; notmuch.el --- run notmuch 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 emacs-based interface to the notmuch mail system.
;
; You will first need to have the notmuch program installed and have a
; notmuch database built in order to use this. See
; http://notmuchmail.org for details.
;
; To install this software, copy it to a directory that is on the
; `load-path' variable within emacs (a good candidate is
; /usr/local/share/emacs/site-lisp). If you are viewing this from the
; notmuch source distribution then you can simply run:
;
;	sudo make install-emacs
;
; to install it.
;
; Then, to actually run it, add:
;
;	(require 'notmuch)
;
; to your ~/.emacs file, and then run "M-x notmuch" from within emacs,
; or run:
;
;	emacs -f notmuch
;
; Have fun, and let us know if you have any comment, questions, or
; kudos: Notmuch list <notmuch@notmuchmail.org> (subscription is not
; required, but is available from http://notmuchmail.org).

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

(defvar notmuch-show-mode-map
  (let ((map (make-sparse-keymap)))
    ; I don't actually want all of these toggle commands occupying
    ; keybindings. They steal valuable key-binding space, are hard
    ; to remember, and act globally rather than locally.
    ;
    ; Will be much preferable to switch to direct manipulation for
    ; toggling visibility of these components. Probably using
    ; overlays-at to query and manipulate the current overlay.
    (define-key map "a" 'notmuch-show-archive-thread)
    (define-key map "A" 'notmuch-show-mark-read-then-archive-thread)
    (define-key map "f" 'notmuch-show-forward-current)
    (define-key map "m" 'message-mail)
    (define-key map "MA" 'notmuch-show-wide-reply-current)
    (define-key map "MR" 'notmuch-show-reply-current)
    (define-key map "MF" 'notmuch-show-followup-current)
    (define-key map "n" 'notmuch-show-next-message)
    (define-key map "N" 'notmuch-show-mark-read-then-next-open-message)
    (define-key map "p" 'notmuch-show-previous-message)
    (define-key map (kbd "C-n") 'notmuch-show-next-line)
    (define-key map (kbd "C-p") 'notmuch-show-previous-line)
    (define-key map "q" 'kill-this-buffer)
    (define-key map "r" 'notmuch-show-reply)
    (define-key map "s" 'notmuch-search)
    (define-key map "v" 'notmuch-show-view-all-mime-parts)
    (define-key map "w" 'notmuch-show-view-raw-message)
    (define-key map "x" 'kill-this-buffer)
    (define-key map "+" 'notmuch-show-add-tag)
    (define-key map "-" 'notmuch-show-remove-tag)
    (define-key map (kbd "DEL") 'notmuch-show-rewind)
    (define-key map " " 'notmuch-show-advance-marking-read-and-archiving)
    (define-key map "|" 'notmuch-show-pipe-message)
    (define-key map "?" 'describe-mode)
    (define-key map (kbd "TAB") 'notmuch-show-next-button)
    (define-key map (kbd "M-TAB") 'notmuch-show-previous-button)
    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-lines-max 12
  "Maximum length of signature that will be hidden by default.")

(defvar notmuch-command "notmuch"
  "Command to run the notmuch binary.")

(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-regexp " depth:\\([0-9]*\\) ")
(defvar notmuch-show-filename-regexp "filename:\\(.*\\)$")
(defvar notmuch-show-tags-regexp "(\\([^)]*\\))$")

(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)

; XXX: This should be a generic function in emacs somewhere, not here
(defun point-invisible-p ()
  "Return whether the character at point is invisible.

Here visibility is determined by `buffer-invisibility-spec' and
the invisible property of any overlays for point. It doesn't have
anything to do with whether point is currently being displayed
within the current window."
  (let ((prop (get-char-property (point) 'invisible)))
    (if (eq buffer-invisibility-spec t)
	prop
      (or (memq prop buffer-invisibility-spec)
	  (assq prop buffer-invisibility-spec)))))

(defun notmuch-select-tag-with-completion (prompt &rest search-terms)
  (let ((tag-list
	 (with-output-to-string
	   (with-current-buffer standard-output
	     (apply 'call-process notmuch-command nil t nil "search-tags" search-terms)))))
    (completing-read prompt (split-string tag-list "\n+" t) nil nil 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 `next-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-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-maybe-mark-read (markread)
  (save-excursion
    (goto-char (point-min))
    (while (not (eobp))
      (if markread
	  (notmuch-show-remove-tag "unread" "inbox")
	(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-mark-read-then-archive-thread ()
  "Remove \"unread\" tag from each message, then archive and show next thread.

