;; notmuch-show.el --- display notmuch messages within emacs
;;
;; Copyright © Carl Worth
;;
;; This file is part of Notmuch.
;;
;; Notmuch 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.
;;
;; Notmuch 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 Notmuch.  If not, see <http://www.gnu.org/licenses/>.
;;
;; Authors: Carl Worth <cworth@cworth.org>

;; This is an part of an emacs-based interface to the notmuch mail system.

(require 'cl)
(require 'mm-view)
(require 'message)

(require 'notmuch-lib)

(declare-function notmuch-call-notmuch-process "notmuch" (&rest args))
(declare-function notmuch-count-attachments "notmuch" (mm-handle))
(declare-function notmuch-reply "notmuch" (query-string))
(declare-function notmuch-fontify-headers "notmuch" nil)
(declare-function notmuch-toggle-invisible-action "notmuch" (cite-button))
(declare-function notmuch-select-tag-with-completion "notmuch" (prompt &rest search-terms))
(declare-function notmuch-search-show-thread "notmuch" nil)
(declare-function notmuch-save-attachments "notmuch" (mm-handle &optional queryp))

(defvar notmuch-show-stash-map
  (let ((map (make-sparse-keymap)))
    (define-key map "c" 'notmuch-show-stash-cc)
    (define-key map "d" 'notmuch-show-stash-date)
    (define-key map "F" 'notmuch-show-stash-filename)
    (define-key map "f" 'notmuch-show-stash-from)
    (define-key map "i" 'notmuch-show-stash-message-id)
    (define-key map "s" 'notmuch-show-stash-subject)
    (define-key map "T" 'notmuch-show-stash-tags)
    (define-key map "t" 'notmuch-show-stash-to)
    map)
  "Submap for stash commands"
  )

(fset 'notmuch-show-stash-map notmuch-show-stash-map)

(defvar notmuch-show-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "?" 'notmuch-help)
    (define-key map "q" 'kill-this-buffer)
    (define-key map (kbd "C-p") 'notmuch-show-previous-line)
    (define-key map (kbd "C-n") 'notmuch-show-next-line)
    (define-key map (kbd "M-TAB") 'notmuch-show-previous-button)
    (define-key map (kbd "TAB") 'notmuch-show-next-button)
    (define-key map "s" 'notmuch-search)
    (define-key map "m" 'message-mail)
    (define-key map "f" 'notmuch-show-forward-current)
    (define-key map "r" 'notmuch-show-reply)
    (define-key map "|" 'notmuch-show-pipe-message)
    (define-key map "w" 'notmuch-show-save-attachments)
    (define-key map "V" 'notmuch-show-view-raw-message)
    (define-key map "v" 'notmuch-show-view-all-mime-parts)
    (define-key map "c" 'notmuch-show-stash-map)
    (define-key map "b" 'notmuch-show-toggle-current-body)
    (define-key map "h" 'notmuch-show-toggle-current-header)
    (define-key map "-" 'notmuch-show-remove-tag)
    (define-key map "+" 'notmuch-show-add-tag)
    (define-key map "x" 'notmuch-show-archive-thread-then-exit)
    (define-key map "a" 'notmuch-show-archive-thread)
    (define-key map "P" 'notmuch-show-previous-message)
    (define-key map "N" 'notmuch-show-next-message)
    (define-key map "p" 'notmuch-show-previous-open-message)
    (define-key map "n" 'notmuch-show-next-open-message)
    (define-key map (kbd "DEL") 'notmuch-show-rewind)
    (define-key map " " 'notmuch-show-advance-and-archive)
    map)
  "Keymap for \"notmuch show\" buffers.")
(fset 'notmuch-show-mode-map notmuch-show-mode-map)

(defvar notmuch-show-signature-regexp "\\(-- ?\\|_+\\)$"
  "Pattern to match a line that separates content from signature.

The regexp can (and should) include $ to match the end of the
line, but should not include ^ to match the beginning of the
line. This is because notmuch may have inserted additional space
for indentation at the beginning of the line. But notmuch will
move past the indentation when testing this pattern, (so that the
pattern can still test against the entire line).")

(defvar notmuch-show-signature-button-format
  "[ %d-line signature. Click/Enter to toggle visibility. ]"
  "String used to construct button text for hidden signatures

Can use up to one integer format parameter, i.e. %d")

(defvar notmuch-show-citation-button-format
  "[ %d more citation lines. Click/Enter to toggle visibility. ]"
  "String used to construct button text for hidden citations.

Can use up to one integer format parameter, i.e. %d")

(defvar notmuch-show-signature-lines-max 12
  "Maximum length of signature that will be hidden by default.")

(defvar notmuch-show-citation-lines-prefix 4
  "Always show at least this many lines of a citation.

If there is one more line, show that, otherwise collapse
remaining lines into a button.")

