;; notmuch-pick.el --- displaying notmuch forests.
;;
;; Copyright © Carl Worth
;; Copyright © David Edmondson
;; Copyright © Mark Walters
;;
;; 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: David Edmondson <dme@dme.org>
;;          Mark Walters <markwalters1009@gmail.com>

(require 'mail-parse)

(require 'notmuch-lib)
(require 'notmuch-query)
(require 'notmuch-show)
(require 'notmuch) ;; XXX ATM, as notmuch-search-mode-map is defined here

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

(declare-function notmuch-call-notmuch-process "notmuch" (&rest args))
(declare-function notmuch-show "notmuch-show" (&rest args))
(declare-function notmuch-tag "notmuch" (query &rest tags))
(declare-function notmuch-show-strip-re "notmuch-show" (subject))
(declare-function notmuch-show-spaces-n "notmuch-show" (n))
(declare-function notmuch-read-query "notmuch" (prompt))
(declare-function notmuch-read-tag-changes "notmuch" (&optional initial-input &rest search-terms))
(declare-function notmuch-update-tags "notmuch" (current-tags tag-changes))
(declare-function notmuch-hello-trim "notmuch-hello" (search))
(declare-function notmuch-search-find-thread-id "notmuch" ())
(declare-function notmuch-search-find-subject "notmuch" ())

;; the following variable is defined in notmuch.el
(defvar notmuch-search-query-string)

(defgroup notmuch-pick nil
  "Showing message and thread structure."
  :group 'notmuch)

;; This is ugly. We can't run setup-show-out until it has been defined
;; which needs the keymap to be defined. So we defer setting up to
;; notmuch-pick-init.
(defcustom notmuch-pick-show-out nil
  "View selected messages in new window rather than split-pane."
  :type 'boolean
  :group 'notmuch-pick
  :set (lambda (symbol value)
	 (set-default symbol value)
	 (when (fboundp 'notmuch-pick-setup-show-out)
	   (notmuch-pick-setup-show-out))))

(defcustom notmuch-pick-result-format
  `(("date" . "%12s  ")
    ("authors" . "%-20s")
    ("subject" . " %-54s ")
    ("tags" . "(%s)"))
  "Result formatting for Pick. Supported fields are: date,
        authors, subject, tags Note: subject includes the tree
        structure graphics, and the author string should not
        contain whitespace (put it in the neighbouring fields
        instead).  For example:
        (setq notmuch-pick-result-format \(\(\"authors\" . \"%-40s\"\)
                                             \(\"subject\" . \"%s\"\)\)\)"
  :type '(alist :key-type (string) :value-type (string))
  :group 'notmuch-pick)

;; Faces for messages that match the query.
(defface notmuch-pick-match-date-face
  '((t :inherit default))
  "Face used in pick mode for the date in messages matching the query."
  :group 'notmuch-pick
  :group 'notmuch-faces)

(defface notmuch-pick-match-author-face
  '((((class color)
      (background dark))
     (:foreground "OliveDrab1"))
    (((class color)
      (background light))
     (:foreground "dark blue"))
    (t
     (:bold t)))
  "Face used in pick mode for the date in messages matching the query."
  :group 'notmuch-pick
  :group 'notmuch-faces)

(defface notmuch-pick-match-subject-face
  '((t :inherit default))
  "Face used in pick mode for the subject in messages matching the query."
  :group 'notmuch-pick
  :group 'notmuch-faces)

(defface notmuch-pick-match-tag-face
  '((((class color)
      (background dark))
     (:foreground "OliveDrab1"))
    (((class color)
      (background light))
     (:foreground "navy blue" :bold t))
    (t
     (:bold t)))
  "Face used in pick mode for tags in messages matching the query."
  :group 'notmuch-pick
  :group 'notmuch-faces)

;; Faces for messages that do not match the query.
(defface notmuch-pick-no-match-date-face
  '((t (:foreground "gray")))
  "Face used in pick mode for non-matching dates."
  :group 'notmuch-pick
  :group 'notmuch-faces)

(defface notmuch-pick-no-match-subject-face
  '((t (:foreground "gray")))
  "Face used in pick mode for non-matching subjects."
  :group 'notmuch-pick
  :group 'notmuch-faces)

(defface notmuch-pick-no-match-author-face
  '((t (:foreground "gray")))
  "Face used in pick mode for the date in messages matching the query."
  :group 'notmuch-pick
  :group 'notmuch-faces)