Archive each message currently shown by removing the \"unread\"
and \"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)
  (notmuch-show-archive-thread-maybe-mark-read t))

(defun notmuch-show-archive-thread ()
  "Archive each message in thread, and 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)
  (notmuch-show-archive-thread-maybe-mark-read nil))

(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 (according to mailcap) to view all MIME-encoded parts."
  (interactive)
  (with-current-notmuch-show-message
   (mm-display-parts (mm-dissect-buffer))))

(defun notmuch-reply (query-string)
  (switch-to-buffer (generate-new-buffer "notmuch-draft"))
  (call-process notmuch-command nil t nil "reply" query-string)
  (message-insert-signature)
  (goto-char (point-min))
  (if (re-search-forward "^$" nil t)
      (progn
	(insert "--text follows this line--")
	(forward-line)))
  (message-mode))

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

(defun notmuch-show-reply-current ()
  (interactive)
  (with-current-notmuch-show-message
   (message-reply)))

(defun notmuch-show-wide-reply-current ()
  (interactive)
  (with-current-notmuch-show-message
   (message-wide-reply)))

(defun notmuch-show-followup-current ()
  (interactive)
  (with-current-notmuch-show-message
   (message-followup)))

(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
not 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 ()
  "Preficate testing whether current message is unread."
  (member "unread" (notmuch-show-get-tags)))

(defun notmuch-show-next-message ()
  "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."
  (interactive)
  (notmuch-show-move-to-current-message-summary-line)
  (if (re-search-forward notmuch-show-message-begin-regexp nil t)
      (notmuch-show-move-to-current-message-summary-line)
    (goto-char (- (point-max) 1))
    (while (point-invisible-p)
      (backward-char)))
  (recenter 0))

(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)
      (point))))

(defun notmuch-show-next-unread-message ()
  "Advance to the beginning of the next unread message in the buffer.

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)
  (while (and (not (notmuch-show-last-message-p))
	      (not (notmuch-show-message-unread-p)))
    (notmuch-show-next-message))
  (if (not (notmuch-show-message-unread-p))
      (notmuch-show-next-message)))

(defun notmuch-show-next-open-message ()
  "Advance to the next message which is not hidden.

If read messages are currently hidden, advance to the next unread
message. Otherwise, advance to the next message."
  (if (or (memq 'notmuch-show-body-read buffer-invisibility-spec)
	  (assq 'notmuch-show-body-read buffer-invisibility-spec))
      (notmuch-show-next-unread-message)
    (notmuch-show-next-message)))

(defun notmuch-show-previous-message ()
  "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."
  (interactive)
  (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)))

(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)
      (point))))

(defun notmuch-show-mark-read-then-next-open-message ()
  "Remove unread tag from current message, then advance to next unread message."
  (interactive)
  (notmuch-show-remove-tag "unread")
  (notmuch-show-next-open-message))

(defun notmuch-show-rewind ()
  "Do reverse scrolling compared to `notmuch-show-advance-marking-read-and-archiving'

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-marking-read-and-archiving'."
  (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)))
      (notmuch-show-previous-message))))

(defun notmuch-show-advance-marking-read-and-archiving ()
  "Advance through buffer, marking read and archiving.

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), remove the \"unread\" tag (if present) from the
current message and 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-mark-read-then-next-open-message)
	(if last
	    (notmuch-show-archive-thread))))))

(defun notmuch-show-next-button ()
  "Advance point to the next button in the buffer."
  (interactive)
  (goto-char (button-start (next-button (point)))))

(defun notmuch-show-previous-button ()
  "Move point back to the previous button in the buffer."
  (interactive)
  (goto-char (button-start (previous-button (point)))))

(defun notmuch-toggle-invisible-action (cite-button)
  (let ((invis-spec (button-get button 'invisibility-spec)))
        (if (invisible-p invis-spec)
            (remove-from-invisibility-spec invis-spec)
          (add-to-invisibility-spec invis-spec)
          ))
  (force-window-update)
  (redisplay t))