(defvar notmuch-show-message-begin-regexp    "\fmessage{")
(defvar notmuch-show-message-end-regexp      "\fmessage}")
(defvar notmuch-show-header-begin-regexp     "\fheader{")
(defvar notmuch-show-header-end-regexp       "\fheader}")
(defvar notmuch-show-body-begin-regexp       "\fbody{")
(defvar notmuch-show-body-end-regexp         "\fbody}")
(defvar notmuch-show-attachment-begin-regexp "\fattachment{")
(defvar notmuch-show-attachment-end-regexp   "\fattachment}")
(defvar notmuch-show-part-begin-regexp       "\fpart{")
(defvar notmuch-show-part-end-regexp         "\fpart}")
(defvar notmuch-show-marker-regexp "\f\\(message\\|header\\|body\\|attachment\\|part\\)[{}].*$")

(defvar notmuch-show-id-regexp "\\(id:[^ ]*\\)")
(defvar notmuch-show-depth-match-regexp " depth:\\([0-9]*\\).*match:\\([01]\\) ")
(defvar notmuch-show-filename-regexp "filename:\\(.*\\)$")
(defvar notmuch-show-contentype-regexp "Content-type: \\(.*\\)")

(defvar notmuch-show-tags-regexp "(\\([^)]*\\))$")

(defvar notmuch-show-parent-buffer nil)
(defvar notmuch-show-body-read-visible nil)
(defvar notmuch-show-citations-visible nil)
(defvar notmuch-show-signatures-visible nil)
(defvar notmuch-show-headers-visible nil)

(defun notmuch-show-next-line ()
  "Like builtin `next-line' but ensuring we end on a visible character.

By advancing forward until reaching a visible character.

Unlike builtin `next-line' this version accepts no arguments."
  (interactive)
  (set 'this-command 'next-line)
  (call-interactively 'next-line)
  (while (point-invisible-p)
    (forward-char)))

(defun notmuch-show-previous-line ()
  "Like builtin `previous-line' but ensuring we end on a visible character.

By advancing forward until reaching a visible character.

Unlike builtin `previous-line' this version accepts no arguments."
  (interactive)
  (set 'this-command 'previous-line)
  (call-interactively 'previous-line)
  (while (point-invisible-p)
    (forward-char)))

(defun notmuch-show-get-message-id ()
  (save-excursion
    (beginning-of-line)
    (if (not (looking-at notmuch-show-message-begin-regexp))
	(re-search-backward notmuch-show-message-begin-regexp))
    (re-search-forward notmuch-show-id-regexp)
    (buffer-substring-no-properties (match-beginning 1) (match-end 1))))

(defun notmuch-show-get-filename ()
  (save-excursion
    (beginning-of-line)
    (if (not (looking-at notmuch-show-message-begin-regexp))
	(re-search-backward notmuch-show-message-begin-regexp))
    (re-search-forward notmuch-show-filename-regexp)
    (buffer-substring-no-properties (match-beginning 1) (match-end 1))))

(defun notmuch-show-set-tags (tags)
  (save-excursion
    (beginning-of-line)
    (if (not (looking-at notmuch-show-message-begin-regexp))
	(re-search-backward notmuch-show-message-begin-regexp))
    (re-search-forward notmuch-show-tags-regexp)
    (let ((inhibit-read-only t)
	  (beg (match-beginning 1))
	  (end (match-end 1)))
      (delete-region beg end)
      (goto-char beg)
      (insert (mapconcat 'identity tags " ")))))

(defun notmuch-show-get-tags ()
  (save-excursion
    (beginning-of-line)
    (if (not (looking-at notmuch-show-message-begin-regexp))
	(re-search-backward notmuch-show-message-begin-regexp))
    (re-search-forward notmuch-show-tags-regexp)
    (split-string (buffer-substring (match-beginning 1) (match-end 1)))))

(defun notmuch-show-get-bcc ()
  "Return BCC address(es) of current message"
  (notmuch-show-get-header-field 'bcc))

(defun notmuch-show-get-cc ()
  "Return CC address(es) of current message"
  (notmuch-show-get-header-field 'cc))

(defun notmuch-show-get-date ()
  "Return Date of current message"
  (notmuch-show-get-header-field 'date))

(defun notmuch-show-get-from ()
  "Return From address of current message"
  (notmuch-show-get-header-field 'from))

(defun notmuch-show-get-subject ()
  "Return Subject of current message"
  (notmuch-show-get-header-field 'subject))

(defun notmuch-show-get-to ()
  "Return To address(es) of current message"
  (notmuch-show-get-header-field 'to))

(defun notmuch-show-get-header-field (name)
  "Retrieve the header field NAME from the current message.
NAME should be a symbol, in lower case, as returned by
mail-header-extract-no-properties"
  (let* ((result (assoc name (notmuch-show-get-header)))
        (val (and result (cdr result))))
    val))

