emacs: Use the new JSON reply format and message-cite-original

Use the new JSON reply format to create replies in emacs. Quote HTML
parts nicely by using mm-display-part to turn them into displayable
text, then quoting them with message-cite-original. This is very
useful for users who regularly receive HTML-only email.

Use message-mode's message-cite-original function to create the
quoted body for reply messages. In order to make this act like the
existing notmuch defaults, you will need to set the following in
your emacs configuration:

message-citation-line-format "On %a, %d %b %Y, %f wrote:"
message-citation-line-function 'message-insert-formatted-citation-line

The tests have been updated to reflect the (ugly) emacs default.

3 files changed, 119 insertions, 66 deletions

diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
index 7e3f1109..c146748a 100644
--- a/emacs/notmuch-lib.el
+++ b/emacs/notmuch-lib.el
@@ -206,6 +206,36 @@ the user hasn't set this variable with the old or new value."
 	  (setq seq (nconc (delete elem seq) (list elem))))))
     seq))
 
+(defun notmuch-parts-filter-by-type (parts type)
+  "Given a list of message parts, return a list containing the ones matching
+the given type."
+  (remove-if-not
+   (lambda (part) (notmuch-match-content-type (plist-get part :content-type) type))
+   parts))
+
+;; Helper for parts which are generally not included in the default
+;; JSON output.
+(defun notmuch-get-bodypart-internal (message-id part-number process-crypto)
+  (let ((args '("show" "--format=raw"))
+	(part-arg (format "--part=%s" part-number)))
+    (setq args (append args (list part-arg)))
+    (if process-crypto
+	(setq args (append args '("--decrypt"))))
+    (setq args (append args (list message-id)))
+    (with-temp-buffer
+      (let ((coding-system-for-read 'no-conversion))
+	(progn
+	  (apply 'call-process (append (list notmuch-command nil (list t nil) nil) args))
+	  (buffer-string))))))
+
+(defun notmuch-get-bodypart-content (msg part nth process-crypto)
+  (or (plist-get part :content)
+      (notmuch-get-bodypart-internal (concat "id:" (plist-get msg :id)) nth process-crypto)))
+
+(defun notmuch-plist-to-alist (plist)
+  (loop for (key value . rest) on plist by #'cddr
+	collect (cons (substring (symbol-name key) 1) value)))
+
 ;; Compatibility functions for versions of emacs before emacs 23.
 ;;
 ;; Both functions here were copied from emacs 23 with the following copyright:
diff --git a/emacs/notmuch-mua.el b/emacs/notmuch-mua.el
index 13244eb8..6aae3a05 100644
--- a/emacs/notmuch-mua.el
+++ b/emacs/notmuch-mua.el
@@ -19,11 +19,15 @@
 ;;
 ;; Authors: David Edmondson <dme@dme.org>
 
+(require 'json)
 (require 'message)
+(require 'format-spec)
 
 (require 'notmuch-lib)
 (require 'notmuch-address)
 
+(eval-when-compile (require 'cl))
+
 ;;
 
 (defcustom notmuch-mua-send-hook '(notmuch-mua-message-send-hook)
@@ -72,54 +76,92 @@ list."
 	    (push header message-hidden-headers)))
 	notmuch-mua-hidden-headers))
 
