;;; sieve.el --- Utilities to manage sieve scripts  -*- lexical-binding: t; -*-

;; Copyright (C) 2001-2023 Free Software Foundation, Inc.

;; Author: Simon Josefsson <simon@josefsson.org>

;; This file is part of GNU Emacs.

;; GNU Emacs 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.

;; GNU Emacs 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.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; This file contain utilities to facilitate upload, download and
;; general management of sieve scripts.  Currently only the
;; Managesieve protocol is supported (using sieve-manage.el), but when
;; (useful) alternatives become available, they might be supported as
;; well.
;;
;; The cursor navigation was inspired by biff-mode by Franklin Lee.
;;
;; Release history:
;;
;; 2001-10-31 Committed to Oort Gnus.
;; 2002-07-27 Fix down-mouse-2 and down-mouse-3 in manage-mode.  Fix menubar
;;            in manage-mode.  Change some messages.  Added sieve-deactivate*,
;;            sieve-remove.  Fixed help text in manage-mode.  Suggested by
;;            Ned Ludd.
;;
;; Todo:
;;
;; * Namespace?  This file contains `sieve-manage' and
;;   `sieve-manage-mode', but there is a sieve-manage.el file as well.
;;   Can't think of a good solution though, this file need a *-mode,
;;   and naming it `sieve-mode' would collide with sieve-mode.el.  One
;;   solution would be to come up with some better name that this file
;;   can use that doesn't have the managesieve specific "manage" in
;;   it.  sieve-dired?  i dunno.  we could copy all off sieve.el into
;;   sieve-manage.el too, but I'd like to separate the interface from
;;   the protocol implementation since the backends are likely to
;;   change (well).
;;
;; * Define servers?  We could have a customize buffer to create a server,
;;   with authentication/stream/etc parameters, much like Gnus, and then
;;   only use names of defined servers when interacting with M-x sieve-*.
;;   Right now you can't use STARTTLS, which sieve-manage.el provides

;;; Code:

(require 'sieve-manage)
(require 'sieve-mode)

;; User customizable variables:

(defgroup sieve nil
  "Manage sieve scripts."
  :version "22.1"
  :group 'tools)

(defcustom sieve-new-script "<new script>"
  "Name of name script indicator."
  :type 'string)

(defcustom sieve-buffer "*sieve*"
  "Name of sieve management buffer."
  :type 'string)

(defcustom sieve-template "\
require \"fileinto\";

# Example script (remove comment character '#' to make it effective!):
#
# if header :contains \"from\" \"coyote\" {
#   discard;
# } elsif header :contains [\"subject\"] [\"$$$\"] {
#   discard;
# } else {
#  fileinto \"INBOX\";
# }
"
  "Template sieve script."
  :type 'string)

;; Internal variables:

(defvar sieve-manage-buffer nil)
(defvar sieve-buffer-header-end nil)
(defvar sieve-server-script-list nil
  "Current list of server-side sieve scripts.")
(defvar sieve-buffer-script-name nil
  "The real script name of the buffer.")
(make-local-variable 'sieve-buffer-script-name)

;; Sieve-manage mode:

;; This function is defined by `easy-menu-define' but it's only done
;; at run time and the compiler is not aware of it.
;; FIXME: This is arguably a bug/problem in `easy-menu-define'.
(declare-function sieve-manage-mode-menu "sieve")

(defvar-keymap sieve-manage-mode-map
  :doc "Keymap for `sieve-manage-mode'."
  ;; various
  "?"      #'sieve-help
  "h"      #'sieve-help
  ;; activating
  "m"      #'sieve-activate
  "u"      #'sieve-deactivate
  "M-DEL"  #'sieve-deactivate-all
  ;; navigation keys
  "C-p"    #'sieve-prev-line
  "<up>"   #'sieve-prev-line
  "C-n"    #'sieve-next-line
  "<down>" #'sieve-next-line
  "SPC"    #'sieve-next-line
  "n"      #'sieve-next-line
  "p"      #'sieve-prev-line
  "RET"    #'sieve-edit-script
  "f"      #'sieve-edit-script
  ;; "o"   #'sieve-edit-script-other-window
  "r"      #'sieve-remove
  "q"      #'sieve-bury-buffer
  "Q"      #'sieve-manage-quit
  "<down-mouse-2>" #'sieve-edit-script
  "<down-mouse-3>" #'sieve-manage-mode-menu)

(easy-menu-define sieve-manage-mode-menu sieve-manage-mode-map
  "Sieve Menu."
  '("Manage Sieve"
    ["Edit script" sieve-edit-script t]
    ["Activate script" sieve-activate t]
    ["Deactivate script" sieve-deactivate t]
    ["Quit and close connection" sieve-manage-quit t]))