(defun notmuch-show-get-header ()
  "Retrieve and parse the header from the current message. Returns an alist with of (header . value)
where header is a symbol and value is a string.  The summary from notmuch-show is returned as the
pseudoheader summary"
  (require 'mailheader)
  (save-excursion
    (beginning-of-line)
    (if (not (looking-at notmuch-show-message-begin-regexp))
	(re-search-backward notmuch-show-message-begin-regexp))
    (re-search-forward (concat notmuch-show-header-begin-regexp "\n[[:space:]]*\\(.*\\)\n"))
    (let* ((summary (buffer-substring-no-properties (match-beginning 1) (match-end 1)))
	  (beg (point)))
      (re-search-forward notmuch-show-header-end-regexp)
      (let ((text (buffer-substring beg (match-beginning 0))))
	(with-temp-buffer
	  (insert text)
	  (goto-char (point-min))
	  (while (looking-at "\\([[:space:]]*\\)[A-Za-z][-A-Za-z0-9]*:")
	    (delete-region (match-beginning 1) (match-end 1))
	    (forward-line)
	    )
	  (goto-char (point-min))
	  (cons (cons 'summary summary) (mail-header-extract-no-properties)))))))

(defun notmuch-show-add-tag (&rest toadd)
  "Add a tag to the current message."
  (interactive
   (list (notmuch-select-tag-with-completion "Tag to add: ")))
  (apply 'notmuch-call-notmuch-process
	 (append (cons "tag"
		       (mapcar (lambda (s) (concat "+" s)) toadd))
		 (cons (notmuch-show-get-message-id) nil)))
  (notmuch-show-set-tags (sort (union toadd (notmuch-show-get-tags) :test 'string=) 'string<)))

(defun notmuch-show-remove-tag (&rest toremove)
  "Remove a tag from the current message."
  (interactive
   (list (notmuch-select-tag-with-completion "Tag to remove: " (notmuch-show-get-message-id))))
  (let ((tags (notmuch-show-get-tags)))
    (if (intersection tags toremove :test 'string=)
	(progn
	  (apply 'notmuch-call-notmuch-process
		 (append (cons "tag"
			       (mapcar (lambda (s) (concat "-" s)) toremove))
			 (cons (notmuch-show-get-message-id) nil)))
	  (notmuch-show-set-tags (sort (set-difference tags toremove :test 'string=) 'string<))))))

(defun notmuch-show-archive-thread ()
  "Archive each message in thread, then show next thread from search.

Archive each message currently shown by removing the \"inbox\"
tag from each. Then kill this buffer and show the next thread
from the search from which this thread was originally shown.

Note: This command is safe from any race condition of new messages
being delivered to the same thread. It does not archive the
entire thread, but only the messages shown in the current
buffer."
  (interactive)
  (save-excursion
    (goto-char (point-min))
    (while (not (eobp))
      (notmuch-show-remove-tag "inbox")
      (if (not (eobp))
	  (forward-char))
      (if (not (re-search-forward notmuch-show-message-begin-regexp nil t))
	  (goto-char (point-max)))))
  (let ((parent-buffer notmuch-show-parent-buffer))
    (kill-this-buffer)
    (if parent-buffer
	(progn
	  (switch-to-buffer parent-buffer)
	  (forward-line)
	  (notmuch-search-show-thread)))))

(defun notmuch-show-archive-thread-then-exit ()
  "Archive each message in thread, then exit back to search results."
  (interactive)
  (notmuch-show-archive-thread)
  (kill-this-buffer))

(defun notmuch-show-view-raw-message ()
  "View the raw email of the current message."
  (interactive)
  (view-file (notmuch-show-get-filename)))

(defmacro with-current-notmuch-show-message (&rest body)
  "Evaluate body with current buffer set to the text of current message"
  `(save-excursion
     (let ((filename (notmuch-show-get-filename)))
       (let ((buf (generate-new-buffer (concat "*notmuch-msg-" filename "*"))))
         (with-current-buffer buf
           (insert-file-contents filename nil nil nil t)
           ,@body)
	 (kill-buffer buf)))))

(defun notmuch-show-view-all-mime-parts ()
  "Use external viewers to view all attachments from the current message."
  (interactive)
  (with-current-notmuch-show-message
   ; We ovverride the mm-inline-media-tests to indicate which message
   ; parts are already sufficiently handled by the original
   ; presentation of the message in notmuch-show mode. These parts
   ; will be inserted directly into the temporary buffer of
   ; with-current-notmuch-show-message and silently discarded.
   ;
   ; Any MIME part not explicitly mentioned here will be handled by an
   ; external viewer as configured in the various mailcap files.
   (let ((mm-inline-media-tests '(
				  ("text/.*" ignore identity)
				  ("application/pgp-signature" ignore identity)
				  ("multipart/alternative" ignore identity)
				  ("multipart/mixed" ignore identity)
				  ("multipart/related" ignore identity)
				 )))
     (mm-display-parts (mm-dissect-buffer)))))