(defface notmuch-pick-no-match-tag-face
  '((t (:foreground "gray")))
  "Face used in pick mode face for non-matching tags."
  :group 'notmuch-pick
  :group 'notmuch-faces)

(defvar notmuch-pick-previous-subject
  "The subject of the most recent result shown during the async display")
(make-variable-buffer-local 'notmuch-pick-previous-subject)

(defvar notmuch-pick-basic-query nil
  "A buffer local copy of argument query to the function notmuch-pick")
(make-variable-buffer-local 'notmuch-pick-basic-query)

(defvar notmuch-pick-query-context nil
  "A buffer local copy of argument query-context to the function notmuch-pick")
(make-variable-buffer-local 'notmuch-pick-query-context)

(defvar notmuch-pick-target-msg nil
  "A buffer local copy of argument target to the function notmuch-pick")
(make-variable-buffer-local 'notmuch-pick-target-msg)

(defvar notmuch-pick-open-target nil
  "A buffer local copy of argument open-target to the function notmuch-pick")
(make-variable-buffer-local 'notmuch-pick-open-target)

(defvar notmuch-pick-message-window nil
  "The window of the message pane.

It is set in both the pick buffer and the child show buffer. It
is used to try and close the message pane when quitting pick or
the child show buffer.")
(make-variable-buffer-local 'notmuch-pick-message-window)
(put 'notmuch-pick-message-window 'permanent-local t)

(defvar notmuch-pick-message-buffer nil
  "The buffer name of the show buffer in the message pane.

This is used to try and make sure we don't close the message pane
if the user has loaded a different buffer in that window.")
(make-variable-buffer-local 'notmuch-pick-message-buffer)
(put 'notmuch-pick-message-buffer 'permanent-local t)

(defun notmuch-pick-to-message-pane (func)
  "Execute FUNC in message pane.

This function returns a function (so can be used as a keybinding)
which executes function FUNC in the message pane if it is
open (if the message pane is closed it does nothing)."
  `(lambda ()
      ,(concat "(In message pane) " (documentation func t))
     (interactive)
     (when (window-live-p notmuch-pick-message-window)
       (with-selected-window notmuch-pick-message-window
	 (call-interactively #',func)))))

(defun notmuch-pick-button-activate (&optional button)
  "Activate BUTTON or button at point

This function does not give an error if there is no button."
  (interactive)
  (let ((button (or button (button-at (point)))))
    (when button (button-activate button))))

(defun notmuch-pick-close-message-pane-and (func)
  "Close message pane and execute FUNC.

This function returns a function (so can be used as a keybinding)
which closes the message pane if open and then executes function
FUNC."
  `(lambda ()
      ,(concat "(Close message pane and) " (documentation func t))
     (interactive)
     (notmuch-pick-close-message-window)
     (call-interactively #',func)))

(defvar notmuch-pick-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map [mouse-1] 'notmuch-pick-show-message)
    ;; these use notmuch-show functions directly
    (define-key map "|" 'notmuch-show-pipe-message)
    (define-key map "w" 'notmuch-show-save-attachments)
    (define-key map "v" 'notmuch-show-view-all-mime-parts)
    (define-key map "c" 'notmuch-show-stash-map)

    ;; these apply to the message pane
    (define-key map (kbd "M-TAB") (notmuch-pick-to-message-pane #'notmuch-show-previous-button))
    (define-key map (kbd "<backtab>")  (notmuch-pick-to-message-pane #'notmuch-show-previous-button))
    (define-key map (kbd "TAB") (notmuch-pick-to-message-pane #'notmuch-show-next-button))
    (define-key map "e" (notmuch-pick-to-message-pane #'notmuch-pick-button-activate))

    ;; bindings from show (or elsewhere) but we close the message pane first.
    (define-key map "m" (notmuch-pick-close-message-pane-and #'notmuch-mua-new-mail))
    (define-key map "f" (notmuch-pick-close-message-pane-and #'notmuch-show-forward-message))
    (define-key map "r" (notmuch-pick-close-message-pane-and #'notmuch-show-reply-sender))
    (define-key map "R" (notmuch-pick-close-message-pane-and #'notmuch-show-reply))
    (define-key map "V" (notmuch-pick-close-message-pane-and #'notmuch-show-view-raw-message))
    (define-key map "?" (notmuch-pick-close-message-pane-and #'notmuch-help))