(define-derived-mode sieve-manage-mode special-mode "Sieve-manage"
  "Mode used for sieve script management."
  (buffer-disable-undo (current-buffer))
  (setq truncate-lines t))

;; Commands used in sieve-manage mode:

(defun sieve-manage-quit ()
  "Quit Manage Sieve and close the connection."
  (interactive)
  (sieve-manage-close sieve-manage-buffer)
  (kill-buffer sieve-manage-buffer)
  (when-let ((buffer (get-buffer sieve-buffer)))
    (kill-buffer buffer)))

(defun sieve-bury-buffer ()
  "Bury the Manage Sieve buffer without closing the connection."
  (interactive)
  (bury-buffer))

(defun sieve-activate (&optional _pos)
  (interactive)
  (let ((name (sieve-script-at-point)) err)
    (when (or (null name) (string-equal name sieve-new-script))
      (error "No sieve script at point"))
    (message "Activating script %s..." name)
    (setq err (sieve-manage-setactive name sieve-manage-buffer))
    (sieve-refresh-scriptlist)
    (if (sieve-manage-ok-p err)
	(message "Activating script %s...done" name)
      (message "Activating script %s...failed: %s" name (nth 2 err)))))

(defun sieve-deactivate-all (&optional _pos)
  (interactive)
  (message "Deactivating scripts...")
  (let (;; (name (sieve-script-at-point))
        (err (sieve-manage-setactive "" sieve-manage-buffer)))
    (sieve-refresh-scriptlist)
    (if (sieve-manage-ok-p err)
	(message "Deactivating scripts...done")
      (message "Deactivating scripts...failed: %s" (nth 2 err)))))

(defalias 'sieve-deactivate #'sieve-deactivate-all)

(defun sieve-remove (&optional _pos)
  (interactive)
  (let ((name (sieve-script-at-point)) err)
    (when (or (null name) (string-equal name sieve-new-script))
      (error "No sieve script at point"))
    (message "Removing sieve script %s..." name)
    (setq err (sieve-manage-deletescript name sieve-manage-buffer))
    (unless (sieve-manage-ok-p err)
      (error "Removing sieve script %s...failed: " err))
    (sieve-refresh-scriptlist)
    (message "Removing sieve script %s...done" name)))

(defun sieve-edit-script (&optional _pos)
  (interactive)
  (let ((name (sieve-script-at-point)))
    (unless name
      (error "No sieve script at point"))
    (if (not (string-equal name sieve-new-script))
	(let ((newbuf (generate-new-buffer name))
	      err)
          (with-current-buffer newbuf
            (set-buffer-file-coding-system sieve-manage--coding-system))
	  (setq err (sieve-manage-getscript name newbuf sieve-manage-buffer))
	  (switch-to-buffer newbuf)
	  (if (sieve-manage-ok-p err)
	      (set-buffer-modified-p nil)
	    (error "Sieve download failed: %s" err)))
      (switch-to-buffer (get-buffer-create "template.siv"))
      (insert sieve-template)
      (setq name (read-string "Name for new script: "))
      (when (string-match "\\.sieve\\'" name)
        ;; The server will append .sieve to the script name.
        (setq name (replace-match "" t t name))))
    (sieve-mode)
    (setq sieve-buffer-script-name name)
    (goto-char (point-min))
    (set-buffer-modified-p nil)
    (message "Press %s to upload script to server."
             (substitute-command-keys "\\[sieve-upload]"))))

(defmacro sieve-change-region (&rest body)
  "Turn off sieve-region before executing BODY, then re-enables it after.
Used to bracket operations which move point in the sieve-buffer."
  (declare (indent 0) (debug t))
  `(progn
     (sieve-highlight nil)
     ,@body
     (sieve-highlight t)))

(defun sieve-next-line (&optional arg)
  (interactive)
  (unless arg
    (setq arg 1))
  (if (sieve-script-at-point)
      (if (save-excursion
	    (forward-line arg)
	    (sieve-script-at-point))
          (sieve-change-region
	    (forward-line arg))
        (message "End of list"))
    (goto-char (next-overlay-change sieve-buffer-header-end))))

(defun sieve-prev-line (&optional arg)
  (interactive)
  (unless arg
    (setq arg -1))
  (if (sieve-script-at-point)
      (if (save-excursion
	    (forward-line arg)
	    (sieve-script-at-point))
          (sieve-change-region
	    (forward-line arg))
        (message "Beginning of list"))
    (goto-char (previous-overlay-change (point-max)))
    (beginning-of-line)))

