mu/mu4e/mu4e-vars.el

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

;; Copyright (C) 2011-2020 Dirk-Jan C. Binnema

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

;; This file is not 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 <http://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Customization
(require 'mu4e-meta)
(require 'message)

(declare-function mu4e-error "mu4e-utils")

(defgroup mu4e nil
  "mu4e - mu for emacs"
  :group 'mail)

(defcustom mu4e-mu-home nil
  "Location of an alternate mu home dir. If not set, use the
defaults, based on the XDG Base Directory Specification."
  :group 'mu4e
  :type '(choice (const :tag "Default location" nil)
                 (directory :tag "Specify location"))
  :safe 'stringp)

(defcustom mu4e-mu-binary (executable-find "mu")
  "Name of the mu-binary to use.
If it cannot be found in your PATH, you can specify the full
path."
  :type 'file
  :group 'mu4e
  :safe 'stringp)

(make-obsolete-variable 'mu4e-maildir
                        "determined by server; see `mu4e-root-maildir'." "1.3.8")

(defcustom mu4e-org-support t
  "Support org-mode links."
  :type 'boolean
  :group 'mu4e)

(defcustom mu4e-speedbar-support nil
  "Support having a speedbar to navigate folders/bookmarks."
  :type 'boolean
  :group 'mu4e)

(defcustom mu4e-get-mail-command "true"
  "Shell command to run to retrieve new mail.
Common values are \"offlineimap\", \"fetchmail\" or \"mbsync\", but
arbitrary shell-commands can be used.

When set to the literal string \"true\" (the default), the
command simply finishes successfully (running the 'true' command)
without retrieving any mail. This can be useful when mail is
already retrieved in another way."
  :type 'string
  :group 'mu4e
  :safe 'stringp)

(defcustom mu4e-index-update-error-warning t
  "Whether to display warnings during the retrieval process.
This depends on the `mu4e-get-mail-command' exit code."
  :type 'boolean
  :group 'mu4e
  :safe 'booleanp)

(defcustom mu4e-index-update-error-continue t
  "Whether to continue with indexing after an error during retrieval."
  :type 'boolean
  :group 'mu4e
  :safe 'booleanp)

(defcustom mu4e-index-update-in-background t
  "Whether to retrieve mail in the background."
  :type 'boolean
  :group 'mu4e
  :safe 'booleanp)

(defcustom mu4e-index-cleanup t
  "Whether to run a cleanup phase after indexing.
That is, validate that each message in the message store has a
corresponding message file in the filesystem.

Having this option as t ensures that no non-existing messages are
shown but can also be quite slow with large message stores."
  :type 'boolean :group 'mu4e :safe 'booleanp)

(defcustom mu4e-index-lazy-check nil
  "Whether to only use a 'lazy check' during reindexing.
This influences how we decide whether a message
needs (re)indexing or not. When this is set to t, mu only uses
the directory timestamps to decide on whether it needs to check
the messages beneath it, which would miss messages that are
modified outside mu. On the other hand, it's significantly
faster." :type 'boolean :group 'mu4e :safe 'booleanp)

(defcustom mu4e-update-interval nil
  "Number of seconds between mail retrieval/indexing.
If nil, don't update automatically. Note, changes in
`mu4e-update-interval' only take effect after restarting mu4e."
  :type '(choice (const :tag "No automatic update" nil)
                 (integer :tag "Seconds"))
  :group 'mu4e
  :safe 'integerp)

(defvar mu4e-update-pre-hook nil
  "Hook run just *before* the mail-retrieval / database updating process starts.
You can use this hook for example to `mu4e-get-mail-command' with
some specific setting.")

(defcustom mu4e-hide-index-messages nil
  "Whether to hide the \"Indexing...\" and contacts messages."
  :type 'boolean
  :group 'mu4e)

(defcustom mu4e-change-filenames-when-moving nil
  "Change message file names when moving them.
When moving messages to different folders, normally mu/mu4e keep
the base filename the same (the flags-part of the filename may
change still). With this option set to non-nil, mu4e instead
changes the filename. This latter behavior works better with some
IMAP-synchronization programs such as mbsync; the default works
better with e.g. offlineimap."
  :type 'boolean
  :group 'mu4e
  :safe 'booleanp)

