mu4e: improve sorting of contacts for completion

set up the extra machinery for making sure emacs does not try to re-sort
our already-sorted contacts.... Also try to improve the sorting strategy
itself.

mu4e/mu4e-compose.el

@@ -250,12 +250,22 @@ appear on disk."
       (mu4e-message "Saved (%d lines)" (count-lines (point-min) (point-max)))
       ;; update the file on disk -- ie., without the separator
       (mu4e~proc-add (buffer-file-name) mu4e~draft-drafts-folder)) nil t))
-
-
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; address completion; inspired by org-contacts.el and
 ;; https://github.com/nordlow/elisp/blob/master/mine/completion-styles-cycle.el
+(defun mu4e~compose-complete-handler (str pred action)
+  (cond
+    ((eq action nil)
+      (try-completion str mu4e~contacts-for-completion pred))
+    ((eq action t)
+      (all-completions str mu4e~contacts-for-completion pred))
+    ((eq action 'metadata)
+      ;; our contacts are already sorted - just need to tell the
+      ;; completion machinery not to try to undo that...
+      '(metadata
+	 (display-sort-function . identity) ;; i.e., alphabetically
+	 (cycle-sort-function   . identity)))))
 
 (defun mu4e~compose-complete-contact (&optional start)
   "Complete the text at START with a contact.
@@ -276,8 +286,8 @@ Ie. either 'name <email>' or 'email')."
 		    (re-search-backward "\\(\\`\\|[\n:,]\\)[ \t]*")
 		    (goto-char (match-end 0))
 		    (point)))))
-	(list start end mu4e~contacts-for-completion))))) 
- 
+	(list start end 'mu4e~compose-complete-handler)))))
+
 (defun mu4e~compose-setup-completion ()
   "Set up auto-completion of addresses."
   (set (make-local-variable 'completion-ignore-case) t)
@@ -311,8 +321,8 @@ message-thread by removing the In-Reply-To header."
   (progn
     (use-local-map mu4e-compose-mode-map)
 
-    (set (make-local-variable 'global-mode-string) '(:eval (mu4e-context-label))) 
-   
+    (set (make-local-variable 'global-mode-string) '(:eval (mu4e-context-label)))
+
     (set (make-local-variable 'message-signature) mu4e-compose-signature)
     ;; set this to allow mu4e to work when gnus-agent is unplugged in gnus
     (set (make-local-variable 'message-send-mail-real-function) nil)

mu4e/mu4e-utils.el

@@ -638,16 +638,32 @@ process."
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (defsubst mu4e~process-contact (contact)
-  "Process CONTACT, possibly rewriting it, or return nil if
-should be removed."
+  "Process CONTACT, and either return nil when it should not be included,
+or (rfc822-string . CONTACT) otherwise."
   (when mu4e-contact-rewrite-function
     (setq contact (funcall mu4e-contact-rewrite-function contact)))
   (when contact
     (let ((name (plist-get contact :name))
 	   (mail (plist-get contact :mail))) 
       (unless (and mail (string-match mu4e-compose-complete-ignore-address-regexp mail))
-	(if name (format "%s <%s>" (mu4e~rfc822-quoteit name) mail) mail)))))  
-	
+	(cons
+	  (if name (format "%s <%s>" (mu4e~rfc822-quoteit name) mail) mail)
+	  contact)))))
+
+(defun mu4e~sort-contacts (contacts)
+  "Sort the contacts (only for cycling). Sort by last-use when
+that is at most 10 days old. Otherwise, sort by frequency."
+  (let ((recent (- (float-time) (* 10 24 3600))))
+    (sort contacts
+      (lambda (c1 c2)
+	(let* ((freq1 (plist-get c1 :freq))
+		(freq2 (plist-get c2 :freq))
+		(tstamp1 (plist-get c1 :tstamp))
+		(tstamp2 (plist-get c2 :tstamp)))
+	  (if (or (> tstamp1 recent) (> tstamp2 recent))
+	    (< tstamp1 tstamp2)
+	    (< freq1 freq2)))))))
+
 ;; start and stopping
 (defun mu4e~fill-contacts (contacts)
   "We receive a list of contacts, which each contact of the form
@@ -656,25 +672,8 @@ and fill the list `mu4e~contacts-for-completion' with it, with
 each element looking like
   name <email>
 This is used by the completion function in mu4e-compose."
-  (setq
-    mu4e~contact-list contacts
-    mu4e~contacts-for-completion nil)
-  (let ((lst)
-	 ;; sort by the frequency (ascending), then timestamp (ascending)
-	 ;; note -- this the opposite order we'd want, but the
-	 ;; `push' below reverses the order
-	 
-	 ;; FIXME: sadly, the emacs completion subsystem re-sorts the list
-	 ;; before showing candidates, so this doesn't do anything useful yet.
-	 (contacts (sort contacts
-		     (lambda (c1 c2)
-		       (let ((freq1 (plist-get c1 :freq))
-			      (tstamp1 (plist-get c1 :tstamp))
-			      (freq2 (plist-get c2 :freq))
-			      (tstamp2 (plist-get c2 :tstamp)))
-			 (if (equal freq1 freq2)
-			   (< tstamp1 tstamp2)
-			   (< freq1 freq2)))))))
+  (let ((contacts (mu4e~sort-contacts contacts)))
+    (setq mu4e~contacts-for-completion nil)
     (dolist (contact contacts)
       (let ((contact (mu4e~process-contact contact)))
 	(when contact (push contact mu4e~contacts-for-completion))))    
@@ -1173,6 +1172,5 @@ the view and compose modes."
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 
-
 (provide 'mu4e-utils)
 ;;; End of mu4e-utils.el

mu4e/mu4e-vars.el

@@ -771,10 +771,6 @@ for an example.")
 This is used by the completion functions in mu4e-compose, filled
 when mu4e starts.")
 
-(defvar mu4e~contact-list nil
-  "List of contacts, where each contact is a plist
-  (:name NAME :mail EMAIL :tstamp TIMESTAMP :freq FREQUENCY).")
-
 (defvar mu4e~server-props nil
   "Properties we receive from the mu4e server process.
 \(in the 'pong-handler').")