(defun notmuch-show-save-attachments ()
  "Save all attachments from the current message."
  (interactive)
  (with-current-notmuch-show-message
   (let ((mm-handle (mm-dissect-buffer)))
     (notmuch-save-attachments
      mm-handle (> (notmuch-count-attachments mm-handle) 1))))
  (message "Done"))

(defun notmuch-show-reply ()
  "Begin composing a reply to the current message in a new buffer."
  (interactive)
  (let ((message-id (notmuch-show-get-message-id)))
    (notmuch-reply message-id)))

(defun notmuch-show-forward-current ()
  "Forward the current message."
  (interactive)
  (with-current-notmuch-show-message
   (message-forward)))

(defun notmuch-show-pipe-message (command)
  "Pipe the contents of the current message to the given command.

The given command will be executed with the raw contents of the
current email message as stdin. Anything printed by the command
to stdout or stderr will appear in the *Messages* buffer."
  (interactive "sPipe message to command: ")
  (apply 'start-process-shell-command "notmuch-pipe-command" "*notmuch-pipe*"
	 (list command " < " (shell-quote-argument (notmuch-show-get-filename)))))

(defun notmuch-show-move-to-current-message-summary-line ()
  "Move to the beginning of the one-line summary of the current message.

This gives us a stable place to move to and work from since the
summary line is always visible. This is important since moving to
an invisible location is unreliable, (the main command loop moves
point either forward or backward to the next visible character
when a command ends with point on an invisible character).

Emits an error if point is not within a valid message, (that is
no pattern of `notmuch-show-message-begin-regexp' could be found
by searching backward)."
  (beginning-of-line)
  (if (not (looking-at notmuch-show-message-begin-regexp))
      (if (re-search-backward notmuch-show-message-begin-regexp nil t)
	  (forward-line 2)
	(error "Not within a valid message."))
    (forward-line 2)))

(defun notmuch-show-last-message-p ()
  "Predicate testing whether point is within the last message."
  (save-window-excursion
    (save-excursion
      (notmuch-show-move-to-current-message-summary-line)
      (not (re-search-forward notmuch-show-message-begin-regexp nil t)))))

(defun notmuch-show-message-unread-p ()
  "Predicate testing whether current message is unread."
  (member "unread" (notmuch-show-get-tags)))

(defun notmuch-show-message-open-p ()
  "Predicate testing whether current message is open (body is visible)."
  (let ((btn (previous-button (point) t)))
    (while (not (button-has-type-p btn 'notmuch-button-body-toggle-type))
      (setq btn (previous-button (button-start btn))))
    (not (invisible-p (button-get btn 'invisibility-spec)))))

(defun notmuch-show-next-message-without-marking-read ()
  "Advance to the beginning of the next message in the buffer.

Moves to the last visible character of the current message if
already on the last message in the buffer.

Returns nil if already on the last message in the buffer."
  (notmuch-show-move-to-current-message-summary-line)
  (if (re-search-forward notmuch-show-message-begin-regexp nil t)
      (progn
	(notmuch-show-move-to-current-message-summary-line)
	(recenter 0)
	t)
    (goto-char (- (point-max) 1))
    (while (point-invisible-p)
      (backward-char))
    (recenter 0)
    nil))

(defun notmuch-show-next-message ()
  "Advance to the next message (whether open or closed)
and remove the unread tag from that message.

Moves to the last visible character of the current message if
already on the last message in the buffer.

Returns nil if already on the last message in the buffer."
  (interactive)
  (notmuch-show-next-message-without-marking-read)
  (notmuch-show-mark-read))

(defun notmuch-show-find-next-message ()
  "Returns the position of the next message in the buffer.

Or the position of the last visible character of the current
message if already within the last message in the buffer."
  ; save-excursion doesn't save our window position
  ; save-window-excursion doesn't save point
  ; Looks like we have to use both.
  (save-excursion
    (save-window-excursion
      (notmuch-show-next-message-without-marking-read)
      (point))))

(defun notmuch-show-next-unread-message ()
  "Advance to the next unread message.

Moves to the last visible character of the current message if
there are no more unread messages past the current point."
  (notmuch-show-next-message-without-marking-read)
  (while (and (not (notmuch-show-last-message-p))
	      (not (notmuch-show-message-unread-p)))
    (notmuch-show-next-message-without-marking-read))
  (if (not (notmuch-show-message-unread-p))
      (notmuch-show-next-message-without-marking-read))
  (notmuch-show-mark-read))

(defun notmuch-show-next-open-message ()
  "Advance to the next open message (that is, body is visible).

Moves to the last visible character of the final message in the buffer
if there are no more open messages."
  (interactive)
  (while (and (notmuch-show-next-message-without-marking-read)
	      (not (notmuch-show-message-open-p))))
  (notmuch-show-mark-read))

(defun notmuch-show-previous-message-without-marking-read ()
  "Backup to the beginning of the previous message in the buffer.

