From a5dd24f754efd5762b642d39e1234f4b7ba2252c Mon Sep 17 00:00:00 2001
From: Kyle Meyer <kyle@kyleam.com>
Date: Sun, 3 May 2020 02:17:07 -0400
Subject: Add basic support for Notmuch

---
 Makefile        |   2 +-
 piem-notmuch.el | 111 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 piem.texi       |   4 ++
 3 files changed, 116 insertions(+), 1 deletion(-)
 create mode 100644 piem-notmuch.el

diff --git a/Makefile b/Makefile
index 80f50c5..60545c8 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@
 # Rely on EMACSLOADPATH for everything but the current directory.
 BATCH = emacs -Q --batch -L .
 
-all: loadpath piem.elc piem-b4.elc piem.info
+all: loadpath piem.elc piem-b4.elc piem-notmuch.elc piem.info
 
 .PHONY: clean
 clean:
diff --git a/piem-notmuch.el b/piem-notmuch.el
new file mode 100644
index 0000000..6ef6cdb
--- /dev/null
+++ b/piem-notmuch.el
@@ -0,0 +1,111 @@
+;;; piem-notmuch.el --- Notmuch integration for piem  -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2020  Kyle Meyer
+
+;; Author: Kyle Meyer <kyle@kyleam.com>
+;; Keywords: vc, tools
+;; Version: 0.0.0
+;; Package-Requires: ((emacs "26.3"))
+
+;; This program 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.
+
+;; This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;
+
+;;; Code:
+
+(require 'message)
+(require 'notmuch)
+(require 'piem)
+(require 'subr-x)
+
+(defgroup piem-notmuch nil
+  "Notmuch integration for piem."
+  :link '(info-link "(piem)Notmuch integration")
+  :group 'piem)
+
+(defcustom piem-notmuch-executable "notmuch"
+  "Which notmuch executable to use."
+  :type 'string)
+
+(defmacro piem-notmuch--with-current-message (&rest body)
+  (let ((rv (make-symbol "rv")))
+    `(let (,rv)
+       (with-current-notmuch-show-message
+        (setq ,rv ,(macroexp-progn body)))
+       ,rv)))
+
+(defun piem-notmuch-get-inbox ()
+  "Return inbox name from a `notmuch-show-mode' buffer."
+  (pcase-let ((`(,listid ,to ,cc)
+               (when (derived-mode-p 'notmuch-show-mode)
+                 (piem-notmuch--with-current-message
+                  (message-narrow-to-headers-or-head)
+                  (list (message-fetch-field "list-id")
+                        (message-fetch-field "to")
+                        (message-fetch-field "cc"))))))
+    (catch 'hit
+      (dolist (inbox piem-inboxes)
+        (let* ((info (cdr inbox))
+               (p-listid (plist-get info :listid)))
+          (when (and listid
+                     p-listid
+                     (string-match-p (concat "<" (regexp-quote p-listid) ">")
+                                     listid))
+            (throw 'hit (car inbox)))
+          (when-let ((addr (plist-get info :address))
+                     (to (mapconcat #'identity (list to cc)
+                                    " ")))
+            (when (string-match-p (regexp-quote addr) to)
+              (throw 'hit (car inbox)))))))))
+
+(defun piem-notmuch-get-mid ()
+  "Return the message ID of a `notmuch-show-mode' buffer."
+  (notmuch-show-get-message-id 'bare))
+
+(defun piem-notmuch-mid-to-thread (mid)
+  "Return a function that inserts an mbox for MID's thread."
+  (let ((query (concat "id:" mid)))
+    (when (equal query
+                 (string-trim-right
+                  (with-output-to-string
+                    (with-current-buffer standard-output
+                      (call-process piem-notmuch-executable
+                                    nil '(t nil) nil
+                                    "search" "--output=messages" query)))))
+      (lambda ()
+        (call-process piem-notmuch-executable
+                      nil '(t nil) nil
+                      "show" "--format=mbox" "--entire-thread=true"
+                      query)))))
+
+(define-minor-mode piem-notmuch-mode
+  "Toggle Notmuch support for piem.
+With a prefix argument ARG, enable piem-notmuch mode if ARG is
+positive, and disable it otherwise.  If called from Lisp, enable
+the mode if ARG is omitted or nil."
+  :global t
+  :init-value nil
+  (if piem-notmuch-mode
+      (progn
+        (add-hook 'piem-get-inbox-functions #'piem-notmuch-get-inbox)
+        (add-hook 'piem-get-mid-functions #'piem-notmuch-get-mid)
+        (add-hook 'piem-mid-to-thread-functions #'piem-notmuch-mid-to-thread))
+    (remove-hook 'piem-get-inbox-functions #'piem-notmuch-get-inbox)
+    (remove-hook 'piem-get-mid-functions #'piem-notmuch-get-mid)
+    (remove-hook 'piem-mid-to-thread-functions #'piem-notmuch-mid-to-thread)))
+
+;;; piem-notmuch.el ends here
+(provide 'piem-notmuch)
diff --git a/piem.texi b/piem.texi
index 137a7cb..5679006 100644
--- a/piem.texi
+++ b/piem.texi
@@ -46,6 +46,7 @@ This manual is for piem version @value{VERSION}.
 @menu
 * Overview::
 * b4 interface::
+* Notmuch integration::
 * Related tools::
 * Contributing::
 
@@ -68,6 +69,9 @@ Indices
 @node b4 interface
 @chapter b4 interface
 
+@node Notmuch integration
+@chapter Notmuch integration
+
 @node Related tools
 @chapter Related tools
 
-- 
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