(defcustom mu4e-attachment-dir (expand-file-name "~/")
  "Default directory for saving attachments.
This can be either a string (a file system path), or a function
that takes a filename and the mime-type as arguments, and returns
the attachment dir. See Info node `(mu4e) Attachments' for details."
  :type 'directory
  :group 'mu4e
  :safe 'stringp)

;; don't use the older vars anymore
(make-obsolete-variable 'mu4e-user-mail-address-regexp
                        'mu4e-user-mail-address-list "0.9.9.x")
(make-obsolete-variable 'mu4e-my-email-addresses
                        'mu4e-user-mail-address-list "0.9.9.x")
(make-obsolete-variable 'mu4e-user-mail-address-list
                        "determined by server; see `mu4e-personal-addresses'." "1.3.8")

(defcustom mu4e-use-fancy-chars nil
  "When set, allow fancy (Unicode) characters for marks/threads.
You can customize the exact fancy characters used with
`mu4e-marks' and various `mu4e-headers-..-mark' and
`mu4e-headers..-prefix' variables."
  :type 'boolean
  :group 'mu4e)

(defcustom mu4e-date-format-long "%c"
  "Date format to use in the message view.
Follows the format of `format-time-string'."
  :type 'string
  :group 'mu4e)

(defcustom mu4e-modeline-max-width 30
  "Determines the maximum length of the modeline string.
If the string exceeds this limit, it will be truncated to fit."
  :type 'integer
  :group 'mu4e)

(defvar mu4e-debug nil
  "When set to non-nil, log debug information to the *mu4e-log* buffer.")

;; for backward compatibility, when a bookmark was defined with defstruct.
(cl-defun make-mu4e-bookmark (&key name query key)
  "Create a mu4e proplist with the following elements:
- `name': the user-visible name of the bookmark
- `key': a single key to search for this bookmark
- `show-unread' whether to show an indicator for read/unread messages. Specifying
this for too many bookmarks may incur slowdowns in  showing the mu4e main page.
- `query': the query for this bookmark. Either a literal string or a function
   that evaluates to a string."
  `(:name ,name :query ,query :key ,key))
(make-obsolete 'make-mu4e-bookmark "`unneeded; `mu4e-bookmarks'
are plists" "1.3.7")

(defcustom mu4e-bookmarks
  '(( :name  "Unread messages"
             :query "flag:unread AND NOT flag:trashed"
             :key ?u)
    ( :name "Today's messages"
            :query "date:today..now"
            :key ?t)
    ( :name "Last 7 days"
            :query "date:7d..now"
            :show-unread t
            :key ?w)
    ( :name "Messages with images"
            :query "mime:image/*"
            :key ?p))
  "List of pre-defined queries that are shown on the main screen.

Each of the list elements is a plist with at least:
:name  - the name of the query
:query - the query expression or function
:key   - the shortcut key.

Note that the :query parameter can be a function/lambda.

Optionally, you can add the following:
:hide  - if t, bookmark is hdden from the main-view and speedbar.
:hide-unread - do not show the counts of unread/total number
 of matches for the query in the main-view. This can be useful
if a bookmark uses  a very slow query. :hide-unread
is implied from :hide. Furthermore, it is implied from the query
not being a string.

Note that the queries used to determine the unread/all counts do
current not apply `mu4e-query-rewrite-function', so if your
bookmarks depend on that, the results may differ."
  :type '(repeat (plist))
  :group 'mu4e)

(defcustom mu4e-split-view 'horizontal
  "How to show messages / headers.
A symbol which is either:
 * `horizontal':    split horizontally (headers on top)
 * `vertical':      split vertically (headers on the left).
 * `single-window': view and headers in one window (mu4e will try not to
        touch your window layout), main view in minibuffer
 * anything else:   don't split (show either headers or messages,
        not both)
Also see `mu4e-headers-visible-lines'
and `mu4e-headers-visible-columns'."
  :type '(choice (const :tag "Split horizontally" horizontal)
                 (const :tag "Split vertically" vertical)
                 (const :tag "Single window" single-window)
                 (const :tag "Don't split" nil))
  :group 'mu4e-headers)

(defcustom mu4e-view-max-specpdl-size 4096
  "The value of `max-specpdl-size' for displaying messages with Gnus."
  :type 'integer
  :group 'mu4e-view)

(defcustom mu4e-view-show-images nil
  "If non-nil, automatically display images in the view buffer."
  :type 'boolean
  :group 'mu4e-view)