If within a message rather than at the beginning of it, then
simply move to the beginning of the current message.

Returns nil if already on the first message in the buffer."
  (let ((start (point)))
    (notmuch-show-move-to-current-message-summary-line)
    (if (not (< (point) start))
	; Go backward twice to skip the current message's marker
	(progn
	  (re-search-backward notmuch-show-message-begin-regexp nil t)
	  (re-search-backward notmuch-show-message-begin-regexp nil t)
	  (notmuch-show-move-to-current-message-summary-line)
	  (recenter 0)
	  (if (= (point) start)
	      nil
	    t))
      (recenter 0)
      nil)))

(defun notmuch-show-previous-message ()
  "Backup to the previous message (whether open or closed)
and remove the unread tag from that message.

If within a message rather than at the beginning of it, then
simply move to the beginning of the current message."
  (interactive)
  (notmuch-show-previous-message-without-marking-read)
  (notmuch-show-mark-read))

(defun notmuch-show-find-previous-message ()
  "Returns the position of the previous message in the buffer.

Or the position of the beginning of the current message if point
is originally within the message rather than at the beginning of
it."
  ; save-excursion doesn't save our window position
  ; save-window-excursion doesn't save point
  ; Looks like we have to use both.
  (save-excursion
    (save-window-excursion
      (notmuch-show-previous-message-without-marking-read)
      (point))))

(defun notmuch-show-previous-open-message ()
  "Backup to previous open message (that is, body is visible).

Moves to the first message in the buffer if there are no previous
open messages."
  (interactive)
  (while (and (notmuch-show-previous-message-without-marking-read)
	      (not (notmuch-show-message-open-p))))
  (notmuch-show-mark-read))

(defun notmuch-show-rewind ()
  "Backup through the thread, (reverse scrolling compared to \\[notmuch-show-advance-and-archive]).

Specifically, if the beginning of the previous email is fewer
than `window-height' lines from the current point, move to it
just like `notmuch-show-previous-message'.

Otherwise, just scroll down a screenful of the current message.

This command does not modify any message tags, (it does not undo
any effects from previous calls to
`notmuch-show-advance-and-archive'."
  (interactive)
  (let ((previous (notmuch-show-find-previous-message)))
    (if (> (count-lines previous (point)) (- (window-height) next-screen-context-lines))
	(progn
	  (condition-case nil
	      (scroll-down nil)
	    ((beginning-of-buffer) nil))
	  (goto-char (window-start))
	  ; Because count-lines counts invivisible lines, we may have
	  ; scrolled to far. If so., notice this and fix it up.
	  (if (< (point) previous)
	      (progn
		(goto-char previous)
		(recenter 0))))
      (notmuch-show-previous-message))))

(defun notmuch-show-advance-and-archive ()
  "Advance through thread and archive.

This command is intended to be one of the simplest ways to
process a thread of email. It does the following:

If the current message in the thread is not yet fully visible,
scroll by a near screenful to read more of the message.

Otherwise, (the end of the current message is already within the
current window), advance to the next open message.

Finally, if there is no further message to advance to, and this
last message is already read, then archive the entire current
thread, (remove the \"inbox\" tag from each message). Also kill
this buffer, and display the next thread from the search from
which this thread was originally shown."
  (interactive)
  (let ((next (notmuch-show-find-next-message))
	(unread (notmuch-show-message-unread-p)))
    (if (> next (window-end))
	(scroll-up nil)
      (let ((last (notmuch-show-last-message-p)))
	(notmuch-show-next-open-message)
	(if last
	    (notmuch-show-archive-thread))))))

(defun notmuch-show-next-button ()
  "Advance point to the next button in the buffer."
  (interactive)
  (forward-button 1))

(defun notmuch-show-previous-button ()
  "Move point back to the previous button in the buffer."
  (interactive)
  (backward-button 1))

(defun notmuch-show-toggle-current-body ()
  "Toggle the display of the current message body."
  (interactive)
  (save-excursion
    (notmuch-show-move-to-current-message-summary-line)
    (unless (button-at (point))
      (notmuch-show-next-button))
    (push-button))
  )

(defun notmuch-show-toggle-current-header ()
  "Toggle the display of the current message header."
  (interactive)
  (save-excursion
    (notmuch-show-move-to-current-message-summary-line)
    (forward-line)
    (unless (button-at (point))
      (notmuch-show-next-button))
    (push-button))
  )

(defun notmuch-show-citation-regexp (depth)
  "Build a regexp for matching citations at a given DEPTH (indent)"
  (let ((line-regexp (format "[[:space:]]\\{%d\\}>.*\n" depth)))
    (concat "\\(?:^" line-regexp
	    "\\(?:[[:space:]]*\n" line-regexp
	    "\\)?\\)+")))

(defun notmuch-show-region-to-button (beg end type prefix button-text)
  "Auxilary function to do the actual making of overlays and buttons

BEG and END are buffer locations. TYPE should a string, either
\"citation\" or \"signature\". PREFIX is some arbitrary text to
insert before the button, probably for indentation.  BUTTON-TEXT
is what to put on the button."