    ;; The main pick bindings
    (define-key map "q" 'notmuch-pick-quit)
    (define-key map "x" 'notmuch-pick-quit)
    (define-key map "A" 'notmuch-pick-archive-thread)
    (define-key map "a" 'notmuch-pick-archive-message-then-next)
    (define-key map "=" 'notmuch-pick-refresh-view)
    (define-key map "s" 'notmuch-pick-to-search)
    (define-key map "z" 'notmuch-pick-to-pick)
    (define-key map "n" 'notmuch-pick-next-matching-message)
    (define-key map "p" 'notmuch-pick-prev-matching-message)
    (define-key map "N" 'notmuch-pick-next-message)
    (define-key map "P" 'notmuch-pick-prev-message)
    (define-key map (kbd "M-p") 'notmuch-pick-prev-thread)
    (define-key map (kbd "M-n") 'notmuch-pick-next-thread)
    (define-key map "-" 'notmuch-pick-remove-tag)
    (define-key map "+" 'notmuch-pick-add-tag)
    (define-key map "*" 'notmuch-pick-tag-thread)
    (define-key map " " 'notmuch-pick-scroll-or-next)
    (define-key map "b" 'notmuch-pick-scroll-message-window-back)
    map))
(fset 'notmuch-pick-mode-map notmuch-pick-mode-map)

(defun notmuch-pick-setup-show-out ()
  "Set up the keymap for showing a thread

This uses the value of the defcustom notmuch-pick-show-out to
decide whether to show a message in the message pane or in the
whole window."
  (let ((map notmuch-pick-mode-map))
    (if notmuch-pick-show-out
	(progn
	  (define-key map (kbd "M-RET") 'notmuch-pick-show-message)
	  (define-key map (kbd "RET") 'notmuch-pick-show-message-out))
      (progn
	(define-key map (kbd "RET") 'notmuch-pick-show-message)
	(define-key map (kbd "M-RET") 'notmuch-pick-show-message-out)))))

(defun notmuch-pick-get-message-properties ()
  "Return the properties of the current message as a plist.

Some useful entries are:
:headers - Property list containing the headers :Date, :Subject, :From, etc.
:tags - Tags for this message"
  (save-excursion
    (beginning-of-line)
    (get-text-property (point) :notmuch-message-properties)))

;; XXX This should really be a lib function but we are trying to
;; reduce impact on the code base.
(defun notmuch-show-get-prop (prop &optional props)
  "This is a pick overridden version of notmuch-show-get-prop

It gets property PROP from PROPS or, if PROPS is nil, the current
message in either pick or show. This means that several functions
in notmuch-show now work unchanged in pick as they just need the
correct message properties."
  (let ((props (or props
		   (cond ((eq major-mode 'notmuch-show-mode)
			  (notmuch-show-get-message-properties))
			 ((eq major-mode 'notmuch-pick-mode)
			  (notmuch-pick-get-message-properties))))))
    (plist-get props prop)))

(defun notmuch-pick-set-message-properties (props)
  (save-excursion
    (beginning-of-line)
    (put-text-property (point) (+ (point) 1) :notmuch-message-properties props)))

(defun notmuch-pick-set-prop (prop val &optional props)
  (let ((inhibit-read-only t)
	(props (or props
		   (notmuch-pick-get-message-properties))))
    (plist-put props prop val)
    (notmuch-pick-set-message-properties props)))

(defun notmuch-pick-get-prop (prop &optional props)
  (let ((props (or props
		   (notmuch-pick-get-message-properties))))
    (plist-get props prop)))

(defun notmuch-pick-set-tags (tags)
  "Set the tags of the current message."
  (notmuch-pick-set-prop :tags tags))

(defun notmuch-pick-get-tags ()
  "Return the tags of the current message."
  (notmuch-pick-get-prop :tags))

(defun notmuch-pick-get-message-id ()
  "Return the message id of the current message."
  (let ((id (notmuch-pick-get-prop :id)))
    (if id
	(notmuch-id-to-query id)
      nil)))

(defun notmuch-pick-get-match ()
  "Return whether the current message is a match."
  (interactive)
  (notmuch-pick-get-prop :match))

(defun notmuch-pick-refresh-result ()
  "Redisplay the current message line.

