Add :link (custom-group-link font-lock-faces) to defgroup.

[emacs.git] / lisp / mh-e / mh-comp.el

;;; mh-comp.el --- MH-E functions for composing messages

;; Copyright (C) 1993, 1995, 1997,
;;  2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.

;; Author: Bill Wohler <wohler@newt.com>
;; Maintainer: Bill Wohler <wohler@newt.com>
;; Keywords: mail
;; See: mh-e.el

;; 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., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; Internal support for MH-E package.

;;; Change Log:

;;; Code:

(eval-when-compile (require 'mh-acros))
(mh-require-cl)
(require 'mh-e)
(require 'gnus-util)
(require 'easymenu)
(require 'mh-gnus)
(eval-when (compile load eval)
  (ignore-errors (require 'mailabbrev)))

;; Shush the byte-compiler
(defvar adaptive-fill-first-line-regexp)
(defvar font-lock-defaults)
(defvar mark-active)
(defvar sendmail-coding-system)
(defvar mh-identity-list)
(defvar mh-identity-default)
(defvar mh-mml-mode-default)
(defvar mh-identity-menu)

;;; Autoloads
(autoload 'mail-mode-fill-paragraph "sendmail")
(autoload 'mm-handle-displayed-p "mm-decode")

(autoload 'sc-cite-original "sc"
  "Workhorse citing function which performs the initial citation.
This is callable from the various mail and news readers' reply
function according to the agreed upon standard.  See `sc-describe'
for more details.  `sc-cite-original' does not do any yanking of the
original message but it does require a few things:

     1) The reply buffer is the current buffer.

     2) The original message has been yanked and inserted into the
        reply buffer.

     3) Verbose mail headers from the original message have been
        inserted into the reply buffer directly before the text of the
        original message.

     4) Point is at the beginning of the verbose headers.

     5) Mark is at the end of the body of text to be cited.

For Emacs 19's, the region need not be active (and typically isn't
when this function is called.  Also, the hook `sc-pre-hook' is run
before, and `sc-post-hook' is run after the guts of this function.")

;;; Site customization (see also mh-utils.el):

(defvar mh-send-prog "send"
  "Name of the MH send program.
Some sites need to change this because of a name conflict.")

(defvar mh-redist-background nil
  "If non-nil redist will be done in background like send.
This allows transaction log to be visible if -watch, -verbose or -snoop are
used.")

;;; Scan Line Formats

(defvar mh-note-repl ?-
  "Messages that have been replied to are marked by this character.")

(defvar mh-note-forw ?F
  "Messages that have been forwarded are marked by this character.")

(defvar mh-note-dist ?R
  "Messages that have been redistributed are marked by this character.")

(defvar mh-yank-hooks nil
  "Obsolete hook for modifying a citation just inserted in the mail buffer.
Each hook function can find the citation between point and mark.
And each hook function should leave point and mark around the citation
text as modified.

This is a normal hook, misnamed for historical reasons.
It is semi-obsolete and is only used if `mail-citation-hook' is nil.")

(defvar mh-comp-formfile "components"
  "Name of file to be used as a skeleton for composing messages.
Default is \"components\".  If not an absolute file name, the file
is searched for first in the user's MH directory, then in the
system MH lib directory.")

(defvar mh-repl-formfile "replcomps"
  "Name of file to be used as a skeleton for replying to messages.
Default is \"replcomps\".  If not an absolute file name, the file
is searched for first in the user's MH directory, then in the
system MH lib directory.")

(defvar mh-repl-group-formfile "replgroupcomps"
  "Name of file to be used as a skeleton for replying to messages.
This file is used to form replies to the sender and all recipients of a
message. Only used if `(mh-variant-p 'nmh)' is non-nil.
Default is \"replgroupcomps\".
If not an absolute file name, the file is searched for first in the user's MH
directory, then in the system MH lib directory.")

(defvar mh-rejected-letter-start
  (format "^%s$"
          (regexp-opt
           '("Content-Type: message/rfc822" ;MIME MDN
             "------ This is a copy of the message, including all the headers. ------";from exim
             "--- Below this line is a copy of the message."; from qmail
             "   ----- Unsent message follows -----" ;from sendmail V5
             " --------Unsent Message below:" ; from sendmail at BU
             "   ----- Original message follows -----" ;from sendmail V8
             "------- Unsent Draft"     ;from MH itself
             "----------  Original Message  ----------" ;from zmailer
             "  --- The unsent message follows ---" ;from AIX mail system
             "    Your message follows:" ;from MMDF-II
             "Content-Description: Returned Content" ;1993 KJ sendmail
             ))))

(defvar mh-new-draft-cleaned-headers
  "^Date:\\|^Received:\\|^Message-Id:\\|^From:\\|^Sender:\\|^Errors-To:\\|^Delivery-Date:\\|^Return-Path:"
  "Regexp of header lines to remove before offering a message as a new draft.
Used by the \\<mh-folder-mode-map>`\\[mh-edit-again]' and `\\[mh-extract-rejected-mail]' commands.")

(defvar mh-to-field-choices '(("t" . "To:") ("s" . "Subject:") ("c" . "Cc:")
                              ("b" . "Bcc:") ("f" . "Fcc:") ("r" . "From:")
                              ("d" . "Dcc:"))
  "Alist of (final-character . field-name) choices for `mh-to-field'.")

(defvar mh-letter-mode-map (copy-keymap text-mode-map)
  "Keymap for composing mail.")

(defvar mh-letter-mode-syntax-table nil
  "Syntax table used by MH-E while in MH-Letter mode.")

(if mh-letter-mode-syntax-table
    ()
  (setq mh-letter-mode-syntax-table
        (make-syntax-table text-mode-syntax-table))
  (modify-syntax-entry ?% "." mh-letter-mode-syntax-table))

(defvar mh-sent-from-folder nil
  "Folder of msg assoc with this letter.")

(defvar mh-sent-from-msg nil
  "Number of msg assoc with this letter.")

(defvar mh-send-args nil
  "Extra args to pass to \"send\" command.")

(defvar mh-annotate-char nil
  "Character to use to annotate `mh-sent-from-msg'.")

(defvar mh-annotate-field nil
  "Field name for message annotation.")

(defvar mh-insert-auto-fields-done-local nil
  "Buffer-local variable set when `mh-insert-auto-fields' called successfully.")
(make-variable-buffer-local 'mh-insert-auto-fields-done-local)

;;;###autoload
(defun mh-smail ()
  "Compose a message with the MH mail system.
See `mh-send' for more details on composing mail."
  (interactive)
  (mh-find-path)
  (call-interactively 'mh-send))

;;;###autoload
(defun mh-smail-other-window ()
  "Compose a message with the MH mail system in other window.
See `mh-send' for more details on composing mail."
  (interactive)
  (mh-find-path)
  (call-interactively 'mh-send-other-window))

(defvar mh-error-if-no-draft nil)       ;raise error over using old draft

;;;###autoload
(defun mh-smail-batch (&optional to subject other-headers &rest ignored)
  "Compose a message with the MH mail system.

This function does not prompt the user for any header fields, and thus
is suitable for use by programs that want to create a mail buffer. Users
should use \\[mh-smail] to compose mail.

Optional arguments for setting certain fields include TO, SUBJECT, and
OTHER-HEADERS. Additional arguments are IGNORED."
  (mh-find-path)
  (let ((mh-error-if-no-draft t))
    (mh-send (or to "") "" (or subject ""))))

;; XEmacs needs this:
;;;###autoload
(defun mh-user-agent-compose (&optional to subject other-headers continue
                                        switch-function yank-action
                                        send-actions)
  "Set up mail composition draft with the MH mail system.
This is `mail-user-agent' entry point to MH-E.

The optional arguments TO and SUBJECT specify recipients and the
initial Subject field, respectively.

OTHER-HEADERS is an alist specifying additional
header fields.  Elements look like (HEADER . VALUE) where both
HEADER and VALUE are strings.

CONTINUE, SWITCH-FUNCTION, YANK-ACTION and SEND-ACTIONS are ignored."
  (mh-find-path)
  (let ((mh-error-if-no-draft t))
    (mh-send to "" subject)
    (while other-headers
      (mh-insert-fields (concat (car (car other-headers)) ":")
                        (cdr (car other-headers)))
      (setq other-headers (cdr other-headers)))))

;;;###mh-autoload
(defun mh-edit-again (message)
  "Edit a MESSAGE to send it again.

If you don't complete a draft for one reason or another, and if the draft
buffer is no longer available, you can pick your draft up again with this
command. If you don't use a draft folder, your last \"draft\" file will be
used. If you use draft folders, you'll need to visit the draft folder with
\"\\[mh-visit-folder] drafts <RET>\", use \\[mh-next-undeleted-msg] to move to
the appropriate message, and then use \\[mh-edit-again] to prepare the message
for editing.

This command can also be used to take messages that were sent to you and to
send them to more people.

Don't use this command to re-edit a message from a Mailer-Daemon who
complained that your mail wasn't posted for some reason or another (see
`mh-extract-rejected-mail').

The default message is the current message.

See also `mh-send'."
  (interactive (list (mh-get-msg-num t)))
  (let* ((from-folder mh-current-folder)
         (config (current-window-configuration))
         (draft
          (cond ((and mh-draft-folder (equal from-folder mh-draft-folder))
                 (pop-to-buffer (find-file-noselect (mh-msg-filename message))
                                t)
                 (rename-buffer (format "draft-%d" message))
                 ;; Make buffer writable...
                 (setq buffer-read-only nil)
                 ;; If buffer was being used to display the message reinsert
                 ;; from file...
                 (when (eq major-mode 'mh-show-mode)
                   (erase-buffer)
                   (insert-file-contents buffer-file-name))
                 (buffer-name))
                (t
                 (mh-read-draft "clean-up" (mh-msg-filename message) nil)))))
    (mh-clean-msg-header (point-min) mh-new-draft-cleaned-headers nil)
    (mh-insert-header-separator)
    (goto-char (point-min))
    (save-buffer)
    (mh-compose-and-send-mail draft "" from-folder nil nil nil nil nil nil
                              config)
    (mh-letter-mode-message)
    (mh-letter-adjust-point)))

;;;###mh-autoload
(defun mh-extract-rejected-mail (message)
  "Edit a MESSAGE that was returned by the mail system.

This command prepares the message for editing by removing the Mailer-Daemon
envelope and unneeded header fields. Fix whatever addressing problem you had,
and send the message again with \\[mh-send-letter].

