;;; gnus-msg.el --- mail and post interface for Gnus  -*- lexical-binding: t; -*-

;; Copyright (C) 1995-2021 Free Software Foundation, Inc.

;; Author: Masanobu UMEDA <umerin@flab.flab.fujitsu.junet>
;;	Lars Magne Ingebrigtsen <larsi@gnus.org>
;; Keywords: 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 3 of the License, 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.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

(eval-when-compile (require 'cl-lib))

(require 'gnus)
(require 'message)
(require 'gnus-art)
(require 'gnus-util)

(defcustom gnus-post-method 'current
  "Preferred method for posting USENET news.

If this variable is `current' (which is the default), Gnus will use
the \"current\" select method when posting.  If it is `native', Gnus
will use the native select method when posting.

This method will not be used in mail groups and the like, only in
\"real\" newsgroups.

If not `native' nor `current', the value must be a valid method as discussed
in the documentation of `gnus-select-method'.  It can also be a list of
methods.  If that is the case, the user will be queried for what select
method to use when posting."
  :group 'gnus-group-foreign
  :link '(custom-manual "(gnus)Posting Server")
  :type `(choice (const native)
		 (const current)
		 (sexp :tag "Methods" ,gnus-select-method)))

(defcustom gnus-outgoing-message-group nil
  "All outgoing messages will be put in this group.
If you want to store all your outgoing mail and articles in the group
\"nnml:archive\", you set this variable to that value.  This variable
can also be a list of group names.

If you want to have greater control over what group to put each
message in, you can set this variable to a function that checks the
current newsgroup name and then returns a suitable group name (or list
of names)."
  :group 'gnus-message
  :type '(choice (const nil)
		 (function)
		 (string :tag "Group")
		 (repeat :tag "List of groups" (string :tag "Group"))))

(make-obsolete-variable 'gnus-outgoing-message-group 'gnus-message-archive-group "24.1")

(defcustom gnus-mailing-list-groups nil
  "If non-nil a regexp matching groups that are really mailing lists.
This is useful when you're reading a mailing list that has been
gatewayed to a newsgroup, and you want to followup to an article in
the group."
  :group 'gnus-message
  :type '(choice (regexp)
		 (const nil)))

(defcustom gnus-add-to-list nil
  "If non-nil, add a `to-list' parameter automatically."
  :group 'gnus-message
  :type 'boolean)

(defcustom gnus-crosspost-complaint
  "Hi,

You posted the article below with the following Newsgroups header:

Newsgroups: %s

The %s group, at least, was an inappropriate recipient
of this message.  Please trim your Newsgroups header to exclude this
group before posting in the future.

Thank you.

"
  "Format string to be inserted when complaining about crossposts.
The first %s will be replaced by the Newsgroups header;
the second with the current group name."
  :group 'gnus-message
  :type 'string)

(defcustom gnus-message-setup-hook nil
  "Hook run after setting up a message buffer."
  :group 'gnus-message
  :options '(message-remove-blank-cited-lines)
  :type 'hook)

(defcustom gnus-posting-styles nil
  "Alist of styles to use when posting.
See Info node `(gnus)Posting Styles'."
  :group 'gnus-message
  :link '(custom-manual "(gnus)Posting Styles")
  :type '(repeat (cons (choice (regexp)
			       (variable)
			       (list (const header)
				     (string :tag "Header")
				     (regexp :tag "Regexp"))
			       (function)
			       (sexp))
		       (repeat (list
				(choice (const signature)
					(const signature-file)
					(const organization)
					(const address)
					(const x-face-file)
					(const name)
					(const body)
					(symbol)
					(string :tag "Header"))
				(choice (string)
					(function)
					(variable)
					(sexp)))))))

(defcustom gnus-gcc-mark-as-read nil
  "If non-nil, automatically mark Gcc articles as read."
  :version "22.1"
  :group 'gnus-message
  :type 'boolean)

(defcustom gnus-gcc-externalize-attachments nil
  "Should local-file attachments be included as external parts in Gcc copies?
If it is `all', attach files as external parts;
if a regexp and matches the Gcc group name, attach files as external parts;
if nil, attach files as normal parts."
  :version "22.1"
  :group 'gnus-message
  :type '(choice (const :tag "None" nil)
                 (const :tag "Any"  all)
                 regexp))

(defcustom gnus-gcc-self-resent-messages 'no-gcc-self
  "Like `gcc-self' group parameter, only for unmodified resent messages.
Applied to messages sent by `gnus-summary-resend-message'.  Non-nil
value of this variable takes precedence over any existing Gcc header.

If this is `none', no Gcc copy will be made.  If this is t, messages
resent will be Gcc'd to the current group.  If this is a string, it
specifies a group to which resent messages will be Gcc'd.  If this is
nil, Gcc will be done according to existing Gcc header(s), if any.
If this is `no-gcc-self', resent messages will be Gcc'd to groups that
existing Gcc header specifies, except for the current group."
  :version "24.3"
  :group 'gnus-message
  :type '(choice (const none) (const t) string (const nil)
		 (const no-gcc-self)))

(gnus-define-group-parameter
 posting-charset-alist
 :type list
 :function-document
 "Return the permitted unencoded charsets for posting of GROUP."
 :variable gnus-group-posting-charset-alist
 :variable-default
  '(("^\\(no\\|fr\\)\\.[^,]*\\(,[ \t\n]*\\(no\\|fr\\)\\.[^,]*\\)*$" iso-8859-1 (iso-8859-1))
    ("^\\(fido7\\|relcom\\)\\.[^,]*\\(,[ \t\n]*\\(fido7\\|relcom\\)\\.[^,]*\\)*$" koi8-r (koi8-r))
    (message-this-is-mail nil nil)
    (message-this-is-news nil t))
 :variable-document
  "Alist of regexps and permitted unencoded charsets for posting.
Each element of the alist has the form (TEST HEADER BODY-LIST), where
TEST is either a regular expression matching the newsgroup header or a
variable to query,
HEADER is the charset which may be left unencoded in the header (nil
means encode all charsets),
BODY-LIST is a list of charsets which may be encoded using 8bit
content-transfer encoding in the body, or one of the special values
nil (always encode using quoted-printable) or t (always use 8bit).

Note that any value other than nil for HEADER infringes some RFCs, so
use this option with care."
 :variable-group gnus-charset
 :variable-type
 '(repeat (list :tag "Permitted unencoded charsets"
		(choice :tag "Where"
			(regexp :tag "Group")
			(const :tag "Mail message" :value message-this-is-mail)
			(const :tag "News article" :value message-this-is-news))
		(choice :tag "Header"
			(const :tag "None" nil)
			(symbol :tag "Charset"))
		(choice :tag "Body"
			(const :tag "Any" :value t)
			(const :tag "None" :value nil)
			(repeat :tag "Charsets"
				(symbol :tag "Charset")))))
 :parameter-type '(choice :tag "Permitted unencoded charsets"
			  :value nil
			  (repeat (symbol)))
 :parameter-document       "\
List of charsets that are permitted to be unencoded.")

(defcustom gnus-debug-files
  '("gnus.el" "gnus-sum.el" "gnus-group.el"
    "gnus-art.el" "gnus-start.el" "gnus-async.el"
    "gnus-msg.el" "gnus-score.el" "gnus-win.el" "gnus-topic.el"
    "gnus-agent.el" "gnus-cache.el" "gnus-srvr.el"
    "mm-util.el" "mm-decode.el" "nnmail.el" "message.el")
  "Files whose variables will be reported in `gnus-bug'."
  :version "22.1"
  :group 'gnus-message
  :type '(repeat file))

(make-obsolete-variable 'gnus-debug-files "it is no longer used." "24.1")

(defcustom gnus-debug-exclude-variables
  '(mm-mime-mule-charset-alist
    nnmail-split-fancy message-minibuffer-local-map)
  "Variables that should not be reported in `gnus-bug'."
  :version "22.1"
  :group 'gnus-message
  :type '(repeat variable))

(make-obsolete-variable
 'gnus-debug-exclude-variables "it is no longer used." "24.1")

(defcustom gnus-discouraged-post-methods
  '(nndraft nnml nnimap nnmaildir nnmh nnfolder nndir)
  "A list of back ends that are not used in \"real\" newsgroups.
This variable is used only when `gnus-post-method' is `current'."
  :version "22.1"
  :group 'gnus-group-foreign
  :type '(repeat (symbol :tag "Back end")))

(defcustom gnus-message-replysign
  nil
  "Automatically sign replies to signed messages.
See also the `mml-default-sign-method' variable."
  :group 'gnus-message
  :type 'boolean)

(defcustom gnus-message-replyencrypt t
  "Automatically encrypt replies to encrypted messages.
See also the `mml-default-encrypt-method' variable."
  :version "24.1"
  :group 'gnus-message
  :type 'boolean)

(defcustom gnus-message-replysignencrypted
  t
  "Setting this causes automatically encrypted messages to also be signed."
  :group 'gnus-message
  :type 'boolean)

(defcustom gnus-confirm-mail-reply-to-news (and gnus-novice-user
						(not gnus-expert-user))
  "If non-nil, Gnus requests confirmation when replying to news.
This is done because new users often reply by mistake when reading
news.
This can also be a function receiving the group name as the only
parameter, which should return non-nil if a confirmation is needed; or
a regexp, in which case a confirmation is asked for if the group name
matches the regexp."
  :version "23.1" ;; No Gnus (default changed)
  :group 'gnus-message
  :type '(choice (const :tag "No" nil)
		 (const :tag "Yes" t)
		 (regexp :tag "If group matches regexp")
		 (function :tag "If function evaluates to non-nil")))

