;;; mu4e.el --- Mu4e, the mu mail user agent -*- lexical-binding: t -*-

;; Copyright (C) 2011-2023 Dirk-Jan C. Binnema

;; Author: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
;; Maintainer: Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
;; Keywords: email

;; This file is not part of GNU Emacs.

;; mu4e 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.

;; mu4e 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 mu4e.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:
(require 'mu4e-obsolete)

(require 'mu4e-vars)
(require 'mu4e-window)
(require 'mu4e-helpers)
(require 'mu4e-folders)
(require 'mu4e-context)
(require 'mu4e-contacts)
(require 'mu4e-headers)
(require 'mu4e-search)
(require 'mu4e-view)
(require 'mu4e-compose)
(require 'mu4e-bookmarks)
(require 'mu4e-update)
(require 'mu4e-main)
(require 'mu4e-notification)
(require 'mu4e-server)     ;; communication with backend



(when mu4e-speedbar-support
  (require 'mu4e-speedbar)) ;; support for speedbar
(when mu4e-org-support
  (require 'mu4e-org))      ;; support for org-mode links

;; We can't properly use compose buffers that are revived using
;; desktop-save-mode; so let's turn that off.
(with-eval-after-load 'desktop
  (eval '(add-to-list 'desktop-modes-not-to-save 'mu4e-compose-mode)))


;;;###autoload
(defun mu4e (&optional background)
  "If mu4e is not running yet, start it.
Then, show the main window, unless BACKGROUND (prefix-argument)
is non-nil."
  (interactive "P")
  (if (not (mu4e-running-p))
      (progn
        (mu4e--init-handlers)
        (mu4e--start (unless background #'mu4e--main-view)))
    ;; mu4e already running; show unless BACKGROUND
    (unless background
      (if (buffer-live-p (get-buffer mu4e-main-buffer-name))
          (switch-to-buffer mu4e-main-buffer-name)
        (mu4e--main-view)))))

(defun mu4e-quit(&optional bury)
  "Quit the mu4e session or bury the buffer.

If prefix-argument BURY is non-nil, merely bury the buffer.
Otherwise, completely quit mu4e, including automatic updating."
  (interactive "P")
  (if bury
      (bury-buffer)
    (if mu4e-confirm-quit
        (when (y-or-n-p (mu4e-format "Are you sure you want to quit?"))
          (mu4e--stop))
      (mu4e--stop))))

;;; Internals

(defun mu4e--check-requirements ()
  "Check for the settings required for running mu4e."
  (unless (>= emacs-major-version 25)
    (mu4e-error "Emacs >= 25.x is required for mu4e"))
  (when (mu4e-server-properties)
    (unless (string= (mu4e-server-version) mu4e-mu-version)
      (mu4e-error "The mu server has version %s, but we need %s"
                  (mu4e-server-version) mu4e-mu-version)))
  (unless (and mu4e-mu-binary (file-executable-p mu4e-mu-binary))
    (mu4e-error "Please set `mu4e-mu-binary' to the full path to the mu
    binary"))
  (dolist (var '(mu4e-sent-folder mu4e-drafts-folder
                                  mu4e-trash-folder))
    (unless (and (boundp var) (symbol-value var))
      (mu4e-error "Please set %S" var))
    (unless (functionp (symbol-value var)) ;; functions are okay, too
      (let* ((dir (symbol-value var))
             (path (mu4e-join-paths (mu4e-root-maildir) dir)))
        (unless (string= (substring dir 0 1) "/")
          (mu4e-error "%S must start with a '/'" dir))
        (unless (mu4e-create-maildir-maybe path)
          (mu4e-error "%s (%S) does not exist" path var))))))

;;; Starting / getting mail / updating the index

(defun mu4e--pong-handler (_data func)
  "Handle \"pong\" responses from the mu server.
Invoke FUNC if non-nil."
  (let ((doccount (plist-get (mu4e-server-properties) :doccount)))
    (mu4e--check-requirements)
    (when func (funcall func))
    (when (zerop doccount)
      (mu4e-message "Store is empty; try indexing (M-x mu4e-update-index)."))
    (when (and mu4e-update-interval (null mu4e--update-timer))
      (setq mu4e--update-timer
            (run-at-time 0 mu4e-update-interval
                         (lambda () (mu4e-update-mail-and-index
                                     mu4e-index-update-in-background)))))))

(defun mu4e--start (&optional func)
  "Start mu4e.
If `mu4e-contexts' have been defined, but we don't have a context
yet, switch to the matching one, or none matches, the first. If
mu4e is already running, invoke FUNC (if non-nil).

Otherwise, check requirements, then start mu4e. When successful, invoke
 FUNC (if non-nil) afterwards."
  (unless (mu4e-context-current)
    (mu4e--context-autoswitch nil mu4e-context-policy))
  (setq mu4e-pong-func
        (lambda (info) (mu4e--pong-handler info func)))
  ;; show some notification?
  (when mu4e-notification-support
    (add-hook 'mu4e-query-items-updated-hook #'mu4e--notification))
  ;; modeline support
  (when mu4e-modeline-support
    (mu4e--modeline-register #'mu4e--bookmarks-modeline-item 'global)
    (mu4e-modeline-mode)
    (add-hook 'mu4e-query-items-updated-hook #'mu4e--modeline-update))
  (mu4e-modeline-mode (if mu4e-modeline-support 1 -1))
  ;; redraw main buffer if there is one.
  (add-hook 'mu4e-query-items-updated-hook #'mu4e--main-redraw)
  (mu4e--query-items-refresh 'reset-baseline)
  (mu4e--server-ping)
  ;; ask for the maildir-list
  (mu4e--server-data 'maildirs)
  ;; maybe request the list of contacts, automatically refreshed after
  ;; re-indexing
  (unless mu4e--contacts-set
    (mu4e--request-contacts-maybe)))