+(defun notmuch-mua-get-quotable-parts (parts)
+  (loop for part in parts
+	if (notmuch-match-content-type (plist-get part :content-type) "multipart/alternative")
+	  collect (let* ((subparts (plist-get part :content))
+			(types (mapcar (lambda (part) (plist-get part :content-type)) subparts))
+			(chosen-type (car (notmuch-multipart/alternative-choose types))))
+		   (loop for part in (reverse subparts)
+			 if (notmuch-match-content-type (plist-get part :content-type) chosen-type)
+			 return part))
+	else if (notmuch-match-content-type (plist-get part :content-type) "multipart/*")
+	  append (notmuch-mua-get-quotable-parts (plist-get part :content))
+	else if (notmuch-match-content-type (plist-get part :content-type) "text/*")
+	  collect part))
+
 (defun notmuch-mua-reply (query-string &optional sender reply-all)
-  (let (headers
-	body
-	(args '("reply")))
-    (if notmuch-show-process-crypto
-	(setq args (append args '("--decrypt"))))
+  (let ((args '("reply" "--format=json"))
+	reply
+	original)
+    (when notmuch-show-process-crypto
+      (setq args (append args '("--decrypt"))))
+
     (if reply-all
 	(setq args (append args '("--reply-to=all")))
       (setq args (append args '("--reply-to=sender"))))
     (setq args (append args (list query-string)))
-    ;; This make assumptions about the output of `notmuch reply', but
-    ;; really only that the headers come first followed by a blank
-    ;; line and then the body.
+
+    ;; Get the reply object as JSON, and parse it into an elisp object.
     (with-temp-buffer
       (apply 'call-process (append (list notmuch-command nil (list t t) nil) args))
       (goto-char (point-min))
-      (if (re-search-forward "^$" nil t)
-	  (save-excursion
-	    (save-restriction
-	      (narrow-to-region (point-min) (point))
-	      (goto-char (point-min))
-	      (setq headers (mail-header-extract)))))
-      (forward-line 1)
-      ;; Original message may contain (malicious) MML tags. We must
-      ;; properly quote them in the reply.
-      (mml-quote-region (point) (point-max))
-      (setq body (buffer-substring (point) (point-max))))
-    ;; If sender is non-nil, set the From: header to its value.
-    (when sender
-      (mail-header-set 'from sender headers))
-    (let
-	;; Overlay the composition window on that being used to read
-	;; the original message.
-	((same-window-regexps '("\\*mail .*")))
-      (notmuch-mua-mail (mail-header 'to headers)
-			(mail-header 'subject headers)
-			(message-headers-to-generate headers t '(to subject))))
-    ;; insert the message body - but put it in front of the signature
-    ;; if one is present
-    (goto-char (point-max))
-    (if (re-search-backward message-signature-separator nil t)
+      (let ((json-object-type 'plist)
+	    (json-array-type 'list)
+	    (json-false 'nil))
+	(setq reply (json-read))))
+
+    ;; Extract the original message to simplify the following code.
+    (setq original (plist-get reply :original))
+
+    ;; Extract the headers of both the reply and the original message.
+    (let* ((original-headers (plist-get original :headers))
+	   (reply-headers (plist-get reply :reply-headers)))
+
+      ;; If sender is non-nil, set the From: header to its value.
+      (when sender
+	(plist-put reply-headers :From sender))
+      (let
+	  ;; Overlay the composition window on that being used to read
+	  ;; the original message.
+	  ((same-window-regexps '("\\*mail .*")))
+	(notmuch-mua-mail (plist-get reply-headers :To)
+			  (plist-get reply-headers :Subject)
+			  (notmuch-plist-to-alist reply-headers)))
+      ;; Insert the message body - but put it in front of the signature
+      ;; if one is present
+      (goto-char (point-max))
+      (if (re-search-backward message-signature-separator nil t)
 	  (forward-line -1)
-      (goto-char (point-max)))
-    (insert body)
-    (push-mark))
-  (set-buffer-modified-p nil)
-
-  (message-goto-body))
+	(goto-char (point-max)))
+
+      (let ((from (plist-get original-headers :From))
+	    (date (plist-get original-headers :Date))
+	    (start (point)))
+
+	;; message-cite-original constructs a citation line based on the From and Date
+	;; headers of the original message, which are assumed to be in the buffer.
+	(insert "From: " from "\n")
+	(insert "Date: " date "\n\n")
+
+	;; Get the parts of the original message that should be quoted; this includes
+	;; all the text parts, except the non-preferred ones in a multipart/alternative.
+	(let ((quotable-parts (notmuch-mua-get-quotable-parts (plist-get original :body))))
+	  (mapc (lambda (part)
+		  (insert (notmuch-get-bodypart-content original part
+							(plist-get part :id)
+							notmuch-show-process-crypto)))
+		quotable-parts))
+
+	(set-mark (point))
+	(goto-char start)
+	;; Quote the original message according to the user's configured style.
+	(message-cite-original))))
+
+  (goto-char (point-max))
+  (push-mark)
+  (message-goto-body)
+  (set-buffer-modified-p nil))
 
 (defun notmuch-mua-forward-message ()
   (message-forward)
@@ -145,7 +187,7 @@ OTHER-ARGS are passed through to `message-mail'."
       (when (not (string= "" user-agent))
 	(push (cons "User-Agent" user-agent) other-headers))))
 
-  (unless (mail-header 'from other-headers)
+  (unless (mail-header 'From other-headers)
     (push (cons "From" (concat
 			(notmuch-user-name) " <" (notmuch-user-primary-email) ">")) other-headers))
 
