required-mail-headers))
    (insert message-default-mail-headers))
  (message-insert-signature)
  (message-set-auto-save-file-name)
  (save-restriction
    (message-narrow-to-headers)
    (run-hooks 'message-header-setup-hook))
  (set-buffer-modified-p nil)
  (run-hooks 'message-setup-hook)
  (message-position-point)
  (undo-boundary))

(defun message-set-auto-save-file-name ()
  "Associate the message buffer with a file in the drafts directory."
  (when message-autosave-directory
    (unless (file-exists-p message-autosave-directory)
      (make-directory message-autosave-directory t))
    (let ((name (make-temp-name
                 (concat (file-name-as-directory message-autosave-directory)
                         "msg."))))
      (setq buffer-auto-save-file-name
            (save-excursion
              (prog1
                  (progn
                    (set-buffer (get-buffer-create " *draft tmp*"))
                    (setq buffer-file-name name)
                    (make-auto-save-file-name))
                (kill-buffer (current-buffer)))))
      (clear-visited-file-modtime))))

\f

;;;
;;; Commands for interfacing with message
;;;

;;;###autoload
(defun message-mail (&optional to subject)
  "Start editing a mail message to be sent."
  (interactive)
  (message-pop-to-buffer "*mail message*")
  (message-setup `((To . ,(or to "")) (Subject . ,(or subject "")))))

;;;###autoload
(defun message-news (&optional newsgroups subject)
  "Start editing a news article to be sent."
  (interactive)
  (message-pop-to-buffer "*news message*")
  (message-setup `((Newsgroups . ,(or newsgroups "")) 
                   (Subject . ,(or subject "")))))

;;;###autoload
(defun message-reply (&optional to-address wide)
  "Start editing a reply to the article in the current buffer."
  (interactive)
  (let ((cur (current-buffer))
        from subject date reply-to message-of to cc
        references message-id sender follow-to sendto elt new-cc new-to
        mct never-mct gnus-warning)
    (save-restriction
      (narrow-to-region
       (goto-char (point-min))
       (if (search-forward "\n\n" nil t)
           (1- (point))
         (point-max)))
      ;; Allow customizations to have their say.
      (if (not wide)
          ;; This is a regular reply.
          (if (message-functionp message-reply-to-function)
              (setq follow-to (funcall message-reply-to-function)))
        ;; This is a followup.
        (if (message-functionp message-wide-reply-to-function)
            (save-excursion
              (setq follow-to
                    (funcall message-wide-reply-to-function)))))
      ;; Find all relevant headers we need.
      (setq from (mail-fetch-field "from")
            date (mail-fetch-field "date") 
            sender (mail-fetch-field "sender")
            subject (or (mail-fetch-field "subject") "none")
            to (mail-fetch-field "to")
            cc (mail-fetch-field "cc")
            mct (mail-fetch-field "mail-copies-to")
            reply-to (mail-fetch-field "reply-to")
            references (mail-fetch-field "references")
            message-id (mail-fetch-field "message-id"))
      ;; Remove any (buggy) Re:'s that are present and make a
      ;; proper one.
      (when (string-match "^[ \t]*[Re][Ee]:[ \t]*" subject)
        (setq subject (substring subject (match-end 0))))
      (setq subject (concat "Re: " subject))

      (when (and (setq gnus-warning (mail-fetch-field "gnus-warning"))
                 (string-match "<[^>]+>" gnus-warning))
        (setq message-id (match-string 0 gnus-warning)))
            
      ;; Handle special values of Mail-Copies-To.
      (when mct
        (cond ((equal (downcase mct) "never")
               (setq never-mct t)
               (setq mct nil))
              ((equal (downcase mct) "always")
               (setq mct (or reply-to from)))))

      (unless follow-to
        (if (or (not wide)
                to-address)
            (setq follow-to (list (cons 'To (or to-address reply-to from))))
          (let (ccalist)
            (save-excursion
              (message-set-work-buffer)
              (unless never-mct
                (insert (or reply-to from "")))
              (insert 
               (if (bolp) "" ", ") (or to "")
               (if mct (concat (if (bolp) "" ", ") mct) "")
               (if cc (concat (if (bolp) "" ", ") cc) ""))
              ;; Remove addresses that match `rmail-dont-reply-to-names'. 
              (insert (prog1 (rmail-dont-reply-to (buffer-string))
                        (erase-buffer)))
              (goto-char (point-min))
              (setq ccalist
                    (mapcar
                     (lambda (addr)
                       (cons (mail-strip-quoted-names addr) addr))
                     (nreverse (mail-parse-comma-list))))
              (let ((s ccalist))
                (while s
                  (setq ccalist (delq (assoc (car (pop s)) s) ccalist)))))
            (setq follow-to (list (cons 'To (cdr (pop ccalist)))))
            (when ccalist
              (push (cons 'Cc
                          (mapconcat (lambda (addr) (cdr addr)) ccalist ", "))
                    follow-to)))))
      (widen))