(make-obsolete-variable 'mu4e-show-images
                        'mu4e-view-show-images "0.9.9.x")

(defcustom mu4e-confirm-quit t
  "Whether to confirm to quit mu4e."
  :type 'boolean
  :group 'mu4e)

(defcustom mu4e-cited-regexp
  "^\\(\\([[:alpha:]]+\\)\\|\\( *\\)\\)\\(\\(>+ ?\\)+\\)"
  "Regex that determines whether a line is a citation.
This recognizes lines starting with numbers of '>'
and spaces as well as citations of the type \"John> ... \"."
  :type 'string
  :group 'mu4e)

(defcustom mu4e-completing-read-function 'ido-completing-read
  "Function to be used to receive user-input during completion.
This is used to receive the name of the maildir to switch to via
`mu4e~headers-jump-to-maildir'.

Suggested possible values are:
 * `completing-read':      built-in completion method
 * `ido-completing-read':  dynamic completion within the minibuffer."
  :type 'function
  :options '(completing-read ido-completing-read)
  :group 'mu4e)

(defcustom mu4e-context-policy 'ask-if-none
  "The policy to determine the context when entering the mu4e main view.

If the value is `always-ask', ask the user unconditionally.

In all other cases, if any context matches (using its match
function), this context is used. Otherwise, if none of the
contexts match, we have the following choices:

- `pick-first': pick the first of the contexts available (ie. the default)
- `ask': ask the user
- `ask-if-none': ask if there is no context yet, otherwise leave it as it is
-  nil: return nil; leaves the current context as is.

Also see `mu4e-compose-context-policy'."
  :type '(choice
          (const :tag "Always ask what context to use, even if one matches"
                 always-ask)
          (const :tag "Ask if none of the contexts match" ask)
          (const :tag "Ask when there's no context yet" ask-if-none)
          (const :tag "Pick the first context if none match" pick-first)
          (const :tag "Don't change the context when none match" nil))
  :group 'mu4e)

;; crypto
(defgroup mu4e-crypto nil
  "Crypto-related settings."
  :group 'mu4e)

(defcustom mu4e-auto-retrieve-keys nil
  "Attempt to automatically retrieve public keys when needed."
  :type 'boolean
  :group 'mu4e-crypto)

(defcustom mu4e-decryption-policy t
  "Policy for dealing with encrypted parts.
The setting is a symbol:
 * t:     try to decrypt automatically
 * `ask': ask before decrypting anything
 * nil:   don't try to decrypt anything."
  :type '(choice (const :tag "Try to decrypt automatically" t)
                 (const :tag "Ask before decrypting anything" ask)
                 (const :tag "Don't try to decrypt anything" nil))
  :group 'mu4e-crypto)

;; completion; we put them here rather than in mu4e-compose, as mu4e-utils needs
;; the variables.

(defgroup mu4e-compose nil
  "Message-composition related settings."
  :group 'mu4e)

;; address completion
(defcustom mu4e-compose-complete-addresses t
  "Whether to do auto-completion of e-mail addresses."
  :type 'boolean
  :group 'mu4e-compose)

(defcustom mu4e-compose-complete-only-personal nil
  "Whether to consider only 'personal' e-mail addresses for completion.
That is, addresses from messages where user was explicitly in one
of the address fields (this excludes mailing list messages).
These addresses are the ones specified with `mu init'."
  :type 'boolean
  :group 'mu4e-compose)

(defcustom mu4e-compose-complete-only-after "2014-01-01"
  "Consider only contacts last seen after this date.

Date must be a string of the form YYY-MM-DD.

This is useful for limiting a potentially enormous set of
contacts for auto-completion to just those that are present in
the e-mail corpus in recent timses. Set to nil to not have any
time-based restriction."
  :type 'string
  :group 'mu4e-compose)

;;; names and mail-addresses can be mapped onto their canonical
;;; counterpart.  use the customizeable function
;;; mu4e-canonical-contact-function to do that.  below the identity
;;; function for mapping a contact onto the canonical one.
(defun mu4e-contact-identity (contact)
  "Return the name and the mail-address of a CONTACT.
It is used as the identity function for converting contacts to
their canonical counterpart; useful as an example."
  (let ((name (plist-get contact :name))
        (mail (plist-get contact :mail)))
    (list :name name :mail mail)))

(make-obsolete-variable 'mu4e-contacts-rewrite-function
                        "mu4e-contact-process-function (see docstring)" "mu4e 1.3.2")
(make-obsolete-variable 'mu4e-compose-complete-ignore-address-regexp
                        "mu4e-contact-process-function (see docstring)" "mu4e 1.3.2")

(defcustom mu4e-contact-process-function nil
  "Function for processing contact information for use in auto-completion.