;; This uses some slightly tricky conversions between strings and
;; symbols because of the way the button code works. Note that
;; replacing intern-soft with make-symbol will cause this to fail,
;; since the newly created symbol has no plist.

  (let ((overlay (make-overlay beg end))
	(invis-spec (make-symbol (concat "notmuch-" type "-region")))
	(button-type (intern-soft (concat "notmuch-button-"
					  type "-toggle-type"))))
    (add-to-invisibility-spec invis-spec)
    (overlay-put overlay 'invisible invis-spec)
    (goto-char (1+ end))
    (save-excursion
      (goto-char (1- beg))
      (insert prefix)
      (insert-button button-text
		     'invisibility-spec invis-spec
		     :type button-type)
      )))

(defun notmuch-show-markup-citations-region (beg end depth)
  "Markup citations, and up to one signature in the given region"
  ;; it would be nice if the untabify was not required, but
  ;; that would require notmuch to indent with spaces.
  (untabify beg end)
  (let ((citation-regexp (notmuch-show-citation-regexp depth))
	(signature-regexp (concat (format "^[[:space:]]\\{%d\\}" depth)
				  notmuch-show-signature-regexp))
	(indent (concat "\n" (make-string depth ? ))))
    (goto-char beg)
    (beginning-of-line)
    (while (and (< (point) end)
		(re-search-forward citation-regexp end t))
      (let* ((cite-start (match-beginning 0))
	     (cite-end 	(match-end 0))
	     (cite-lines (count-lines cite-start cite-end)))
	(overlay-put (make-overlay cite-start cite-end) 'face 'message-cited-text-face)
	(when (> cite-lines (1+ notmuch-show-citation-lines-prefix))
	  (goto-char cite-start)
	  (forward-line notmuch-show-citation-lines-prefix)
	  (notmuch-show-region-to-button
	   (point) cite-end
	   "citation"
	   indent
	   (format notmuch-show-citation-button-format
		   (- cite-lines notmuch-show-citation-lines-prefix))
	   ))))
    (if (and (< (point) end)
	     (re-search-forward signature-regexp end t))
	(let* ((sig-start (match-beginning 0))
	       (sig-end (match-end 0))
	       (sig-lines (1- (count-lines sig-start end))))
	  (if (<= sig-lines notmuch-show-signature-lines-max)
	      (progn
		(overlay-put (make-overlay sig-start end) 'face 'message-cited-text-face)
		(notmuch-show-region-to-button
		 sig-start
		 end
		 "signature"
		 indent
		 (format notmuch-show-signature-button-format sig-lines)
		 )))))))

(defun notmuch-show-markup-part (beg end depth)
  (if (re-search-forward notmuch-show-part-begin-regexp nil t)
      (progn
        (let (mime-message mime-type)
          (save-excursion
            (re-search-forward notmuch-show-contentype-regexp end t)
            (setq mime-type (car (split-string (buffer-substring
                                                (match-beginning 1) (match-end 1))))))

          (if (equal mime-type "text/html")
              (let ((filename (notmuch-show-get-filename)))
                (with-temp-buffer
                  (insert-file-contents filename nil nil nil t)
                  (setq mime-message (mm-dissect-buffer)))))
          (forward-line)
          (let ((beg (point-marker)))
            (re-search-forward notmuch-show-part-end-regexp)
            (let ((end (copy-marker (match-beginning 0))))
              (goto-char end)
              (if (not (bolp))
                  (insert "\n"))
              (indent-rigidly beg end depth)
              (if (not (eq mime-message nil))
                  (save-excursion
                    (goto-char beg)
                    (forward-line -1)
                    (let ((handle-type (mm-handle-type mime-message))
                          mime-type)
                      (if (sequencep (car handle-type))
                          (setq mime-type (car handle-type))
                        (setq mime-type (car (car (cdr handle-type))))
                        )
                      (if (equal mime-type "text/html")
                          (mm-display-part mime-message))))
                )
              (notmuch-show-markup-citations-region beg end depth)
              ; Advance to the next part (if any) (so the outer loop can
              ; determine whether we've left the current message.
              (if (re-search-forward notmuch-show-part-begin-regexp nil t)
                  (beginning-of-line)))))
        (goto-char end))
    (goto-char end)))

(defun notmuch-show-markup-parts-region (beg end depth)
  (save-excursion
    (goto-char beg)
    (while (< (point) end)
      (notmuch-show-markup-part beg end depth))))

(defun notmuch-show-markup-body (depth match btn)
  "Markup a message body, (indenting, buttonizing citations,
etc.), and hiding the body itself if the message does not match
the current search.