The default message is the current message.

See also `mh-send'."
  (interactive (list (mh-get-msg-num t)))
  (let ((from-folder mh-current-folder)
        (config (current-window-configuration))
        (draft (mh-read-draft "extraction" (mh-msg-filename message) nil)))
    (goto-char (point-min))
    (cond ((re-search-forward mh-rejected-letter-start nil t)
           (skip-chars-forward " \t\n")
           (delete-region (point-min) (point))
           (mh-clean-msg-header (point-min) mh-new-draft-cleaned-headers nil))
          (t
           (message "Does not appear to be a rejected letter")))
    (mh-insert-header-separator)
    (goto-char (point-min))
    (save-buffer)
    (mh-compose-and-send-mail draft "" from-folder message
                              (mh-get-header-field "To:")
                              (mh-get-header-field "From:")
                              (mh-get-header-field "Cc:")
                              nil nil config)
    (mh-letter-mode-message)))

;;;###mh-autoload
(defun mh-forward (to cc &optional range)
  "Forward message(s).

You are prompted for the TO and CC recipients. You are given a draft to edit
that looks like it would if you had run the MH command \"forw\". You are given
a chance to add some text.

You can forward several messages by using a RANGE. All of the messages in the
range are inserted into your draft. Check the documentation of
`mh-interactive-range' to see how RANGE is read in interactive use.

The default message is the current message.

See also `mh-compose-forward-as-mime-flag', `mh-forward-subject-format',
and `mh-send'."
  (interactive (list (mh-interactive-read-address "To: ")
                     (mh-interactive-read-address "Cc: ")
                     (mh-interactive-range "Forward")))
  (let* ((folder mh-current-folder)
         (msgs (mh-range-to-msg-list range))
         (config (current-window-configuration))
         (fwd-msg-file (mh-msg-filename (car msgs) folder))
         ;; forw always leaves file in "draft" since it doesn't have -draft
         (draft-name (expand-file-name "draft" mh-user-path))
         (draft (cond ((or (not (file-exists-p draft-name))
                           (y-or-n-p "The file 'draft' exists.  Discard it? "))
                       (mh-exec-cmd "forw" "-build"
                                    (if (and (mh-variant-p 'nmh)
                                             mh-compose-forward-as-mime-flag)
                                        "-mime")
                                    mh-current-folder
                                    (mh-coalesce-msg-list msgs))
                       (prog1
                           (mh-read-draft "" draft-name t)
                         (mh-insert-fields "To:" to "Cc:" cc)
                         (save-buffer)))
                      (t
                       (mh-read-draft "" draft-name nil)))))
    (let (orig-from
          orig-subject)
      (save-excursion
        (set-buffer (get-buffer-create mh-temp-buffer))
        (erase-buffer)
        (insert-file-contents fwd-msg-file)
        (setq orig-from (mh-get-header-field "From:"))
        (setq orig-subject (mh-get-header-field "Subject:")))
      (let ((forw-subject
             (mh-forwarded-letter-subject orig-from orig-subject)))
        (mh-insert-fields "Subject:" forw-subject)
        (goto-char (point-min))
        ;; If using MML, translate MH-style directive
        (if (equal mh-compose-insertion 'mml)
            (save-excursion
              (goto-char (mh-mail-header-end))
              (while
                  (re-search-forward
                   "^#forw \\[\\([^]]+\\)\\] \\(+\\S-+\\) \\(.*\\)$"
                   (point-max) t)
                (let ((description (if (equal (match-string 1)
                                              "forwarded messages")
                                       "forwarded message %d"
                                     (match-string 1)))
                      (msgs (split-string (match-string 3)))
                      (i 0))
                  (beginning-of-line)
                  (delete-region (point) (progn (forward-line 1) (point)))
                  (dolist (msg msgs)
                    (setq i (1+ i))
                    (mh-mml-forward-message (format description i)
                                            folder msg))))))
        ;; Postition just before forwarded message
        (if (re-search-forward "^------- Forwarded Message" nil t)
            (forward-line -1)
          (goto-char (mh-mail-header-end))
          (forward-line 1))
        (delete-other-windows)
        (mh-add-msgs-to-seq msgs 'forwarded t)
        (mh-compose-and-send-mail draft "" folder msgs
                                  to forw-subject cc
                                  mh-note-forw "Forwarded:"
                                  config)
        (mh-letter-mode-message)
        (mh-letter-adjust-point)
        (run-hooks 'mh-forward-hook)))))

(defun mh-forwarded-letter-subject (from subject)
  "Return a Subject suitable for a forwarded message.
Original message has headers FROM and SUBJECT."
  (let ((addr-start (string-match "<" from))
        (comment (string-match "(" from)))
    (cond ((and addr-start (> addr-start 0))
           ;; Full Name <luser@host>
           (setq from (substring from 0 (1- addr-start))))
          (comment
           ;; luser@host (Full Name)
           (setq from (substring from (1+ comment) (1- (length from)))))))
  (format mh-forward-subject-format from subject))

;;;###mh-autoload
(defun mh-redistribute (to cc &optional message)
  "Redistribute a message.

This command is similar in function to forwarding mail, but it does not allow
you to edit the message, nor does it add your name to the \"From\" header
field. It appears to the recipient as if the message had come from the
original sender. When you run this command, you are prompted for the TO and CC
recipients. The default MESSAGE is the current message.

Also investigate the \\[mh-edit-again] command for another way to redistribute
messages.

See also `mh-redist-full-contents-flag'."
  (interactive (list (mh-read-address "Redist-To: ")
                     (mh-read-address "Redist-Cc: ")
                     (mh-get-msg-num t)))
  (or message
      (setq message (mh-get-msg-num t)))
  (save-window-excursion
    (let ((folder mh-current-folder)
          (draft (mh-read-draft "redistribution"
                                (if mh-redist-full-contents-flag
                                    (mh-msg-filename message)
                                  nil)
                                nil)))
      (mh-goto-header-end 0)
      (insert "Resent-To: " to "\n")
      (if (not (equal cc "")) (insert "Resent-cc: " cc "\n"))
      (mh-clean-msg-header
       (point-min)
       "^Message-Id:\\|^Received:\\|^Return-Path:\\|^Sender:\\|^Date:\\|^From:"
       nil)
      (save-buffer)
      (message "Redistributing...")
      (let ((env "mhdist=1"))
        ;; Setup environment...
        (setq env (concat env " mhaltmsg="
                          (if mh-redist-full-contents-flag
                              buffer-file-name
                            (mh-msg-filename message folder))))
        (unless mh-redist-full-contents-flag
          (setq env (concat env " mhannotate=1")))
        ;; Redistribute...
        (if mh-redist-background
            (mh-exec-cmd-env-daemon env mh-send-prog nil buffer-file-name)
          (mh-exec-cmd-error env mh-send-prog "-push" buffer-file-name))
        ;; Annotate...
        (mh-annotate-msg message folder mh-note-dist
                         "-component" "Resent:"
                         "-text" (format "\"%s %s\"" to cc)))
      (kill-buffer draft)
      (message "Redistributing...done"))))

(defun mh-show-buffer-message-number (&optional buffer)
  "Message number of displayed message in corresponding show buffer.
Return nil if show buffer not displayed.
If in `mh-letter-mode', don't display the message number being replied to,
but rather the message number of the show buffer associated with our
originating folder buffer.
Optional argument BUFFER can be used to specify the buffer."
  (save-excursion
    (if buffer
        (set-buffer buffer))
    (cond ((eq major-mode 'mh-show-mode)
           (let ((number-start (mh-search-from-end ?/ buffer-file-name)))
             (car (read-from-string (substring buffer-file-name
                                               (1+ number-start))))))
          ((and (eq major-mode 'mh-folder-mode)
                mh-show-buffer
                (get-buffer mh-show-buffer))
           (mh-show-buffer-message-number mh-show-buffer))
          ((and (eq major-mode 'mh-letter-mode)
                mh-sent-from-folder
                (get-buffer mh-sent-from-folder))
           (mh-show-buffer-message-number mh-sent-from-folder))
          (t
           nil))))

;;;###mh-autoload
(defun mh-reply (message &optional reply-to includep)
  "Reply to a MESSAGE.

When you reply to a message, you are first prompted with \"Reply to whom?\"
\(unless the optional argument REPLY-TO is provided). You have several choices
here.

     Response     Reply Goes To

     from         The person who sent the message.  This is the default,
                  so <RET> is sufficient.

     to           Replies to the sender, plus all recipients in the
                  \"To:\" header field.

     all
     cc           Forms a reply to the sender, plus all recipients.

Depending on your answer, \"repl\" is given a different argument to form your
reply. Specifically, a choice of \"from\" or none at all runs \"repl -nocc
all\", and a choice of \"to\" runs \"repl -cc to\". Finally, either \"cc\" or
\"all\" runs \"repl -cc all -nocc me\".

Two windows are then created. One window contains the message to which you are
replying in an MH-Show buffer. Your draft, in MH-Letter mode
\(see `mh-letter-mode'), is in the other window.

If you supply a prefix argument INCLUDEP, the message you are replying to is
inserted in your reply after having first been run through \"mhl\" with the
format file \"mhl.reply\".

Alternatively, you can customize the option `mh-yank-behavior' and choose one
of its \"Automatically\" variants to do the same thing. If you do so, the
prefix argument has no effect.

Another way to include the message automatically in your draft is to use
\"repl: -filter repl.filter\" in your MH profile.

If you wish to customize the header or other parts of the reply draft, please
see \"repl\" and \"mh-format\".