The function receives the contact as a string, e.g
   \"Foo Bar <foo.bar@example.com>\"
   \"cuux@example.com\"

The function should return either:
- nil: do not use this contact for completion
- the (possibly rewritten) address, which must be
an RFC-2822-compatible e-mail address."
  :type 'function
  :group 'mu4e-compose)

(defcustom mu4e-compose-reply-ignore-address
  '("no-?reply")
  "Addresses to prune when doing wide replies.

This can be a regexp matching the address, a list of regexps or a
predicate function. A value of nil keeps all the addresses."
  :type '(choice
          (const nil)
          function
          string
          (repeat string))
  :group 'mu4e-compose)

(defcustom mu4e-compose-reply-recipients 'ask
  "Which recipients to use when replying to a message.
May be 'ask, 'all, 'sender. Note that that only applies to
non-mailing-list message; for those, mu4e always asks."
  :type '(choice ask
                 all
                 sender)
  :group 'mu4e-compose)

(defcustom mu4e-compose-reply-to-address nil
  "The Reply-To address.
Useful when this is not equal to the From: address."
  :type 'string
  :group 'mu4e-compose)

(defcustom mu4e-compose-forward-as-attachment nil
  "Whether to forward messages as attachments instead of inline."
  :type 'boolean
  :group 'mu4e-compose)

;; backward compatibility
(make-obsolete-variable 'mu4e-reply-to-address
                        'mu4e-compose-reply-to-address
                        "v0.9.9")

(defcustom mu4e-compose-keep-self-cc nil
  "When non-nil. keep your e-mail address in Cc: when replying."
  :type 'boolean
  :group 'mu4e-compose)

(defvar mu4e-compose-parent-message nil
  "The parent message plist.
This is the message being replied to, forwarded or edited; used
in `mu4e-compose-pre-hook'. For new messages, it is nil.")

(defgroup mu4e-icalendar nil
  "Icalendar related settings."
  :group 'mu4e)

(defcustom mu4e-icalendar-trash-after-reply nil
  "If non-nil, trash the icalendar invitation after replying."
  :type 'boolean
  :group 'mu4e-icalendar)

(defcustom mu4e-icalendar-diary-file nil
  "If non-nil, the file in which to add events upon reply."
  :type '(choice (const :tag "Do not insert a diary entry" nil)
                 (string :tag "Insert a diary entry in this file"))
  :group 'mu4e-icalendar)


;; Folders
(defgroup mu4e-folders nil
  "Special folders."
  :group 'mu4e)

(defcustom mu4e-drafts-folder "/drafts"
  "Your folder for draft messages, relative to `mu4e-maildir'.
For instance, \"/drafts\". Instead of a string, may also be a
function that takes a message (a msg plist, see
`mu4e-message-field'), and returns a folder. Note, the message
parameter refers to the original message being replied to / being
forwarded / re-edited and is nil otherwise. `mu4e-drafts-folder'
is only evaluated once."
  :type '(choice
          (string :tag "Folder name")
          (function :tag "Function return folder name"))
  :group 'mu4e-folders)

(defcustom mu4e-refile-folder "/archive"
  "Your folder for refiling messages, relative to `mu4e-maildir'.
For instance \"/Archive\". Instead of a string, may also be a
function that takes a message (a msg plist, see
`mu4e-message-field'), and returns a folder. Note that the
message parameter refers to the message-at-point."
  :type '(choice
          (string :tag "Folder name")
          (function :tag "Function return folder name"))
  :group 'mu4e-folders)

(defcustom mu4e-sent-folder "/sent"
  "Your folder for sent messages, relative to `mu4e-maildir'.
For instance, \"/Sent Items\". Instead of a string, may also be a
function that takes a message (a msg plist, see
`mu4e-message-field'), and returns a folder. Note that the
message parameter refers to the original message being replied to
/ being forwarded / re-edited, and is nil otherwise."
  :type '(choice
          (string :tag "Folder name")
          (function :tag "Function return folder name"))
  :group 'mu4e-folders)