    (message-pop-to-buffer "*mail message*")

    (setq message-reply-headers
          (vector 0 subject from date message-id references 0 0 ""))

    (message-setup
     `((Subject . ,subject)
       ,@follow-to 
       (References . ,(concat (or references "") (and references " ")
                              (or message-id ""))))
     cur)))

;;;###autoload
(defun message-wide-reply (&optional to-address)
  (interactive)
  (message-reply to-address t))

;;;###autoload
(defun message-followup ()
  (interactive)
  (let ((cur (current-buffer))
        from subject date message-of reply-to mct
        references message-id follow-to sendto elt 
        followup-to distribution newsgroups gnus-warning)
    (save-restriction
      (narrow-to-region
       (goto-char (point-min))
       (if (search-forward "\n\n" nil t)
           (1- (point))
         (point-max)))
      (when (message-functionp message-followup-to-function)
        (setq follow-to
              (funcall message-followup-to-function)))
      (setq from (mail-fetch-field "from")
            date (mail-fetch-field "date") 
            subject (or (mail-fetch-field "subject") "none")
            references (mail-fetch-field "references")
            message-id (mail-fetch-field "message-id")
            followup-to (mail-fetch-field "followup-to")
            newsgroups (mail-fetch-field "newsgroups")
            reply-to (mail-fetch-field "reply-to")
            distribution (mail-fetch-field "distribution")
            mct (mail-fetch-field "mail-copies-to"))
      (when (and (setq gnus-warning (mail-fetch-field "gnus-warning"))
                 (string-match "<[^>]+>" gnus-warning))
        (setq message-id (match-string 0 gnus-warning)))
      ;; Remove bogus distribution.
      (and (stringp distribution)
           (string-match "world" distribution)
           (setq distribution nil))
      ;; Remove any (buggy) Re:'s that are present and make a
      ;; proper one.
      (when (string-match "^[ \t]*[Re][Ee]:[ \t]*" subject)
        (setq subject (substring subject (match-end 0))))
      (setq subject (concat "Re: " subject))
      (widen))

    (message-pop-to-buffer "*news message*")

    (message-setup
     `((Subject . ,subject)
       ,@(cond 
          (follow-to follow-to)
          ((and followup-to message-use-followup-to)
           (list
            (cond 
             ((equal (downcase followup-to) "poster")
              (if (or (eq message-use-followup-to 'use)
                      (y-or-n-p "Use Followup-To \"poster\"? "))
                  (cons 'To (or reply-to from ""))
                (cons 'Newsgroups newsgroups)))
             (t
              (if (or (equal followup-to newsgroups)
                      (not (eq message-use-followup-to 'ask))
                      (y-or-n-p (format "Use Followup-To %s? " followup-to)))
                  (cons 'Newsgroups followup-to)
                (cons 'Newsgroups newsgroups))))))
          (t
           `((Newsgroups . ,newsgroups))))
       ,@(and distribution (list (cons 'Distribution distribution)))
       (References . ,(concat (or references "") (and references " ")
                              (or message-id "")))
       ,@(when (and mct
                    (not (equal (downcase mct) "never")))
           (list (cons 'Cc (if (equal (downcase mct) "always")
                               (or reply-to from "")
                             mct)))))

     cur)

    (setq message-reply-headers
          (vector 0 subject from date message-id references 0 0 ""))))


;;;###autoload
(defun message-cancel-news ()
  "Cancel an article you posted."
  (interactive)
  (unless (message-news-p)
    (error "This is not a news article; canceling is impossible"))
  (when (yes-or-no-p "Do you really want to cancel this article? "))
  (let (from newsgroups message-id distribution buf)
    (save-excursion
      ;; Get header info. from original article.
      (save-restriction
        (message-narrow-to-head)
        (setq from (mail-fetch-field "from")
              newsgroups (mail-fetch-field "newsgroups")
              message-id (mail-fetch-field "message-id")
              distribution (mail-fetch-field "distribution")))
      ;; Make sure that this article was written by the user.
      (unless (string-equal
               (downcase (mail-strip-quoted-names from))
               (downcase (message-make-address)))
        (error "This article is not yours"))
      ;; Make control message.
      (setq buf (set-buffer (get-buffer-create " *message cancel*")))
      (buffer-disable-undo (current-buffer))
      (erase-buffer)
      (insert "Newsgroups: " newsgroups "\n"
              "From: " (message-make-from) "\n"
              "Subject: cmsg cancel " message-id "\n"
              "Control: cancel " message-id "\n"
              (if distribution
                  (concat "Distribution: " distribution "\n")
                "")
              mail-header-separator "\n"
              "This is a cancel message from " from ".\n")
      (message "Canceling your article...")
      (let (message-syntax-checks)
        (funcall message-send-news-function))
      (message "Canceling your article...done")
      (kill-buffer buf))))