(defcustom gnus-confirm-treat-mail-like-news
  nil
  "If non-nil, Gnus will treat mail like news with regard to confirmation
when replying by mail.  See the `gnus-confirm-mail-reply-to-news' variable
for fine-tuning this.
If nil, Gnus will never ask for confirmation if replying to mail."
  :version "22.1"
  :group 'gnus-message
  :type 'boolean)

(defcustom gnus-summary-resend-default-address t
  "If non-nil, Gnus tries to suggest a default address to resend to.
If nil, the address field will always be empty after invoking
`gnus-summary-resend-message'."
  :version "22.1"
  :group 'gnus-message
  :type 'boolean)

(defcustom gnus-message-highlight-citation
  t ;; gnus-treat-highlight-citation ;; gnus-cite dependency
  "Enable highlighting of different citation levels in message-mode."
  :version "23.1" ;; No Gnus
  :group 'gnus-cite
  :group 'gnus-message
  :type 'boolean)

(defcustom gnus-gcc-pre-body-encode-hook nil
  "A hook called before encoding the body of the Gcc copy of a message.
The current buffer (when the hook is run) contains the message
including the message header.  Changes made to the message will
only affect the Gcc copy, but not the original message."
  :group 'gnus-message
  :version "24.3"
  :type 'hook)

(defcustom gnus-gcc-post-body-encode-hook nil
    "A hook called after encoding the body of the Gcc copy of a message.
The current buffer (when the hook is run) contains the message
including the message header.  Changes made to the message will
only affect the Gcc copy, but not the original message."
  :group 'gnus-message
  :version "24.3"
  :type 'hook)

(autoload 'gnus-message-citation-mode "gnus-cite" nil t)

;;; Internal variables.

(defvar gnus-inhibit-posting-styles nil
  "Inhibit the use of posting styles.")

(defvar gnus-article-yanked-articles nil)
(defvar gnus-message-buffer "*Mail Gnus*")
(defvar gnus-article-copy nil)
(defvar gnus-last-posting-server nil)
(defvar gnus-message-group-art nil)

(defvar gnus-msg-force-broken-reply-to nil)

(autoload 'gnus-uu-post-news "gnus-uu" nil t)

\f
;;;
;;; Gnus Posting Functions
;;;

(gnus-define-keys (gnus-summary-send-map "S" gnus-summary-mode-map)
  "p" gnus-summary-post-news
  "i" gnus-summary-news-other-window
  "f" gnus-summary-followup
  "F" gnus-summary-followup-with-original
  "c" gnus-summary-cancel-article
  "s" gnus-summary-supersede-article
  "r" gnus-summary-reply
  "y" gnus-summary-yank-message
  "R" gnus-summary-reply-with-original
  "L" gnus-summary-reply-to-list-with-original
  "w" gnus-summary-wide-reply
  "W" gnus-summary-wide-reply-with-original
  "v" gnus-summary-very-wide-reply
  "V" gnus-summary-very-wide-reply-with-original
  "n" gnus-summary-followup-to-mail
  "N" gnus-summary-followup-to-mail-with-original
  "m" gnus-summary-mail-other-window
  "u" gnus-uu-post-news
  "A" gnus-summary-attach-article
  "\M-c" gnus-summary-mail-crosspost-complaint
  "Br" gnus-summary-reply-broken-reply-to
  "BR" gnus-summary-reply-broken-reply-to-with-original
  "om" gnus-summary-mail-forward
  "op" gnus-summary-post-forward
  "Om" gnus-uu-digest-mail-forward
  "Op" gnus-uu-digest-post-forward)

(gnus-define-keys (gnus-send-bounce-map "D" gnus-summary-send-map)
  "b" gnus-summary-resend-bounced-mail
  ;; "c" gnus-summary-send-draft
  "r" gnus-summary-resend-message
  "e" gnus-summary-resend-message-edit)

;;; Internal functions.

(defun gnus-inews-make-draft (articles)
  (let ((gn gnus-newsgroup-name))
    (lambda ()
      (gnus-inews-make-draft-meta-information
       gn articles))))

(autoload 'nnselect-article-number "nnselect" nil nil 'macro)
(autoload 'nnselect-article-group "nnselect" nil nil 'macro)
(autoload 'gnus-nnselect-group-p "nnselect")

(defvar gnus-article-reply nil)
(defmacro gnus-setup-message (config &rest forms)
  (declare (indent 1) (debug t))
  (let ((winconf (make-symbol "gnus-setup-message-winconf"))
	(winconf-name (make-symbol "gnus-setup-message-winconf-name"))
	(buffer (make-symbol "gnus-setup-message-buffer"))
	(article (make-symbol "gnus-setup-message-article"))
	(oarticle (make-symbol "gnus-setup-message-oarticle"))
	(yanked (make-symbol "gnus-setup-yanked-articles"))
	(group (make-symbol "gnus-setup-message-group")))
    `(let ((,winconf (current-window-configuration))
	   (,winconf-name gnus-current-window-configuration)
	   (,buffer (buffer-name (current-buffer)))
	   (,article   (when gnus-article-reply
			 (or (nnselect-article-number
			      (or (car-safe gnus-article-reply)
				  gnus-article-reply))
			     gnus-article-reply)))
	   (,oarticle gnus-article-reply)
	   (,yanked gnus-article-yanked-articles)
           (,group (if gnus-article-reply
		       (or (nnselect-article-group
			    (or (car-safe gnus-article-reply)
			        gnus-article-reply))
                           gnus-newsgroup-name)
                     gnus-newsgroup-name))
	   (message-header-setup-hook
	    (copy-sequence message-header-setup-hook))
	   (mbl mml-buffer-list)
	   (message-mode-hook (copy-sequence message-mode-hook)))
       (setq mml-buffer-list nil)
       (add-hook 'message-header-setup-hook (lambda ()
					      (gnus-inews-insert-gcc ,group)))
       ;; message-newsreader and message-mailer were formerly set in
       ;; gnus-inews-add-send-actions, but this is too late when
       ;; message-generate-headers-first is used. --ansel
       (add-hook 'message-mode-hook
		 (lambda nil
		   (setq message-newsreader
			 (setq message-mailer (gnus-extended-version)))))
       ;; #### FIXME: for a reason that I did not manage to identify yet,
       ;; the variable `gnus-newsgroup-name' does not honor a dynamically
       ;; scoped or setq'ed value from a caller like `C-u gnus-summary-mail'.
       ;; After evaluation of @forms below, it gets the value we actually want
       ;; to override, and the posting styles are used. For that reason, I've
       ;; added an optional argument to `gnus-configure-posting-styles' to
       ;; make sure that the correct value for the group name is used. -- drv
       (add-hook 'message-mode-hook
		 (if (memq ,config '(reply-yank reply))
		     (lambda ()
		       (gnus-configure-posting-styles ,group))
		   (lambda ()
		     ;; There may be an old " *gnus article copy*" buffer.
		     (let (gnus-article-copy)
		       (gnus-configure-posting-styles ,group)))))
       (gnus-alist-pull ',(intern gnus-draft-meta-information-header)
		  message-required-headers)
       (when (and ,group
		  (not (string= ,group "")))
	 (push (cons
		(intern gnus-draft-meta-information-header)
		(gnus-inews-make-draft (or ,yanked ,article)))
	       message-required-headers))
       (unwind-protect
	   (progn
	     ,@forms)
	 (gnus-inews-add-send-actions ,winconf ,buffer ,oarticle ,config
				      ,yanked ,winconf-name)
	 (setq gnus-message-buffer (current-buffer))
         (setq-local gnus-message-group-art (cons ,group ,article))
         ;; Enable highlighting of different citation levels
         (when gnus-message-highlight-citation
           (gnus-message-citation-mode 1))
         (gnus-run-hooks 'gnus-message-setup-hook)
         (if (eq major-mode 'message-mode)
             (let ((mbl1 mml-buffer-list))
               (setq mml-buffer-list mbl)  ;; Global value
               (setq-local mml-buffer-list mbl1) ;; Local value
               (add-hook 'change-major-mode-hook #'mml-destroy-buffers nil t)
               (add-hook 'kill-buffer-hook #'mml-destroy-buffers t t))
           (mml-destroy-buffers)
           (setq mml-buffer-list mbl)))
       (message-hide-headers)
       (gnus-add-buffer)
       (gnus-configure-windows ,config t)
       (run-hooks 'post-command-hook)
       (set-buffer-modified-p nil))))

(defun gnus-inews-make-draft-meta-information (group articles)
  (when (numberp articles)
    (setq articles (list articles)))
  (concat "(\"" group "\""
	  (if articles
	      (concat " "
		      (mapconcat
		       (lambda (elem)
			 (number-to-string
			  (if (consp elem)
			      (car elem)
			    elem)))
		       articles " "))
	    "")
	  ")"))