(defcustom mu4e-trash-folder "/trash"
  "Your folder for trashed messages, relative to `mu4e-maildir'.
For instance, \"/trash\". Instead of a string, may also be a
function that takes a message (a msg plist, see
`mu4e-message-field'), and returns a folder. When using
`mu4e-trash-folder' in the headers view (when marking messages
for trash). Note that the message parameter refers to the
message-at-point. When using it when composing a message (see
`mu4e-sent-messages-behavior'), this refers to the original
message being replied to / being forwarded / re-edited, and is
nil otherwise."
  :type '(choice
          (string :tag "Folder name")
          (function :tag "Function return folder name"))
  :group 'mu4e-folders)

(defcustom mu4e-maildir-shortcuts nil
  "A list of maildir shortcuts.
This makes it possible to quickly go to a particular
maildir (folder), or quickly moving messages to them (e.g., for
archiving or refiling). The list contains elements of the
form (maildir . shortcut), where MAILDIR is a maildir (such as
\"/archive/\"), and shortcut is a single character.

You can use these shortcuts in the headers and view buffers, for
example with `mu4e-mark-for-move-quick' (or 'm', by default) or
`mu4e-jump-to-maildir' (or 'j', by default), followed by the
designated shortcut character for the maildir.

Unlike in search queries, folder names with spaces in them must NOT
be quoted, since mu4e does this automatically for you."
  :type '(repeat (cons (string :tag "Maildir") character))
  :group 'mu4e-folders)

(defcustom mu4e-display-update-status-in-modeline nil
  "Non-nil value will display the update status in the modeline."
  :group 'mu4e
  :type 'boolean)

;; Faces
(defgroup mu4e-faces nil
  "Type faces (fonts) used in mu4e."
  :group 'mu4e
  :group 'faces)

(defface mu4e-unread-face
  '((t :inherit font-lock-keyword-face :bold t))
  "Face for an unread message header."
  :group 'mu4e-faces)

(defface mu4e-moved-face
  '((t :inherit font-lock-comment-face :slant italic))
  "Face for a message header that has been moved to some folder.
\(It's still visible in the search results, since we cannot
be sure it no longer matches)."
  :group 'mu4e-faces)

(defface mu4e-trashed-face
  '((t :inherit font-lock-comment-face :strike-through t))
  "Face for an message header in the trash folder."
  :group 'mu4e-faces)

(defface mu4e-draft-face
  '((t :inherit font-lock-string-face))
  "Face for a draft message header
I.e. a message with the draft flag set."
  :group 'mu4e-faces)

(defface mu4e-flagged-face
  '((t :inherit font-lock-constant-face :bold t))
  "Face for a flagged message header."
  :group 'mu4e-faces)

(defface mu4e-replied-face
  '((t :inherit font-lock-builtin-face :bold nil))
  "Face for a replied message header."
  :group 'mu4e-faces)

(defface mu4e-forwarded-face
  '((t :inherit font-lock-builtin-face :bold nil))
  "Face for a passed (forwarded) message header."
  :group 'mu4e-faces)

(defface mu4e-header-face
  '((t :inherit default))
  "Face for a header without any special flags."
  :group 'mu4e-faces)

(defface mu4e-header-title-face
  '((t :inherit font-lock-type-face))
  "Face for a header title in the headers view."
  :group 'mu4e-faces)

(defface mu4e-header-highlight-face
  '((t :inherit hl-line :weight bold :underline t))
  "Face for the header at point."
  :group 'mu4e-faces)

(defface mu4e-header-marks-face
  '((t :inherit font-lock-preprocessor-face))
  "Face for the mark in the headers list."
  :group 'mu4e-faces)

(defface mu4e-header-key-face
  '((t :inherit message-header-name :bold t))
  "Face for a header key (such as \"Foo\" in \"Subject:\ Foo\")."
  :group 'mu4e-faces)

(defface mu4e-header-value-face
  '((t :inherit font-lock-type-face))
  "Face for a header value (such as \"Re: Hello!\")."
  :group 'mu4e-faces)

(defface mu4e-special-header-value-face
  '((t :inherit font-lock-builtin-face))
  "Face for special header values."
  :group 'mu4e-faces)