@@ -208,7 +250,7 @@ the From: address first."
   (interactive "P")
   (let ((other-headers
 	 (when (or prompt-for-sender notmuch-always-prompt-for-sender)
-	   (list (cons 'from (notmuch-mua-prompt-for-sender))))))
+	   (list (cons 'From (notmuch-mua-prompt-for-sender))))))
     (notmuch-mua-mail nil nil other-headers)))
 
 (defun notmuch-mua-new-forward-message (&optional prompt-for-sender)
diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index ed938bf2..0cd7d826 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -488,7 +488,7 @@ message at DEPTH in the current thread."
 	 (setq notmuch-show-process-crypto ,process-crypto)
 	 ;; Always acquires the part via `notmuch part', even if it is
 	 ;; available in the JSON output.
-	 (insert (notmuch-show-get-bodypart-internal ,message-id ,nth))
+	 (insert (notmuch-get-bodypart-internal ,message-id ,nth notmuch-show-process-crypto))
 	 ,@body))))
 
 (defun notmuch-show-save-part (message-id nth &optional filename content-type)
@@ -536,7 +536,7 @@ current buffer, if possible."
 	;; test whether we are able to inline it (which includes both
 	;; capability and suitability tests).
 	(when (mm-inlined-p handle)
-	  (insert (notmuch-show-get-bodypart-content msg part nth))
+	  (insert (notmuch-get-bodypart-content msg part nth notmuch-show-process-crypto))
 	  (when (mm-inlinable-p handle)
 	    (set-buffer display-buffer)
 	    (mm-display-part handle)
@@ -613,8 +613,8 @@ current buffer, if possible."
 	  ;; times (hundreds!), which results in many calls to
 	  ;; `notmuch part'.
 	  (unless content
-	    (setq content (notmuch-show-get-bodypart-internal (concat "id:" message-id)
-							      part-number))
+	    (setq content (notmuch-get-bodypart-internal (concat "id:" message-id)
+							      part-number notmuch-show-process-crypto))
 	    (with-current-buffer w3m-current-buffer
 	      (notmuch-show-w3m-cid-store-internal url
 						   message-id
@@ -734,7 +734,7 @@ current buffer, if possible."
     ;; insert a header to make this clear.
     (if (> nth 1)
 	(notmuch-show-insert-part-header nth declared-type content-type (plist-get part :filename)))
-    (insert (notmuch-show-get-bodypart-content msg part nth))
+    (insert (notmuch-get-bodypart-content msg part nth notmuch-show-process-crypto))
     (save-excursion
       (save-restriction
 	(narrow-to-region start (point-max))
@@ -744,7 +744,7 @@ current buffer, if possible."
 (defun notmuch-show-insert-part-text/calendar (msg part content-type nth depth declared-type)
   (notmuch-show-insert-part-header nth declared-type content-type (plist-get part :filename))
   (insert (with-temp-buffer
-	    (insert (notmuch-show-get-bodypart-content msg part nth))
+	    (insert (notmuch-get-bodypart-content msg part nth notmuch-show-process-crypto))
 	    (goto-char (point-min))
 	    (let ((file (make-temp-file "notmuch-ical"))
 		  result)
@@ -806,25 +806,6 @@ current buffer, if possible."
 		(intern (concat "notmuch-show-insert-part-" content-type))))
     result))
 
-;; Helper for parts which are generally not included in the default
-;; JSON output.
-(defun notmuch-show-get-bodypart-internal (message-id part-number)
-  (let ((args '("show" "--format=raw"))
-	(part-arg (format "--part=%s" part-number)))
-    (setq args (append args (list part-arg)))
-    (if notmuch-show-process-crypto
-	(setq args (append args '("--decrypt"))))
-    (setq args (append args (list message-id)))
-    (with-temp-buffer
-      (let ((coding-system-for-read 'no-conversion))
-	(progn
-	  (apply 'call-process (append (list notmuch-command nil (list t nil) nil) args))
-	  (buffer-string))))))
-
-(defun notmuch-show-get-bodypart-content (msg part nth)
-  (or (plist-get part :content)
-      (notmuch-show-get-bodypart-internal (concat "id:" (plist-get msg :id)) nth)))
-
 ;; 
 
 (defun notmuch-show-insert-bodypart-internal (msg part content-type nth depth declared-type)