;;;###autoload
(defun gnus-msg-mail (&optional to subject other-headers continue
				switch-action yank-action send-actions
				return-action)
  "Start editing a mail message to be sent.
Like `message-mail', but with Gnus paraphernalia, particularly the
Gcc: header for archiving purposes.
If Gnus isn't running, a plain `message-mail' setup is used
instead."
  (interactive)
  (if (not (gnus-alive-p))
      (progn
	(message "Gnus not running; using plain Message mode")
	(message-mail to subject other-headers continue
                      switch-action yank-action send-actions return-action))
    (let ((buf (current-buffer))
	  ;; Don't use posting styles corresponding to any existing group.
	  ;; (group-name gnus-newsgroup-name)
	  mail-buf)
      (let ((gnus-newsgroup-name ""))
	(gnus-setup-message
	 'message
	 (message-mail to subject other-headers continue
		       nil yank-action send-actions return-action)))
      (when switch-action
	(setq mail-buf (current-buffer))
	(switch-to-buffer buf)
	(apply switch-action mail-buf nil))
      ;; COMPOSEFUNC should return t if succeed.  Undocumented ???
      t)))

;;;###autoload
(defun gnus-button-mailto (address)
  "Mail to ADDRESS."
  (set-buffer (gnus-copy-article-buffer))
  (gnus-setup-message 'message
    (message-reply address)))

;;;###autoload
(defun gnus-button-reply (&optional to-address wide)
  "Like `message-reply'."
  (interactive)
  (gnus-setup-message 'message
    (message-reply to-address wide)))

;;;###autoload
(define-mail-user-agent 'gnus-user-agent
  'gnus-msg-mail 'message-send-and-exit
  'message-kill-buffer 'message-send-hook)

(defun gnus-setup-posting-charset (group)
  (let ((alist gnus-group-posting-charset-alist)
	(group (or group ""))
	elem)
    (when group
      (catch 'found
	(while (setq elem (pop alist))
	  (when (or (and (stringp (car elem))
			 (string-match (car elem) group))
		    (and (functionp (car elem))
			 (funcall (car elem) group))
		    (and (symbolp (car elem))
			 (symbol-value (car elem))))
	    (throw 'found (cons (cadr elem) (caddr elem)))))))))

(declare-function gnus-agent-possibly-do-gcc "gnus-agent" ())
(declare-function gnus-cache-possibly-remove-article "gnus-cache"
                  (article ticked dormant unread &optional force))

(defun gnus-inews-add-send-actions (winconf buffer article
					    &optional config yanked
					    winconf-name)
  (add-hook 'message-sent-hook (if gnus-agent #'gnus-agent-possibly-do-gcc
				 #'gnus-inews-do-gcc)
	    nil t)
  (when gnus-agent
    (add-hook 'message-header-hook #'gnus-agent-possibly-save-gcc nil t))
  (setq message-post-method
	(let ((gn gnus-newsgroup-name))
	  (lambda (&optional arg) (gnus-post-method arg gn))))
  (message-add-action
   `(progn
      (setq gnus-current-window-configuration ',winconf-name)
      (when (gnus-buffer-live-p ,buffer)
	(set-window-configuration ,winconf)))
   'exit 'postpone 'kill)
  (let ((to-be-marked (cond
		       (yanked
			(mapcar
			 (lambda (x) (if (listp x) (car x) x)) yanked))
		       (article (if (listp article) article (list article)))
		       (t nil))))
    (message-add-action
     `(when (gnus-buffer-live-p ,buffer)
	(with-current-buffer ,buffer
	  ,(when to-be-marked
	     (if (eq config 'forward)
		 `(gnus-summary-mark-article-as-forwarded ',to-be-marked)
	       `(gnus-summary-mark-article-as-replied ',to-be-marked)))))
     'send)))

;;; Post news commands of Gnus group mode and summary mode

(defun gnus-group-mail (&optional arg)
  "Start composing a mail.
If ARG, use the group under the point to find a posting style.
If ARG is 1, prompt for a group name to find the posting style."
  (interactive "P")
  (let* (;;(group gnus-newsgroup-name)
	 ;; make sure last viewed article doesn't affect posting styles:
	 (gnus-article-copy)
	 ;; (buffer (current-buffer))
	 (gnus-newsgroup-name
	  (if arg
	      (if (= 1 (prefix-numeric-value arg))
		  (gnus-group-completing-read
		   "Use posting style of group"
		   nil (gnus-read-active-file-p))
		(gnus-group-group-name))
	    "")))
    (gnus-setup-message 'message (message-mail))))

(defun gnus-group-news (&optional arg)
  "Start composing a news.
If ARG, post to group under point.
If ARG is 1, prompt for group name to post to.

This function prepares a news even when using mail groups.  This is useful
for posting messages to mail groups without actually sending them over the
network.  The corresponding back end must have a `request-post' method."
  (interactive "P")
  (let* (;;(group gnus-newsgroup-name)
	 ;; make sure last viewed article doesn't affect posting styles:
	 (gnus-article-copy)
	 ;; (buffer (current-buffer))
	 (gnus-newsgroup-name
	  (if arg
	      (if (= 1 (prefix-numeric-value arg))
		  (gnus-group-completing-read "Use group"
					      nil
					      (gnus-read-active-file-p))
		(gnus-group-group-name))
	    "")))
    (gnus-setup-message
     'message
     (message-news (gnus-group-real-name gnus-newsgroup-name)))))

(defun gnus-group-post-news (&optional arg)
  "Start composing a message (a news by default).
If ARG, post to group under point.  If ARG is 1, prompt for group name.
Depending on the selected group, the message might be either a mail or
a news."
  (interactive "P" gnus-group-mode)
  ;; Bind this variable here to make message mode hooks work ok.
  (let ((gnus-newsgroup-name
	 (if arg
	     (if (= 1 (prefix-numeric-value arg))
		 (gnus-group-completing-read "Newsgroup" nil
					     (gnus-read-active-file-p))
	       (or (gnus-group-group-name) ""))
	   ""))
	;; make sure last viewed article doesn't affect posting styles:
	(gnus-article-copy))
    (gnus-post-news 'post gnus-newsgroup-name nil nil nil nil
		    (string= gnus-newsgroup-name ""))))

(defun gnus-summary-mail-other-window (&optional arg)
  "Start composing a mail in another window.
Use the posting of the current group by default.
If ARG, don't do that.  If ARG is 1, prompt for group name to find the
posting style."
  (interactive "P" gnus-summary-mode)
  (let* (;;(group gnus-newsgroup-name)
	 ;; make sure last viewed article doesn't affect posting styles:
	 (gnus-article-copy)
	 ;; (buffer (current-buffer))
	 (gnus-newsgroup-name
	  (if arg
	      (if (= 1 (prefix-numeric-value arg))
		  (gnus-group-completing-read "Use group"
					      nil
					      (gnus-read-active-file-p))
		"")
	    gnus-newsgroup-name)))
    (gnus-setup-message 'message (message-mail))))

(defun gnus-summary-news-other-window (&optional arg)
  "Start composing a news in another window.
Post to the current group by default.
If ARG, don't do that.  If ARG is 1, prompt for group name to post to.

This function prepares a news even when using mail groups.  This is useful
for posting messages to mail groups without actually sending them over the
network.  The corresponding back end must have a `request-post' method."
  (interactive "P" gnus-summary-mode)
  (let* (;;(group gnus-newsgroup-name)
	 ;; make sure last viewed article doesn't affect posting styles:
	 (gnus-article-copy)
	 ;; (buffer (current-buffer))
	 (gnus-newsgroup-name
	  (if arg
	      (if (= 1 (prefix-numeric-value arg))
		  (gnus-group-completing-read "Use group"
					      nil
					      (gnus-read-active-file-p))
		"")
	    gnus-newsgroup-name)))
    (gnus-setup-message
     'message
     (progn
       (message-news (gnus-group-real-name gnus-newsgroup-name))
       (setq-local gnus-discouraged-post-methods
	           (remove
	            (car (gnus-find-method-for-group gnus-newsgroup-name))
	            gnus-discouraged-post-methods))))))

(defun gnus-summary-post-news (&optional arg)
  "Start composing a message.  Post to the current group by default.
If ARG, don't do that.  If ARG is 1, prompt for a group name to post to.
Depending on the selected group, the message might be either a mail or
a news."
  (interactive "P" gnus-summary-mode)
  ;; Bind this variable here to make message mode hooks work ok.
  (let ((gnus-newsgroup-name
	 (if arg
	     (if (= 1 (prefix-numeric-value arg))
		 (gnus-group-completing-read "Newsgroup" nil
					     (gnus-read-active-file-p))
	       "")
	   gnus-newsgroup-name))
	;; make sure last viewed article doesn't affect posting styles:
	(gnus-article-copy))
    (gnus-post-news 'post gnus-newsgroup-name)))


(defun gnus-summary-followup (yank &optional force-news)
  "Compose a followup to an article.
If prefix argument YANK is non-nil, the original article is yanked
automatically.
YANK is a list of elements, where the car of each element is the
article number, and the cdr is the string to be yanked."
  (interactive (list (and current-prefix-arg
			  (gnus-summary-work-articles 1)))
	       gnus-summary-mode)
  (when yank
    (gnus-summary-goto-subject
     (if (listp (car yank))
	 (caar yank)
       (car yank))))
  (save-window-excursion
    (gnus-summary-select-article))
  (let ((headers (gnus-summary-article-header (gnus-summary-article-number)))
	(gnus-newsgroup-name gnus-newsgroup-name))
    ;; Send a followup.
    (gnus-post-news nil gnus-newsgroup-name
		    headers gnus-article-buffer
		    yank nil force-news)
    (gnus-summary-handle-replysign)))