See also `mh-reply-show-message-flag', `mh-reply-default-reply-to', and
`mh-send'."
  (interactive (list
                (mh-get-msg-num t)
                (let ((minibuffer-help-form
                       "from => Sender only\nto => Sender and primary recipients\ncc or all => Sender and all recipients"))
                  (or mh-reply-default-reply-to
                      (completing-read "Reply to whom: [from] "
                                       '(("from") ("to") ("cc") ("all"))
                                       nil
                                       t)))
                current-prefix-arg))
  (let* ((folder mh-current-folder)
         (show-buffer mh-show-buffer)
         (config (current-window-configuration))
         (group-reply (or (equal reply-to "cc") (equal reply-to "all")))
         (form-file (cond ((and (mh-variant-p 'nmh 'mu-mh) group-reply
                                (stringp mh-repl-group-formfile))
                           mh-repl-group-formfile)
                          ((stringp mh-repl-formfile) mh-repl-formfile)
                          (t nil))))
    (message "Composing a reply...")
    (mh-exec-cmd "repl" "-build" "-noquery" "-nodraftfolder"
                 (if form-file
                     (list "-form" form-file))
                 mh-current-folder message
                 (cond ((or (equal reply-to "from") (equal reply-to ""))
                        '("-nocc" "all"))
                       ((equal reply-to "to")
                        '("-cc" "to"))
                       (group-reply (if (mh-variant-p 'nmh 'mu-mh)
                                        '("-group" "-nocc" "me")
                                      '("-cc" "all" "-nocc" "me"))))
                 (cond ((or (eq mh-yank-behavior 'autosupercite)
                            (eq mh-yank-behavior 'autoattrib))
                        '("-noformat"))
                       (includep '("-filter" "mhl.reply"))
                       (t '())))
    (let ((draft (mh-read-draft "reply"
                                (expand-file-name "reply" mh-user-path)
                                t)))
      (delete-other-windows)
      (save-buffer)

      (let ((to (mh-get-header-field "To:"))
            (subject (mh-get-header-field "Subject:"))
            (cc (mh-get-header-field "Cc:")))
        (goto-char (point-min))
        (mh-goto-header-end 1)
        (or includep
            (not mh-reply-show-message-flag)
            (mh-in-show-buffer (show-buffer)
              (mh-display-msg message folder)))
        (mh-add-msgs-to-seq message 'answered t)
        (message "Composing a reply...done")
        (mh-compose-and-send-mail draft "" folder message to subject cc
                                  mh-note-repl "Replied:" config))
      (when (and (or (eq 'autosupercite mh-yank-behavior)
                     (eq 'autoattrib mh-yank-behavior))
                 (eq (mh-show-buffer-message-number) mh-sent-from-msg))
        (undo-boundary)
        (mh-yank-cur-msg))
      (mh-letter-mode-message))))

;;;###mh-autoload
(defun mh-send (to cc subject)
  "Compose a message.

Your letter appears in an Emacs buffer whose mode is MH-Letter (see
`mh-letter-mode').

The arguments TO, CC, and SUBJECT can be used to prefill the draft fields or
suppress the prompts if `mh-compose-prompt-flag' is on. They are also passed
to the function set in the option `mh-compose-letter-function'.

See also `mh-insert-x-mailer-flag' and `mh-letter-mode-hook'.

Outside of an MH-Folder buffer (`mh-folder-mode'), you must call either
\\[mh-smail] or \\[mh-smail-other-window] to compose a new message."
  (interactive (list
                (mh-interactive-read-address "To: ")
                (mh-interactive-read-address "Cc: ")
                (mh-interactive-read-string "Subject: ")))
  (let ((config (current-window-configuration)))
    (delete-other-windows)
    (mh-send-sub to cc subject config)))

;;;###mh-autoload
(defun mh-send-other-window (to cc subject)
  "Compose a message in another window.

See `mh-send' for more information and a description of how the TO, CC, and
SUBJECT arguments are used."
  (interactive (list
                (mh-interactive-read-address "To: ")
                (mh-interactive-read-address "Cc: ")
                (mh-interactive-read-string "Subject: ")))
  (let ((pop-up-windows t))
    (mh-send-sub to cc subject (current-window-configuration))))

(defun mh-send-sub (to cc subject config)
  "Do the real work of composing and sending a letter.
Expects the TO, CC, and SUBJECT fields as arguments.
CONFIG is the window configuration before sending mail."
  (let ((folder mh-current-folder)
        (msg-num (mh-get-msg-num nil)))
    (message "Composing a message...")
    (let ((draft (mh-read-draft
                  "message"
                  (let (components)
                    (cond
                     ((file-exists-p
                       (setq components
                             (expand-file-name mh-comp-formfile mh-user-path)))
                      components)
                     ((file-exists-p
                       (setq components
                             (expand-file-name mh-comp-formfile mh-lib)))
                      components)
                     ((file-exists-p
                       (setq components
                             (expand-file-name mh-comp-formfile
                                               ;; What is this mh-etc ??  -sm
                                               ;; This is dead code, so
                                               ;; remove it.
                                        ;(and (boundp 'mh-etc) mh-etc)
                                               )))
                      components)
                     (t
                      (error "Can't find components file \"%s\""
                             components))))
                  nil)))
      (mh-insert-fields "To:" to "Subject:" subject "Cc:" cc)
      (goto-char (point-max))
      (mh-compose-and-send-mail draft "" folder msg-num
                                to subject cc
                                nil nil config)
      (mh-letter-mode-message)
      (mh-letter-adjust-point))))

(defun mh-read-draft (use initial-contents delete-contents-file)
  "Read draft file into a draft buffer and make that buffer the current one.
USE is a message used for prompting about the intended use of the message.
INITIAL-CONTENTS is filename that is read into an empty buffer, or nil
if buffer should not be modified.  Delete the initial-contents file if
DELETE-CONTENTS-FILE flag is set.
Returns the draft folder's name.
If the draft folder facility is enabled in ~/.mh_profile, a new buffer is
used each time and saved in the draft folder.  The draft file can then be
reused."
  (cond (mh-draft-folder
         (let ((orig-default-dir default-directory)
               (draft-file-name (mh-new-draft-name)))
           (pop-to-buffer (generate-new-buffer
                           (format "draft-%s"
                                   (file-name-nondirectory draft-file-name))))
           (condition-case ()
               (insert-file-contents draft-file-name t)
             (file-error))
           (setq default-directory orig-default-dir)))
        (t
         (let ((draft-name (expand-file-name "draft" mh-user-path)))
           (pop-to-buffer "draft")      ; Create if necessary
           (if (buffer-modified-p)
               (if (y-or-n-p "Draft has been modified; kill anyway? ")
                   (set-buffer-modified-p nil)
                 (error "Draft preserved")))
           (setq buffer-file-name draft-name)
           (clear-visited-file-modtime)
           (unlock-buffer)
           (cond ((and (file-exists-p draft-name)
                       (not (equal draft-name initial-contents)))
                  (insert-file-contents draft-name)
                  (delete-file draft-name))))))
  (cond ((and initial-contents
              (or (zerop (buffer-size))
                  (if (y-or-n-p
                       (format "A draft exists.  Use for %s? " use))
                      (if mh-error-if-no-draft
                          (error "A prior draft exists"))
                    t)))
         (erase-buffer)
         (insert-file-contents initial-contents)
         (if delete-contents-file (delete-file initial-contents))))
  (auto-save-mode 1)
  (if mh-draft-folder
      (save-buffer))                    ; Do not reuse draft name
  (buffer-name))

(defun mh-new-draft-name ()
  "Return the pathname of folder for draft messages."
  (save-excursion
    (mh-exec-cmd-quiet t "mhpath" mh-draft-folder "new")
    (buffer-substring (point-min) (1- (point-max)))))

(defun mh-annotate-msg (msg buffer note &rest args)
  "Mark MSG in BUFFER with character NOTE and annotate message with ARGS.
MSG can be a message number, a list of message numbers, or a sequence."
  (apply 'mh-exec-cmd "anno" buffer
         (if (listp msg) (append msg args) (cons msg args)))
  (save-excursion
    (cond ((get-buffer buffer)          ; Buffer may be deleted
           (set-buffer buffer)
           (mh-iterate-on-range nil msg
             (mh-notate nil note
                        (+ mh-cmd-note mh-scan-field-destination-offset)))))))

(defun mh-insert-fields (&rest name-values)
  "Insert the NAME-VALUES pairs in the current buffer.
If the field exists, append the value to it.
Do not insert any pairs whose value is the empty string."
  (let ((case-fold-search t))
    (while name-values
      (let ((field-name (car name-values))
            (value (car (cdr name-values))))
        (if (not (string-match "^.*:$" field-name))
            (setq field-name (concat field-name ":")))
        (cond ((equal value "")
               nil)
              ((mh-position-on-field field-name)
               (insert " " (or value "")))
              (t
               (insert field-name " " value "\n")))
        (setq name-values (cdr (cdr name-values)))))))

(defun mh-position-on-field (field &optional ignored)
  "Move to the end of the FIELD in the header.
Move to end of entire header if FIELD not found.
Returns non-nil iff FIELD was found.
The optional second arg is for pre-version 4 compatibility and is IGNORED."
  (cond ((mh-goto-header-field field)
         (mh-header-field-end)
         t)
        ((mh-goto-header-end 0)
         nil)))

;;;###mh-autoload
(defun mh-get-header-field (field)
  "Find and return the body of FIELD in the mail header.
Returns the empty string if the field is not in the header of the
current buffer."
  (if (mh-goto-header-field field)
      (progn
        (skip-chars-forward " \t")      ;strip leading white space in body
        (let ((start (point)))
          (mh-header-field-end)
          (buffer-substring-no-properties start (point))))
    ""))

(fset 'mh-get-field 'mh-get-header-field) ;MH-E 4 compatibility

(defun mh-goto-header-field (field)
  "Move to FIELD in the message header.
Move to the end of the FIELD name, which should end in a colon.
Returns t if found, nil if not."
  (goto-char (point-min))
  (let ((case-fold-search t)
        (headers-end (save-excursion
                       (mh-goto-header-end 0)
                       (point))))
    (re-search-forward (format "^%s" field) headers-end t)))

(defun mh-goto-header-end (arg)
  "Move the cursor ARG lines after the header."
  (if (re-search-forward "^-*$" nil nil)
      (forward-line arg)))

(defun mh-extract-from-header-value ()
  "Extract From: string from header."
  (save-excursion
    (if (not (mh-goto-header-field "From:"))
        nil
      (skip-chars-forward " \t")
      (buffer-substring-no-properties
       (point) (progn (mh-header-field-end)(point))))))

\f

;;; Mode for composing and sending a draft message.