(define-button-type 'notmuch-button-invisibility-toggle-type 'action 'notmuch-toggle-invisible-action 'follow-link t)
(define-button-type 'notmuch-button-citation-toggle-type 'help-echo "mouse-1, RET: Show citation"
  :supertype 'notmuch-button-invisibility-toggle-type)
(define-button-type 'notmuch-button-signature-toggle-type 'help-echo "mouse-1, RET: Show signature"
  :supertype 'notmuch-button-invisibility-toggle-type)
(define-button-type 'notmuch-button-headers-toggle-type 'help-echo "mouse-1, RET: Show headers"
  :supertype 'notmuch-button-invisibility-toggle-type)
(define-button-type 'notmuch-button-body-toggle-type 'help-echo "mouse-1, RET: Show message"
  :supertype 'notmuch-button-invisibility-toggle-type)

(defun notmuch-show-markup-citations-region (beg end depth)
  (goto-char beg)
  (beginning-of-line)
  (while (< (point) end)
    (let ((beg-sub (point-marker))
	  (indent (make-string depth ? ))
	  (citation "[[:space:]]*>"))
      (if (looking-at citation)
	  (progn
	    (while (looking-at citation)
	      (forward-line))
	    (let ((overlay (make-overlay beg-sub (point)))
                  (invis-spec (make-symbol "notmuch-citation-region")))
              (add-to-invisibility-spec invis-spec)
	      (overlay-put overlay 'invisible invis-spec)
              (let ((p (point))
                    (cite-button-text
                     (concat "["  (number-to-string (count-lines beg-sub (point)))
                             "-line citation.]")))
                (goto-char (- beg-sub 1))
                (insert (concat "\n" indent))
                (insert-button cite-button-text
                               'invisibility-spec invis-spec
                               :type 'notmuch-button-citation-toggle-type)
                (insert "\n")
                (goto-char (+ (length cite-button-text) p))
              ))))
      (move-to-column depth)
      (if (looking-at notmuch-show-signature-regexp)
	  (let ((sig-lines (- (count-lines beg-sub end) 1)))
	    (if (<= sig-lines notmuch-show-signature-lines-max)
		(progn
                  (let ((invis-spec (make-symbol "notmuch-signature-region")))
                    (add-to-invisibility-spec invis-spec)
                    (overlay-put (make-overlay beg-sub end)
                                 'invisible invis-spec)
                  
                    (goto-char (- beg-sub 1))
                    (insert (concat "\n" indent))
                    (let ((sig-button-text (concat "[" (number-to-string sig-lines)
                                                   "-line signature.]")))
                      (insert-button sig-button-text 'invisibility-spec invis-spec
                                     :type 'notmuch-button-signature-toggle-type)
                     )
                    (insert "\n")
                    (goto-char end))))))
      (forward-line))))

(defun notmuch-show-markup-part (beg end depth)
  (if (re-search-forward notmuch-show-part-begin-regexp nil t)
      (progn
	(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)
	    (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)))

(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 btn)
  (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 (notmuch-show-message-unread-p))
            (add-to-invisibility-spec invis-spec)))
      (set-marker beg nil)
      (set-marker end nil)
      )))

(defun notmuch-show-markup-header (depth)
  (re-search-forward notmuch-show-header-begin-regexp)
  (forward-line)
  (let ((beg (point-marker))
        (btn nil))
    (end-of-line)
    ; Inverse video for subject
    (overlay-put (make-overlay beg (point)) 'face '(:inverse-video t))
    (setq btn (make-button beg (point) :type 'notmuch-button-body-toggle-type))
    (forward-line 1)
    (end-of-line)
    (let ((beg-hidden (point-marker)))
      (re-search-forward notmuch-show-header-end-regexp)
      (beginning-of-line)
      (let ((end (point-marker)))
        (goto-char beg)
        (forward-line)
        (while (looking-at "[A-Za-z][-A-Za-z0-9]*:")
          (beginning-of-line)
          (overlay-put (make-overlay (point) (re-search-forward ":"))
                       'face 'bold)
          (forward-line)
          )
	(indent-rigidly beg end depth)
        (let ((invis-spec (make-symbol "notmuch-show-header")))
          (add-to-invisibility-spec (cons invis-spec t))
          (overlay-put (make-overlay beg-hidden end)
                       'invisible invis-spec)
          (goto-char beg)
          (forward-line)
          (make-button (line-beginning-position) (line-end-position)
                        'invisibility-spec (cons invis-spec t)
                        :type 'notmuch-button-headers-toggle-type))
        (goto-char end)
        (insert "\n")
	(set-marker beg nil)
	(set-marker beg-hidden nil)
	(set-marker end nil)
	))
    btn))

(defun notmuch-show-markup-message ()
  (if (re-search-forward notmuch-show-message-begin-regexp nil t)
      (progn
	(re-search-forward notmuch-show-depth-regexp)
	(let ((depth (string-to-number (buffer-substring (match-beginning 1) (match-end 1))))
              (btn nil))
	  (setq btn (notmuch-show-markup-header depth))
	  (notmuch-show-markup-body depth 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 invisible to help you
focus on the most important things, (new text from unread
messages). See the various commands below for toggling the
visibility of hidden components.

