; 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>

(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 "b" 'notmuch-show-toggle-body-read-visible)
    (define-key map "c" 'notmuch-show-toggle-citations-visible)
    (define-key map "h" 'notmuch-show-toggle-headers-visible)
    (define-key map "n" 'notmuch-show-mark-read-then-next-message)
    (define-key map "p" 'notmuch-show-previous-message)
    (define-key map "q" 'kill-this-buffer)
    (define-key map "s" 'notmuch-show-toggle-signatures-visible)
    (define-key map "x" 'kill-this-buffer)
    (define-key map "+" 'notmuch-show-add-tag)
    (define-key map "-" 'notmuch-show-remove-tag)
    map)
  "Keymap for \"notmuch show\" buffers.")
(fset 'notmuch-show-mode-map notmuch-show-mode-map)

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

(defvar notmuch-show-id-regexp "ID: \\(.*\\)$")
(defvar notmuch-show-tags-regexp "(\\([^)]*\\))$")

(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 (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 (tag)
  (interactive "sTag to add: ")
  (notmuch-call-notmuch-process "tag" (concat "+" tag) (concat "id:" (notmuch-show-get-message-id)))
  (notmuch-show-set-tags (delete-dups (sort (cons tag (notmuch-show-get-tags)) 'string<))))

(defun notmuch-show-remove-tag (tag)
  (interactive "sTag to remove: ")
  (notmuch-call-notmuch-process "tag" (concat "-" tag) (concat "id:" (notmuch-show-get-message-id)))
  (notmuch-show-set-tags (delete tag (notmuch-show-get-tags))))

(defun notmuch-show-archive-thread ()
  "Archive each message currrently shown by removing the \"inbox\" tag from each.

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))))))

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

Does nothing if already on the last message."
  (interactive)
  ; First, ensure we get off the current message marker
  (if (not (eobp))
      (forward-char))
  (re-search-forward notmuch-show-message-begin-regexp nil t)
  ; This dance might look pointless, but it's important. I originally
  ; just had (beginning-of-line) here which looked right on the
  ; display but actually put point all the way back to the first
  ; character of the first invisible line. That is, it put point into
  ; the closing markers of the previous message rather than at the
  ; beginning of the current message. And that in turn meant that
  ; looking up the current message-ID would actually return the
  ; previous message ID.
  ;
  ; So this dance ensures that we're actually on the current message
  ; when it looks like we are.
  (end-of-visible-line)
  (beginning-of-line)
  (recenter 0))

(defun notmuch-show-previous-message ()
  "Backup to the beginning of the previous message in the buffer.

Does nothing if already on the first message in the buffer."
  (interactive)
  ; First, ensure we get off the current message marker
  (if (not (bobp))
      (previous-line))
  (re-search-backward notmuch-show-message-begin-regexp nil t)
  ; This dance might look pointless, but it's important. I originally
  ; just had (beginning-of-line) here which looked right on the
  ; display but actually put point all the way back to the first
  ; character of the first invisible line. That is, it put point into
  ; the closing markers of the previous message rather than at the
  ; beginning of the current message. And that in turn meant that
  ; looking up the current message-ID would actually return the
  ; previous message ID.
  ;
  ; So this dance ensures that we're actually on the current message
  ; when it looks like we are.
  (end-of-visible-line)
  (beginning-of-line)
  (recenter 0))

(defun notmuch-show-mark-read-then-next-message ()
  "Remove uread tag from current message, then advance to next message."
  (interactive)
  (if (member "unread" (notmuch-show-get-tags))
      (notmuch-show-remove-tag "unread"))
  (notmuch-show-next-message))

(defun notmuch-show-markup-citations-region (beg end)
  (goto-char beg)
  (beginning-of-line)
  (while (< (point) end)
    (let ((beg-sub (point)))
      (if (looking-at ">")
	  (progn
	    (while (looking-at ">")
	      (next-line))
	    (let ((overlay (make-overlay beg-sub (point))))
	      (overlay-put overlay 'invisible 'notmuch-show-citation)
	      (overlay-put overlay 'before-string
			   (concat "[" (number-to-string (count-lines beg-sub (point)))
				   " quoted lines.]")))))
      (if (looking-at "--[ ]?$")
	  (let ((overlay (make-overlay beg-sub end)))
	    (overlay-put overlay 'invisible 'notmuch-show-signature)
	    (overlay-put overlay 'before-string
			 (concat "[" (number-to-string (count-lines beg-sub (point)))
				 "-line signature.]"))
	    (goto-char end)))
      (next-line))))