(defface mu4e-link-face
  '((t :inherit link))
  "Face for showing URLs and attachments in the message view."
  :group 'mu4e-faces)

(defface mu4e-contact-face
  '((t :inherit font-lock-variable-name-face))
  "Face for showing URLs and attachments in the message view."
  :group 'mu4e-faces)

(defface mu4e-highlight-face
  '((t :inherit highlight))
  "Face for highlighting things."
  :group 'mu4e-faces)

(defface mu4e-title-face
  '((t :inherit font-lock-type-face :bold t))
  "Face for a header title in the headers view."
  :group 'mu4e-faces)

(defface mu4e-context-face
  '((t :inherit mu4e-title-face :bold t))
  "Face for displaying the context in the modeline."
  :group 'mu4e-faces)

(defface mu4e-modeline-face
  '((t :inherit font-lock-string-face :bold t))
  "Face for the query in the mode-line."
  :group 'mu4e-faces)

(defface mu4e-view-body-face
  '((t :inherit default))
  "Face for the body in the message-view."
  :group 'mu4e-faces)

(defface mu4e-footer-face
  '((t :inherit font-lock-comment-face))
  "Face for message footers (signatures)."
  :group 'mu4e-faces)

(defface mu4e-url-number-face
  '((t :inherit font-lock-constant-face :bold t))
  "Face for the number tags for URLs."
  :group 'mu4e-faces)

(defface mu4e-attach-number-face
  '((t :inherit font-lock-variable-name-face :bold t))
  "Face for the number tags for attachments."
  :group 'mu4e-faces)

(defface mu4e-cited-1-face
  '((t :inherit font-lock-builtin-face :bold nil :italic t))
  "Face for cited message parts (level 1)."
  :group 'mu4e-faces)

(defface mu4e-cited-2-face
  '((t :inherit font-lock-preprocessor-face :bold nil :italic t))
  "Face for cited message parts (level 2)."
  :group 'mu4e-faces)

(defface mu4e-cited-3-face
  '((t :inherit font-lock-variable-name-face :bold nil :italic t))
  "Face for cited message parts (level 3)."
  :group 'mu4e-faces)

(defface mu4e-cited-4-face
  '((t :inherit font-lock-keyword-face :bold nil :italic t))
  "Face for cited message parts (level 4)."
  :group 'mu4e-faces)

(defface mu4e-cited-5-face
  '((t :inherit font-lock-comment-face :bold nil :italic t))
  "Face for cited message parts (level 5)."
  :group 'mu4e-faces)

(defface mu4e-cited-6-face
  '((t :inherit font-lock-comment-delimiter-face :bold nil :italic t))
  "Face for cited message parts (level 6)."
  :group 'mu4e-faces)

(defface mu4e-cited-7-face
  '((t :inherit font-lock-type-face :bold nil :italic t))
  "Face for cited message parts (level 7)."
  :group 'mu4e-faces)

(defface mu4e-system-face
  '((t :inherit font-lock-comment-face :slant italic))
  "Face for system message (such as the footers for message headers)."
  :group 'mu4e-faces)

(defface mu4e-ok-face
  '((t :inherit font-lock-comment-face :bold t :slant normal))
  "Face for things that are okay."
  :group 'mu4e-faces)

(defface mu4e-warning-face
  '((t :inherit font-lock-warning-face :bold t :slant normal))
  "Face for warnings / error."
  :group 'mu4e-faces)

(defface mu4e-compose-separator-face
  '((t :inherit message-separator :slant italic))
  "Face for the separator between headers / message in
mu4e-compose-mode."
  :group 'mu4e-faces)

(defface mu4e-compose-header-face
  '((t :inherit message-separator :slant italic))
  "Face for the separator between headers / message in
mu4e-compose-mode."
  :group 'mu4e-faces)

(defface mu4e-region-code
    '((t (:background "DarkSlateGray")))
  "Face for highlighting marked region in mu4e-view buffer."
  :group 'mu4e-faces)