The `notmuch-show-next-message' and
`notmuch-show-previous-message' commands, (bound to 'n' and 'p by
default), allow you to navigate to the next and previous
messages. Each time you navigate away from a message with
`notmuch-show-next-message' the current message will have its
\"unread\" tag removed.

You can add or remove tags from the current message with '+' and
'-'.  You can also archive all messages in the current
view, (remove the \"inbox\" tag from each), with
`notmuch-show-archive-thread' (bound to 'a' by default).

\\{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))

(defgroup notmuch nil
  "Notmuch mail reader for Emacs."
  :group 'mail)

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

(defcustom notmuch-search-hook nil
  "List of functions to call when notmuch displays the search results."
  :type 'hook
  :options '(hl-line-mode)
  :group 'notmuch)

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

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

(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)
  "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)."
  (interactive "sNotmuch show: ")
  (let ((buffer (get-buffer-create (concat "*notmuch-show-" thread-id "*"))))
    (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
	(call-process notmuch-command nil t nil "show" thread-id)
	(notmuch-show-markup-messages)
	)
      (run-hooks 'notmuch-show-hook)
      ; Move straight to the first unread message
      (if (not (notmuch-show-message-unread-p))
	  (progn
	    (notmuch-show-next-unread-message)
	    ; But if there are no unread messages, go back to the
	    ; beginning of the buffer, and open up the bodies of all
	    ; read message.
	    (if (not (notmuch-show-message-unread-p))
		(progn
		  (goto-char (point-min))
                  (let ((btn (forward-button 1)))
                    (while btn
                      (if (button-has-type-p btn 'notmuch-button-body-toggle-type)
                          (push-button))
                      (condition-case err
                          (setq btn (forward-button 1))
                        (error (setq btn nil)))
                    ))
                  (beginning-of-buffer)
                  ))))
      )))

(defvar notmuch-search-authors-width 40
  "Number of columns to use to display authors in a notmuch-search buffer.")

(defvar notmuch-search-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "a" 'notmuch-search-archive-thread)
    (define-key map "b" 'notmuch-search-scroll-down)
    (define-key map "f" 'notmuch-search-filter)
    (define-key map "m" 'message-mail)
    (define-key map "n" 'next-line)
    (define-key map "o" 'notmuch-search-toggle-order)
    (define-key map "p" 'previous-line)
    (define-key map "q" 'kill-this-buffer)
    (define-key map "r" 'notmuch-search-reply-to-thread)
    (define-key map "s" 'notmuch-search)
    (define-key map "t" 'notmuch-search-filter-by-tag)
    (define-key map "x" 'kill-this-buffer)
    (define-key map (kbd "RET") 'notmuch-search-show-thread)
    (define-key map [mouse-1] 'notmuch-search-show-thread)
    (define-key map "+" 'notmuch-search-add-tag)
    (define-key map "-" 'notmuch-search-remove-tag)
    (define-key map "<" 'beginning-of-buffer)
    (define-key map ">" 'notmuch-search-goto-last-thread)
    (define-key map "=" 'notmuch-search-refresh-view)
    (define-key map "\M->" 'notmuch-search-goto-last-thread)
    (define-key map " " 'notmuch-search-scroll-up)
    (define-key map (kbd "<DEL>") 'notmuch-search-scroll-down)
    (define-key map "?" 'describe-mode)
    map)
  "Keymap for \"notmuch search\" buffers.")
(fset 'notmuch-search-mode-map notmuch-search-mode-map)

(defvar notmuch-search-query-string)
(defvar notmuch-search-oldest-first t
  "Show the oldest mail first in the search-mode")


(defun notmuch-search-scroll-up ()
  "Scroll up, moving point to last message in thread if at end."
  (interactive)
  (condition-case nil
      (scroll-up nil)
    ((end-of-buffer) (notmuch-search-goto-last-thread))))