(put 'mh-letter-mode 'mode-class 'special)

;;; Menu extracted from mh-menubar.el V1.1 (31 July 2001)
(eval-when-compile (defvar mh-letter-menu nil))
(easy-menu-define
  mh-letter-menu mh-letter-mode-map "Menu for MH-E letter mode."
  '("Letter"
    ["Send This Draft"          mh-send-letter t]
    ["Split Current Line"       mh-open-line t]
    ["Check Recipient"          mh-check-whom t]
    ["Yank Current Message"     mh-yank-cur-msg t]
    ["Insert a Message..."      mh-insert-letter t]
    ["Insert Signature"         mh-insert-signature t]
    ("Encrypt/Sign Message"
     ["Sign Message"
      mh-mml-secure-message-sign mh-pgp-support-flag]
     ["Encrypt Message"
      mh-mml-secure-message-encrypt mh-pgp-support-flag]
     ["Sign+Encrypt Message"
      mh-mml-secure-message-signencrypt mh-pgp-support-flag]
     ["Disable Security"
      mh-mml-unsecure-message mh-pgp-support-flag]
     "--"
     "Security Method"
     ["PGP (MIME)" (setq mh-mml-method-default "pgpmime")
      :style radio
      :selected (equal mh-mml-method-default "pgpmime")]
     ["PGP" (setq mh-mml-method-default "pgp")
      :style radio
      :selected (equal mh-mml-method-default "pgp")]
     ["S/MIME" (setq mh-mml-method-default "smime")
      :style radio
      :selected (equal mh-mml-method-default "smime")]
     "--"
     ["Save Method as Default"
      (customize-save-variable 'mh-mml-method-default mh-mml-method-default) t]
     )
    ["Compose Insertion..."      mh-compose-insertion t]
    ["Compose Compressed tar (MH)..."
     mh-mh-compose-external-compressed-tar t]
    ["Compose Get File (MH)..."       mh-mh-compose-anon-ftp t]
    ["Compose Forward..."        mh-compose-forward t]
    ;; The next two will have to be merged. But I also need to make sure the
    ;; user can't mix tags of both types.
    ["Pull in All Compositions (MH)"
     mh-mh-to-mime (mh-mh-directive-present-p)]
    ["Pull in All Compositions (MML)"
     mh-mml-to-mime (mh-mml-tag-present-p)]
    ["Revert to Non-MIME Edit (MH)"
     mh-mh-to-mime-undo (equal mh-compose-insertion 'mh)]
    ["Kill This Draft"          mh-fully-kill-draft t]))

;;; Help Messages
;;; Group messages logically, more or less.
(defvar mh-letter-mode-help-messages
  '((nil
     "Send letter:          \\[mh-send-letter]"
     "\t\tOpen line:            \\[mh-open-line]\n"
     "Kill letter:          \\[mh-fully-kill-draft]"
     "\t\tInsert:\n"
     "Check recipients:     \\[mh-check-whom]"
     "\t\t  Current message:    \\[mh-yank-cur-msg]\n"
     "\t\t  Attachment:             \\[mh-compose-insertion]\n"
     "\t\t  Message to forward:     \\[mh-compose-forward]\n"
     "                          "
     "Security:"
     "\t\t  Encrypt message:          \\[mh-mml-secure-message-encrypt]"
     "\t\t  Sign+Encrypt message:     \\[mh-mml-secure-message-signencrypt]"
     "\t\t  Sign message:             \\[mh-mml-secure-message-sign]\n"
     "                          "
     "\t\t  Signature:              \\[mh-insert-signature]"))
  "Key binding cheat sheet.

This is an associative array which is used to show the most common commands.
The key is a prefix char. The value is one or more strings which are
concatenated together and displayed in the minibuffer if ? is pressed after
the prefix character. The special key nil is used to display the
non-prefixed commands.

The substitutions described in `substitute-command-keys' are performed as
well.")

;;;###mh-autoload
(defun mh-fill-paragraph-function (arg)
  "Fill paragraph at or after point.
Prefix ARG means justify as well. This function enables `fill-paragraph' to
work better in MH-Letter mode (see `mh-letter-mode')."
  (interactive "P")
  (let ((fill-paragraph-function) (fill-prefix))
    (if (mh-in-header-p)
        (mail-mode-fill-paragraph arg)
      (fill-paragraph arg))))

;; Avoid compiler warnings in XEmacs and Emacs 20
(eval-when-compile
  (defvar tool-bar-mode)
  (defvar tool-bar-map))

(defvar mh-letter-buttons-init-flag nil)

;;;###autoload
(define-derived-mode mh-letter-mode text-mode "MH-Letter"
  "Mode for composing letters in MH-E.\\<mh-letter-mode-map>

When you have finished composing, type \\[mh-send-letter] to send the message
using the MH mail handling system.

There are two types of tags used by MH-E when composing MIME messages: MML and
MH. The option `mh-compose-insertion' controls what type of tags are inserted
by MH-E commands. These tags can be converted to MIME body parts by running
\\[mh-mh-to-mime] for MH-style directives or \\[mh-mml-to-mime] for MML tags.

Options that control this mode can be changed with \\[customize-group];
specify the \"mh-compose\" group.

When a message is composed, the hooks `text-mode-hook' and
`mh-letter-mode-hook' are run.

\\{mh-letter-mode-map}"
  (mh-find-path)
  (make-local-variable 'mh-send-args)
  (make-local-variable 'mh-annotate-char)
  (make-local-variable 'mh-annotate-field)
  (make-local-variable 'mh-previous-window-config)
  (make-local-variable 'mh-sent-from-folder)
  (make-local-variable 'mh-sent-from-msg)
  (mh-do-in-gnu-emacs
   (unless mh-letter-buttons-init-flag
     (mh-tool-bar-letter-buttons-init)
     (setq mh-letter-buttons-init-flag t)))
  ;; Set the local value of mh-mail-header-separator according to what is
  ;; present in the buffer...
  (set (make-local-variable 'mh-mail-header-separator)
       (save-excursion
         (goto-char (mh-mail-header-end))
         (buffer-substring-no-properties (point) (line-end-position))))
  (make-local-variable 'mail-header-separator)
  (setq mail-header-separator mh-mail-header-separator) ;override sendmail.el
  (make-local-variable 'mh-help-messages)
  (setq mh-help-messages mh-letter-mode-help-messages)
  (setq buffer-invisibility-spec '((vanish . t) t))
  (set (make-local-variable 'line-move-ignore-invisible) t)

  ;; From sendmail.el for proper paragraph fill
  ;; sendmail.el also sets a normal-auto-fill-function (not done here)
  (make-local-variable 'paragraph-separate)
  (make-local-variable 'paragraph-start)
  (make-local-variable 'fill-paragraph-function)
  (setq fill-paragraph-function 'mh-fill-paragraph-function)
  (make-local-variable 'adaptive-fill-regexp)
  (setq adaptive-fill-regexp
        (concat adaptive-fill-regexp
                "\\|[ \t]*[-[:alnum:]]*>+[ \t]*"))
  (make-local-variable 'adaptive-fill-first-line-regexp)
  (setq adaptive-fill-first-line-regexp
        (concat adaptive-fill-first-line-regexp
                "\\|[ \t]*[-[:alnum:]]*>+[ \t]*"))
  ;; `-- ' precedes the signature.  `-----' appears at the start of the
  ;; lines that delimit forwarded messages.
  ;; Lines containing just >= 3 dashes, perhaps after whitespace,
  ;; are also sometimes used and should be separators.
  (setq paragraph-start (concat (regexp-quote mail-header-separator)
                                "\\|\t*\\([-|#;>* ]\\|(?[0-9]+[.)]\\)+$"
                                "\\|[ \t]*[[:alnum:]]*>+[ \t]*$\\|[ \t]*$\\|"
                                "-- $\\|---+$\\|"
                                page-delimiter))
  (setq paragraph-separate paragraph-start)
  ;; --- End of code from sendmail.el ---

  ;; Enable undo since a show-mode buffer might have been reused.
  (buffer-enable-undo)
  (set (make-local-variable 'tool-bar-map) mh-letter-tool-bar-map)
  (mh-funcall-if-exists mh-toolbar-init :letter)
  (make-local-variable 'font-lock-defaults)
  (cond
   ((or (equal mh-highlight-citation-p 'font-lock)
        (equal mh-highlight-citation-p 'gnus))
    ;; Let's use font-lock even if gnus is used in show-mode.  The reason
    ;; is that gnus uses static text properties which are not appropriate
    ;; for a buffer that will be edited.  So the choice here is either fontify
    ;; the citations and header...
    (setq font-lock-defaults '(mh-letter-font-lock-keywords t)))
   (t
    ;; ...or the header only
    (setq font-lock-defaults '(mh-show-font-lock-keywords t))))
  (easy-menu-add mh-letter-menu)
  (setq fill-column mh-letter-fill-column)
  ;; If text-mode-hook turned on auto-fill, tune it for messages
  (when auto-fill-function
    (make-local-variable 'auto-fill-function)
    (setq auto-fill-function 'mh-auto-fill-for-letter)))

(defun mh-font-lock-field-data (limit)
  "Find header field region between point and LIMIT."
  (and (< (point) (mh-letter-header-end))
       (< (point) limit)
       (let ((end (min limit (mh-letter-header-end)))
             (point (point))
             data-end data-begin field)
         (end-of-line)
         (setq data-end (if (re-search-forward "^[^ \t]" end t)
                            (match-beginning 0)
                          end))
         (goto-char (1- data-end))
         (if (not (re-search-backward "\\(^[^ \t][^:]*\\):[ \t]*" nil t))
             (setq data-begin (point-min))
           (setq data-begin (match-end 0))
           (setq field (match-string 1)))
         (setq data-begin (max point data-begin))
         (goto-char (if (equal point data-end) (1+ data-end) data-end))
         (cond ((and field (mh-letter-skipped-header-field-p field))
                (set-match-data nil)
                nil)
               (t (set-match-data
                   (list data-begin data-end data-begin data-end))
                  t)))))

(defun mh-letter-header-end ()
  "Find the end of the message header.
This function is to be used only for font locking. It works by searching for
`mh-mail-header-separator' in the buffer."
  (save-excursion
    (goto-char (point-min))
    (cond ((equal mh-mail-header-separator "") (point-min))
          ((search-forward (format "\n%s\n" mh-mail-header-separator) nil t)
           (line-beginning-position 0))
          (t (point-min)))))

(defun mh-auto-fill-for-letter ()
  "Perform auto-fill for message.
Header is treated specially by inserting a tab before continuation lines."
  (if (mh-in-header-p)
      (let ((fill-prefix "\t"))
        (do-auto-fill))
    (do-auto-fill)))

(defun mh-insert-header-separator ()
  "Insert `mh-mail-header-separator', if absent."
  (save-excursion
    (goto-char (point-min))
    (rfc822-goto-eoh)
    (if (looking-at "$")
        (insert mh-mail-header-separator))))

