;; This file 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 2, 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 GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.
;;
;; To use this as the fcc handler for message-mode,
;; customize the notmuch-fcc-dirs variable

(require 'message)

(require 'notmuch-lib)

(defvar notmuch-maildir-fcc-count 0)

(defcustom notmuch-fcc-dirs nil
 "Determines the maildir directory to save outgoing mails in.

 If set to non-nil, this will cause message mode to file your
 mail in the specified directory (fcc).

 It is either a string if you only need one fcc directory or a
 list if they depend on your From address (see example).

 In the former case it is a string such as \"INBOX.Sent\".

 In the fancy setup, where you want different outboxes depending
 on your From address, you supply a list like this:

     ((\"defaultinbox\")
      (\"Sebastian Spaeth <Sebastian@SSpaeth.de>\" . \"privat\")
      (\"Sebastian Spaeth <spaetz@sspaeth.de>\" . \"OUTBOX.OSS\")
     )

 The outbox that matches a key (case insensitive) will be
 used. The first entry is used as a default fallback when nothing
 else matches.

 In all cases, a relative FCC directory will be understood to
 specify a directory within the notmuch mail store, (as set by
 the database.path option in the notmuch configuration file).

 You will be prompted to create the directory if it does not exist yet when 
 sending a mail.

 This function will not modify the headers if there is a FCC
 header, but will check that the target directory exists."

 :require 'notmuch-fcc-initialization
 :group 'notmuch
)

(defun notmuch-fcc-initialization ()
  "If notmuch-fcc-directories is set,
   hook them into the message-fcc-handler-function"
    ;; Set up the message-fcc-handler to move mails to the maildir in Fcc
    ;; The parameter is set to mark messages as "seen"
    (setq message-fcc-handler-function
          '(lambda (destdir)
             (notmuch-maildir-fcc-write-buffer-to-maildir destdir t)))
    ;;add a hook to actually insert the Fcc header when sending
    (add-hook 'message-send-hook 'notmuch-fcc-header-setup))

(defun notmuch-fcc-header-setup ()
  "Adds an appropriate fcc header to the current mail buffer

   Can be added to message-send-hook and will set the FCC header
   based on the values of notmuch-fcc-directories (see the
   variable customization there for examples). It uses the first
   entry as default fallback if no From address matches."
  ;; only do something if notmuch-fcc-dirs is set
  (when notmuch-fcc-dirs
    (let (subdir)
      (if (stringp notmuch-fcc-dirs)
          ;; notmuch-fcc-dirs is a string, just use it as subdir
          (setq subdir notmuch-fcc-dirs)
        ;; else: it's a list of alists (("sent") ("name1" . "sent1"))
        (setq subdir (cdr (assoc-string (message-fetch-field "from") notmuch-fcc-dirs t)))
         ;; if we found no hit, use the first entry as default fallback
         (unless subdir (setq subdir (car (car notmuch-fcc-dirs)))))

  ;; if there is no fcc header yet, add ours
  (unless (message-fetch-field "fcc")
    (message-add-header (concat "Fcc: "
				(if (= (elt subdir 0) ?/)
				    subdir
				  (concat (notmuch-database-path) "/" subdir)))))

  ;; finally test if fcc points to a valid maildir
  (let ((fcc-header (message-fetch-field "fcc")))
    (unless (notmuch-maildir-fcc-dir-is-maildir-p fcc-header)
      (cond ((not (file-writable-p fcc-header))
             (error (format "%s is not a maildir, but you don't have permission to create one." fcc-header)))
            ((y-or-n-p (format "%s is not a maildir. Create it? "
                               fcc-header))
             (notmuch-maildir-fcc-create-maildir fcc-header))
            (t
             (error "Not sending message."))))))))
 
(defun notmuch-maildir-fcc-host-fixer (hostname)
  (replace-regexp-in-string "/\\|:"
			    '(lambda (s)
                               (cond ((string-equal s "/") "\\057")
                                     ((string-equal s ":") "\\072")
                                     (t s)))
			    hostname
			    t
			    t))

(defun notmuch-maildir-fcc-make-uniq-maildir-id ()
   (let* ((ct (current-time))
	  (timeid (+ (* (car ct) 65536) (cadr ct)))
	  (microseconds (car (cdr (cdr ct))))
	  (hostname (notmuch-maildir-fcc-host-fixer system-name)))
     (setq notmuch-maildir-fcc-count (+ notmuch-maildir-fcc-count 1))
     (format "%d.%d_%d_%d.%s"
	     timeid
	     (emacs-pid)
	     microseconds
	     notmuch-maildir-fcc-count
	     hostname)))

(defun notmuch-maildir-fcc-dir-is-maildir-p (dir)
  (and (file-exists-p (concat dir "/cur/"))
       (file-exists-p (concat dir "/new/"))
       (file-exists-p (concat dir "/tmp/"))))

(defun notmuch-maildir-fcc-create-maildir (path)
  (cond ((or (not (file-exists-p path)) (file-directory-p path))
	 (make-directory (concat path "/cur/") t)
	 (make-directory (concat path "/new/") t)
	 (make-directory (concat path "/tmp/") t))
	((file-regular-p path)
	 (error "%s is a file. Can't creat maildir." path))
	(t
	 (error "I don't know how to create a maildir here"))))

(defun notmuch-maildir-fcc-save-buffer-to-tmp (destdir)
  "Returns the msg id of the message written to the temp directory
if successful, nil if not."
  (let ((msg-id (notmuch-maildir-fcc-make-uniq-maildir-id)))
    (while (file-exists-p (concat destdir "/tmp/" msg-id))
      (setq msg-id (notmuch-maildir-fcc-make-uniq-maildir-id)))
    (cond ((notmuch-maildir-fcc-dir-is-maildir-p destdir)
	   (write-file (concat destdir "/tmp/" msg-id))
	   msg-id)
	  (t
	   (error (format "Can't write to %s. Not a maildir."
			  destdir))
	   nil))))

(defun notmuch-maildir-fcc-move-tmp-to-new (destdir msg-id)
  (add-name-to-file
   (concat destdir "/tmp/" msg-id)
   (concat destdir "/new/" msg-id ":2,")))

(defun notmuch-maildir-fcc-move-tmp-to-cur (destdir msg-id &optional mark-seen)
  (add-name-to-file
   (concat destdir "/tmp/" msg-id)
   (concat destdir "/cur/" msg-id ":2," (when mark-seen "S"))))

(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
return t if successful, and nil otherwise."
  (let ((orig-buffer (buffer-name)))
    (with-temp-buffer
      (insert-buffer-substring orig-buffer)
      (catch 'link-error
	(let ((msg-id (notmuch-maildir-fcc-save-buffer-to-tmp destdir)))
	  (when msg-id
	    (cond (mark-seen
		   (condition-case err
		       (notmuch-maildir-fcc-move-tmp-to-cur destdir msg-id t)
		     (file-already-exists
		      (throw 'link-error nil))))
		  (t
		   (condition-case err
		       (notmuch-maildir-fcc-move-tmp-to-new destdir msg-id)
		     (file-already-exists
		      (throw 'link-error nil))))))
	  (delete-file (concat destdir "/tmp/" msg-id))))
      t)))

(notmuch-fcc-initialization)
(provide 'notmuch-maildir-fcc)