DEPTH specifies the depth at which this message appears in the
tree of the current thread, (the top-level messages have depth 0
and each reply increases depth by 1). MATCH indicates whether
this message is regarded as matching the current search. BTN is
the button which is used to toggle the visibility of this
message.

When this function is called, point must be within the message, but
before the delimiter marking the beginning of the body."
  (re-search-forward notmuch-show-body-begin-regexp)
  (forward-line)
  (let ((beg (point-marker)))
    (re-search-forward notmuch-show-body-end-regexp)
    (let ((end (copy-marker (match-beginning 0))))
      (notmuch-show-markup-parts-region beg end depth)
      (let ((invis-spec (make-symbol "notmuch-show-body-read")))
        (overlay-put (make-overlay beg end)
                     'invisible invis-spec)
        (button-put btn 'invisibility-spec invis-spec)
        (if (not match)
            (add-to-invisibility-spec invis-spec)))
      (set-marker beg nil)
      (set-marker end nil)
      )))

(defun notmuch-show-markup-header (message-begin depth)
  "Buttonize and decorate faces in a message header.

MESSAGE-BEGIN is the position of the absolute first character in
the message (including all delimiters that will end up being
invisible etc.). This is to allow a button to reliably extend to
the beginning of the message even if point is positioned at an
invisible character (such as the beginning of the buffer).

DEPTH specifies the depth at which this message appears in the
tree of the current thread, (the top-level messages have depth 0
and each reply increases depth by 1)."
  (re-search-forward notmuch-show-header-begin-regexp)
  (forward-line)
  (let ((beg (point-marker))
	(summary-end (copy-marker (line-beginning-position 2)))
	(subject-end (copy-marker (line-end-position 2)))
	(invis-spec (make-symbol "notmuch-show-header"))
        (btn nil))
    (re-search-forward notmuch-show-header-end-regexp)
    (beginning-of-line)
    (let ((end (point-marker)))
      (indent-rigidly beg end depth)
      (goto-char beg)
      (setq btn (make-button message-begin summary-end :type 'notmuch-button-body-toggle-type))
      (forward-line)
      (add-to-invisibility-spec invis-spec)
      (overlay-put (make-overlay subject-end end)
		   'invisible invis-spec)
      (make-button (line-beginning-position) subject-end
		   'invisibility-spec invis-spec
		   :type 'notmuch-button-headers-toggle-type)
      (while (looking-at "[[:space:]]*[A-Za-z][-A-Za-z0-9]*:")
	(beginning-of-line)
	(notmuch-fontify-headers)
	(forward-line)
	)
      (goto-char end)
      (insert "\n")
      (set-marker beg nil)
      (set-marker summary-end nil)
      (set-marker subject-end nil)
      (set-marker end nil)
      )
  btn))

(defun notmuch-show-markup-message ()
  (if (re-search-forward notmuch-show-message-begin-regexp nil t)
      (let ((message-begin (match-beginning 0)))
	(re-search-forward notmuch-show-depth-match-regexp)
	(let ((depth (string-to-number (buffer-substring (match-beginning 1) (match-end 1))))
	      (match (string= "1" (buffer-substring (match-beginning 2) (match-end 2))))
              (btn nil))
	  (setq btn (notmuch-show-markup-header message-begin depth))
	  (notmuch-show-markup-body depth match btn)))
    (goto-char (point-max))))

(defun notmuch-show-hide-markers ()
  (save-excursion
    (goto-char (point-min))
    (while (not (eobp))
      (if (re-search-forward notmuch-show-marker-regexp nil t)
	  (progn
	    (overlay-put (make-overlay (match-beginning 0) (+ (match-end 0) 1))
			 'invisible 'notmuch-show-marker))
	(goto-char (point-max))))))

(defun notmuch-show-markup-messages ()
  (save-excursion
    (goto-char (point-min))
    (while (not (eobp))
      (notmuch-show-markup-message)))
  (notmuch-show-hide-markers))

;;;###autoload
(defun notmuch-show-mode ()
  "Major mode for viewing a thread with notmuch.

This buffer contains the results of the \"notmuch show\" command
for displaying a single thread of email from your email archives.

By default, various components of email messages, (citations,
signatures, already-read messages), are hidden. You can make
these parts visible by clicking with the mouse button or by
pressing RET after positioning the cursor on a hidden part, (for
which \\[notmuch-show-next-button] and \\[notmuch-show-previous-button] are helpful).

Reading the thread sequentially is well-supported by pressing
\\[notmuch-show-advance-and-archive]. This will
scroll the current message (if necessary), advance to the next
message, or advance to the next thread (if already on the last
message of a thread).