;;;###autoload
(defun message-supersede ()
  "Start composing a message to supersede the current message.
This is done simply by taking the old article and adding a Supersedes
header line with the old Message-ID."
  (interactive)
  (let ((cur (current-buffer)))
    ;; Check whether the user owns the article that is to be superseded. 
    (unless (string-equal
             (downcase (mail-strip-quoted-names (mail-fetch-field "from")))
             (downcase (mail-strip-quoted-names (message-make-address))))
      (error "This article is not yours"))
    ;; Get a normal message buffer.
    (message-pop-to-buffer "*supersede message*")
    (insert-buffer-substring cur)
    (message-narrow-to-head)
    ;; Remove unwanted headers.
    (when message-ignored-supersedes-headers
      (message-remove-header message-ignored-supersedes-headers t))
    (goto-char (point-min))
    (if (not (re-search-forward "^Message-ID: " nil t))
        (error "No Message-ID in this article")
      (replace-match "Supersedes: " t t))
    (goto-char (point-max))
    (insert mail-header-separator)
    (widen)
    (forward-line 1)))

;;;###autoload
(defun message-recover ()
  "Reread contents of current buffer from its last auto-save file."
  (interactive)
  (let ((file-name (make-auto-save-file-name)))
    (cond ((save-window-excursion
             (if (not (eq system-type 'vax-vms))
                 (with-output-to-temp-buffer "*Directory*"
                   (buffer-disable-undo standard-output)
                   (let ((default-directory "/"))
                     (call-process
                      "ls" nil standard-output nil "-l" file-name))))
             (yes-or-no-p (format "Recover auto save file %s? " file-name)))
           (let ((buffer-read-only nil))
             (erase-buffer)
             (insert-file-contents file-name nil)))
          (t (error "message-recover cancelled")))))

;;; Forwarding messages.

(defun message-make-forward-subject ()
  "Return a Subject header suitable for the message in the current buffer."
  (concat "[" (mail-fetch-field (if (message-news-p) "newsgroups" "from"))
          "] " (or (mail-fetch-field "Subject") "")))

;;;###autoload
(defun message-forward (&optional news)
  "Forward the current message via mail.  
Optional NEWS will use news to forward instead of mail."
  (interactive "P")
  (let ((cur (current-buffer))
        (subject (message-make-forward-subject)))
    (if news (message-news nil subject) (message-mail nil subject))
    ;; Put point where we want it before inserting the forwarded
    ;; message. 
    (if message-signature-before-forwarded-message
        (goto-char (point-max))
      (message-goto-body))
    ;; Narrow to the area we are to insert.
    (narrow-to-region (point) (point))
    ;; Insert the separators and the forwarded buffer.
    (insert message-forward-start-separator)
    (insert-buffer-substring cur)
    (goto-char (point-max))
    (insert message-forward-end-separator)
    (set-text-properties (point-min) (point-max) nil)
    ;; Remove all unwanted headers.
    (goto-char (point-min))
    (forward-line 1)
    (narrow-to-region (point) (if (search-forward "\n\n" nil t)
                                  (1- (point))
                                (point)))
    (goto-char (point-min))
    (message-remove-header message-included-forward-headers t nil t)
    (widen)
    (message-position-point)))

;;;###autoload
(defun message-resend (address)
  "Resend the current article to ADDRESS."
  (interactive "sResend message to: ")
  (save-excursion
    (let ((cur (current-buffer))
          beg)
      ;; We first set up a normal mail buffer.
      (message-set-work-buffer)
      (message-setup `((To . ,address)))
      ;; Insert our usual headers.
      (message-narrow-to-headers)
      (message-generate-headers '(From Date To))
      (goto-char (point-min))
      ;; Rename them all to "Resent-*".
      (while (re-search-forward "^[A-Za-z]" nil t)
        (forward-char -1)
        (insert "Resent-"))
      (widen)
      (forward-line)
      (delete-region (point) (point-max))
      (setq beg (point))
      ;; Insert the message to be resent.
      (insert-buffer-substring cur)
      (goto-char (point-min))
      (search-forward "\n\n")
      (forward-char -1)
      (save-restriction
        (narrow-to-region beg (point))
        (message-remove-header message-ignored-resent-headers t)
        (goto-char (point-max)))
      (insert mail-header-separator)
      ;; Rename all old ("Also-")Resent headers.
      (while (re-search-backward "^\\(Also-\\)?Resent-" beg t)
        (beginning-of-line)
        (insert "Also-"))
      ;; Send it.
      (funcall message-send-mail-function))))