(defun mu4e--stop ()
  "Stop mu4e."
  (when mu4e--update-timer
    (cancel-timer mu4e--update-timer)
    (setq mu4e--update-timer nil))

  (setq ;; clear some caches
   mu4e-maildir-list nil
   mu4e--contacts-set nil
   mu4e--contacts-tstamp "0")

  (remove-hook 'mu4e-query-items-updated-hook #'mu4e--main-redraw)
  (remove-hook 'mu4e-query-items-updated-hook #'mu4e--modeline-update)
  (remove-hook 'mu4e-query-items-updated-hook #'mu4e--notification)
  (mu4e-kill-update-mail)
  (mu4e-modeline-mode -1)
  (mu4e--server-kill)
  ;; kill all mu4e buffers
  (mapc
   (lambda (buf)
     ;; the view buffer has the kill-buffer-hook function
     ;; mu4e--view-kill-mime-handles which kills the mm-* buffers created by
     ;; Gnus' article mode. Those have been returned by `buffer-list' but might
     ;; already be deleted in case the view buffer has been killed first. So we
     ;; need a `buffer-live-p' check here.
     (when (buffer-live-p buf)
       (with-current-buffer buf
         (when (member major-mode
                       '(mu4e-headers-mode mu4e-view-mode mu4e-main-mode))
           (kill-buffer)))))
   (buffer-list)))

;;; Handlers
(defun mu4e--default-handler (&rest args)
  "Dummy handler function with arbitrary ARGS."
  (mu4e-error "Not handled: %s" args))

(defun mu4e--error-handler (errcode errmsg)
  "Handler function for showing an error with ERRCODE and ERRMSG."
  ;; don't use mu4e-error here; it's running in the process filter context
  (pcase errcode
    ('4 (mu4e-warn "No matches for this search query."))
    ('110 (display-warning 'mu4e errmsg :error)) ;; schema version.
    (_ (mu4e-error "Error %d: %s" errcode errmsg))))

(defun mu4e--update-status (info)
  "Update the status message with INFO."
  (setq mu4e-index-update-status
        `(:tstamp ,(current-time)
          :checked ,(plist-get info :checked)
          :updated  ,(plist-get info :updated)
          :cleaned-up ,(plist-get info :cleaned-up))))

(defun mu4e--info-handler (info)
  "Handler function for (:INFO ...) sexps received from server."
  (let* ((type (plist-get info :info))
         (checked (plist-get info :checked))
         (updated (plist-get info :updated))
         (cleaned-up (plist-get info :cleaned-up)))
    (cond
     ((eq type 'add) t) ;; do nothing
     ((eq type 'index)
      (if (eq (plist-get info :status) 'running)
          (mu4e-index-message
           "Indexing... checked %d, updated %d" checked updated)
        (progn ;; i.e. 'complete
          (mu4e--update-status info)
          (mu4e-index-message
           "%s completed; checked %d, updated %d, cleaned-up %d"
           (if mu4e-index-lazy-check "Lazy indexing" "Indexing")
           checked updated cleaned-up)
          ;; index done; grab updated queries
          (mu4e--query-items-refresh)
          (run-hooks 'mu4e-index-updated-hook)
          ;; backward compatibility...
          (unless (zerop (+ updated cleaned-up))
            mu4e-message-changed-hook)
          (unless (and (not (string= mu4e--contacts-tstamp "0"))
                       (zerop (plist-get info :updated)))
            (mu4e--request-contacts-maybe)
            (mu4e--server-data 'maildirs)) ;; update maildir list
          (mu4e--main-redraw))))
     ((plist-get info :message)
      (mu4e-index-message "%s" (plist-get info :message))))))

(defun mu4e--init-handlers()
  "Initialize the server message handlers.
Only set set them if they were nil before, so overriding has a
chance."
  (mu4e-setq-if-nil mu4e-error-func            #'mu4e--error-handler)
  (mu4e-setq-if-nil mu4e-update-func           #'mu4e~headers-update-handler)
  (mu4e-setq-if-nil mu4e-remove-func           #'mu4e~headers-remove-handler)
  (mu4e-setq-if-nil mu4e-view-func             #'mu4e~headers-view-handler)
  (mu4e-setq-if-nil mu4e-headers-append-func   #'mu4e~headers-append-handler)
  (mu4e-setq-if-nil mu4e-found-func            #'mu4e~headers-found-handler)
  (mu4e-setq-if-nil mu4e-erase-func            #'mu4e~headers-clear)

  (mu4e-setq-if-nil mu4e-sent-func             #'mu4e--default-handler)
  (mu4e-setq-if-nil mu4e-contacts-func         #'mu4e--update-contacts)
  (mu4e-setq-if-nil mu4e-info-func             #'mu4e--info-handler)
  (mu4e-setq-if-nil mu4e-pong-func             #'mu4e--default-handler)

  (mu4e-setq-if-nil mu4e-queries-func      #'mu4e--query-items-queries-handler))

;;;
(provide 'mu4e)
;;; mu4e.el ends here