(defun notmuch-show-markup-body ()
  (re-search-forward notmuch-show-body-begin-regexp)
  (next-line 1)
  (beginning-of-line)
  (let ((beg (point)))
    (re-search-forward notmuch-show-body-end-regexp)
    (let ((end (match-beginning 0)))
      (if (not (member "unread" (notmuch-show-get-tags)))
	  (overlay-put (make-overlay beg end)
		       'invisible 'notmuch-show-body-read))
      (notmuch-show-markup-citations-region beg end))))

(defun notmuch-show-markup-header ()
  (re-search-forward notmuch-show-header-begin-regexp)
  (next-line 2)
  (beginning-of-line)
  (let ((beg (point)))
    (re-search-forward notmuch-show-header-end-regexp)
    (overlay-put (make-overlay beg (match-beginning 0))
		 'invisible 'notmuch-show-header)))

(defun notmuch-show-markup-message ()
  (if (re-search-forward notmuch-show-message-begin-regexp nil t)
      (progn
	(notmuch-show-markup-header)
	(notmuch-show-markup-body))
    (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))

(defun notmuch-show-toggle-citations-visible ()
  "Toggle visibility of citations"
  (interactive)
  (if notmuch-show-citations-visible
      (add-to-invisibility-spec 'notmuch-show-citation)
    (remove-from-invisibility-spec 'notmuch-show-citation))
  (set 'notmuch-show-citations-visible (not notmuch-show-citations-visible))
  ; Need to force the redisplay for some reason
  (force-window-update)
  (redisplay t))

(defun notmuch-show-toggle-signatures-visible ()
  "Toggle visibility of signatures"
  (interactive)
  (if notmuch-show-signatures-visible
      (add-to-invisibility-spec 'notmuch-show-signature)
    (remove-from-invisibility-spec 'notmuch-show-signature))
  (set 'notmuch-show-signatures-visible (not notmuch-show-signatures-visible))
  ; Need to force the redisplay for some reason
  (force-window-update)
  (redisplay t))

(defun notmuch-show-toggle-headers-visible ()
  "Toggle visibility of header fields"
  (interactive)
  (if notmuch-show-headers-visible
      (add-to-invisibility-spec 'notmuch-show-header)
    (remove-from-invisibility-spec 'notmuch-show-header))
  (set 'notmuch-show-headers-visible (not notmuch-show-headers-visible))
  ; Need to force the redisplay for some reason
  (force-window-update)
  (redisplay t))

(defun notmuch-show-toggle-body-read-visible ()
  "Toggle visibility of message bodies of read messages"
  (interactive)
  (if notmuch-show-body-read-visible
      (add-to-invisibility-spec 'notmuch-show-body-read)
    (remove-from-invisibility-spec 'notmuch-show-body-read))
  (set 'notmuch-show-body-read-visible (not notmuch-show-body-read-visible))
  ; Need to force the redisplay for some reason
  (force-window-update)
  (redisplay t))

;;;###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)
  (set (make-local-variable 'notmuch-show-headers-visible) t)
  (notmuch-show-toggle-headers-visible)
  (set (make-local-variable 'notmuch-show-body-read-visible) t)
  (notmuch-show-toggle-body-read-visible)
  (set (make-local-variable 'notmuch-show-citations-visible) t)
  (notmuch-show-toggle-citations-visible)
  (set (make-local-variable 'notmuch-show-signatures-visible) t)
  (notmuch-show-toggle-signatures-visible)
  (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))