(defun sieve-help ()
  "Display help for various sieve commands."
  (interactive)
  (if (eq last-command 'sieve-help)
      ;; would need minor-mode for log-edit-mode
      (describe-function 'sieve-mode)
    (message "%s" (substitute-command-keys "\
`\\[sieve-edit-script]':edit `\\[sieve-activate]':activate \
`\\[sieve-deactivate]':deactivate `\\[sieve-remove]':remove \
`\\[sieve-manage-quit]':quit"))))

;; Create buffer:

(defun sieve-setup-buffer (server port)
  (setq buffer-read-only nil)
  (erase-buffer)
  (buffer-disable-undo)
  (let* ((port (or port sieve-manage-default-port))
         (header (format "Server : %s:%s\n\n" server port)))
    (insert header))
  (setq-local sieve-buffer-header-end (point-max)))

(defun sieve-script-at-point (&optional pos)
  "Return name of sieve script at point POS, or nil."
  (interactive "d")
  (get-char-property (or pos (point)) 'script-name))

(defun sieve-highlight (on)
  "Turn ON or off highlighting on the current language overlay."
  (overlay-put (car (overlays-at (point))) 'face (if on 'highlight 'default)))

(defun sieve-insert-scripts (scripts)
  "Format and insert LANGUAGE-LIST strings into current buffer at point."
  (while scripts
    (let ((p (point))
	  (ext nil)
	  (script (pop scripts)))
      (if (consp script)
	  (insert (format " ACTIVE %s" (cdr script)))
	(insert (format "        %s" script)))
      (setq ext (make-overlay p (point)))
      (overlay-put ext 'mouse-face 'highlight)
      (overlay-put ext 'script-name (if (consp script)
					(cdr script)
				      script))
      (insert "\n"))))

(defun sieve-open-server (server &optional port)
  "Open SERVER (on PORT) and authenticate."
  (with-current-buffer
      (or ;; open server
       (setq-local sieve-manage-buffer
                   (sieve-manage-open server port))
       (error "Error opening server %s" server))
    (sieve-manage-authenticate)))

(defun sieve-refresh-scriptlist ()
  (interactive)
  (with-current-buffer sieve-buffer
    (setq buffer-read-only nil)
    (delete-region (or sieve-buffer-header-end (point-max)) (point-max))
    (goto-char (point-max))
    ;; get list of script names and print them
    (let* ((scripts (sieve-manage-listscripts sieve-manage-buffer))
           (count (length scripts))
           (keys (substitute-command-keys "\\[sieve-edit-script]")))
      (setq sieve-server-script-list
            (mapcar (lambda (elt) (if (consp elt) (cdr elt) elt))
                    scripts))
      (insert
       (if (null scripts)
           (format
            "No scripts on server, press %s on %s to create a new script.\n"
            keys sieve-new-script)
         (format (concat (ngettext "%d script on server"
                                   "%d scripts on server"
                                   count)
                         ", press %s on a script name to edit it, or"
                         "\npress %s on %s to create a new script.\n")
                 count keys keys sieve-new-script)))
      (save-excursion
	(sieve-insert-scripts (list sieve-new-script))
	(sieve-insert-scripts scripts)))
    (sieve-highlight t)
    (setq buffer-read-only t)))

;;;###autoload
(defun sieve-manage (server &optional port)
  (interactive "sServer: ")
  (switch-to-buffer (get-buffer-create sieve-buffer))
  (sieve-manage-mode)
  (sieve-setup-buffer server port)
  (if (sieve-open-server server port)
      (sieve-refresh-scriptlist)
    (message "Could not open server %s" server)))

;;;###autoload
(defun sieve-upload (&optional name)
  (interactive)
  (when (or (get-buffer sieve-buffer)
            (save-current-buffer (call-interactively 'sieve-manage)))
    (let ((script (buffer-string))
          (script-name (file-name-sans-extension (buffer-name)))
          err)
      (with-current-buffer (get-buffer sieve-buffer)
	(setq err (sieve-manage-putscript
                   (or name sieve-buffer-script-name script-name)
                   script sieve-manage-buffer))
        (if (not (sieve-manage-ok-p err))
            (message "Sieve upload failed: %s" (nth 2 err))
          (message "Sieve upload done.  Use %s to manage scripts."
                   (substitute-command-keys "\\[sieve-manage]"))
          (when (not (member script-name sieve-server-script-list))
            (sieve-refresh-scriptlist))))
      (set-buffer-modified-p nil))))

;;;###autoload
(defun sieve-upload-and-bury (&optional name)
  (interactive)
  (sieve-upload name)
  (bury-buffer))

;;;###autoload
(defun sieve-upload-and-kill (&optional name)
  (interactive)
  (sieve-upload name)
  (kill-buffer))

(provide 'sieve)

;;; sieve.el ends here