(defun gnus-summary-followup-with-original (n &optional force-news)
  "Compose a followup to an article and include the original article.
The text in the region will be yanked.  If the region isn't
active, the entire article will be yanked."
  (interactive "P" gnus-summary-mode)
  (gnus-summary-followup (gnus-summary-work-articles n) force-news))

(defun gnus-summary-followup-to-mail (&optional arg)
  "Followup to the current mail message via news."
  (interactive (list (and current-prefix-arg
			  (gnus-summary-work-articles 1)))
	       gnus-summary-mode)
  (gnus-summary-followup arg t))

(defun gnus-summary-followup-to-mail-with-original (&optional arg)
  "Followup to the current mail message via news."
  (interactive "P" gnus-summary-mode)
  (gnus-summary-followup (gnus-summary-work-articles arg) t))

(defun gnus-inews-yank-articles (articles)
  (let (beg article yank-string)
    (message-goto-body)
    (while (setq article (pop articles))
      (when (listp article)
	(setq yank-string (nth 1 article)
	      article (nth 0 article)))
      (save-window-excursion
	(set-buffer gnus-summary-buffer)
	(gnus-summary-select-article nil nil nil article)
	(gnus-summary-remove-process-mark article))
      (gnus-copy-article-buffer nil yank-string)
      (let ((message-reply-buffer gnus-article-copy)
	    (message-reply-headers
	     ;; The headers are decoded.
	     (with-current-buffer gnus-article-copy
	       (save-restriction
		 (nnheader-narrow-to-headers)
		 (nnheader-parse-head t)))))
	(message-yank-original)
	(message-exchange-point-and-mark)
	(setq beg (or beg (mark t))))
      (when articles
	(insert "\n")))
    (push-mark)
    (goto-char beg)))

(defun gnus-summary-cancel-article (&optional n symp)
  "Cancel an article you posted.
Uses the process-prefix convention.  If given the symbolic
prefix `a', cancel using the standard posting method; if not
post using the current select method."
  (interactive (gnus-interactive "P\ny") gnus-summary-mode)
  (let ((message-post-method
	 (let ((gn gnus-newsgroup-name))
	   (lambda (_arg) (gnus-post-method (eq symp 'a) gn))))
	(custom-address user-mail-address))
    (dolist (article (gnus-summary-work-articles n))
      (when (gnus-summary-select-article t nil nil article)
	;; Pretend that we're doing a followup so that we can see what
	;; the From header would have ended up being.
	(save-window-excursion
	  (save-excursion
	    (gnus-summary-followup nil)
	    (let ((from (message-fetch-field "from")))
	      (when from
		(setq custom-address
		      (car (mail-header-parse-address from)))))
	    (kill-buffer (current-buffer))))
	;; Now cancel the article using the From header we got.
	(when (gnus-eval-in-buffer-window gnus-original-article-buffer
		(let ((user-mail-address (or custom-address user-mail-address)))
		  (message-cancel-news)))
	  (gnus-summary-mark-as-read article gnus-canceled-mark)
	  (gnus-cache-remove-article 1))
	(gnus-article-hide-headers-if-wanted))
      (gnus-summary-remove-process-mark article))))

(defun gnus-summary-supersede-article ()
  "Compose an article that will supersede a previous article.
This is done simply by taking the old article and adding a Supersedes
header line with the old Message-ID."
  (interactive nil gnus-summary-mode)
  (let ((article (gnus-summary-article-number))
	(mail-parse-charset gnus-newsgroup-charset))
    (gnus-setup-message 'reply-yank
      (gnus-summary-select-article t)
      (set-buffer gnus-original-article-buffer)
      (message-supersede)
      (push
       (let ((buf gnus-summary-buffer))
         (lambda ()
           (when (gnus-buffer-live-p buf)
	     (with-current-buffer buf
	       (gnus-cache-possibly-remove-article article nil nil nil t)
	       (gnus-summary-mark-as-read article gnus-canceled-mark)))))
       message-send-actions)
      ;; Add Gcc header.
      (gnus-inews-insert-gcc))))

\f

(defun gnus-copy-article-buffer (&optional article-buffer yank-string)
  ;; make a copy of the article buffer with all text properties removed
  ;; this copy is in the buffer gnus-article-copy.
  ;; if ARTICLE-BUFFER is nil, gnus-article-buffer is used
  ;; this buffer should be passed to all mail/news reply/post routines.
  (setq gnus-article-copy (gnus-get-buffer-create " *gnus article copy*"))
  (with-current-buffer gnus-article-copy
    (mm-enable-multibyte))
  (let ((article-buffer (or article-buffer gnus-article-buffer))
	end beg)
    (if (not (gnus-buffer-live-p article-buffer))
	(error "Can't find any article buffer")
      (with-current-buffer article-buffer
	(let ((gnus-newsgroup-charset (or gnus-article-charset
					  gnus-newsgroup-charset))
	      (inhibit-read-only t)
	      (gnus-newsgroup-ignored-charsets
	       (or gnus-article-ignored-charsets
		   gnus-newsgroup-ignored-charsets)))
	  (save-restriction
	    ;; Copy over the (displayed) article buffer, delete
	    ;; hidden text and remove text properties.
	    (widen)
	    (copy-to-buffer gnus-article-copy (point-min) (point-max))
	    (set-buffer gnus-article-copy)
	    (when yank-string
	      (message-goto-body)
	      (delete-region (point) (point-max))
	      (insert yank-string))
	    (gnus-article-delete-text-of-type 'annotation)
	    (gnus-article-delete-text-of-type 'multipart)
	    (gnus-remove-text-with-property 'gnus-prev)
	    (gnus-remove-text-with-property 'gnus-next)
	    (gnus-remove-text-with-property 'gnus-decoration)
	    (insert
	     (prog1
		 (buffer-substring-no-properties (point-min) (point-max))
	       (erase-buffer)))
	    ;; Find the original headers.
	    (set-buffer gnus-original-article-buffer)
	    (goto-char (point-min))
	    (while (looking-at message-unix-mail-delimiter)
	      (forward-line 1))
	    (let ((mail-header-separator ""))
	      (setq beg (point)
		    end (or (message-goto-body)
			    ;; There may be just a header.
			    (point-max))))
	    ;; Delete the headers from the displayed articles.
	    (set-buffer gnus-article-copy)
	    (let ((mail-header-separator ""))
	      (delete-region (goto-char (point-min))
			     (or (message-goto-body) (point-max))))
	    ;; Insert the original article headers.
	    (insert-buffer-substring gnus-original-article-buffer beg end)
	    ;; Decode charsets.
	    (let ((gnus-article-decode-hook
		   (delq 'article-decode-charset
			 (copy-sequence gnus-article-decode-hook)))
		  (rfc2047-quote-decoded-words-containing-tspecials t))
	      (run-hooks 'gnus-article-decode-hook)))))
      gnus-article-copy)))

(defun gnus-post-news (post &optional group header article-buffer yank _subject
			    force-news)
  (when article-buffer
    (gnus-copy-article-buffer))
  (let ((gnus-article-reply (and article-buffer (gnus-summary-article-number)))
	(gnus-article-yanked-articles yank)
	(add-to-list gnus-add-to-list))
    (gnus-setup-message (cond (yank 'reply-yank)
			      (article-buffer 'reply)
			      (t 'message))
      (let* ((group (or group gnus-newsgroup-name))
	     (charset (gnus-group-name-charset nil group))
	     (pgroup group)
	     to-address to-group mailing-list to-list
	     newsgroup-p)
	(when group
	  (setq to-address (gnus-parameter-to-address group)
		to-group (gnus-group-find-parameter group 'to-group)
		to-list (gnus-parameter-to-list group)
		newsgroup-p (gnus-group-find-parameter group 'newsgroup)
		mailing-list (when gnus-mailing-list-groups
			       (string-match gnus-mailing-list-groups group))
		group (gnus-group-name-decode (gnus-group-real-name group)
					      charset)))
	(if (or (and to-group
		     (gnus-news-group-p to-group))
		newsgroup-p
		force-news
		(and (gnus-news-group-p
		      (or pgroup gnus-newsgroup-name)
		      (or header gnus-current-article))
		     (not mailing-list)
		     (not to-list)
		     (not to-address)))
	    ;; This is news.
	    (if post
		(message-news
		 (or to-group
		     (and (not (gnus-virtual-group-p pgroup)) group)))
	      (set-buffer gnus-article-copy)
	      (gnus-msg-treat-broken-reply-to)
	      (message-followup (if (or newsgroup-p force-news)
				    (if (save-restriction
					  (article-narrow-to-head)
					  (message-fetch-field "newsgroups"))
					nil
				      "")
				  to-group)))
	  ;; The is mail.
	  (if post
	      (progn
		(message-mail (or to-address to-list))
		;; Arrange for mail groups that have no `to-address' to
		;; get that when the user sends off the mail.
		(when (and (not to-list)
			   (not to-address)
			   add-to-list)
		  (push (list 'gnus-inews-add-to-address pgroup)
			message-send-actions)))
	    (set-buffer gnus-article-copy)
	    (gnus-msg-treat-broken-reply-to)
	    (message-wide-reply to-address)))
	(when yank
	  (gnus-inews-yank-articles yank))))))

(defun gnus-msg-treat-broken-reply-to (&optional force)
  "Remove the Reply-To header if broken-reply-to."
  (when (or force
	    (gnus-group-find-parameter
	     gnus-newsgroup-name 'broken-reply-to))
    (save-restriction
      (message-narrow-to-head)
      (message-remove-header "reply-to"))))