This redisplays the current line based on the messages
properties (as they are now). This is used when tags are
updated."
  (let ((init-point (point))
	(end (line-end-position))
	(msg (notmuch-pick-get-message-properties))
	(inhibit-read-only t))
    (beginning-of-line)
    ;; This is a little tricky: we override
    ;; notmuch-pick-previous-subject to get the decision between
    ;; ... and a subject right and it stops notmuch-pick-insert-msg
    ;; from overwriting the buffer local copy of
    ;; notmuch-pick-previous-subject if this is called while the
    ;; buffer is displaying.
    (let ((notmuch-pick-previous-subject (notmuch-pick-get-prop :previous-subject)))
      (delete-region (point) (1+ (line-end-position)))
      (notmuch-pick-insert-msg msg))
    (let ((new-end (line-end-position)))
      (goto-char (if (= init-point end)
		     new-end
		   (min init-point (- new-end 1)))))))

(defun notmuch-pick-tag-update-display (&optional tag-changes)
  "Update display for TAG-CHANGES to current message.

Does NOT change the database."
  (let* ((current-tags (notmuch-pick-get-tags))
	 (new-tags (notmuch-update-tags current-tags tag-changes)))
    (unless (equal current-tags new-tags)
      (notmuch-pick-set-tags new-tags)
      (notmuch-pick-refresh-result))))

(defun notmuch-pick-tag (&optional tag-changes)
  "Change tags for the current message"
  (interactive)
  (setq tag-changes (notmuch-tag (notmuch-pick-get-message-id) tag-changes))
  (notmuch-pick-tag-update-display tag-changes))

(defun notmuch-pick-add-tag ()
  "Same as `notmuch-pick-tag' but sets initial input to '+'."
  (interactive)
  (notmuch-pick-tag "+"))

(defun notmuch-pick-remove-tag ()
  "Same as `notmuch-pick-tag' but sets initial input to '-'."
  (interactive)
  (notmuch-pick-tag "-"))

;; The next two functions close the message window before searching or
;; picking but they do so after the user has entered the query (in
;; case the user was basing the query on something in the message
;; window).

(defun notmuch-pick-to-search ()
  "Run \"notmuch search\" with the given `query' and display results."
  (interactive)
  (let ((query (notmuch-read-query "Notmuch search: ")))
    (notmuch-pick-close-message-window)
    (notmuch-search query)))

(defun notmuch-pick-to-pick ()
  "Run a query and display results in experimental notmuch-pick mode"
  (interactive)
  (let ((query (notmuch-read-query "Notmuch pick: ")))
    (notmuch-pick-close-message-window)
    (notmuch-pick query)))

;; This function should be in notmuch-hello.el but we are trying to
;; minimise impact on the rest of the codebase.
(defun notmuch-pick-from-hello (&optional search)
  "Run a query and display results in experimental notmuch-pick mode"
  (interactive)
  (unless (null search)
    (setq search (notmuch-hello-trim search))
    (let ((history-delete-duplicates t))
      (add-to-history 'notmuch-search-history search)))
  (notmuch-pick search))

;; This function should be in notmuch-show.el but be we trying to
;; minimise impact on the rest of the codebase.
(defun notmuch-pick-from-show-current-query ()
  "Call notmuch pick with the current query"
  (interactive)
  (notmuch-pick notmuch-show-thread-id
		notmuch-show-query-context
		(notmuch-show-get-message-id)))

;; This function should be in notmuch.el but be we trying to minimise
;; impact on the rest of the codebase.
(defun notmuch-pick-from-search-current-query ()
  "Call notmuch pick with the current query"
  (interactive)
  (notmuch-pick notmuch-search-query-string))

;; This function should be in notmuch.el but be we trying to minimise
;; impact on the rest of the codebase.
(defun notmuch-pick-from-search-thread ()
  "Show the selected thread with notmuch-pick"
  (interactive)
  (notmuch-pick (notmuch-search-find-thread-id)
                notmuch-search-query-string
		nil
                (notmuch-prettify-subject (notmuch-search-find-subject))
		t))

(defun notmuch-pick-message-window-kill-hook ()
  "Close the message pane when exiting the show buffer."
  (let ((buffer (current-buffer)))
    (when (and (window-live-p notmuch-pick-message-window)
	       (eq (window-buffer notmuch-pick-message-window) buffer))
      ;; We do not want an error if this is the sole window in the
      ;; frame and I do not know how to test for that in emacs pre
      ;; 24. Hence we just ignore-errors.
      (ignore-errors
	(delete-window notmuch-pick-message-window)))))