;;;###mh-autoload
(defun mh-to-field ()
  "Move to specified header field.
The field is indicated by the previous keystroke (the last keystroke
of the command) according to the list in the variable `mh-to-field-choices'.
Create the field if it does not exist.  Set the mark to point before moving."
  (interactive)
  (expand-abbrev)
  (let ((target (cdr (or (assoc (char-to-string (logior last-input-char ?`))
                                mh-to-field-choices)
                         ;; also look for a char for version 4 compat
                         (assoc (logior last-input-char ?`)
                                mh-to-field-choices))))
        (case-fold-search t))
    (push-mark)
    (cond ((mh-position-on-field target)
           (let ((eol (point)))
             (skip-chars-backward " \t")
             (delete-region (point) eol))
           (if (and (not (eq (logior last-input-char ?`) ?s))
                    (save-excursion
                      (backward-char 1)
                      (not (looking-at "[:,]"))))
               (insert ", ")
             (insert " ")))
          (t
           (if (mh-position-on-field "To:")
               (forward-line 1))
           (insert (format "%s \n" target))
           (backward-char 1)))))

;;;###mh-autoload
(defun mh-to-fcc (&optional folder)
  "Move to \"Fcc:\" header field.
This command will prompt you for the FOLDER name in which to file a copy of
the draft."
  (interactive)
  (or folder
      (setq folder (mh-prompt-for-folder
                    "Fcc"
                    (or (and mh-default-folder-for-message-function
                             (save-excursion
                               (goto-char (point-min))
                               (funcall
                                mh-default-folder-for-message-function)))
                        "")
                    t)))
  (let ((last-input-char ?\C-f))
    (expand-abbrev)
    (save-excursion
      (mh-to-field)
      (insert (if (mh-folder-name-p folder)
                  (substring folder 1)
                folder)))))

(defun mh-file-is-vcard-p (file)
  "Return t if FILE is a .vcf vcard."
  (let ((case-fold-search t))
    (and (stringp file)
         (file-exists-p file)
         (or (and (not (mh-have-file-command))
                  (not (null (string-match "\.vcf$" file))))
             (and (mh-have-file-command)
                  (string-equal "text/x-vcard" (mh-file-mime-type file)))))))

;;;###mh-autoload
(defun mh-insert-signature (&optional file)
  "Insert signature in message.
This command inserts your signature at the current cursor location.

By default, the text of your signature is taken from the file
\"~/.signature\". You can read from other sources by changing the option
`mh-signature-file-name' or passing in a signature FILE.

A signature separator (\"-- \") will be added if the signature block does not
contain one and `mh-signature-separator-flag' is on.

The value of `mh-letter-insert-signature-hook' is a list of functions to be
called, with no arguments, after the signature is inserted. These functions
may access the actual name of the file or the function used to insert the
signature with `mh-signature-file-name'.

The signature can also be inserted using Identities (see `mh-identity-list')"
  (interactive)
  (save-excursion
    (insert "\n")
    (let ((mh-signature-file-name (or file mh-signature-file-name))
          (mh-mh-p (mh-mh-directive-present-p))
          (mh-mml-p (mh-mml-tag-present-p)))
      (save-restriction
        (narrow-to-region (point) (point))
        (cond
         ((mh-file-is-vcard-p mh-signature-file-name)
          (if (equal mh-compose-insertion 'mml)
              (insert "<#part type=\"text/x-vcard\" filename=\""
                      mh-signature-file-name
                      "\" disposition=inline description=VCard>\n<#/part>")
            (insert "#text/x-vcard; name=\""
                    (file-name-nondirectory mh-signature-file-name)
                    "\" [VCard] " (expand-file-name mh-signature-file-name))))
         (t
          (cond
           (mh-mh-p
            (insert "#\n" "Content-Description: Signature\n"))
           (mh-mml-p
            (mml-insert-tag 'part 'type "text/plain" 'disposition "inline"
                            'description "Signature")))
          (cond ((null mh-signature-file-name))
                ((and (stringp mh-signature-file-name)
                      (file-readable-p mh-signature-file-name))
                 (insert-file-contents mh-signature-file-name))
                ((functionp mh-signature-file-name)
                 (funcall mh-signature-file-name)))))
        (save-restriction
          (widen)
          (run-hooks 'mh-letter-insert-signature-hook))
        (goto-char (point-min))
        (when (and (not (mh-file-is-vcard-p mh-signature-file-name))
                   mh-signature-separator-flag
                   (> (point-max) (point-min))
                   (not (mh-signature-separator-p)))
          (cond (mh-mh-p
                 (forward-line 2))
                (mh-mml-p
                 (forward-line 1)))
          (insert mh-signature-separator))
        (if (not (> (point-max) (point-min)))
            (message "No signature found")))))
  (force-mode-line-update))

;;;###mh-autoload
(defun mh-check-whom ()
  "Verify recipients, showing expansion of any aliases.
This command expands aliases so you can check the actual address(es) in the
alias. A new buffer named \"*MH-E Recipients*\" is created with the output of
\"whom\"."
  (interactive)
  (let ((file-name buffer-file-name))
    (save-buffer)
    (message "Checking recipients...")
    (mh-in-show-buffer (mh-recipients-buffer)
      (bury-buffer (current-buffer))
      (erase-buffer)
      (mh-exec-cmd-output "whom" t file-name))
    (message "Checking recipients...done")))

(defun mh-tidy-draft-buffer ()
  "Run when a draft buffer is destroyed."
  (let ((buffer (get-buffer mh-recipients-buffer)))
    (if buffer
        (kill-buffer buffer))))

\f

;;; Routines to compose and send a letter.

(defun mh-insert-x-face ()
  "Append X-Face, Face or X-Image-URL field to header.
If the field already exists, this function does nothing."
  (when (and (file-exists-p mh-x-face-file)
             (file-readable-p mh-x-face-file))
    (save-excursion
      (unless (or (mh-position-on-field "X-Face")
                  (mh-position-on-field "Face")
                  (mh-position-on-field "X-Image-URL"))
        (save-excursion
          (goto-char (+ (point) (cadr (insert-file-contents mh-x-face-file))))
          (if (not (looking-at "^"))
              (insert "\n")))
        (unless (looking-at "\\(X-Face\\|Face\\|X-Image-URL\\): ")
          (insert "X-Face: "))))))

(defvar mh-x-mailer-string nil
  "*String containing the contents of the X-Mailer header field.
If nil, this variable is initialized to show the version of MH-E, Emacs, and
MH the first time a message is composed.")

(defun mh-insert-x-mailer ()
  "Append an X-Mailer field to the header.
The versions of MH-E, Emacs, and MH are shown."
  ;; Lazily initialize mh-x-mailer-string.
  (when (and mh-insert-x-mailer-flag (null mh-x-mailer-string))
    (setq mh-x-mailer-string
          (format "MH-E %s; %s; %sEmacs %s"
                  mh-version mh-variant-in-use
                  (if mh-xemacs-flag "X" "GNU ")
                  (cond ((not mh-xemacs-flag) emacs-version)
                        ((string-match "[0-9.]*\\( +\([ a-z]+[0-9]+\)\\)?"
                                       emacs-version)
                         (match-string 0 emacs-version))
                        (t (format "%s.%s" emacs-major-version
                                   emacs-minor-version))))))
  ;; Insert X-Mailer, but only if it doesn't already exist.
  (save-excursion
    (when (and mh-insert-x-mailer-flag
               (null (mh-goto-header-field "X-Mailer")))
      (mh-insert-fields "X-Mailer:" mh-x-mailer-string))))

(defun mh-regexp-in-field-p (regexp &rest fields)
  "Non-nil means REGEXP was found in FIELDS."
  (save-excursion
    (let ((search-result nil)
          (field))
      (while fields
        (setq field (car fields))
        (if (and (mh-goto-header-field field)
                 (re-search-forward
                  regexp (save-excursion (mh-header-field-end)(point)) t))
            (setq fields nil
                  search-result t)
          (setq fields (cdr fields))))
      search-result)))

;;;###mh-autoload
(defun mh-insert-auto-fields (&optional non-interactive)
  "Insert custom fields if recipient is found in `mh-auto-fields-list'.
Sets buffer-local `mh-insert-auto-fields-done-local' when done and inserted
something.  If NON-INTERACTIVE is non-nil, do not be verbose and only
attempt matches if `mh-insert-auto-fields-done-local' is nil.

An `identity' entry is skipped if one was already entered manually.

Return t if fields added; otherwise return nil."
  (interactive)
  (when (or (not non-interactive)
            (not mh-insert-auto-fields-done-local))
    (save-excursion
      (when (and (or (mh-goto-header-field "To:")
                     (mh-goto-header-field "cc:")))
        (let ((list mh-auto-fields-list)
              (fields-inserted nil))
          (while list
            (let ((regexp (nth 0 (car list)))
                  (entries (nth 1 (car list))))
              (when (mh-regexp-in-field-p regexp "To:" "cc:")
                (setq mh-insert-auto-fields-done-local t)
                (setq fields-inserted t)
                (if (not non-interactive)
                    (message "Fields for %s added" regexp))
                (let ((entry-list entries))
                  (while entry-list
                    (let ((field (caar entry-list))
                          (value (cdar entry-list)))
                      (cond
                       ((equal ":identity" field)
                        (when ;;(and (not mh-identity-local)
                            ;; Bug 1204506.  But do we need to be able
                            ;;  to set an identity manually that won't be
                            ;;  overridden by mh-insert-auto-fields?
                                   (assoc value mh-identity-list)
                                   ;;)
                          (mh-insert-identity value)))
                       (t
                        (mh-modify-header-field field value
                                                (equal field "From")))))
                    (setq entry-list (cdr entry-list))))))
            (setq list (cdr list)))
          fields-inserted)))))

(defun mh-modify-header-field (field value &optional overwrite-flag)
  "To header FIELD add VALUE.
If OVERWRITE-FLAG is non-nil then the old value, if present, is discarded."
  (cond ((and overwrite-flag
              (mh-goto-header-field (concat field ":")))
         (insert " " value)
         (delete-region (point) (line-end-position)))
        ((and (not overwrite-flag)
              (mh-regexp-in-field-p (concat "\\b" value "\\b") field))
         ;; Already there, do nothing.
         )
        ((and (not overwrite-flag)
              (mh-goto-header-field (concat field ":")))
         (insert " " value ","))
        (t
         (mh-goto-header-end 0)
         (insert field ": " value "\n"))))