(defun notmuch-search-scroll-down ()
  "Scroll down, moving point to first message in thread if at beginning."
  (interactive)
  ; I don't know why scroll-down doesn't signal beginning-of-buffer
  ; the way that scroll-up signals end-of-buffer, but c'est la vie.
  ;
  ; So instead of trapping a signal we instead check whether the
  ; window begins on the first line of the buffer and if so, move
  ; directly to that position. (We have to count lines since the
  ; window-start position is not the same as point-min due to the
  ; invisible thread-ID characters on the first line.
  (if (equal (count-lines (point-min) (window-start)) 1)
      (goto-char (window-start))
    (scroll-down nil)))

(defun notmuch-search-goto-last-thread ()
  "Move point to the last thread in the buffer."
  (interactive)
  (goto-char (point-max))
  (forward-line -1))

;;;###autoload
(defun notmuch-search-mode ()
  "Major mode for searching mail with notmuch.

This buffer contains the results of a \"notmuch search\" of your
email archives. Each line in the buffer represents a single
thread giving a relative date for the thread and a subject.

Pressing RET on any line displays that thread. The '+' and '-'
keys can be used to add or remove tags from a thread. The 'a' key
is a convenience key for archiving a thread (removing the
\"inbox\" tag).

Other useful commands are `notmuch-search-filter' for filtering
the current search based on an additional query string,
`notmuch-search-filter-by-tag' for filtering to include only
messages with a given tag, and `notmuch-search' to execute a new,
global search.

\\{notmuch-search-mode-map}"
  (interactive)
  (kill-all-local-variables)
  (make-local-variable 'notmuch-search-query-string)
  (make-local-variable 'notmuch-search-oldest-first)
  (set (make-local-variable 'scroll-preserve-screen-position) t)
  (add-to-invisibility-spec 'notmuch-search)
  (use-local-map notmuch-search-mode-map)
  (setq truncate-lines t)
  (setq major-mode 'notmuch-search-mode
	mode-name "notmuch-search")
  (setq buffer-read-only t))

(defun notmuch-search-find-thread-id ()
  "Return the thread for the current thread"
  (get-text-property (point) 'notmuch-search-thread-id))

(defun notmuch-search-show-thread ()
  (interactive)
  (let ((thread-id (notmuch-search-find-thread-id)))
    (if (> (length thread-id) 0)
	(notmuch-show thread-id (current-buffer))
      (error "End of search results"))))

(defun notmuch-search-reply-to-thread ()
  "Begin composing a reply to the entire current thread in a new buffer."
  (interactive)
  (let ((message-id (notmuch-search-find-thread-id)))
    (notmuch-reply message-id)))

(defun notmuch-call-notmuch-process (&rest args)
  "Synchronously invoke \"notmuch\" with the given list of arguments.

Output from the process will be presented to the user as an error
and will also appear in a buffer named \"*Notmuch errors*\"."
  (let ((error-buffer (get-buffer-create "*Notmuch errors*")))
    (with-current-buffer error-buffer
	(erase-buffer))
    (if (eq (apply 'call-process notmuch-command nil error-buffer nil args) 0)
	(point)
      (progn
	(with-current-buffer error-buffer
	  (let ((beg (point-min))
		(end (- (point-max) 1)))
	    (error (buffer-substring beg end))
	    ))))))

(defun notmuch-search-set-tags (tags)
  (save-excursion
    (end-of-line)
    (re-search-backward "(")
    (forward-char)
    (let ((beg (point))
	  (inhibit-read-only t))
      (re-search-forward ")")
      (backward-char)
      (let ((end (point)))
	(delete-region beg end)
	(insert (mapconcat  'identity tags " "))))))

(defun notmuch-search-get-tags ()
  (save-excursion
    (end-of-line)
    (re-search-backward "(")
    (let ((beg (+ (point) 1)))
      (re-search-forward ")")
      (let ((end (- (point) 1)))
	(split-string (buffer-substring beg end))))))

(defun notmuch-search-add-tag (tag)
  (interactive
   (list (notmuch-select-tag-with-completion "Tag to add: ")))
  (notmuch-call-notmuch-process "tag" (concat "+" tag) (notmuch-search-find-thread-id))
  (notmuch-search-set-tags (delete-dups (sort (cons tag (notmuch-search-get-tags)) 'string<))))

(defun notmuch-search-remove-tag (tag)
  (interactive
   (list (notmuch-select-tag-with-completion "Tag to remove: " (notmuch-search-find-thread-id))))
  (notmuch-call-notmuch-process "tag" (concat "-" tag) (notmuch-search-find-thread-id))
  (notmuch-search-set-tags (delete tag (notmuch-search-get-tags))))

(defun notmuch-search-archive-thread ()
  "Archive the current thread (remove its \"inbox\" tag).