(defun notmuch-pick-show-message ()
  "Show the current message (in split-pane)."
  (interactive)
  (let ((id (notmuch-pick-get-message-id))
	(inhibit-read-only t)
	buffer)
    (when id
      ;; We close and reopen the window to kill off un-needed buffers
      ;; this might cause flickering but seems ok.
      (notmuch-pick-close-message-window)
      (setq notmuch-pick-message-window
	    (split-window-vertically (/ (window-height) 4)))
      (with-selected-window notmuch-pick-message-window
	;; Since we are only displaying one message do not indent.
	(let ((notmuch-show-indent-messages-width 0)
	      (notmuch-show-only-matching-messages t))
	  (setq buffer (notmuch-show id nil nil nil))))
      ;; We need the `let' as notmuch-pick-message-window is buffer local.
      (let ((window notmuch-pick-message-window))
	(with-current-buffer buffer
	  (setq notmuch-pick-message-window window)
	  (add-hook 'kill-buffer-hook 'notmuch-pick-message-window-kill-hook)))
      (when notmuch-show-mark-read-tags
	(notmuch-pick-tag-update-display notmuch-show-mark-read-tags))
      (setq notmuch-pick-message-buffer buffer))))

(defun notmuch-pick-show-message-out ()
  "Show the current message (in whole window)."
  (interactive)
  (let ((id (notmuch-pick-get-message-id))
	(inhibit-read-only t)
	buffer)
    (when id
      ;; We close the window to kill off un-needed buffers.
      (notmuch-pick-close-message-window)
      (notmuch-show id nil nil nil))))

(defun notmuch-pick-scroll-message-window ()
  "Scroll the message window (if it exists)"
  (interactive)
  (when (window-live-p notmuch-pick-message-window)
    (with-selected-window notmuch-pick-message-window
      (if (pos-visible-in-window-p (point-max))
	  t
	(scroll-up)))))

(defun notmuch-pick-scroll-message-window-back ()
  "Scroll the message window back(if it exists)"
  (interactive)
  (when (window-live-p notmuch-pick-message-window)
    (with-selected-window notmuch-pick-message-window
      (if (pos-visible-in-window-p (point-min))
	  t
	(scroll-down)))))

(defun notmuch-pick-scroll-or-next ()
  "Scroll the message window. If it at end go to next message."
  (interactive)
  (when (notmuch-pick-scroll-message-window)
    (notmuch-pick-next-matching-message)))

(defun notmuch-pick-quit ()
  "Close the split view or exit pick."
  (interactive)
  (unless (notmuch-pick-close-message-window)
    (kill-buffer (current-buffer))))

(defun notmuch-pick-close-message-window ()
  "Close the message-window. Return t if close succeeds."
  (interactive)
  (when (and (window-live-p notmuch-pick-message-window)
	     (eq (window-buffer notmuch-pick-message-window) notmuch-pick-message-buffer))
    (delete-window notmuch-pick-message-window)
    (unless (get-buffer-window-list notmuch-pick-message-buffer)
      (kill-buffer notmuch-pick-message-buffer))
    t))

(defun notmuch-pick-archive-message (&optional unarchive)
  "Archive the current message.

Archive the current message by applying the tag changes in
`notmuch-archive-tags' to it. If a prefix argument is given, the
message will be \"unarchived\", i.e. the tag changes in
`notmuch-archive-tags' will be reversed."
  (interactive "P")
  (when notmuch-archive-tags
    (apply 'notmuch-pick-tag
	   (notmuch-tag-change-list notmuch-archive-tags unarchive))))

(defun notmuch-pick-archive-message-then-next (&optional unarchive)
  "Archive the current message and move to next matching message."
  (interactive "P")
  (notmuch-pick-archive-message unarchive)
  (notmuch-pick-next-matching-message))

(defun notmuch-pick-next-message ()
  "Move to next message."
  (interactive)
  (forward-line)
  (when (window-live-p notmuch-pick-message-window)
    (notmuch-pick-show-message)))

(defun notmuch-pick-prev-message ()
  "Move to previous message."
  (interactive)
  (forward-line -1)
  (when (window-live-p notmuch-pick-message-window)
    (notmuch-pick-show-message)))

(defun notmuch-pick-prev-matching-message ()
  "Move to previous matching message."
  (interactive)
  (forward-line -1)
  (while (and (not (bobp)) (not (notmuch-pick-get-match)))
    (forward-line -1))
  (when (window-live-p notmuch-pick-message-window)
    (notmuch-pick-show-message)))