(defun mh-compose-and-send-mail (draft send-args
                                       sent-from-folder sent-from-msg
                                       to subject cc
                                       annotate-char annotate-field
                                       config)
  "Edit and compose a draft message in buffer DRAFT and send or save it.
SEND-ARGS is the argument passed to the send command.
SENT-FROM-FOLDER is buffer containing scan listing of current folder, or
nil if none exists.
SENT-FROM-MSG is the message number or sequence name or nil.
The TO, SUBJECT, and CC fields are passed to the
`mh-compose-letter-function'.
If ANNOTATE-CHAR is non-null, it is used to notate the scan listing of the
message.  In that case, the ANNOTATE-FIELD is used to build a string
for `mh-annotate-msg'.
CONFIG is the window configuration to restore after sending the letter."
  (pop-to-buffer draft)
  (mh-letter-mode)

  ;; Insert identity.
  (if (and (boundp 'mh-identity-default)
           mh-identity-default
           (not mh-identity-local))
      (mh-insert-identity mh-identity-default))
  (mh-identity-make-menu)
  (easy-menu-add mh-identity-menu)

  ;; Insert extra fields.
  (mh-insert-x-mailer)
  (mh-insert-x-face)

  (mh-letter-hide-all-skipped-fields)

  (setq mh-sent-from-folder sent-from-folder)
  (setq mh-sent-from-msg sent-from-msg)
  (setq mh-send-args send-args)
  (setq mh-annotate-char annotate-char)
  (setq mh-annotate-field annotate-field)
  (setq mh-previous-window-config config)
  (setq mode-line-buffer-identification (list "    {%b}"))
  (mh-logo-display)
  (mh-make-local-hook 'kill-buffer-hook)
  (add-hook 'kill-buffer-hook 'mh-tidy-draft-buffer nil t)
  (if (and (boundp 'mh-compose-letter-function)
           mh-compose-letter-function)
      ;; run-hooks will not pass arguments.
      (let ((value mh-compose-letter-function))
        (if (and (listp value) (not (eq (car value) 'lambda)))
            (while value
              (funcall (car value) to subject cc)
              (setq value (cdr value)))
          (funcall mh-compose-letter-function to subject cc)))))

(defun mh-letter-mode-message ()
  "Display a help message for users of `mh-letter-mode'.
This should be the last function called when composing the draft."
  (message "%s" (substitute-command-keys
                 (concat "Type \\[mh-send-letter] to send message, "
                         "\\[mh-help] for help"))))

(defun mh-ascii-buffer-p ()
  "Check if current buffer is entirely composed of ASCII.
The function doesn't work for XEmacs since `find-charset-region' doesn't exist
there."
  (loop for charset in (mh-funcall-if-exists
                        find-charset-region (point-min) (point-max))
        unless (eq charset 'ascii) return nil
        finally return t))

;;;###mh-autoload
(defun mh-send-letter (&optional arg)
  "Save draft and send message.
When you are all through editing a message, you send it with this command. You
can give an argument ARG to monitor the first stage of the delivery\; this
output can be found in a buffer called \"*MH-E Mail Delivery*\".

The value of `mh-before-send-letter-hook' is a list of functions to be called
at the beginning of this command. For example, if you want to check your
spelling in your message before sending, add the `ispell-message' function.

In case the MH \"send\" program is installed under a different name, use
`mh-send-prog' to tell MH-E the name."
  (interactive "P")
  (run-hooks 'mh-before-send-letter-hook)
  (if (and (mh-insert-auto-fields t)
           mh-auto-fields-prompt-flag
           (goto-char (point-min)))
      (if (not (y-or-n-p "Auto fields inserted, send? "))
          (error "Send aborted")))
  (cond ((mh-mh-directive-present-p)
         (mh-mh-to-mime))
        ((or (mh-mml-tag-present-p) (not (mh-ascii-buffer-p)))
         (mh-mml-to-mime)))
  (save-buffer)
  (message "Sending...")
  (let ((draft-buffer (current-buffer))
        (file-name buffer-file-name)
        (config mh-previous-window-config)
        (coding-system-for-write
         (if (and (local-variable-p 'buffer-file-coding-system
                                    (current-buffer)) ;XEmacs needs two args
                  ;; We're not sure why, but buffer-file-coding-system
                  ;; tends to get set to undecided-unix.
                  (not (memq buffer-file-coding-system
                             '(undecided undecided-unix undecided-dos))))
             buffer-file-coding-system
           (or (and (boundp 'sendmail-coding-system) sendmail-coding-system)
               (and (boundp 'default-buffer-file-coding-system )
                    default-buffer-file-coding-system)
               'iso-latin-1))))
    ;; The default BCC encapsulation will make a MIME message unreadable.
    ;; With nmh use the -mime arg to prevent this.
    (if (and (mh-variant-p 'nmh)
             (mh-goto-header-field "Bcc:")
             (mh-goto-header-field "Content-Type:"))
        (setq mh-send-args (format "-mime %s" mh-send-args)))
    (cond (arg
           (pop-to-buffer mh-mail-delivery-buffer)
           (erase-buffer)
           (mh-exec-cmd-output mh-send-prog t "-watch" "-nopush"
                               "-nodraftfolder" mh-send-args file-name)
           (goto-char (point-max))      ; show the interesting part
           (recenter -1)
           (set-buffer draft-buffer))   ; for annotation below
          (t
           (mh-exec-cmd-daemon mh-send-prog nil "-nodraftfolder" "-noverbose"
                               mh-send-args file-name)))
    (if mh-annotate-char
        (mh-annotate-msg mh-sent-from-msg
                         mh-sent-from-folder
                         mh-annotate-char
                         "-component" mh-annotate-field
                         "-text" (format "\"%s %s\""
                                         (mh-get-header-field "To:")
                                         (mh-get-header-field "Cc:"))))

    (cond ((or (not arg)
               (y-or-n-p "Kill draft buffer? "))
           (kill-buffer draft-buffer)
           (if config
               (set-window-configuration config))))
    (if arg
        (message "Sending...done")
      (message "Sending...backgrounded"))))

;;;###mh-autoload
(defun mh-insert-letter (folder message verbatim)
  "Insert a message.
This command prompts you for the FOLDER and MESSAGE number and inserts the
message, indented by `mh-ins-buf-prefix' (\"> \") unless `mh-yank-behavior' is
set to one of the supercite flavors in which case supercite is used to format
the message. Certain undesirable header fields (see
`mh-invisible-header-fields-compiled') are removed before insertion.

If given a prefix argument VERBATIM, the header is left intact, the message is
not indented, and \"> \" is not inserted before each line. This command leaves
the mark before the letter and point after it."
  (interactive
   (list (mh-prompt-for-folder "Message from" mh-sent-from-folder nil)
         (read-string (concat "Message number"
                              (if (numberp mh-sent-from-msg)
                                  (format " (default %d): " mh-sent-from-msg)
                                ": ")))
         current-prefix-arg))
  (save-restriction
    (narrow-to-region (point) (point))
    (let ((start (point-min)))
      (if (and (equal message "") (numberp mh-sent-from-msg))
          (setq message (int-to-string mh-sent-from-msg)))
      (insert-file-contents
       (expand-file-name message (mh-expand-file-name folder)))
      (when (not verbatim)
        (mh-clean-msg-header start mh-invisible-header-fields-compiled nil)
        (goto-char (point-max))         ;Needed for sc-cite-original
        (push-mark)                     ;Needed for sc-cite-original
        (goto-char (point-min))         ;Needed for sc-cite-original
        (mh-insert-prefix-string mh-ins-buf-prefix)))))

(defun mh-extract-from-attribution ()
  "Extract phrase or comment from From header field."
  (save-excursion
    (if (not (mh-goto-header-field "From: "))
        nil
      (skip-chars-forward " ")
      (cond
       ((looking-at "\"\\([^\"\n]+\\)\" \\(<.+>\\)")
        (format "%s %s " (match-string 1)(match-string 2)))
       ((looking-at "\\([^<\n]+<.+>\\)$")
        (format "%s " (match-string 1)))
       ((looking-at "\\([^ ]+@[^ ]+\\) +(\\(.+\\))$")
        (format "%s <%s> " (match-string 2)(match-string 1)))
       ((looking-at " *\\(.+\\)$")
        (format "%s " (match-string 1)))))))

;;;###mh-autoload
(defun mh-yank-cur-msg ()
  "Insert the current message into the draft buffer.

It is often useful to insert a snippet of text from a letter that someone
mailed to provide some context for your reply. This command does this by
adding an attribution, yanking a portion of text from the message to which
you're replying, and inserting `mh-ins-buf-prefix' (`> ') before each line.

The attribution consists of the sender's name and email address
followed by the content of the `mh-extract-from-attribution-verb'
option.

You can also turn on the `mh-delete-yanked-msg-window-flag' option to delete
the window containing the original message after yanking it to make more room
on your screen for your reply.

You can control how the message to which you are replying is yanked
into your reply using `mh-yank-behavior'.

If this isn't enough, you can gain full control over the appearance of the
included text by setting `mail-citation-hook' to a function that modifies it."
  (interactive)
  (if (and mh-sent-from-folder
           (save-excursion (set-buffer mh-sent-from-folder) mh-show-buffer)
           (save-excursion (set-buffer mh-sent-from-folder)
                           (get-buffer mh-show-buffer))
           mh-sent-from-msg)
      (let ((to-point (point))
            (to-buffer (current-buffer)))
        (set-buffer mh-sent-from-folder)
        (if mh-delete-yanked-msg-window-flag
            (delete-windows-on mh-show-buffer))
        (set-buffer mh-show-buffer)     ; Find displayed message
        (let* ((from-attr (mh-extract-from-attribution))
               (yank-region (mh-mark-active-p nil))
               (mh-ins-str
                (cond ((and yank-region
                            (or (eq 'supercite mh-yank-behavior)
                                (eq 'autosupercite mh-yank-behavior)
                                (eq t mh-yank-behavior)))
                       ;; supercite needs the full header
                       (concat
                        (buffer-substring (point-min) (mh-mail-header-end))
                        "\n"
                        (buffer-substring (region-beginning) (region-end))))
                      (yank-region
                       (buffer-substring (region-beginning) (region-end)))
                      ((or (eq 'body mh-yank-behavior)
                           (eq 'attribution mh-yank-behavior)
                           (eq 'autoattrib mh-yank-behavior))
                       (buffer-substring
                        (save-excursion
                          (goto-char (point-min))
                          (mh-goto-header-end 1)
                          (point))
                        (point-max)))
                      ((or (eq 'supercite mh-yank-behavior)
                           (eq 'autosupercite mh-yank-behavior)
                           (eq t mh-yank-behavior))
                       (buffer-substring (point-min) (point-max)))
                      (t
                       (buffer-substring (point) (point-max))))))
          (set-buffer to-buffer)
          (save-restriction
            (narrow-to-region to-point to-point)
            (insert (mh-filter-out-non-text mh-ins-str))
            (goto-char (point-max))     ;Needed for sc-cite-original
            (push-mark)                 ;Needed for sc-cite-original
            (goto-char (point-min))     ;Needed for sc-cite-original
            (mh-insert-prefix-string mh-ins-buf-prefix)
            (when (or (eq 'attribution mh-yank-behavior)
                      (eq 'autoattrib mh-yank-behavior))
              (insert from-attr)
              (mh-identity-insert-attribution-verb nil)
              (insert "\n\n"))
            ;; If the user has selected a region, he has already "edited" the
            ;; text, so leave the cursor at the end of the yanked text. In
            ;; either case, leave a mark at the opposite end of the included
            ;; text to make it easy to jump or delete to the other end of the
            ;; text.
            (push-mark)
            (goto-char (point-max))
            (if (null yank-region)
                (mh-exchange-point-and-mark-preserving-active-mark)))))
    (error "There is no current message")))

