[PATCH 1/4] emacs: Add a thread's tags to notmuch-show header-line

[Damien Cassou <damien.cassou@gmail.com>]

Signed-off-by: Damien Cassou <damien.cassou@gmail.com>
---
 emacs/notmuch-lib.el    |   11 +++++++++--
 emacs/notmuch-show.el   |   37 +++++++++++++++++++++++++++++--------
 emacs/notmuch-tagger.el |   35 +++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 10 deletions(-)
 create mode 100644 emacs/notmuch-tagger.el

diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
index 9c4ee71..3541bb7 100644
--- a/emacs/notmuch-lib.el
+++ b/emacs/notmuch-lib.el
@@ -603,8 +603,15 @@ left it."
     ;; Clear out what we've parsed
     (delete-region (point-min) (point))))
 
-
-
+(defun notmuch-intersperse (list sep)
+  "Return a list with all elements of LIST separated by SEP."
+  (let ((first t)
+        (res nil))
+    (dolist (elt list (nreverse res))
+      (unless first
+        (push sep res))
+      (setq first nil)
+      (push elt res))))
 
 (provide 'notmuch-lib)
 
diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index 7d9f8a9..9c5a85e 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -36,6 +36,7 @@
 (require 'notmuch-mua)
 (require 'notmuch-crypto)
 (require 'notmuch-print)
+(require 'notmuch-tagger)
 
 (declare-function notmuch-call-notmuch-process "notmuch" (&rest args))
 (declare-function notmuch-fontify-headers "notmuch" nil)
@@ -355,7 +356,7 @@ operation on the contents of the current buffer."
   "Return a string comprised of `n' spaces."
   (make-string n ? ))
 
-(defun notmuch-show-update-tags (tags)
+(defun notmuch-show-update-tags (tags &optional no-headerline-update)
   "Update the displayed tags of the current message."
   (save-excursion
     (goto-char (notmuch-show-message-top))
@@ -364,7 +365,9 @@ operation on the contents of the current buffer."
 	  (replace-match (concat "("
 				 (propertize (mapconcat 'identity tags " ")
 					     'face 'notmuch-tag-face)
-				 ")"))))))
+				 ")")))))
+  (unless no-headerline-update
+    (notmuch-show-update-header-line)))
 
 (defun notmuch-clean-address (address)
   "Try to clean a single email ADDRESS for display. Return a cons
@@ -1136,11 +1139,28 @@ function is used."
 
       (jit-lock-register #'notmuch-show-buttonise-links)
 
-      ;; Set the header line to the subject of the first message.
-      (setq header-line-format (notmuch-show-strip-re (notmuch-show-get-subject)))
-
+      (notmuch-show-update-header-line)
       (run-hooks 'notmuch-show-hook))))
 
+(defun notmuch-show-thread-tags ()
+  "Return the list of tags for the current thread."
+  (let ((tags (list)))
+    (notmuch-show-mapc (lambda ()
+			 (mapcar (lambda (elt)
+				   ;; Avoid adding duplicate tags
+				   (add-to-list 'tags elt))
+				 (notmuch-show-get-tags))))
+    (sort tags 'string<)))
+
+(defun notmuch-show-update-header-line ()
+  "Make the header-line show the thread's subject and tags."
+  (let ((thread-subject (notmuch-show-strip-re (notmuch-show-get-subject))))
+    (setq header-line-format
+	  (list
+	   thread-subject
+	   " "
+	   (notmuch-tagger-format-tags-header-line (notmuch-show-thread-tags))))))
+
 (defun notmuch-show-capture-state ()
   "Capture the state of the current buffer.
 
@@ -1443,10 +1463,10 @@ current thread."
 (defun notmuch-show-get-depth ()
   (notmuch-show-get-prop :depth))
 
-(defun notmuch-show-set-tags (tags)
+(defun notmuch-show-set-tags (tags &optional no-headerline-update)
   "Set the tags of the current message."
   (notmuch-show-set-prop :tags tags)
-  (notmuch-show-update-tags tags))
+  (notmuch-show-update-tags tags no-headerline-update))
 
 (defun notmuch-show-get-tags ()
   "Return the tags of the current message."
@@ -1760,7 +1780,8 @@ See `notmuch-tag' for information on the format of TAG-CHANGES."
      (let* ((current-tags (notmuch-show-get-tags))
 	    (new-tags (notmuch-update-tags current-tags tag-changes)))
        (unless (equal current-tags new-tags)
-	 (notmuch-show-set-tags new-tags))))))
+	 (notmuch-show-set-tags new-tags t)))))
+  (notmuch-show-update-header-line))
 
 (defun notmuch-show-add-tag ()
   "Same as `notmuch-show-tag' but sets initial input to '+'."
diff --git a/emacs/notmuch-tagger.el b/emacs/notmuch-tagger.el
new file mode 100644
index 0000000..6fcebff
--- /dev/null
+++ b/emacs/notmuch-tagger.el
@@ -0,0 +1,35 @@
+;; notmuch-tagger.el --- Library to improve the way tags are displayed
+;;
+;; Copyright © Damien Cassou
+;;
+;; 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: Damien Cassou <damien.cassou@gmail.com>
+;;; Commentary:
+;;
+;;; Code:
+;;
+
+(defun notmuch-tagger-format-tags-header-line (tags)
+  "Format TAGS as a `mode-line-format' template.
+The result is suitable for inclusion in `header-line-format'."
+  (list
+   "("
+   (notmuch-intersperse tags " ")
+   ")"))
+
+(provide 'notmuch-tagger)
+;;; notmuch-tagger.el ends here
-- 
1.7.10.4