(defun notmuch-pick-next-matching-message ()
  "Move to next matching message."
  (interactive)
  (forward-line)
  (while (and (not (eobp)) (not (notmuch-pick-get-match)))
    (forward-line))
  (when (window-live-p notmuch-pick-message-window)
    (notmuch-pick-show-message)))

(defun notmuch-pick-refresh-view ()
  "Refresh view."
  (interactive)
  (let ((inhibit-read-only t)
	(basic-query notmuch-pick-basic-query)
	(query-context notmuch-pick-query-context)
	(target (notmuch-pick-get-message-id)))
    (erase-buffer)
    (notmuch-pick-worker basic-query
			 query-context
			 target)))

(defun notmuch-pick-thread-top ()
  (when (notmuch-pick-get-message-properties)
    (while (not (or (notmuch-pick-get-prop :first) (eobp)))
      (forward-line -1))))

(defun notmuch-pick-prev-thread ()
  (interactive)
  (forward-line -1)
  (notmuch-pick-thread-top))

(defun notmuch-pick-next-thread ()
  (interactive)
  (forward-line 1)
  (while (not (or (notmuch-pick-get-prop :first) (eobp)))
    (forward-line 1)))

(defun notmuch-pick-thread-mapcar (function)
  "Iterate through all messages in the current thread
 and call FUNCTION for side effects."
  (save-excursion
    (notmuch-pick-thread-top)
    (loop collect (funcall function)
	  do (forward-line)
	  while (and (notmuch-pick-get-message-properties)
		     (not (notmuch-pick-get-prop :first))))))

(defun notmuch-pick-get-messages-ids-thread-search ()
  "Return a search string for all message ids of messages in the current thread."
  (mapconcat 'identity
	     (notmuch-pick-thread-mapcar 'notmuch-pick-get-message-id)
	     " or "))

(defun notmuch-pick-tag-thread (&optional tag-changes)
  "Tag all messages in the current thread"
  (interactive)
  (when (notmuch-pick-get-message-properties)
    (let ((tag-changes (notmuch-tag (notmuch-pick-get-messages-ids-thread-search) tag-changes)))
      (notmuch-pick-thread-mapcar
       (lambda () (notmuch-pick-tag-update-display tag-changes))))))

(defun notmuch-pick-archive-thread (&optional unarchive)
  "Archive each message in thread.

Archive each message currently shown by applying the tag changes
in `notmuch-archive-tags' to each. If a prefix argument is given,
the messages will be \"unarchived\", i.e. the tag changes in
`notmuch-archive-tags' will be reversed.

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 "P")
  (when notmuch-archive-tags
    (notmuch-pick-tag-thread
     (notmuch-tag-change-list notmuch-archive-tags unarchive))))

;; Functions below here display the pick buffer itself.

(defun notmuch-pick-clean-address (address)
  "Try to clean a single email ADDRESS for display. Return
AUTHOR_NAME if present, otherwise return AUTHOR_EMAIL. Return
unchanged ADDRESS if parsing fails."
  (let* ((clean-address (notmuch-clean-address address))
	 (p-address (car clean-address))
	 (p-name (cdr clean-address)))

    ;; If we have a name return that otherwise return the address.
    (or p-name p-address)))

(defun notmuch-pick-insert-field (field format-string msg)
  (let* ((headers (plist-get msg :headers))
	(match (plist-get msg :match)))
    (cond
     ((string-equal field "date")
      (let ((face (if match
		      'notmuch-pick-match-date-face
		    'notmuch-pick-no-match-date-face)))
	(insert (propertize (format format-string (plist-get msg :date_relative))
			    'face face))))

     ((string-equal field "subject")
      (let ((tree-status (plist-get msg :tree-status))
	    (bare-subject (notmuch-show-strip-re (plist-get headers :Subject)))
	    (face (if match
		      'notmuch-pick-match-subject-face
		    'notmuch-pick-no-match-subject-face)))
	(insert (propertize (format format-string
				    (concat
				     (mapconcat #'identity (reverse tree-status) "")
				     (if (string= notmuch-pick-previous-subject bare-subject)
					 " ..."
				       bare-subject)))
			    'face face))
	(setq notmuch-pick-previous-subject bare-subject)))

     ((string-equal field "authors")
      (let ((author (notmuch-pick-clean-address (plist-get headers :From)))
	    (len (length (format format-string "")))
	    (face (if match
		      'notmuch-pick-match-author-face
		    'notmuch-pick-no-match-author-face)))
	(when (> (length author) len)
	  (setq author (substring author 0 len)))
	(insert (propertize (format format-string author)
			    'face face))))

