;;; acdw-mail.el --- My email configuration  -*- lexical-binding: t; -*-

;;; Code:

(require 'cl-lib)
(require 'message)

;;; Variables

(defcustom +message-send-dispatch-rules nil
  "Alist to set variables based on the current from address."
  :group 'message
  :type '(alist :key-type (string :tag "From address")
                :value-type (alist :tag "Rules"
                                   :key-type (symbol :tag "Variable")
                                   :value-type (sexp :tag "Value"))))

(defcustom +notmuch-spam-tags '("+spam -inbox -unread")
  "List of tag changes to apply when marking a thread as spam."
  :group 'notmuch
  :type '(repeat string))

;;; Functions

(defun +message-send-set-variables ()
  "Set variables for `message-send' depending on the From: header.
Useful in `message-send-hook'."
  (unless +message-send-dispatch-rules
    (load notmuch-init-file)
    (or +message-send-dispatch-rules
        (error "`+message-send-dispatch-rules' isn't set!")))
  (let ((from (message-fetch-field "from")))
    (cl-loop for (var . val) in (cl-loop for (address . bindings)
                                         in +message-send-dispatch-rules
                                         if (string-match-p address from)
                                         return bindings)
             do (set (make-local-variable var) val))))

;; Thanks to Alex Schroeder!
;; https://www.emacswiki.org/emacs/Change_Signature_Dynamically
(defun +message-check-for-signature-change (&rest ignore)
  "Check for a change in the To: or Cc: fields"
  (when (and (message--in-tocc-p)
             (not (buffer-narrowed-p)))
    (save-excursion
      (goto-char (point-max))
      (let ((end (point)))
        (when (re-search-backward message-signature-separator nil t)
          (delete-region (1- (match-beginning 0)) end)))
      (message-insert-signature))))

(defun +message-signature-setup ()
  (make-local-variable 'after-change-functions)
  (push '+message-check-for-signature-change after-change-functions))

(defun +notmuch-field-match-p (field regexp)
  "Return whether message FIELD matches REGEXP."
  (string-match-p regexp (or (message-fetch-field field) "")))

(defun +notmuch-query-concat (&rest queries)
  "Concatenate `notmuch' QUERIES with AND."
  (mapconcat #'identity queries " AND "))

;;;###autoload
(defun +notmuch-goto (&optional prefix)
  "Perform a saved `notmuch' search.
Without a PREFIX argument, perform the first search in
`notmuch-saved-searches'.  With a single PREFIX argument
(\\[universal-argument]), prompt the user as to which saved
search to perform.  With two PREFIX arguments, prompt the user
for a free-form search.  With any other PREFIX argument, open
`notmuch-hello'."
  (interactive "P")
  (pcase prefix
    ('nil (notmuch-search (plist-get (car notmuch-saved-searches) :query)))
    ('(4) (notmuch-search
           (plist-get (cl-find (completing-read "Saved search: "
                                                (mapcar (lambda (elt)
                                                          (plist-get elt :name))
                                                        notmuch-saved-searches))
                               notmuch-saved-searches
                               :key (lambda (elt) (plist-get elt :name))
                               :test #'equal)
                      :query)))
    ('(16) (notmuch-search))
    (_ (notmuch-hello))))

(defun +notmuch-search-mark-spam (&optional ham start end)
  "Mark the current thread or region as spam.
That is, add the tags in `+notmuch-spam-tags' to the message.
With an optional HAM argument (interactively,
\\[universal-argument]), mark the message as not-spam, or ham, by
reversing the tag changes."
  (interactive (cons current-prefix-arg (notmuch-interactive-region)))
  (when +notmuch-spam-tags
    (notmuch-search-tag (notmuch-tag-change-list +notmuch-spam-tags ham)
                        start end))
  (when (eq start end)
    (notmuch-search-next-thread)))