;; headers info
(defconst mu4e-header-info
  '((:attachments
     . (:name "Attachments"
        :shortname "Atts"
        :help "Message attachments"
        :require-full t
        :sortable nil))
    (:bcc
     . (:name "Bcc"
        :shortname "Bcc"
        :help "Blind Carbon-Copy recipients for the message"
        :sortable t))
    (:cc
     . (:name "Cc"
        :shortname "Cc"
        :help "Carbon-Copy recipients for the message"
        :sortable t))
    (:date
     . (:name "Date"
        :shortname "Date"
        :help "Date/time when the message was written"
        :sortable t))
    (:human-date
     . (:name "Date"
        :shortname "Date"
        :help "Date/time when the message was written."
        :sortable :date))
    (:flags
     . (:name "Flags"
        :shortname "Flgs"
        :help "Flags for the message"
        :sortable nil))
    (:from
     . (:name "From"
        :shortname "From"
        :help "The sender of the message"
        :sortable t))
    (:from-or-to
     . (:name "From/To"
        :shortname "From/To"
        :help "Sender of the message if it's not me; otherwise the recipient"
        :sortable nil))
    (:maildir
     . (:name "Maildir"
        :shortname "Maildir"
        :help "Maildir for this message"
        :sortable t))
    (:list
     . (:name "List-Id"
        :shortname "List"
        :help "Mailing list id for this message"
        :sortable t))
    (:mailing-list
     . (:name "List"
        :shortname "List"
        :help "Mailing list friendly name for this message"
        :sortable :list))
    (:message-id
     . (:name "Message-Id"
        :shortname "MsgID"
        :help "Message-Id for this message"
        :sortable nil))
    (:path
     . (:name "Path"
        :shortname "Path"
        :help "Full filesystem path to the message"
        :sortable t))
    (:signature
     . (:name "Signature"
        :shortname "Sgn"
        :help "Check for the cryptographic signature"
        :require-full t
        :sortable nil))
    (:decryption
     . (:name "Decryption"
        :shortname "Dec"
        :help "Check the cryptographic decryption status"
        :require-full t
        :sortable nil))
    (:size
     . (:name "Size"
        :shortname "Size"
        :help "Size of the message"
        :sortable t))
    (:subject
     . (:name "Subject"
        :shortname "Subject"
        :help "Subject of the message"
        :sortable t))
    (:tags
     . (:name "Tags"
        :shortname "Tags"
        :help "Tags for the message"
        :sortable nil))
    (:thread-subject
     . (:name "Subject"
        :shortname "Subject"
        :help "Subject of the thread"
        :sortable :subject))
    (:to
     . (:name "To"
        :shortname "To"
        :help "Recipient of the message"
        :sortable t))
    (:user-agent
     . (:name "User-Agent"
        :shortname "UA"
        :help "Program used for writing this message"
        :require-full t
        :sortable t)))
  "An alist of all possible header fields and information about them.
This is used in the user-interface (the column headers in the header list, and
the fields the message view).

Most fields should be self-explanatory. A special one is
`:from-or-to', which is equal to `:from' unless `:from' matches one
of the addresses in `mu4e-user-mail-address-list', in which case it
will be equal to `:to'.

Furthermore, the property `:sortable' determines whether we can
sort by this field.  This can be either a boolean (nil or t), or a
symbol for /another/ field. For example, the `:human-date' field
uses `:date' for that.

Fields which have the property `:require-full' set to
non-nil require a full message; in practice this means that you
cannot use such fieds as part of `mu4e-headers-fields', but only
in `mu4e-view-fields.'

Note, `:sortable' is not supported for custom header fields.")

(defvar mu4e-header-info-custom
  '( (:recipnum .
                ( :name "Number of recipients"
                        :shortname "Recip#"
                        :help "Number of recipients for this message"
                        :function
                        (lambda (msg)
                          (format "%d"
                                  (+ (length (mu4e-message-field msg :to))
                                     (length (mu4e-message-field msg :cc))))))))
  "A list of custom (user-defined) headers.
The format is similar
to `mu4e-header-info', but adds a :function property, which
should point to a function that takes a message p-list as
argument, and returns a string. See the default value of
`mu4e-header-info-custom for an example.")

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; run-time vars used in multiple places

;; headers
(defconst mu4e~headers-buffer-name "*mu4e-headers*"
  "Name of the buffer for message headers.")

;; view
(defconst mu4e~view-buffer-name "*mu4e-view*"
  "Name for the message view buffer.")

(defconst mu4e~view-embedded-buffer-name " *mu4e-embedded-view*"
  "Name for the embedded message view buffer.")

(defvar mu4e~contacts nil
  "Hash that maps contacts (ie. 'name <e-mail>') to an integer for sorting.
We need to keep this information around to quickly re-sort
subsets of the contacts in the completions function in
mu4e-compose.")