     ((string-equal field "tags")
      (let ((tags (plist-get msg :tags))
	    (face (if match
			  'notmuch-pick-match-tag-face
			'notmuch-pick-no-match-tag-face)))
	(when tags
	  (insert (propertize (format format-string
				      (mapconcat #'identity tags ", "))
			      'face face))))))))

(defun notmuch-pick-insert-msg (msg)
  "Insert the message MSG according to notmuch-pick-result-format"
  ;; We need to save the previous subject as it will get overwritten
  ;; by the insert-field calls.
  (let ((previous-subject notmuch-pick-previous-subject))
    (dolist (spec notmuch-pick-result-format)
      (notmuch-pick-insert-field (car spec) (cdr spec) msg))
    (notmuch-pick-set-message-properties msg)
    (notmuch-pick-set-prop :previous-subject previous-subject)
    (insert "\n")))

(defun notmuch-pick-goto-and-insert-msg (msg)
  "Insert msg at the end of the buffer. Move point to msg if it is the target"
  (save-excursion
    (goto-char (point-max))
    (notmuch-pick-insert-msg msg))
  (let ((msg-id (notmuch-id-to-query (plist-get msg :id)))
	(target notmuch-pick-target-msg))
    (when (or (and (not target) (plist-get msg :match))
	      (string= msg-id target))
      (setq notmuch-pick-target-msg "found")
      (goto-char (point-max))
      (forward-line -1)
      (when notmuch-pick-open-target
	(notmuch-pick-show-message)))))

(defun notmuch-pick-insert-tree (tree depth tree-status first last)
  "Insert the message tree TREE at depth DEPTH in the current thread.

A message tree is another name for a single sub-thread: i.e., a
message together with all its descendents."
  (let ((msg (car tree))
	(replies (cadr tree)))

      (cond
       ((and (< 0 depth) (not last))
	(push "├" tree-status))
       ((and (< 0 depth) last)
	(push "╰" tree-status))
       ((and (eq 0 depth) first last)
;;	  (push "─" tree-status)) choice between this and next line is matter of taste.
	(push " " tree-status))
       ((and (eq 0 depth) first (not last))
	  (push "┬" tree-status))
       ((and (eq 0 depth) (not first) last)
	(push "╰" tree-status))
       ((and (eq 0 depth) (not first) (not last))
	(push "├" tree-status)))

      (push (concat (if replies "┬" "─") "►") tree-status)
      (plist-put msg :first (and first (eq 0 depth)))
      (notmuch-pick-goto-and-insert-msg (plist-put msg :tree-status tree-status))
      (pop tree-status)
      (pop tree-status)

      (if last
	  (push " " tree-status)
	(push "│" tree-status))

    (notmuch-pick-insert-thread replies (1+ depth) tree-status)))

(defun notmuch-pick-insert-thread (thread depth tree-status)
  "Insert the collection of sibling sub-threads THREAD at depth DEPTH in the current forest."
  (let ((n (length thread)))
    (loop for tree in thread
	  for count from 1 to n

	  do (notmuch-pick-insert-tree tree depth tree-status (eq count 1) (eq count n)))))

(defun notmuch-pick-insert-forest-thread (forest-thread)
  "Insert a single complete thread."
  (let (tree-status)
    ;; Reset at the start of each main thread.
    (setq notmuch-pick-previous-subject nil)
    (notmuch-pick-insert-thread forest-thread 0 tree-status)))

(defun notmuch-pick-insert-forest (forest)
  "Insert a forest of threads.

This function inserts a collection of several complete threads as
passed to it by notmuch-pick-process-filter."
  (mapc 'notmuch-pick-insert-forest-thread forest))

(defun notmuch-pick-mode ()
  "Major mode displaying messages (as opposed to threads) of of a notmuch search.

This buffer contains the results of a \"notmuch pick\" of your
email archives. Each line in the buffer represents a single
message giving the relative date, the author, subject, and any
tags.

Pressing \\[notmuch-pick-show-message] on any line displays that message.