Other commands are available to read or manipulate the thread more
selectively, (such as '\\[notmuch-show-next-message]' and '\\[notmuch-show-previous-message]' to advance to messages without
removing any tags, and '\\[notmuch-show-archive-thread]' to archive an entire thread without
scrolling through with \\[notmuch-show-advance-and-archive]).

You can add or remove arbitary tags from the current message with
'\\[notmuch-show-add-tag]' or '\\[notmuch-show-remove-tag]'.

All currently available key bindings:

\\{notmuch-show-mode-map}"
  (interactive)
  (kill-all-local-variables)
  (add-to-invisibility-spec 'notmuch-show-marker)
  (use-local-map notmuch-show-mode-map)
  (setq major-mode 'notmuch-show-mode
	mode-name "notmuch-show")
  (setq buffer-read-only t))

(defcustom notmuch-show-hook nil
  "List of functions to call when notmuch displays a message."
  :type 'hook
  :options '(goto-address)
  :group 'notmuch)

(defun notmuch-show-do-stash (text)
    (kill-new text)
    (message (concat "Saved: " text)))

(defun notmuch-show-stash-cc ()
  "Copy CC field of current message to kill-ring."
  (interactive)
  (notmuch-show-do-stash (notmuch-show-get-cc)))

(defun notmuch-show-stash-date ()
  "Copy date of current message to kill-ring."
  (interactive)
  (notmuch-show-do-stash (notmuch-show-get-date)))

(defun notmuch-show-stash-filename ()
  "Copy filename of current message to kill-ring."
  (interactive)
  (notmuch-show-do-stash (notmuch-show-get-filename)))

(defun notmuch-show-stash-from ()
  "Copy From address of current message to kill-ring."
  (interactive)
  (notmuch-show-do-stash (notmuch-show-get-from)))

(defun notmuch-show-stash-message-id ()
  "Copy message ID of current message to kill-ring."
  (interactive)
  (notmuch-show-do-stash (notmuch-show-get-message-id)))

(defun notmuch-show-stash-subject ()
  "Copy Subject field of current message to kill-ring."
  (interactive)
  (notmuch-show-do-stash (notmuch-show-get-subject)))

(defun notmuch-show-stash-tags ()
  "Copy tags of current message to kill-ring as a comma separated list."
  (interactive)
  (notmuch-show-do-stash (mapconcat 'identity (notmuch-show-get-tags) ",")))

(defun notmuch-show-stash-to ()
  "Copy To address of current message to kill-ring."
  (interactive)
  (notmuch-show-do-stash (notmuch-show-get-to)))

; Make show mode a bit prettier, highlighting URLs and using word wrap

(defun notmuch-show-mark-read ()
  (notmuch-show-remove-tag "unread"))

(defun notmuch-show-pretty-hook ()
  (goto-address-mode 1)
  (visual-line-mode))

(add-hook 'notmuch-show-hook 'notmuch-show-mark-read)
(add-hook 'notmuch-show-hook 'notmuch-show-pretty-hook)
(add-hook 'notmuch-search-hook
	  (lambda()
	    (hl-line-mode 1) ))

(defun notmuch-show (thread-id &optional parent-buffer query-context buffer-name)
  "Run \"notmuch show\" with the given thread ID and display results.

The optional PARENT-BUFFER is the notmuch-search buffer from
which this notmuch-show command was executed, (so that the next
thread from that buffer can be show when done with this one).

The optional QUERY-CONTEXT is a notmuch search term. Only
messages from the thread matching this search term are shown if
non-nil.

The optional BUFFER-NAME provides the name of the buffer in which
the message thread is shown. If it is nil (which occurs when the
command is called interactively) the argument to the function is
used."
  (interactive "sNotmuch show: ")
  (when (null buffer-name)
    (setq buffer-name (concat "*notmuch-" thread-id "*")))
  (let* ((thread-buffer-name (generate-new-buffer-name buffer-name))
	 (buffer (get-buffer-create thread-buffer-name)))
    (switch-to-buffer buffer)
    (notmuch-show-mode)
    (set (make-local-variable 'notmuch-show-parent-buffer) parent-buffer)
    (let ((proc (get-buffer-process (current-buffer)))
	  (inhibit-read-only t))
      (if proc
	  (error "notmuch search process already running for query `%s'" thread-id)
	)
      (erase-buffer)
      (goto-char (point-min))
      (save-excursion
	(let* ((basic-args (list notmuch-command nil t nil "show" "--entire-thread" thread-id))
		(args (if query-context (append basic-args (list "and (" query-context ")")) basic-args)))
	  (apply 'call-process args)
	  (when (and (eq (buffer-size) 0) query-context)
	    (apply 'call-process basic-args)))
	(notmuch-show-markup-messages)
	)
      (run-hooks 'notmuch-show-hook)
      ; Move straight to the first open message
      (if (not (notmuch-show-message-open-p))
	  (notmuch-show-next-open-message))
      )))

(provide 'notmuch-show)