emacs: maildir-fcc: prepare for use of notmuch insert

We move some code around in preparation for the use of notmuch
insert. In particular, we move the check for a valid maildir for the
fcc to when the message is sent rather than when the fcc header is
inserted. The main motivation is consistency with the insert version
(coming later) where we cannot check the validity until send.

We allow the user some chance to correct the header; the choice here
is intended to be consistent with the insert version to come.

emacs/notmuch-maildir-fcc.el

@@ -65,11 +65,9 @@ yet when sending a mail."
  :require 'notmuch-fcc-initialization
  :group 'notmuch-send)
 
-(defun notmuch-fcc-handler (destdir)
-  "Write buffer to `destdir', marking it as sent
 
-Intended to be dynamically bound to `message-fcc-handler-function'"
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-    (notmuch-maildir-fcc-write-buffer-to-maildir destdir t))
+;; Functions which set up the fcc header in the message buffer.
 
 (defun notmuch-fcc-header-setup ()
   "Add an Fcc header to the current message buffer.
@@ -110,6 +108,9 @@ by notmuch-mua-mail"
 	   (error "Invalid `notmuch-fcc-dirs' setting (neither string nor list)")))))
 
     (when subdir
+      (notmuch-maildir-add-file-style-fcc-header subdir))))
+
+(defun notmuch-maildir-add-file-style-fcc-header (subdir)
   (message-add-header
    (concat "Fcc: "
 	   (file-truename
@@ -117,19 +118,14 @@ by notmuch-mua-mail"
 	    ;; prepend the standard notmuch database path.
 	    (if (= (elt subdir 0) ?/)
 		subdir
-		  (concat (notmuch-database-path) "/" subdir)))))
+	      (concat (notmuch-database-path) "/" subdir))))))
 
-      ;; finally test if fcc points to a valid maildir
+(defun notmuch-fcc-handler (fcc-header)
-      (let ((fcc-header (message-field-value "Fcc")))
+  "Store message with file fcc."
-	(unless (notmuch-maildir-fcc-dir-is-maildir-p fcc-header)
+  (notmuch-maildir-fcc-file-fcc fcc-header))
-	  (cond ((not (file-writable-p fcc-header))
+
-		 (error (format "No permission to create %s, which does not exist"
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-				fcc-header)))
+;; Functions for saving a message using file fcc.
-		((y-or-n-p (format "%s is not a maildir. Create it? "
-				   fcc-header))
-		 (notmuch-maildir-fcc-create-maildir fcc-header))
-		(t
-		 (error "Message not sent"))))))))
 
 (defun notmuch-maildir-fcc-host-fixer (hostname)
   (replace-regexp-in-string "/\\|:"
@@ -192,6 +188,29 @@ if successful, nil if not."
    (concat destdir "/tmp/" msg-id)
    (concat destdir "/cur/" msg-id ":2," (when mark-seen "S"))))
 
+(defun notmuch-maildir-fcc-file-fcc (fcc-header)
+  "Write the message to the file specified by FCC-HEADER.
+
+It offers the user a chance to correct the header, or filesystem,
+if needed."
+  (if (notmuch-maildir-fcc-dir-is-maildir-p fcc-header)
+      (notmuch-maildir-fcc-write-buffer-to-maildir fcc-header 't)
+    ;; The fcc-header is not a valid maildir see if the user wants to
+    ;; fix it in some way.
+    (let* ((prompt (format "Fcc %s is not a maildir: (r)etry, (c)reate folder, (i)gnore, or  (e)dit the header? "
+			   fcc-header))
+	    (response (read-char-choice prompt '(?r ?c ?i ?e))))
+	 (case response
+	       (?r (notmuch-maildir-fcc-file-fcc fcc-header))
+	       (?c (if (file-writable-p fcc-header)
+		       (notmuch-maildir-fcc-create-maildir fcc-header)
+		     (message "No permission to create %s." fcc-header)
+		     (sit-for 2))
+		   (notmuch-maildir-fcc-file-fcc fcc-header))
+	       (?i 't)
+	       (?e (notmuch-maildir-fcc-file-fcc
+		    (read-from-minibuffer "Fcc header: " fcc-header)))))))
+
 (defun notmuch-maildir-fcc-write-buffer-to-maildir (destdir &optional mark-seen)
   "Writes the current buffer to maildir destdir. If mark-seen is
 non-nil, it will write it to cur/, and mark it as read. It should