This function advances point to the next line when finished."
  (interactive)
  (notmuch-search-remove-tag "inbox")
  (forward-line))

(defun notmuch-search-process-sentinel (proc msg)
  "Add a message to let user know when \"notmuch search\" exits"
  (let ((buffer (process-buffer proc))
	(status (process-status proc))
	(exit-status (process-exit-status proc)))
    (if (memq status '(exit signal))
	(if (buffer-live-p buffer)
	    (with-current-buffer buffer
	      (save-excursion
		(let ((inhibit-read-only t))
		  (goto-char (point-max))
		  (if (eq status 'signal)
		      (insert "Incomplete search results (search process was killed).\n"))
		  (if (eq status 'exit)
		      (progn
			(insert "End of search results.")
			(if (not (= exit-status 0))
			    (insert (format " (process returned %d)" exit-status)))
			(insert "\n"))))))))))

(defun notmuch-search-process-filter (proc string)
  "Process and filter the output of \"notmuch search\""
  (let ((buffer (process-buffer proc)))
    (if (buffer-live-p buffer)
	(with-current-buffer buffer
	  (save-excursion
	    (let ((line 0)
		  (more t)
		  (inhibit-read-only t))
	      (while more
		(if (string-match "^\\(thread:[0-9A-Fa-f]*\\) \\(.*\\) \\(\\[[0-9/]*\\]\\) \\([^:]*\\); \\(.*\\) (\\([^()]*\\))$" string line)
		    (let* ((thread-id (match-string 1 string))
			   (date (match-string 2 string))
			   (count (match-string 3 string))
			   (authors (match-string 4 string))
			   (authors-length (length authors))
			   (subject (match-string 5 string))
			   (tags (match-string 6 string)))
		      (if (> authors-length 40)
			  (set 'authors (concat (substring authors 0 (- 40 3)) "...")))
		      (goto-char (point-max))
		      (let ((beg (point-marker)))
			(insert (format "%s %-7s %-40s %s (%s)\n" date count authors subject tags))
			(put-text-property beg (point-marker) 'notmuch-search-thread-id thread-id))
		      (set 'line (match-end 0)))
		  (set 'more nil))))))
      (delete-process proc))))

;;;###autoload
(defun notmuch-search (query &optional oldest-first)
  "Run \"notmuch search\" with the given query string and display results."
  (interactive "sNotmuch search: ")
  (let ((buffer (get-buffer-create (concat "*notmuch-search-" query "*"))))
    (switch-to-buffer buffer)
    (notmuch-search-mode)
    (set 'notmuch-search-query-string query)
    (set 'notmuch-search-oldest-first oldest-first)
    (let ((proc (get-buffer-process (current-buffer)))
	  (inhibit-read-only t))
      (if proc
	  (error "notmuch search process already running for query `%s'" query)
	)
      (erase-buffer)
      (goto-char (point-min))
      (save-excursion
	(let ((proc (start-process-shell-command
		     "notmuch-search" buffer notmuch-command "search"
		     (if oldest-first "--sort=oldest-first" "--sort=newest-first")
		     (shell-quote-argument query))))
	  (set-process-sentinel proc 'notmuch-search-process-sentinel)
	  (set-process-filter proc 'notmuch-search-process-filter))))
    (run-hooks 'notmuch-search-hook)))

(defun notmuch-search-refresh-view ()
  "Refresh the current view.

Kills the current buffer and runs a new search with the same
query string as the current search. If the current thread is in
the new search results, then point will be placed on the same
thread. Otherwise, point will be moved to attempt to be in the
same relative position within the new buffer."
  (interactive)
  (let ((here (point))
	(oldest-first notmuch-search-oldest-first)
	(thread (notmuch-search-find-thread-id))
	(query notmuch-search-query-string))
    (kill-this-buffer)
    (notmuch-search query oldest-first)
    (goto-char (point-min))
    (if (re-search-forward (concat "^" thread) nil t)
	(beginning-of-line)
      (goto-char here))))

(defun notmuch-search-toggle-order ()
  "Toggle the current search order.