(defun gnus-post-method (arg group &optional silent)
  "Return the posting method based on GROUP and ARG.
If SILENT, don't prompt the user."
  (let ((gnus-post-method (or (gnus-parameter-post-method group)
			      gnus-post-method))
	(group-method (gnus-find-method-for-group group)))
    (cond
     ;; If the group-method is nil (which shouldn't happen) we use
     ;; the default method.
     ((null group-method)
      (or (and (listp gnus-post-method)	;If not current/native/nil
	       (not (listp (car gnus-post-method))) ; and not a list of methods
	       gnus-post-method)	;then use it.
	  gnus-select-method
	  message-post-method))
     ;; We want the inverse of the default
     ((and arg (not (eq arg 0)))
      (if (eq gnus-post-method 'current)
	  gnus-select-method
	group-method))
     ;; We query the user for a post method.
     ((or arg
	  (and (listp gnus-post-method)
	       (listp (car gnus-post-method))))
      (let* ((methods
	      ;; Collect all methods we know about.
	      (append
	       (when (listp gnus-post-method)
		 (if (listp (car gnus-post-method))
		     gnus-post-method
		   (list gnus-post-method)))
	       gnus-secondary-select-methods
	       (mapcar #'cdr gnus-server-alist)
	       (mapcar #'car gnus-opened-servers)
	       (list gnus-select-method)
	       (list group-method)))
	     method-alist post-methods method)
	;; Weed out all mail methods.
	(while methods
	  (setq method (gnus-server-get-method "" (pop methods)))
	  (when (and (or (gnus-method-option-p method 'post)
			 (gnus-method-option-p method 'post-mail))
		     (not (member method post-methods)))
	    (push method post-methods)))
	;; Create a name-method alist.
	(setq method-alist
	      (mapcar
	       (lambda (m)
		 (if (equal (cadr m) "")
		     (list (symbol-name (car m)) m)
		   (list (concat (cadr m) " (" (symbol-name (car m)) ")") m)))
	       post-methods))
	;; Query the user.
	(cadr
	 (assoc
	  (setq gnus-last-posting-server
		(if (and silent
			 gnus-last-posting-server)
		    ;; Just use the last value.
		    gnus-last-posting-server
		  (gnus-completing-read
		   "Posting method" (mapcar #'car method-alist) t
		   (cons (or gnus-last-posting-server "") 0))))
	  method-alist))))
     ;; Override normal method.
     ((and (eq gnus-post-method 'current)
	   (not (memq (car group-method) gnus-discouraged-post-methods))
	   (gnus-get-function group-method 'request-post t))
      (cl-assert (not arg))
      group-method)
     ;; Use gnus-post-method.
     ((listp gnus-post-method)		;A method...
      (cl-assert (not (listp (car gnus-post-method)))) ;... not a list of methods.
      gnus-post-method)
     ;; Use the normal select method (nil or native).
     (t gnus-select-method))))

\f

(defun gnus-extended-version ()
  "Stringified Gnus version and Emacs version.
See the variable `gnus-user-agent'."
  (if (stringp gnus-user-agent)
      gnus-user-agent
    ;; `gnus-user-agent' is a list:
    (let* ((float-output-format nil)
	   (gnus-v
	    (when (memq 'gnus gnus-user-agent)
	      (concat "Gnus/"
		      (replace-regexp-in-string
		       "0+\\'" ""
		       (format "%1.8f" (gnus-continuum-version gnus-version)))
		      " (" gnus-version ")")))
	   (emacs-v (gnus-emacs-version)))
      (concat gnus-v (when (and gnus-v emacs-v) " ")
	      emacs-v))))

\f
;;;
;;; Gnus Mail Functions
;;;

;;; Mail reply commands of Gnus summary mode

(defun gnus-summary-reply (&optional yank wide very-wide)
  "Start composing a mail reply to the current message.
If prefix argument YANK is non-nil, the original article is yanked
automatically.
If WIDE, make a wide reply.
If VERY-WIDE, make a very wide reply."
  (interactive (list (and current-prefix-arg
			  (gnus-summary-work-articles 1)))
	       gnus-summary-mode)
  ;; Allow user to require confirmation before replying by mail to the
  ;; author of a news article (or mail message).
  (when (or (not (or (gnus-news-group-p gnus-newsgroup-name)
		     gnus-confirm-treat-mail-like-news))
	    (not (cond ((stringp gnus-confirm-mail-reply-to-news)
			(string-match gnus-confirm-mail-reply-to-news
				      gnus-newsgroup-name))
		       ((functionp gnus-confirm-mail-reply-to-news)
			(funcall gnus-confirm-mail-reply-to-news
				 gnus-newsgroup-name))
		       (t gnus-confirm-mail-reply-to-news)))
	    (if (or wide very-wide)
		t ;; Ignore gnus-confirm-mail-reply-to-news for wide and very
		  ;; wide replies.
	      (y-or-n-p "Really reply by mail to article author? ")))
    (let* ((article
	    (if (listp (car yank))
		(caar yank)
	      (car yank)))
	   (gnus-article-reply (or article (gnus-summary-article-number)))
	   (gnus-article-yanked-articles yank)
	   (headers ""))
      ;; Stripping headers should be specified with mail-yank-ignored-headers.
      (when yank
	(gnus-summary-goto-subject article))
      (gnus-setup-message (if yank 'reply-yank 'reply)
	(if (not very-wide)
	    (gnus-summary-select-article)
	  (dolist (article very-wide)
	    (gnus-summary-select-article nil nil nil article)
	    (with-current-buffer (gnus-copy-article-buffer)
	      (gnus-msg-treat-broken-reply-to)
	      (save-restriction
		(message-narrow-to-head)
		(setq headers (concat headers (buffer-string)))))))
	(set-buffer (gnus-copy-article-buffer))
	(gnus-msg-treat-broken-reply-to gnus-msg-force-broken-reply-to)
	(save-restriction
	  (message-narrow-to-head)
	  (when very-wide
	    (erase-buffer)
	    (insert headers))
	  (goto-char (point-max)))
	(mml-quote-region (point) (point-max))
	(message-reply nil wide)
	(when yank
	  (gnus-inews-yank-articles yank))
	(gnus-summary-handle-replysign)))))

(defun gnus-summary-handle-replysign ()
  "Check the various replysign variables and take action accordingly."
  (when (or gnus-message-replysign gnus-message-replyencrypt)
    (let (signed encrypted)
      (with-current-buffer gnus-article-buffer
	(setq signed (memq 'signed gnus-article-wash-types))
	(setq encrypted (memq 'encrypted gnus-article-wash-types)))
      (cond ((and gnus-message-replyencrypt encrypted)
	     (mml-secure-message mml-default-encrypt-method
				 (if gnus-message-replysignencrypted
				     'signencrypt
				   'encrypt)))
	    ((and gnus-message-replysign signed)
	     (mml-secure-message mml-default-sign-method 'sign))))))

(defun gnus-summary-reply-with-original (n &optional wide)
  "Start composing a reply mail to the current message.
The original article will be yanked."
  (interactive "P" gnus-summary-mode)
  (gnus-summary-reply (gnus-summary-work-articles n) wide))

(defun gnus-summary-reply-to-list-with-original (n &optional wide)
  "Start composing a reply mail to the current message.
The reply goes only to the mailing list.
The original article will be yanked."
  (interactive "P" gnus-summary-mode)
  (let ((message-reply-to-function
	 (lambda nil
	   `((To . ,(gnus-mailing-list-followup-to))))))
    (gnus-summary-reply (gnus-summary-work-articles n) wide)))

(defun gnus-summary-reply-broken-reply-to (&optional yank wide very-wide)
  "Like `gnus-summary-reply' except removing reply-to field.
If prefix argument YANK is non-nil, the original article is yanked
automatically.
If WIDE, make a wide reply.
If VERY-WIDE, make a very wide reply."
  (interactive (list (and current-prefix-arg
			  (gnus-summary-work-articles 1)))
	       gnus-summary-mode)
  (let ((gnus-msg-force-broken-reply-to t))
    (gnus-summary-reply yank wide very-wide)))

(defun gnus-summary-reply-broken-reply-to-with-original (n &optional wide)
  "Like `gnus-summary-reply-with-original' except removing reply-to field.
The original article will be yanked."
  (interactive "P" gnus-summary-mode)
  (gnus-summary-reply-broken-reply-to (gnus-summary-work-articles n) wide))

(defun gnus-summary-wide-reply (&optional yank)
  "Start composing a wide reply mail to the current message.
If prefix argument YANK is non-nil, the original article is yanked
automatically."
  (interactive (list (and current-prefix-arg
			  (gnus-summary-work-articles 1)))
	       gnus-summary-mode)
  (gnus-summary-reply yank t))

(defun gnus-summary-wide-reply-with-original (n)
  "Start composing a wide reply mail to the current message.
The original article(s) will be yanked.
Uses the process/prefix convention."
  (interactive "P" gnus-summary-mode)
  (gnus-summary-reply-with-original n t))

(defun gnus-summary-very-wide-reply (&optional yank)
  "Start composing a very wide reply mail to a set of messages.

Uses the process/prefix convention.

The reply will include all From/Cc headers from the original
messages as the To/Cc headers.