Complete list of currently available key bindings:

\\{notmuch-pick-mode-map}"

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

(defun notmuch-pick-process-sentinel (proc msg)
  "Add a message to let user know when \"notmuch pick\" exits"
  (let ((buffer (process-buffer proc))
	(status (process-status proc))
	(exit-status (process-exit-status proc))
	(never-found-target-thread nil))
    (when (memq status '(exit signal))
        (kill-buffer (process-get proc 'parse-buf))
	(if (buffer-live-p buffer)
	    (with-current-buffer buffer
	      (save-excursion
		(let ((inhibit-read-only t)
		      (atbob (bobp)))
		  (goto-char (point-max))
		  (if (eq status 'signal)
		      (insert "Incomplete search results (pick process was killed).\n"))
		  (when (eq status 'exit)
		    (insert "End of search results.")
		    (unless (= exit-status 0)
		      (insert (format " (process returned %d)" exit-status)))
		    (insert "\n")))))))))

(defun notmuch-pick-process-filter (proc string)
  "Process and filter the output of \"notmuch show\" (for pick)"
  (let ((results-buf (process-buffer proc))
        (parse-buf (process-get proc 'parse-buf))
        (inhibit-read-only t)
        done)
    (if (not (buffer-live-p results-buf))
        (delete-process proc)
      (with-current-buffer parse-buf
        ;; Insert new data
        (save-excursion
          (goto-char (point-max))
          (insert string))
	(notmuch-sexp-parse-partial-list 'notmuch-pick-insert-forest-thread
					 results-buf)))))

(defun notmuch-pick-worker (basic-query &optional query-context target open-target)
  (interactive)
  (notmuch-pick-mode)
  (setq notmuch-pick-basic-query basic-query)
  (setq notmuch-pick-query-context query-context)
  (setq notmuch-pick-target-msg target)
  (setq notmuch-pick-open-target open-target)

  (erase-buffer)
  (goto-char (point-min))
  (let* ((search-args (concat basic-query
		       (if query-context (concat " and (" query-context ")"))
		       ))
	 (message-arg "--entire-thread"))
    (if (equal (car (process-lines notmuch-command "count" search-args)) "0")
	(setq search-args basic-query))
    (let ((proc (notmuch-start-notmuch
		 "notmuch-pick" (current-buffer) #'notmuch-pick-process-sentinel
		 "show" "--body=false" "--format=sexp"
		 message-arg search-args))
	  ;; Use a scratch buffer to accumulate partial output.
	  ;; This buffer will be killed by the sentinel, which
	  ;; should be called no matter how the process dies.
	  (parse-buf (generate-new-buffer " *notmuch pick parse*")))
      (process-put proc 'parse-buf parse-buf)
      (set-process-filter proc 'notmuch-pick-process-filter)
      (set-process-query-on-exit-flag proc nil))))

(defun notmuch-pick (&optional query query-context target buffer-name open-target)
  "Run notmuch pick with the given `query' and display the results.

The arguments are:
  QUERY: the main query. This can be any query but in many cases will be
      a single thread. If nil this is read interactively from the minibuffer.
  QUERY-CONTEXT: is an additional term for the query. The query used
      is QUERY and QUERY-CONTEXT unless that does not match any messages
      in which case we fall back to just QUERY.
  TARGET: A message ID (with the id: prefix) that will be made
      current if it appears in the pick results.
  BUFFER-NAME: the name of the buffer to show the pick tree. If
      it is nil \"*notmuch-pick\" followed by QUERY is used.
  OPEN-TARGET: If TRUE open the target message in the message pane."
  (interactive "sNotmuch pick: ")
  (if (null query)
      (setq query (notmuch-read-query "Notmuch pick: ")))
  (let ((buffer (get-buffer-create (generate-new-buffer-name
				    (or buffer-name
					(concat "*notmuch-pick-" query "*")))))
	(inhibit-read-only t))

    (switch-to-buffer buffer))
  ;; Don't track undo information for this buffer
  (set 'buffer-undo-list t)

  (notmuch-pick-worker query query-context target open-target)

  (setq truncate-lines t))


;; Set up key bindings from the rest of notmuch.
(define-key 'notmuch-search-mode-map "z" 'notmuch-pick)
(define-key 'notmuch-search-mode-map "Z" 'notmuch-pick-from-search-current-query)
(define-key 'notmuch-search-mode-map (kbd "M-RET") 'notmuch-pick-from-search-thread)
(define-key 'notmuch-hello-mode-map "z" 'notmuch-pick-from-hello)
(define-key 'notmuch-show-mode-map "z" 'notmuch-pick)
(define-key 'notmuch-show-mode-map "Z" 'notmuch-pick-from-show-current-query)
(notmuch-pick-setup-show-out)
(message "Initialised notmuch-pick")

(provide 'notmuch-pick)