By default, the \"inbox\" view created by `notmuch' is displayed
in chronological order (oldest thread at the beginning of the
buffer), while any global searches created by `notmuch-search'
are displayed in reverse-chronological order (newest thread at
the beginning of the buffer).

This command toggles the sort order for the current search.

Note that any filtered searches created by
`notmuch-search-filter' retain the search order of the parent
search."
  (interactive)
  (set 'notmuch-search-oldest-first (not notmuch-search-oldest-first))
  (notmuch-search-refresh-view))

(defun notmuch-search-filter (query)
  "Filter the current search results based on an additional query string.

Runs a new search matching only messages that match both the
current search results AND the additional query string provided."
  (interactive "sFilter search: ")
  (notmuch-search (concat notmuch-search-query-string " and " query) notmuch-search-oldest-first))

(defun notmuch-search-filter-by-tag (tag)
  "Filter the current search results based on a single tag.

Runs a new search matching only messages that match both the
current search results AND that are tagged with the given tag."
  (interactive
   (list (notmuch-select-tag-with-completion "Filter by tag: ")))
  (notmuch-search (concat notmuch-search-query-string " and tag:" tag) notmuch-search-oldest-first))


;;;###autoload
(defun notmuch ()
  "Run notmuch to display all mail with tag of 'inbox'"
  (interactive)
  (notmuch-search "tag:inbox" notmuch-search-oldest-first))

(setq mail-user-agent 'message-user-agent)

(defvar notmuch-folder-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "n" 'next-line)
    (define-key map "p" 'previous-line)
    (define-key map "x" 'kill-this-buffer)
    (define-key map "q" 'kill-this-buffer)
    (define-key map "s" 'notmuch-search)
    (define-key map (kbd "RET") 'notmuch-folder-show-search)
    (define-key map "<" 'beginning-of-buffer)
    (define-key map "=" 'notmuch-folder)
    (define-key map "?" 'describe-mode)
    (define-key map [mouse-1] 'notmuch-folder-show-search)
    map)
  "Keymap for \"notmuch folder\" buffers.")

(fset 'notmuch-folder-mode-map notmuch-folder-mode-map)

(defcustom notmuch-folders (quote (("inbox" . "tag:inbox") ("unread" . "tag:unread")))
  "List of searches for the notmuch folder view"
  :type '(alist :key-type (string) :value-type (string))
  :group 'notmuch)

(defun notmuch-folder-mode ()
  "Major mode for showing notmuch 'folders'.

This buffer contains a list of messages counts returned by a
customizable set of searches of your email archives. Each line
in the buffer shows the search terms and the resulting message count.

Pressing RET on any line opens a search window containing the
results for the search terms in that line.

\\{notmuch-folder-mode-map}"
  (interactive)
  (kill-all-local-variables)
  (use-local-map 'notmuch-folder-mode-map)
  (setq truncate-lines t)
  (hl-line-mode 1)
  (setq major-mode 'notmuch-folder-mode
	mode-name "notmuch-folder")
  (setq buffer-read-only t))

(defun notmuch-folder-add (folders)
  (if folders
      (let ((name (car (car folders)))
	    (inhibit-read-only t)
	    (search (cdr (car folders))))
	(insert name)
	(indent-to 16 1)
	(call-process notmuch-command nil t nil "count" search)
	(notmuch-folder-add (cdr folders)))))

(defun notmuch-folder-find-name ()
  (save-excursion
    (beginning-of-line)
    (let ((beg (point)))
      (forward-word)
      (filter-buffer-substring beg (point)))))

(defun notmuch-folder-show-search (&optional folder)
  "Show a search window for the search related to the specified folder."
  (interactive)
  (if (null folder)
      (setq folder (notmuch-folder-find-name)))
  (let ((search (assoc folder notmuch-folders)))
    (if search
	(notmuch-search (cdr search) notmuch-search-oldest-first))))

;;;###autoload
(defun notmuch-folder ()
  "Show the notmuch folder view and update the displayed counts."
  (interactive)
  (let ((buffer (get-buffer-create "*notmuch-folders*")))
    (switch-to-buffer buffer)
    (let ((inhibit-read-only t)
	  (n (line-number-at-pos)))
      (erase-buffer)
      (notmuch-folder-mode)
      (notmuch-folder-add notmuch-folders)
      (goto-char (point-min))
      (goto-line n))))

(provide 'notmuch)