If prefix argument YANK is non-nil, the original article(s) will
be yanked automatically."
  (interactive (list (and current-prefix-arg
			  (gnus-summary-work-articles 1)))
	       gnus-summary-mode)
  (gnus-summary-reply yank t (gnus-summary-work-articles yank)))

(defun gnus-summary-very-wide-reply-with-original (n)
  "Start composing a very wide reply mail a set of messages.

Uses the process/prefix convention.

The reply will include all From/Cc headers from the original
messages as the To/Cc headers.

The original article(s) will be yanked."
  (interactive "P" gnus-summary-mode)
  (gnus-summary-reply
   (gnus-summary-work-articles n) t (gnus-summary-work-articles n)))

(defun gnus-summary-mail-forward (&optional arg post)
  "Forward the current message(s) to another user.
If process marks exist, forward all marked messages;
if ARG is nil, see `message-forward-as-mime' and `message-forward-show-mml';
if ARG is 1, decode the message and forward directly inline;
if ARG is 2, forward message as an rfc822 MIME section;
if ARG is 3, decode message and forward as an rfc822 MIME section;
if ARG is 4, forward message directly inline;
otherwise, use flipped `message-forward-as-mime'.
If POST, post instead of mail.
For the \"inline\" alternatives, also see the variable
`message-forward-ignored-headers'."
  (interactive "P" gnus-summary-mode)
  (if (cdr (gnus-summary-work-articles nil))
      ;; Process marks are given.
      (gnus-uu-digest-mail-forward nil post)
    ;; No process marks.
    (let ((message-forward-as-mime message-forward-as-mime)
	  (message-forward-show-mml message-forward-show-mml))
      (cond
       ((null arg))
       ((eq arg 1)
	(setq message-forward-as-mime nil
	      message-forward-show-mml t))
       ((eq arg 2)
	(setq message-forward-as-mime t
	      message-forward-show-mml nil))
       ((eq arg 3)
	(setq message-forward-as-mime t
	      message-forward-show-mml t))
       ((eq arg 4)
	(setq message-forward-as-mime nil
	      message-forward-show-mml nil))
       (t
	(setq message-forward-as-mime (not message-forward-as-mime))))
      (let* ((gnus-article-reply (gnus-summary-article-number))
	     (gnus-article-yanked-articles (list gnus-article-reply)))
	(gnus-setup-message 'forward
	  (gnus-summary-select-article)
	  (let ((mail-parse-charset
		 (or (and (gnus-buffer-live-p gnus-article-buffer)
			  (with-current-buffer gnus-article-buffer
			    gnus-article-charset))
		     gnus-newsgroup-charset))
		(mail-parse-ignored-charsets
		 gnus-newsgroup-ignored-charsets))
	    (set-buffer gnus-original-article-buffer)
	    (message-forward post)))))))

(defun gnus-summary-resend-message-insert-gcc ()
  "Insert Gcc header according to `gnus-gcc-self-resent-messages'."
  (gnus-inews-insert-gcc)
  (let ((gcc (mapcar
	      (lambda (group)
		(encode-coding-string
		 group
		 (gnus-group-name-charset (gnus-inews-group-method group)
					  group)))
	      (message-unquote-tokens
	       (message-tokenize-header (mail-fetch-field "gcc" nil t)
					" ,"))))
	(self (with-current-buffer gnus-summary-buffer
		gnus-gcc-self-resent-messages)))
    (message-remove-header "gcc")
    (when gcc
      (goto-char (point-max))
      (cond ((eq self 'none))
	    ((eq self t)
	     (insert "Gcc: \"" gnus-newsgroup-name "\"\n"))
	    ((stringp self)
	     (insert "Gcc: "
		     (encode-coding-string
		      (if (string-match " " self)
			  (concat "\"" self "\"")
			self)
		      (gnus-group-name-charset (gnus-inews-group-method self)
					       self))
		     "\n"))
	    ((null self)
	     (insert "Gcc: " (mapconcat #'identity gcc ", ") "\n"))
	    ((eq self 'no-gcc-self)
	     (when (setq gcc (delete
			      gnus-newsgroup-name
			      (delete (concat "\"" gnus-newsgroup-name "\"")
				      gcc)))
	       (insert "Gcc: " (mapconcat #'identity gcc ", ") "\n")))))))

(defun gnus-summary-resend-message (address n &optional no-select)
  "Resend the current article to ADDRESS.
Uses the process/prefix convention.  If NO-SELECT, don't display
the message before resending."
  (interactive
   (list (message-read-from-minibuffer
	  "Resend message(s) to: "
	  (when (and gnus-summary-resend-default-address
		     (gnus-buffer-live-p gnus-original-article-buffer))
	    ;; If some other article is currently selected, the
	    ;; initial-contents is wrong. Whatever, it is just the
	    ;; initial-contents.
	    (with-current-buffer gnus-original-article-buffer
	      (nnmail-fetch-field "to"))))
	 current-prefix-arg)
   gnus-summary-mode)
  (let ((message-header-setup-hook (copy-sequence message-header-setup-hook))
	(message-sent-hook (copy-sequence message-sent-hook))
	;; Honor posting-style for `name' and `address' in Resent-From header.
	(styles (gnus-group-find-parameter gnus-newsgroup-name
					   'posting-style t))
	(user-full-name user-full-name)
	(user-mail-address user-mail-address)
	(group gnus-newsgroup-name)
	tem)
    (dolist (style styles)
      (when (stringp (cadr style))
	(setcdr style (list (decode-coding-string (cadr style) 'utf-8)))))
    (dolist (style (if styles
		       (append gnus-posting-styles (list (cons ".*" styles)))
		     gnus-posting-styles))
      (when (and (stringp (car style))
		 (string-match (pop style) gnus-newsgroup-name))
	(when (setq tem (cadr (assq 'name style)))
	  (setq user-full-name tem))
	(when (setq tem (cadr (assq 'address style)))
	  (setq user-mail-address tem))))
    ;; `gnus-summary-resend-message-insert-gcc' must run last.
    (add-hook 'message-header-setup-hook
	      #'gnus-summary-resend-message-insert-gcc t)
    (add-hook 'message-sent-hook
	      (let ((agent gnus-agent))
		(lambda ()
		  (let ((rfc2047-encode-encoded-words nil))
		    (if agent
			(gnus-agent-possibly-do-gcc)
		      (gnus-inews-do-gcc))))))
    (dolist (article (gnus-summary-work-articles n))
      (if no-select
	  (with-current-buffer " *nntpd*"
	    (erase-buffer)
	    (gnus-request-article article group)
	    (let ((gnus-gcc-externalize-attachments nil)
		  (message-inhibit-body-encoding t))
	      (message-resend address)))
	(gnus-summary-select-article nil nil nil article)
	(with-current-buffer gnus-original-article-buffer
	  (let ((gnus-gcc-externalize-attachments nil)
		(message-inhibit-body-encoding t))
	    (message-resend address))))
      (gnus-summary-mark-article-as-forwarded article))))

;; From: Matthieu Moy <Matthieu.Moy@imag.fr>
(defun gnus-summary-resend-message-edit ()
  "Resend an article that has already been sent.
A new buffer will be created to allow the user to modify body and
contents of the message, and then, everything will happen as when
composing a new message."
  (interactive nil gnus-summary-mode)
  (let ((mail-parse-charset gnus-newsgroup-charset))
    (gnus-setup-message 'reply-yank
      (gnus-summary-select-article t)
      (set-buffer gnus-original-article-buffer)
      (let ((cur (current-buffer))
	    (to (message-fetch-field "to")))
	;; Get a normal message buffer.
	(message-pop-to-buffer (message-buffer-name "Resend" to))
	(insert-buffer-substring cur)
	(mime-to-mml)
	(message-narrow-to-head-1)
	;; Gnus will generate a new one when sending.
	(message-remove-header "Message-ID")
	;; Remove unwanted headers.
	(message-remove-header message-ignored-resent-headers t)
	(goto-char (point-max))
	(insert mail-header-separator)
	;; Add Gcc header.
	(gnus-inews-insert-gcc)
	(goto-char (point-min))
	(when (re-search-forward "^To:\\|^Newsgroups:" nil 'move)
	  (forward-char 1))
	(widen)))))

(defun gnus-summary-post-forward (&optional arg)
  "Forward the current article to a newsgroup.
See `gnus-summary-mail-forward' for ARG."
  (interactive "P" gnus-summary-mode)
  (gnus-summary-mail-forward arg t))

(defun gnus-summary-mail-crosspost-complaint (n)
  "Send a complaint about crossposting to the current article(s)."
  (interactive "P" gnus-summary-mode)
  (dolist (article (gnus-summary-work-articles n))
    (set-buffer gnus-summary-buffer)
    (gnus-summary-goto-subject article)
    (let ((group (gnus-group-real-name gnus-newsgroup-name))
	  newsgroups followup-to)
      (gnus-summary-select-article)
      (set-buffer gnus-original-article-buffer)
      (if (and (<= (length (message-tokenize-header
			    (setq newsgroups
				  (mail-fetch-field "newsgroups"))
			    ", "))
		   1)
	       (or (not (setq followup-to (mail-fetch-field "followup-to")))
		   (not (member group (message-tokenize-header
				       followup-to ", ")))))
	  (if followup-to
	      (gnus-message 1 "Followup-To restricted")
	    (gnus-message 1 "Not a crossposted article"))
	(set-buffer gnus-summary-buffer)
	(gnus-summary-reply-with-original 1)
	(set-buffer gnus-message-buffer)
	(message-goto-body)
	(insert (format gnus-crosspost-complaint newsgroups group))
	(message-goto-subject)
	(re-search-forward " *$")
	(replace-match " (crosspost notification)" t t)
	(deactivate-mark)
	(when (gnus-y-or-n-p "Send this complaint? ")
	  (message-send-and-exit))))))