(defun +notmuch-tree-mark-spam (&optional ham _ _)
  "Mark the current message as spam.
That is, add the tags in `+notmuch-spam-tags' to the message.
With an optional HAM argument (interactively,
\\[universal-argument]), mark the message as not-spam, or ham, by
reversing the tag changes."
  (interactive (cons current-prefix-arg (notmuch-interactive-region)))
  (when +notmuch-spam-tags
    (notmuch-tree-tag (notmuch-tag-change-list +notmuch-spam-tags ham)))
  (notmuch-tree-next-matching-message))

(defun +notmuch-define-saved-search (name key search-type &rest queries)
  "Wrapper to ease `notmuch-saved-searches' defining.
NAME, KEY, and SEARCH-TYPE are paired with the corresponding keywords in
`notmuch-saved-searches', which see.  QUERIES are all concatenated together with
AND.  If QUERIES is prepended with more keyword arguments, those are added to
the saved search as well."
  (declare (indent 3))
  (let (extra-keywords)
    (while (keywordp (car queries))
      (push (cadr queries) extra-keywords)
      (push (car queries) extra-keywords)
      (setf queries (cddr queries)))
    (add-to-list 'notmuch-saved-searches
                 (append (list :name name
                               :key key
                               :search-type search-type
                               :query (apply #'+notmuch-query-concat queries))
                         (reverse extra-keywords))
                 :append
                 (lambda (a b)
                   (equal (plist-get a :name)
                          (plist-get b :name))))))

(defun notmuch-async-poll ()
  "Run `notmuch-poll' in an async process."
  (interactive)
  (if (require 'async nil t)
      (progn
        (message "Polling mail (async)...")
        (async-start
         (lambda ()
           (ignore-errors
             (push "~/usr/share/emacs/site-lisp/" load-path)
             (require 'notmuch-lib)
             (notmuch-poll)))
         (lambda (_)
           (message "Polling mail (async)...done"))))
    ;;(user-error "Feature `async' not found!")
    (notmuch-poll)))

;;; https://kitchingroup.cheme.cmu.edu/blog/2015/09/04/Checking-for-email-attachments-before-you-send-email/

(defun email-says-attach-p ()
  "Return t if email suggests there could be an attachment."
  (save-excursion
    (goto-char (point-min))
    (re-search-forward "attach" nil t)))

(defun email-has-attachment-p ()
  "Return t if the currently open email has an attachment."
  (save-excursion
    (goto-char (point-min))
    (re-search-forward "<#part" nil t)))

(defun email-pre-send-check-attachment ()
  (when (and (email-says-attach-p)
             (not (email-has-attachment-p)))
    (unless
        (y-or-n-p
         "Your email suggests an attachment, but none was found. Send anyway?")
      (error "No attachment.  Aborting send."))))

;;; Process ical attachments

(defun notmuch-save-ics ()
  "Save a .ics file in a message."
  (interactive)
  (with-current-notmuch-show-message
   (notmuch-foreach-mime-part
    (lambda (part)
      (message "%S" part)
      (when (and (listp part)
                 (or (equal "application/ics" (caadr part))
                     ;; (equal "text/calendar" (caadr part))
                     ))
        (save-window-excursion
          (let* ((filename "/tmp/notmuch.ics")
                 (buf (find-file-noselect filename)))
            (delete-file filename)
            (kill-buffer (get-file-buffer filename))
            (mm-save-part-to-file part filename)
            (icalendar-import-file filename diary-file)
            (kill-buffer buf)))))
    (mm-dissect-buffer t t))))


;;; Fixes

;; https://nmbug.notmuchmail.org/nmweb/show/87bklhricc.fsf%40tethera.net

(defun notmuch--indent-rigidly (start end count)
  (cond
   ((zerop count) t)
   ((< count 0) (indent-rigidly start end count))
   (t
    (save-excursion
      (let ((startpt (progn (goto-char start) (line-beginning-position)))
            (endpt (progn (goto-char end) (line-end-position)))
            (spaces (spaces-string count)))
        (goto-char startpt)
        (while
            (progn
              (insert spaces)
              (cl-incf endpt count)
              (and (zerop (forward-line 1)) (bolp)
                   (<= (point) endpt)))))))))