(defvar mu4e~headers-last-query nil
  "The present (most recent) query.")

(defvar mu4e~server-props nil
  "Information  we receive from the mu4e server process \(in the 'pong-handler').")

(defun mu4e-root-maildir()
  "Get the root maildir."
  (let ((root-maildir (and mu4e~server-props
                           (plist-get mu4e~server-props :root-maildir))))
    (unless root-maildir
      (mu4e-error "root maildir unknown; did you start mu4e?"))
    root-maildir))

(defun mu4e-database-path()
  "Get the mu4e database path"
  (let ((path (and mu4e~server-props
                   (plist-get mu4e~server-props :database-path))))
    (unless path
      (mu4e-error "database-path unknown; did you start mu4e?"))
    path))

(defun mu4e-personal-addresses()
  "Get the user's personal addresses, if any. If none are set on the server-side,
fall back to the obsolete `mu4e-user-mail-address-list'."
  (let ((addrs (and mu4e~server-props
                    (plist-get mu4e~server-props :personal-addresses))))
    (if addrs addrs mu4e-user-mail-address-list)))

(defun mu4e-server-version()
  "Get the server version, which should match mu4e's."
  (let ((version (and mu4e~server-props (plist-get mu4e~server-props :version))))
    (unless version
      (mu4e-error "version unknown; did you start mu4e?"))
    version))


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; our handlers funcs these handler funcs define what happens when we receive a
;; certain message from the server
(defun mu4e~default-handler (&rest args)
  "Dummy handler function with arbitrary ARGS."
  (error "Not handled: %S" args))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; register our handler functions; these connect server messages to functions
;; to handle them.
;;
;; these form mu4e's central nervous system so it's not really recommended
;; to override them (they reference various internal bits which could change)

(defvar mu4e-error-func 'mu4e-error-handler
  "Function called for each error received.
The function is passed an error plist as argument. See
`mu4e~proc-filter' for the format.")

(defvar mu4e-update-func 'mu4e~headers-update-handler
  "Function called for each :update sexp returned.
The function is passed a msg sexp as argument.
See `mu4e~proc-filter' for the format.")

(defvar mu4e-remove-func  'mu4e~headers-remove-handler
  "Function called for each :remove sexp returned.
This happens when some message has been deleted. The function is
passed the docid of the removed message.")

(defvar mu4e-sent-func  'mu4e~default-handler
  "Function called for each :sent sexp received.
This happens when some message has been sent. The function is
passed the docid and the draft-path of the sent message.")

(defvar mu4e-view-func  'mu4e~headers-view-handler
  "Function called for each single-message sexp.
The function is passed a message sexp as argument. See
`mu4e~proc-filter' for the format.")

(defvar mu4e-header-func  'mu4e~headers-header-handler
  "Function called for each message-header received.
The function is passed a msg plist as argument. See
`mu4e~proc-filter' for the format.")

(defvar mu4e-found-func  'mu4e~headers-found-handler
  "Function called for when we received a :found sexp.
This happens after the headers have been returned, to report on
the number of matches. See `mu4e~proc-filter' for the format.")

(defvar mu4e-erase-func 'mu4e~headers-clear
  "Function called we receive an :erase sexp.
This before new headers are displayed, to clear the current
headers buffer. See `mu4e~proc-filter' for the format.")

(defvar mu4e-compose-func 'mu4e~compose-handler
  "Function called for each compose message received.
I.e., the original message that is used as basis for composing a
new message (i.e., either a reply or a forward); the function is
passed msg and a symbol (either reply or forward). See
`mu4e~proc-filter' for the format of <msg-plist>.")

(defvar mu4e-info-func  'mu4e-info-handler
  "Function called for each (:info type ....) sexp received.
from the server process.")

(defvar mu4e-pong-func 'mu4e~default-handler
  "Function called for each (:pong type ....) sexp received.")

(defvar mu4e-contacts-func 'mu4e-contacts-func
  "A function called for each (:contacts (<list-of-contacts>)
sexp received from the server process.")

(defvar mu4e-temp-func 'mu4e~view-temp-handler
  "A function called for each (:temp <file> <cookie>) sexp.")

;;; _
(provide 'mu4e-vars)
;;; mu4e-vars.el ends here