(defun mh-filter-out-non-text (string)
  "Return STRING but without adornments such as MIME buttons and smileys."
  (with-temp-buffer
    ;; Insert the string to filter
    (insert string)
    (goto-char (point-min))

    ;; Remove the MIME buttons
    (let ((can-move-forward t)
          (in-button nil))
      (while can-move-forward
        (cond ((and (not (get-text-property (point) 'mh-data))
                    in-button)
               (delete-region (1- (point)) (point))
               (setq in-button nil))
              ((get-text-property (point) 'mh-data)
               (delete-region (point)
                              (save-excursion (forward-line) (point)))
               (setq in-button t))
              (t (setq can-move-forward (= (forward-line) 0))))))

    ;; Return the contents without properties... This gets rid of emphasis
    ;; and smileys
    (buffer-substring-no-properties (point-min) (point-max))))

(defun mh-insert-prefix-string (mh-ins-string)
  "Insert prefix string before each line in buffer.
The inserted letter is cited using `sc-cite-original' if `mh-yank-behavior' is
one of 'supercite or 'autosupercite. Otherwise, simply insert MH-INS-STRING
before each line."
  (goto-char (point-min))
  (cond ((or (eq mh-yank-behavior 'supercite)
             (eq mh-yank-behavior 'autosupercite))
         (sc-cite-original))
        (mail-citation-hook
         (run-hooks 'mail-citation-hook))
        (mh-yank-hooks                  ;old hook name
         (run-hooks 'mh-yank-hooks))
        (t
         (or (bolp) (forward-line 1))
         (while (< (point) (point-max))
           (insert mh-ins-string)
           (forward-line 1))
         (goto-char (point-min)))))     ;leave point like sc-cite-original

;;;###mh-autoload
(defun mh-fully-kill-draft ()
  "Quit editing and delete draft message.
If for some reason you are not happy with the draft, you can use the this
command to kill the draft buffer and delete the draft message. Use the
\\[kill-buffer] command if you don't want to delete the draft message."
  (interactive)
  (if (y-or-n-p "Kill draft message? ")
      (let ((config mh-previous-window-config))
        (if (file-exists-p buffer-file-name)
            (delete-file buffer-file-name))
        (set-buffer-modified-p nil)
        (kill-buffer (buffer-name))
        (message "")
        (if config
            (set-window-configuration config)))
    (error "Message not killed")))

(defun mh-current-fill-prefix ()
  "Return the `fill-prefix' on the current line as a string."
  (save-excursion
    (beginning-of-line)
    ;; This assumes that the major-mode sets up adaptive-fill-regexp
    ;; correctly such as mh-letter-mode or sendmail.el's mail-mode.  But
    ;; perhaps I should use the variable and simply inserts its value here,
    ;; and set it locally in a let scope.  --psg
    (if (re-search-forward adaptive-fill-regexp nil t)
        (match-string 0)
      "")))

;;;###mh-autoload
(defun mh-open-line ()
  "Insert a newline and leave point after it.
This command is similar to the \\[open-line] command in that it inserts a
newline after point. It differs in that it also inserts the right number of
quoting characters and spaces so that the next line begins in the same column
as it was. This is useful when breaking up paragraphs in replies."
  (interactive)
  (let ((column (current-column))
        (prefix (mh-current-fill-prefix)))
    (if (> (length prefix) column)
        (message "Sorry, point seems to be within the line prefix")
      (newline 2)
      (insert prefix)
      (while (> column (current-column))
        (insert " "))
      (forward-line -1))))

(mh-do-in-xemacs (defvar mail-abbrevs))

(defmacro mh-display-completion-list-compat (word choices)
  "Completes WORD from CHOICES using `display-completion-list'.
Calls `display-completion-list' correctly in older environments.
Versions of Emacs prior to version 22 lacked a COMMON-SUBSTRING argument
which is used to highlight the next possible character you can enter
in the current list of completions."
  (if (>= emacs-major-version 22)
      `(display-completion-list (all-completions ,word ,choices) ,word)
    `(display-completion-list (all-completions ,word ,choices))))

;;;###mh-autoload
(defun mh-complete-word (word choices begin end)
  "Complete WORD at from CHOICES.
Any match found replaces the text from BEGIN to END."
  (let ((completion (try-completion word choices))
        (completions-buffer "*Completions*"))
    (cond ((eq completion t)
           (ignore-errors
             (kill-buffer completions-buffer))
           (message "Completed: %s" word))
          ((null completion)
           (ignore-errors
             (kill-buffer completions-buffer))
           (message "No completion for `%s'" word))
          ((stringp completion)
           (if (equal word completion)
               (with-output-to-temp-buffer completions-buffer
                 (mh-display-completion-list-compat word choices))
             (ignore-errors
               (kill-buffer completions-buffer))
             (delete-region begin end)
             (insert completion))))))

;;;###mh-autoload
(defun mh-beginning-of-word (&optional n)
  "Return position of the N th word backwards."
  (unless n (setq n 1))
  (let ((syntax-table (syntax-table)))
    (unwind-protect
        (save-excursion
          (mh-mail-abbrev-make-syntax-table)
          (set-syntax-table mail-abbrev-syntax-table)
          (backward-word n)
          (point))
      (set-syntax-table syntax-table))))

(defun mh-folder-expand-at-point ()
  "Do folder name completion in Fcc header field."
  (let* ((end (point))
         (beg (mh-beginning-of-word))
         (folder (buffer-substring beg end))
         (leading-plus (and (> (length folder) 0) (equal (aref folder 0) ?+)))
         (last-slash (mh-search-from-end ?/ folder))
         (prefix (and last-slash (substring folder 0 last-slash)))
         (choices (mapcar #'(lambda (x)
                              (list (cond (prefix (format "%s/%s" prefix x))
                                          (leading-plus (format "+%s" x))
                                          (t x))))
                          (mh-folder-completion-function folder nil t))))
    (mh-complete-word folder choices beg end)))

(defvar mh-letter-complete-function-alist
  '((cc . mh-alias-letter-expand-alias)
    (bcc . mh-alias-letter-expand-alias)
    (dcc . mh-alias-letter-expand-alias)
    (fcc . mh-folder-expand-at-point)
    (from . mh-alias-letter-expand-alias)
    (mail-followup-to . mh-alias-letter-expand-alias)
    (reply-to . mh-alias-letter-expand-alias)
    (to . mh-alias-letter-expand-alias))
  "Alist of header fields and completion functions to use.")

(defun mh-letter-complete (arg)
  "Perform completion on header field or word preceding point.
If the field contains addresses (for example, \"To:\" or \"Cc:\") or folders
\(for example, \"Fcc:\") then this command will provide alias completion. In
the body of the message, this command runs `mh-letter-complete-function'
instead, which is set to \"'ispell-complete-word\" by default. This command
takes a prefix argument ARG that is passed to the
`mh-letter-complete-function'."
  (interactive "P")
  (let ((func nil))
    (cond ((not (mh-in-header-p))
           (funcall mh-letter-complete-function arg))
          ((setq func (cdr (assoc (mh-letter-header-field-at-point)
                                  mh-letter-complete-function-alist)))
           (funcall func))
          (t (funcall mh-letter-complete-function arg)))))

(defun mh-letter-complete-or-space (arg)
  "Perform completion or insert space.
Turn on the `mh-compose-space-does-completion-flag' option to use this command
to perform completion in the header. Otherwise, a space is inserted.

ARG is the number of spaces inserted."
  (interactive "p")
  (let ((func nil)
        (end-of-prev (save-excursion
                       (goto-char (mh-beginning-of-word))
                       (mh-beginning-of-word -1))))
    (cond ((not mh-compose-space-does-completion-flag)
           (self-insert-command arg))
          ((not (mh-in-header-p)) (self-insert-command arg))
          ((> (point) end-of-prev) (self-insert-command arg))
          ((setq func (cdr (assoc (mh-letter-header-field-at-point)
                                  mh-letter-complete-function-alist)))
           (funcall func))
          (t (self-insert-command arg)))))

(defun mh-letter-confirm-address ()
  "Flash alias expansion.
Addresses are separated by a comma\; and when you press the comma, this
command flashes the alias expansion in the minibuffer if
`mh-alias-flash-on-comma' is turned on."
  (interactive)
  (cond ((not (mh-in-header-p)) (self-insert-command 1))
        ((eq (cdr (assoc (mh-letter-header-field-at-point)
                         mh-letter-complete-function-alist))
             'mh-alias-letter-expand-alias)
         (mh-alias-reload-maybe)
         (mh-alias-minibuffer-confirm-address))
        (t (self-insert-command 1))))

(defvar mh-letter-header-field-regexp "^\\([A-Za-z][A-Za-z0-9-]*\\):")

(defun mh-letter-header-field-at-point ()
  "Return the header field name at point.
A symbol is returned whose name is the string obtained by downcasing the field
name."
  (save-excursion
    (end-of-line)
    (and (re-search-backward mh-letter-header-field-regexp nil t)
         (intern (downcase (match-string 1))))))