;;;###autoload
(defun message-bounce ()
  "Re-mail the current message.
This only makes sense if the current message is a bounce message than
contains some mail you have written which has been bounced back to
you."
  (interactive "P")
  (let ((cur (current-buffer)))
    (message-pop-to-buffer "*mail message*")
    (insert-buffer-substring cur)
    (goto-char (point-min))
    (or (and (re-search-forward mail-unsent-separator nil t)
             (forward-line 1))
        (and (search-forward "\n\n" nil t)
             (re-search-forward "^Return-Path:.*\n" nil t)))
    ;; We remove everything before the bounced mail.
    (delete-region 
     (point-min)
     (if (re-search-forward "[^ \t]*:" nil t)
         (match-beginning 0)
       (point)))
    (save-restriction
      (message-narrow-to-head)
      (message-remove-header message-ignored-bounced-headers t)
      (goto-char (point-max))
      (insert mail-header-separator))
    (message-position-point)))

;;;
;;; Interactive entry points for new message buffers.
;;;

;;;###autoload
(defun message-mail-other-window (&optional to subject)
  "Like `message-mail' command, but display mail buffer in another window."
  (interactive)
  (let ((pop-up-windows t)
        (special-display-buffer-names nil)
        (special-display-regexps nil)
        (same-window-buffer-names nil)
        (same-window-regexps nil))
    (message-pop-to-buffer "*mail message*"))
  (message-setup `((To . ,(or to "")) (Subject . ,(or subject "")))))

;;;###autoload
(defun message-mail-other-frame (&optional to subject)
  "Like `message-mail' command, but display mail buffer in another frame."
  (interactive)
  (let ((pop-up-frames t)
        (special-display-buffer-names nil)
        (special-display-regexps nil)
        (same-window-buffer-names nil)
        (same-window-regexps nil))
    (message-pop-to-buffer "*mail message*"))
  (message-setup `((To . ,(or to "")) (Subject . ,(or subject "")))))

;;;###autoload
(defun message-news-other-window (&optional newsgroups subject)
  "Start editing a news article to be sent."
  (interactive)
  (let ((pop-up-windows t)
        (special-display-buffer-names nil)
        (special-display-regexps nil)
        (same-window-buffer-names nil)
        (same-window-regexps nil))
    (message-pop-to-buffer "*news message*"))
  (message-setup `((Newsgroups . ,(or newsgroups "")) 
                   (Subject . ,(or subject "")))))

;;;###autoload
(defun message-news-other-frame (&optional newsgroups subject)
  "Start editing a news article to be sent."
  (interactive)
  (let ((pop-up-frames t)
        (special-display-buffer-names nil)
        (special-display-regexps nil)
        (same-window-buffer-names nil)
        (same-window-regexps nil))
    (message-pop-to-buffer "*news message*"))
  (message-setup `((Newsgroups . ,(or newsgroups "")) 
                   (Subject . ,(or subject "")))))

;;; underline.el

;; This code should be moved to underline.el (from which it is stolen). 

;;;###autoload
(defun bold-region (start end)
  "Bold all nonblank characters in the region.
Works by overstriking characters.
Called from program, takes two arguments START and END
which specify the range to operate on."
  (interactive "r")
  (save-excursion
   (let ((end1 (make-marker)))
     (move-marker end1 (max start end))
     (goto-char (min start end))
     (while (< (point) end1)
       (or (looking-at "[_\^@- ]")
           (insert (following-char) "\b"))
       (forward-char 1)))))

;;;###autoload
(defun unbold-region (start end)
  "Remove all boldness (overstruck characters) in the region.
Called from program, takes two arguments START and END
which specify the range to operate on."
  (interactive "r")
  (save-excursion
   (let ((end1 (make-marker)))
     (move-marker end1 (max start end))
     (goto-char (min start end)) 
     (while (re-search-forward "\b" end1 t)
       (if (eq (following-char) (char-after (- (point) 2)))
           (delete-char -2))))))

(provide 'message)

;;; message.el ends here