(defun gnus-inews-add-to-address (group)
  (let ((to-address (mail-fetch-field "to")))
    (when (and to-address
	       (gnus-alive-p))
      ;; This mail group doesn't have a `to-list', so we add one
      ;; here.  Magic!
      (when (gnus-y-or-n-p
	     (format "Do you want to add this as `to-list': %s? " to-address))
	(gnus-group-add-parameter group (cons 'to-list to-address))))))

(defun gnus-article-mail (yank)
  "Send a reply to the address near point.
If YANK is non-nil, include the original article."
  (interactive "P")
  (let ((address
	 (buffer-substring
	  (save-excursion (re-search-backward "[ \t\n]" nil t) (1+ (point)))
	  (save-excursion (re-search-forward "[ \t\n]" nil t) (1- (point))))))
    (when address
      (gnus-msg-mail address)
      (when yank
	(gnus-inews-yank-articles (list (cdr gnus-article-current)))))))

(defun gnus-bug (subject)
  "Send a bug report to the Emacs maintainers.

Already submitted bugs can be found in the Emacs bug tracker:

  https://debbugs.gnu.org/cgi/pkgreport.cgi?package=emacs;max-bugs=100;base-order=1;bug-rev=1"
  (interactive "sBug Subject: ")
  (report-emacs-bug subject)
  (save-excursion
    (goto-char (point-min))
    (insert (format "X-Debbugs-Package: %s\n" gnus-bug-package))))

(defun gnus-summary-yank-message (buffer n)
  "Yank the current article into a composed message."
  (interactive (list (gnus-completing-read "Buffer" (message-buffers) t)
		     current-prefix-arg)
	       gnus-summary-mode)
  (gnus-summary-iterate n
    (let ((gnus-inhibit-treatment t))
      (gnus-summary-select-article))
    (with-current-buffer buffer
      (message-yank-buffer gnus-article-buffer))))

;;; Treatment of rejected articles.
;;; Bounced mail.

(defun gnus-summary-resend-bounced-mail (&optional fetch)
  "Re-mail the current message.
This only makes sense if the current message is a bounce message that
contains some mail you have written which has been bounced back to
you.
If FETCH, try to fetch the article that this is a reply to, if indeed
this is a reply."
  (interactive "P" gnus-summary-mode)
  (gnus-summary-select-article t)
  (let (summary-buffer parent)
    (if fetch
	(progn
	  (setq summary-buffer (current-buffer))
	  (set-buffer gnus-original-article-buffer)
	  (article-goto-body)
	  (when (re-search-forward "^References:\n?" nil t)
	    (while (memq (char-after) '(?\t ? ))
	      (forward-line 1))
	    (skip-chars-backward "\t\n ")
	    (setq parent
		  (gnus-parent-id (buffer-substring (match-end 0) (point))))))
      (set-buffer gnus-original-article-buffer))
    (gnus-setup-message 'compose-bounce
      (message-bounce)
      ;; Add Gcc header.
      (gnus-inews-insert-gcc)
      ;; If there are references, we fetch the article we answered to.
      (when parent
	(with-current-buffer summary-buffer
	  (gnus-summary-refer-article parent)
	  (gnus-summary-show-all-headers))))))

;;; Gcc handling.

(defun gnus-inews-group-method (group)
  (cond
   ;; If the group doesn't exist, we assume
   ;; it's an archive group...
   ((and (null (gnus-get-info group))
	 (eq (car (gnus-server-to-method gnus-message-archive-method))
	     (car (gnus-server-to-method (gnus-group-method group)))))
    gnus-message-archive-method)
   ;; Use the method.
   ((gnus-info-method (gnus-get-info group))
    (gnus-info-method (gnus-get-info group)))
   ;; Find the method.
   (t (gnus-server-to-method (gnus-group-method group)))))

;; Do Gcc handling, which copied the message over to some group.
(defun gnus-inews-do-gcc (&optional gcc)
  (save-excursion
    (save-restriction
      (message-narrow-to-headers)
      (let ((gcc (or gcc (mail-fetch-field "gcc" nil t)))
	    (cur (current-buffer))
	    (encoded-cache message-encoded-mail-cache)
	    groups group method group-art options
	    mml-externalize-attachments)
	(when gcc
	  (message-remove-header "gcc")
	  (widen)
	  (setq groups (message-unquote-tokens
			(message-tokenize-header gcc " ,\n\t")))
	  ;; Copy the article over to some group(s).
	  (while (setq group (pop groups))
	    (setq method (gnus-inews-group-method group)
		  group (encode-coding-string
			 group
			 (gnus-group-name-charset method group)))
	    (unless (gnus-check-server method)
	      (error "Can't open server %s" (if (stringp method) method
					      (car method))))
	    (unless (gnus-request-group group t method)
	      (gnus-request-create-group group method))
	    (setq mml-externalize-attachments
		  (if (stringp gnus-gcc-externalize-attachments)
		      (string-match gnus-gcc-externalize-attachments group)
		    gnus-gcc-externalize-attachments))
	    (save-excursion
	      (nnheader-set-temp-buffer " *acc*")
	      (setq message-options (with-current-buffer cur message-options))
	      (insert-buffer-substring cur)
	      (run-hooks 'gnus-gcc-pre-body-encode-hook)
	      ;; Avoid re-doing things like GPG-encoding secret parts.
	      (if (not encoded-cache)
		  (message-encode-message-body)
		(erase-buffer)
		(insert encoded-cache))
	      (message-remove-header "gcc")
	      (run-hooks 'gnus-gcc-post-body-encode-hook)
	      (save-restriction
		(message-narrow-to-headers)
		(let* ((newsgroups-field (save-restriction
					   (message-narrow-to-headers-or-head)
					   (message-fetch-field "Newsgroups")))
		       (followup-field (save-restriction
					 (message-narrow-to-headers-or-head)
					 (message-fetch-field "Followup-To")))
		       ;; BUG: We really need to get the charset for
		       ;; each name in the Newsgroups and Followup-To
		       ;; lines to allow crossposting between group
		       ;; names with incompatible character sets.
		       ;; -- Per Abrahamsen <abraham@dina.kvl.dk> 2001-10-08.
		       (group-field-charset
			(gnus-group-name-charset
			 method (or newsgroups-field "")))
		       (followup-field-charset
			(gnus-group-name-charset
			 method (or followup-field "")))
		       (rfc2047-header-encoding-alist
			(append
			 (when group-field-charset
			   (list (cons "Newsgroups" group-field-charset)))
			 (when followup-field-charset
			   (list (cons "Followup-To" followup-field-charset)))
			 rfc2047-header-encoding-alist)))
		  (mail-encode-encoded-word-buffer)))
	      (goto-char (point-min))
	      (when (re-search-forward
		     (concat "^" (regexp-quote mail-header-separator) "$")
		     nil t)
		(replace-match "" t t ))
	      (when (or (not (gnus-check-backend-function
			      'request-accept-article group))
			(not (setq group-art
				   (gnus-request-accept-article
				    group method t t))))
		(gnus-message 1 "Couldn't store article in group %s: %s"
			      group (gnus-status-message method)))
	      (when (stringp method)
		(setq method (gnus-server-to-method method)))
	      (when (and (listp method)
			 (gnus-native-method-p method))
		(setq group (gnus-group-short-name group)))
	      (when (and group-art
			 ;; FIXME: Should gcc-mark-as-read work when
			 ;; Gnus is not running?
			 (gnus-alive-p))
                (if gnus-gcc-mark-as-read
		    (gnus-group-mark-article-read group (cdr group-art))
		  (with-current-buffer gnus-group-buffer
		    (let ((gnus-group-marked (list group))
			  (gnus-get-new-news-hook nil)
			  (inhibit-read-only t))
		      (gnus-group-get-new-news-this-group nil t)))))
	      (setq options message-options)
	      (with-current-buffer cur (setq message-options options))
	      (kill-buffer (current-buffer)))))))))