(defun notmuch-show (thread-id)
  "Run \"notmuch show\" with the given thread ID and display results."
  (interactive "sNotmuch show: ")
  (let ((buffer (get-buffer-create (concat "*notmuch-show-" thread-id "*"))))
    (switch-to-buffer buffer)
    (notmuch-show-mode)
    (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
	(call-process "notmuch" nil t nil "show" thread-id)
	(notmuch-show-markup-messages)
	)
      )))

(defvar notmuch-search-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "a" 'notmuch-search-archive-thread)
    (define-key map "b" 'scroll-down)
    (define-key map "f" 'notmuch-search-filter)
    (define-key map "n" 'next-line)
    (define-key map "p" 'previous-line)
    (define-key map "q" 'kill-this-buffer)
    (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 "\r" '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 " " 'scroll-up)
    (define-key map (kbd "<DEL>") 'scroll-down)
    map)
  "Keymap for \"notmuch search\" buffers.")
(fset 'notmuch-search-mode-map notmuch-search-mode-map)

(defun notmuch-search-goto-last-thread (&optional arg)
  "Move point to the last thread in the buffer."
  (interactive "^P")
  (end-of-buffer arg)
  (beginning-of-line))

;;;###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)
  (set (make-local-variable 'scroll-preserve-screen-position) t)
  (add-to-invisibility-spec 'notmuch-search)
  (use-local-map notmuch-search-mode-map)
  (setq major-mode 'notmuch-search-mode
	mode-name "notmuch-search")
  (setq buffer-read-only t))

(defun notmuch-search-find-thread-id ()
  (save-excursion
    (beginning-of-line)
    (let ((beg (point)))
      (re-search-forward "[a-fA-F0-9]*")
      (filter-buffer-substring beg (point)))))

(defun notmuch-search-markup-this-thread-id ()
  (beginning-of-line)
  (let ((beg (point)))
    (re-search-forward "[a-fA-F0-9]*")
    (forward-char)
    (overlay-put (make-overlay beg (point)) 'invisible 'notmuch-search)))

(defun notmuch-search-markup-thread-ids ()
  (save-excursion
    (goto-char (point-min))
    (while (not (eobp))
      (notmuch-search-markup-this-thread-id)
      (next-line))))

(defun notmuch-search-hide-thread-ids ()
  (interactive)
  (add-to-invisibility-spec 'notmuch-search)
  (force-window-update)
  (redisplay t))

(defun notmuch-search-show-thread-ids ()
  (interactive)
  (remove-from-invisibility-spec 'notmuch-search)
  (force-window-update)
  (redisplay t))

(defun notmuch-search-show-thread ()
  (interactive)
  (notmuch-show (notmuch-search-find-thread-id)))

(defun notmuch-call-notmuch-process (&rest args)
  (let ((error-buffer (get-buffer-create "*Notmuch errors*")))
    (with-current-buffer error-buffer
	(erase-buffer))
    (if (eq (apply 'call-process "notmuch" 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 "sTag to add: ")
  (notmuch-call-notmuch-process "tag" (concat "+" tag) (concat "thread:" (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 "sTag to remove: ")
  (notmuch-call-notmuch-process "tag" (concat "-" tag) (concat "thread:" (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")
  (next-line))

(defun notmuch-search (query)
  "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)
    (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
	(call-process "notmuch" nil t nil "search" query)
	(notmuch-search-markup-thread-ids)
        ; A well-behaved program ends its output with a newline, but we
        ; don't actually want the blank line at the end of the file.
	(goto-char (point-max))
	(if (looking-at "^$")
	    (delete-backward-char 1)
	  )
	))))

(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))
	(thread (notmuch-search-find-thread-id))
	(query notmuch-search-query-string))
    (kill-this-buffer)
    (notmuch-search query)
    (goto-char (point-min))
    (if (re-search-forward (concat "^" thread) nil t)
	(beginning-of-line)
      (goto-char here))))

(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)))

(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 "sFilter by tag: ")
  (notmuch-search (concat notmuch-search-query-string " and tag:" tag)))

(defun notmuch ()
  "Run notmuch to display all mail with tag of 'inbox'"
  (interactive)
  (notmuch-search "tag:inbox"))

(provide 'notmuch)