;;;###mh-autoload
(defun mh-letter-next-header-field-or-indent (arg)
  "Move to next field or indent depending on point.
Within the header of the message, this command moves between fields, but skips
those fields listed in `mh-compose-skipped-header-fields'. After the last
field, this command then moves point to the message body before cycling back
to the first field. If point is already past the first line of the message
body, then this command indents by calling `indent-relative' with the given
prefix argument ARG."
  (interactive "P")
  (let ((header-end (save-excursion
                      (goto-char (mh-mail-header-end))
                      (forward-line)
                      (point))))
    (if (> (point) header-end)
        (indent-relative arg)
      (mh-letter-next-header-field))))

(defun mh-letter-next-header-field ()
  "Cycle to the next header field.
If we are at the last header field go to the start of the message body."
  (let ((header-end (mh-mail-header-end)))
    (cond ((>= (point) header-end) (goto-char (point-min)))
          ((< (point) (progn
                        (beginning-of-line)
                        (re-search-forward mh-letter-header-field-regexp
                                           (line-end-position) t)
                        (point)))
           (beginning-of-line))
          (t (end-of-line)))
    (cond ((re-search-forward mh-letter-header-field-regexp header-end t)
           (if (mh-letter-skipped-header-field-p (match-string 1))
               (mh-letter-next-header-field)
             (mh-letter-skip-leading-whitespace-in-header-field)))
          (t (goto-char header-end)
             (forward-line)))))

;;;###mh-autoload
(defun mh-letter-previous-header-field ()
  "Cycle to the previous header field.
This command moves backwards between the fields and cycles to the body of the
message after the first field. Unlike the
\\[mh-letter-next-header-field-or-indent] command, it will always take point
to the last field from anywhere in the body."
  (interactive)
  (let ((header-end (mh-mail-header-end)))
    (if (>= (point) header-end)
        (goto-char header-end)
      (mh-header-field-beginning))
    (cond ((re-search-backward mh-letter-header-field-regexp nil t)
           (if (mh-letter-skipped-header-field-p (match-string 1))
               (mh-letter-previous-header-field)
           (goto-char (match-end 0))
           (mh-letter-skip-leading-whitespace-in-header-field)))
          (t (goto-char header-end)
             (forward-line)))))

(defun mh-letter-skipped-header-field-p (field)
  "Check if FIELD is to be skipped."
  (let ((field (downcase field)))
    (loop for x in mh-compose-skipped-header-fields
          when (equal (downcase x) field) return t
          finally return nil)))

(defun mh-letter-skip-leading-whitespace-in-header-field ()
  "Skip leading whitespace in a header field.
If the header field doesn't have at least one space after the colon then a
space character is added."
  (let ((need-space t))
    (while (memq (char-after) '(?\t ?\ ))
      (forward-char)
      (setq need-space nil))
    (when need-space (insert " "))))

(defvar mh-hidden-header-keymap
  (let ((map (make-sparse-keymap)))
    (mh-do-in-gnu-emacs
      (define-key map [mouse-2] 'mh-letter-toggle-header-field-display-button))
    (mh-do-in-xemacs
      (define-key map '(button2)
        'mh-letter-toggle-header-field-display-button))
    map))

(defun mh-letter-toggle-header-field-display-button (event)
  "Toggle header field display at location of EVENT.
This function does the same thing as `mh-letter-toggle-header-field-display'
except that it is callable from a mouse button."
  (interactive "e")
  (mh-do-at-event-location event
    (mh-letter-toggle-header-field-display nil)))

(defun mh-letter-toggle-header-field-display (arg)
  "Toggle display of header field at point.

Use this command to display ellipsed header fields. This command is a toggle
so entering it again will hide the field. This command takes a prefix argument
ARG: if negative then the field is hidden, if positive then the field is
displayed."
  (interactive (list nil))
  (when (and (mh-in-header-p)
             (progn
               (end-of-line)
               (re-search-backward mh-letter-header-field-regexp nil t)))
    (let ((buffer-read-only nil)
          (modified-flag (buffer-modified-p))
          (begin (point))
          end)
      (end-of-line)
      (setq end (1- (if (re-search-forward "^[^ \t]" nil t)
                        (match-beginning 0)
                      (point-max))))
      (goto-char begin)
      ;; Make it clickable...
      (add-text-properties begin end `(keymap ,mh-hidden-header-keymap
                                       mouse-face highlight))
      (unwind-protect
          (cond ((or (and (not arg)
                          (text-property-any begin end 'invisible 'vanish))
                     (and (numberp arg) (>= arg 0))
                     (and (eq arg 'long) (> (line-beginning-position 5) end)))
                 (remove-text-properties begin end '(invisible nil))
                 (search-forward ":" (line-end-position) t)
                 (mh-letter-skip-leading-whitespace-in-header-field))
                ;; XXX Redesign to make usable by user. Perhaps use a positive
                ;; numeric prefix to make that many lines visible.
                ((eq arg 'long)
                 (end-of-line 4)
                 (mh-letter-truncate-header-field end)
                 (beginning-of-line))
                (t (end-of-line)
                   (mh-letter-truncate-header-field end)
                   (beginning-of-line)))
        (set-buffer-modified-p modified-flag)))))

(defun mh-letter-truncate-header-field (end)
  "Replace text from current line till END with an ellipsis.
If the current line is too long truncate a part of it as well."
  (let ((max-len (min (window-width) 62)))
    (when (> (+ (current-column) 4) max-len)
      (backward-char (- (+ (current-column) 5) max-len)))
    (when (> end (point))
      (add-text-properties (point) end '(invisible vanish)))))

(defun mh-letter-hide-all-skipped-fields ()
  "Hide all skipped fields."
  (save-excursion
    (goto-char (point-min))
    (save-restriction
      (narrow-to-region (point) (mh-mail-header-end))
      (while (re-search-forward mh-letter-header-field-regexp nil t)
        (if (mh-letter-skipped-header-field-p (match-string 1))
            (mh-letter-toggle-header-field-display -1)
          (mh-letter-toggle-header-field-display 'long))
        (beginning-of-line 2)))))

(defun mh-interactive-read-address (prompt)
  "Read an address.
If `mh-compose-prompt-flag' is non-nil, then read an address with PROMPT.
Otherwise return the empty string."
  (if mh-compose-prompt-flag (mh-read-address prompt) ""))

(defun mh-interactive-read-string (prompt)
  "Read a string.
If `mh-compose-prompt-flag' is non-nil, then read a string with PROMPT.
Otherwise return the empty string."
  (if mh-compose-prompt-flag (read-string prompt) ""))

(defun mh-letter-adjust-point ()
  "Move cursor to first header field if are using the no prompt mode."
  (unless mh-compose-prompt-flag
    (goto-char (point-max))
    (mh-letter-next-header-field)))

;;; Build the letter-mode keymap:
;;; If this changes, modify mh-letter-mode-help-messages accordingly, above.
(gnus-define-keys  mh-letter-mode-map
  " "                   mh-letter-complete-or-space
  ","                   mh-letter-confirm-address
  "\C-c?"               mh-help
  "\C-c\C-\\"           mh-fully-kill-draft ;if no C-q
  "\C-c\C-^"            mh-insert-signature ;if no C-s
  "\C-c\C-c"            mh-send-letter
  "\C-c\C-d"            mh-insert-identity
  "\C-c\C-e"            mh-mh-to-mime
  "\C-c\C-f\C-b"        mh-to-field
  "\C-c\C-f\C-c"        mh-to-field
  "\C-c\C-f\C-d"        mh-to-field
  "\C-c\C-f\C-f"        mh-to-fcc
  "\C-c\C-f\C-r"        mh-to-field
  "\C-c\C-f\C-s"        mh-to-field
  "\C-c\C-f\C-t"        mh-to-field
  "\C-c\C-fb"           mh-to-field
  "\C-c\C-fc"           mh-to-field
  "\C-c\C-fd"           mh-to-field
  "\C-c\C-ff"           mh-to-fcc
  "\C-c\C-fr"           mh-to-field
  "\C-c\C-fs"           mh-to-field
  "\C-c\C-ft"           mh-to-field
  "\C-c\C-i"            mh-insert-letter
  "\C-c\C-m\C-e"        mh-mml-secure-message-encrypt
  "\C-c\C-m\C-f"        mh-compose-forward
  "\C-c\C-m\C-g"        mh-mh-compose-anon-ftp
  "\C-c\C-m\C-i"        mh-compose-insertion
  "\C-c\C-m\C-m"        mh-mml-to-mime
  "\C-c\C-m\C-n"        mh-mml-unsecure-message
  "\C-c\C-m\C-s"        mh-mml-secure-message-sign
  "\C-c\C-m\C-t"        mh-mh-compose-external-compressed-tar
  "\C-c\C-m\C-u"        mh-mh-to-mime-undo
  "\C-c\C-m\C-x"        mh-mh-compose-external-type
  "\C-c\C-mee"          mh-mml-secure-message-encrypt
  "\C-c\C-mes"          mh-mml-secure-message-signencrypt
  "\C-c\C-mf"           mh-compose-forward
  "\C-c\C-mg"           mh-mh-compose-anon-ftp
  "\C-c\C-mi"           mh-compose-insertion
  "\C-c\C-mm"           mh-mml-to-mime
  "\C-c\C-mn"           mh-mml-unsecure-message
  "\C-c\C-mse"          mh-mml-secure-message-signencrypt
  "\C-c\C-mss"          mh-mml-secure-message-sign
  "\C-c\C-mt"           mh-mh-compose-external-compressed-tar
  "\C-c\C-mu"           mh-mh-to-mime-undo
  "\C-c\C-mx"           mh-mh-compose-external-type
  "\C-c\C-o"            mh-open-line
  "\C-c\C-q"            mh-fully-kill-draft
  "\C-c\C-s"            mh-insert-signature
  "\C-c\C-t"            mh-letter-toggle-header-field-display
  "\C-c\C-w"            mh-check-whom
  "\C-c\C-y"            mh-yank-cur-msg
  "\C-c\M-d"            mh-insert-auto-fields
  "\M-\t"               mh-letter-complete
  "\t"                  mh-letter-next-header-field-or-indent
  [backtab]             mh-letter-previous-header-field)

;; "C-c /" prefix is used in mh-letter-mode by pgp.el and mailcrypt.el.

(provide 'mh-comp)

;;; Local Variables:
;;; indent-tabs-mode: nil
;;; sentence-end-double-space: nil
;;; End:

;;; arch-tag: 62865511-e610-4923-b0b5-f45a8ab70a34
;;; mh-comp.el ends here