(defun gnus-inews-insert-gcc (&optional group)
  "Insert the Gcc to say where the article is to be archived."
  (let* ((group (or group gnus-newsgroup-name))
         (var (or gnus-outgoing-message-group gnus-message-archive-group))
	 (gcc-self-val
	  (and group (not (gnus-virtual-group-p group))
	       (gnus-group-find-parameter group 'gcc-self t)))
	 (gcc-self-get (lambda (gcc-self-val group)
			 (if (stringp gcc-self-val)
			     (if (string-match " " gcc-self-val)
				 (concat "\"" gcc-self-val "\"")
			       gcc-self-val)
			   ;; In nndoc groups, we use the parent group name
			   ;; instead of the current group.
			   (let ((group (or (gnus-group-find-parameter
					     gnus-newsgroup-name 'parent-group)
					    group)))
			     (if (string-match " " group)
				 (concat "\"" group "\"")
			       group)))))
	 result
	 (groups
	  (cond
	   ((null gnus-message-archive-method)
	    ;; Ignore.
	    nil)
	   ((stringp var)
	    ;; Just a single group.
	    (list var))
	   ((null var)
	    ;; We don't want this.
	    nil)
	   ((and (listp var) (stringp (car var)))
	    ;; A list of groups.
	    var)
	   ((functionp var)
	    ;; A function.
	    (funcall var group))
	   (group
	    ;; An alist of regexps/functions/forms.
	    (while (and var
			(not
			 (setq result
			       (cond
				((and group
				      (stringp (caar var)))
				 ;; Regexp.
				 (when (string-match (caar var) group)
				   (cdar var)))
				((and group
				      (functionp (car var)))
				 ;; Function.
				 (funcall (car var) group))
				(t
				 (eval (car var) t))))))
	      (setq var (cdr var)))
	    result)))
	 name)
    (when (and (or groups gcc-self-val)
	       (gnus-alive-p))
      (when (stringp groups)
	(setq groups (list groups)))
      (save-excursion
	(save-restriction
	  (message-narrow-to-headers)
	  (goto-char (point-max))
	  (insert "Gcc: ")
	  (if gcc-self-val
	      ;; Use the `gcc-self' param value instead.
	      (progn
		(insert (if (listp gcc-self-val)
			    (mapconcat (lambda (val)
					 (funcall gcc-self-get val group))
				       gcc-self-val ", ")
			    (funcall gcc-self-get gcc-self-val group)))
		(if (not (eq gcc-self-val 'none))
		    (insert "\n")
		  (gnus-delete-line)))
	    ;; Use the list of groups.
	    (while (setq name (pop groups))
	      (let ((str (if (string-match ":" name)
			     name
			   (gnus-group-prefixed-name
			    name gnus-message-archive-method))))
		(insert (if (string-match " " str)
			    (concat "\"" str "\"")
			  str)))
	      (when groups
		(insert " ")))
	    (insert "\n")))))))

(defun gnus-mailing-list-followup-to ()
  "Look at the headers in the current buffer and return a Mail-Followup-To address."
  (let ((x-been-there (gnus-fetch-original-field "x-beenthere"))
	(list-post (gnus-fetch-original-field "list-post")))
    (when (and list-post
	       (string-match "mailto:\\([^>]+\\)" list-post))
      (setq list-post (match-string 1 list-post)))
    (or list-post
	x-been-there)))

;;; Posting styles.

(defun gnus-configure-posting-styles (&optional group-name)
  "Configure posting styles according to `gnus-posting-styles'."
  (unless gnus-inhibit-posting-styles
    (let ((group (or group-name gnus-newsgroup-name ""))
	  (styles (if (gnus-buffer-live-p gnus-summary-buffer)
		      (with-current-buffer gnus-summary-buffer
			gnus-posting-styles)
		    gnus-posting-styles))
	  match value v results matched-string ;; style attribute
	  filep name address element)
      ;; If the group has a posting-style parameter, add it at the end with a
      ;; regexp matching everything, to be sure it takes precedence over all
      ;; the others.
      (when gnus-newsgroup-name
	(let ((tmp-style (gnus-group-find-parameter group 'posting-style t)))
	  (when tmp-style
	    (dolist (style tmp-style)
	      (when (stringp (cadr style))
		(setcdr style (list (decode-coding-string (cadr style)
							  'utf-8)))))
	    (setq styles (append styles (list (cons ".*" tmp-style)))))))
      ;; Go through all styles and look for matches.
      (dolist (style styles)
	(setq match (pop style))
	(goto-char (point-min))
	(when (cond
	       ((stringp match)
		;; Regexp string match on the group name.
		(when (string-match match group)
                  (setq matched-string group)
                  t))
	       ((eq match 'header)
		;; Obsolete format of header match.
		(and (gnus-buffer-live-p gnus-article-copy)
		     (with-current-buffer gnus-article-copy
		       (save-restriction
			 (nnheader-narrow-to-headers)
			 (let ((header (message-fetch-field (pop style))))
			   (and header
				(string-match (pop style) header)))))))
	       ((or (symbolp match)
		    (functionp match))
		(cond
		 ((functionp match)
		  ;; Function to be called.
		  (funcall match))
		 ((boundp match)
		  ;; Variable to be checked.
		  (symbol-value match))))
	       ((listp match)
		(cond
		 ((eq (car match) 'header)
		  ;; New format of header match.
		  (and (gnus-buffer-live-p gnus-article-copy)
		       (with-current-buffer gnus-article-copy
			 (save-restriction
			   (nnheader-narrow-to-headers)
			   (let ((header (message-fetch-field (nth 1 match))))
			     (and header
				  (string-match (nth 2 match) header)
				  (setq matched-string header)))))))
		 (t
		  ;; This is a form to be evalled.
		  (eval match t)))))
	  ;; We have a match, so we set the variables.
	  (dolist (attribute style)
	    (setq element (pop attribute)
		  filep nil)
	    (setq value
		  (cond
		   ((eq (car attribute) :file)
		    (setq filep t)
		    (cadr attribute))
		   ((eq (car attribute) :value)
		    (cadr attribute))
		   (t
		    (car attribute))))
	    ;; We get the value.
	    (setq v
		  (cond
		   ((stringp value)
		    (if (and matched-string
			     (string-match-p "\\\\[&[:digit:]]" value)
			     (match-beginning 1))
			(match-substitute-replacement value nil nil
						      matched-string)
		      value))
		   ((or (symbolp value)
			(functionp value))
		    (cond ((functionp value)
			   (funcall value))
			  ((boundp value)
			   (symbol-value value))))
		   ((listp value)
		    (eval value t))))
	    ;; Translate obsolescent value.
	    (cond
	     ((eq element 'signature-file)
	      (setq element 'signature
		    filep t))
	     ((eq element 'x-face-file)
	      (setq element 'x-face
		    filep t)))
	    ;; Post-processing for the signature posting-style:
	    (and (eq element 'signature) filep
		 message-signature-directory
		 ;; don't actually use the signature directory
		 ;; if message-signature-file contains a path.
		 (not (file-name-directory v))
		 (setq v (nnheader-concat message-signature-directory v)))
	    ;; Get the contents of file elems.
	    (when (and filep v)
	      (setq v (with-temp-buffer
			(insert-file-contents v)
			(buffer-substring
			 (point-min)
			 (progn
			   (goto-char (point-max))
			   (if (zerop (skip-chars-backward "\n"))
			       (point)
			     (1+ (point))))))))
	    (setq results (delq (assoc element results) results))
	    (push (cons element v) results))))
      ;; Now we have all the styles, so we insert them.
      (setq name (assq 'name results)
	    address (assq 'address results))
      (setq results (delq name (delq address results)))
      (setq results (sort results (lambda (x y)
				    (string-lessp (car x) (car y)))))
      (dolist (result results)
	(add-hook 'message-setup-hook
		  (cond
		   ((eq 'eval (car result))
		    #'ignore)
		   ((eq 'body (car result))
		    (let ((txt (cdr result)))
		      (lambda ()
			(save-excursion
			  (message-goto-body)
			  (insert txt)))))
		   ((eq 'signature (car result))
                    (setq-local message-signature nil)
                    (setq-local message-signature-file nil)
		    (let ((txt (cdr result)))
		      (if (not txt)
			  #'ignore
			(lambda ()
			  (save-excursion
			    (let ((message-signature txt))
			      (when message-signature
			        (message-insert-signature))))))))
		   (t
		    (let ((header
			   (if (symbolp (car result))
			       (capitalize (symbol-name (car result)))
			     (car result)))
			  (value (cdr result)))
		      (lambda ()
			(save-excursion
			  (message-remove-header header)
			  (when value
			    (message-goto-eoh)
			    (insert header ": " value)
			    (unless (bolp)
			      (insert "\n"))))))))
		  nil 'local))
      (when (or name address)
	(add-hook 'message-setup-hook
		  (let ((name (or (cdr name) (user-full-name)))
		        (email (or (cdr address) user-mail-address)))
		    (lambda ()
                      (setq-local user-mail-address email)
		      (let ((user-full-name name)
			    (user-mail-address email))
			(save-excursion
			  (message-remove-header "From")
			  (message-goto-eoh)
			  (insert "From: " (message-make-from) "\n")))))
		  nil 'local)))))

(defun gnus-summary-attach-article (n)
  "Attach the current article(s) to an outgoing Message buffer.
If any current in-progress Message buffers exist, the articles
can be attached to them.  If not, a new Message buffer is
created.

This command uses the process/prefix convention, so if you
process-mark several articles, they will all be attached."
  (interactive "P" gnus-summary-mode)
  (let ((buffers (message-buffers))
	destination)
    ;; Set up the destination mail composition buffer.
    (if (and buffers
	     (y-or-n-p "Attach files to existing mail composition buffer? "))
	(setq destination
	      (if (= (length buffers) 1)
		  (get-buffer (car buffers))
		(gnus-completing-read "Attach to buffer"
                                      buffers t nil nil (car buffers))))
      (gnus-summary-mail-other-window)
      (setq destination (current-buffer)))
    (gnus-summary-expand-window)
    (gnus-summary-iterate n
      (gnus-summary-select-article)
      (with-current-buffer destination
	;; Attach at the end of the buffer.
	(save-excursion
	  (goto-char (point-max))
	  (message-forward-make-body-mime gnus-original-article-buffer))))
    (gnus-configure-windows 'message t)))

(provide 'gnus-msg)

;;; gnus-msg.el ends here