(with-eval-after-load 'notmuch-show
  ;; Redefine `notmuch-show-lazy-part' --- XXX: this is the most braindead way
  ;; of doing this
  (defun notmuch-show-lazy-part (part-args button)
    ;; Insert the lazy part after the button for the part. We would just
    ;; move to the start of the new line following the button and insert
    ;; the part but that point might have text properties (eg colours
    ;; from a message header etc) so instead we start from the last
    ;; character of the button by adding a newline and finish by
    ;; removing the extra newline from the end of the part.
    (save-excursion
      (goto-char (button-end button))
      (insert "\n")
      (let* ((inhibit-read-only t)
             ;; We need to use markers for the start and end of the part
             ;; because the part insertion functions do not guarantee
             ;; to leave point at the end of the part.
             (part-beg (copy-marker (point) nil))
             (part-end (copy-marker (point) t))
             ;; We have to save the depth as we can't find the depth
             ;; when narrowed.
             (depth (notmuch-show-get-depth)))
        (save-restriction
          (narrow-to-region part-beg part-end)
          (delete-region part-beg part-end)
          (apply #'notmuch-show-insert-bodypart-internal part-args)
          (notmuch--indent-rigidly part-beg
                                   part-end
                                   (* notmuch-show-indent-messages-width depth)))
        (goto-char part-end)
        (delete-char 1)
        (notmuch-show-record-part-information (cadr part-args)
                                              (button-start button)
                                              part-end)
        ;; Create the overlay. If the lazy-part turned out to be empty/not
        ;; showable this returns nil.
        (notmuch-show-create-part-overlays button part-beg part-end))))
  )


;;; Packages

(use-package bbdb
  :ensure t
  :config
  (setopt bbdb-complete-mail-allow-cycling t
          bbdb-file (private/ "bbdb"))
  (add-hook 'custom-allowed-after-load-hook
            (defun bbdb@after-custom ()
              (require 'bbdb)
              (require 'bbdb-message)
              (bbdb-initialize 'message))))

(use-package bbdb-vcard
  :ensure t
  :after bbdb)

(use-package notmuch
  :when (executable-find "notmuch")
  :load-path "~/usr/share/emacs/site-lisp/"
  :defer 30
  :commands (notmuch-mua-new-mail
             notmuch-search
             notmuch-hello)
  :preface (defdir notmuch/ (sync/ "emacs/notmuch/")
             "Notmuch configuration directory."
             :makedir)
  :config
  ;; Options
  (setopt notmuch-init-file (notmuch/ "notmuch-init.el" t)
          notmuch-address-save-filename (notmuch/ "addresses" t)
          notmuch-address-use-company (featurep 'company)
          notmuch-search-oldest-first nil
          notmuch-archive-tags '("-inbox" "-unread")
          notmuch-draft-tags '("+draft" "-inbox" "-unread")
          +notmuch-spam-tags '("+spam")
          mail-user-agent 'notmuch-user-agent
          message-mail-user-agent t
          notmuch-show-indent-content nil
          message-kill-buffer-on-exit t
          message-auto-save-directory nil
          message-signature "Case Duckworth\nhttps://www.acdw.net"
          send-mail-function #'sendmail-send-it
          mail-specify-envelope-from t
          message-sendmail-envelope-from 'header
          message-envelope-from 'header
          notmuch-saved-searches nil
          notmuch-poll-script "~/usr/scripts/syncmail" ; XXX: Deprecated option
          )
  (load notmuch-init-file)
  ;; Key bindings
  (keymap-set notmuch-search-mode-map "!" #'+notmuch-search-mark-spam)
  (keymap-set notmuch-search-mode-map "RET" #'notmuch-search-show-thread)
  (keymap-set notmuch-search-mode-map "M-RET" #'notmuch-tree-from-search-thread)
  (keymap-set notmuch-tree-mode-map "!" #'+notmuch-tree-mark-spam)
  ;; Saved searches
  (+notmuch-define-saved-search "inbox+unread" "m" 'tree
    "tag:inbox" "tag:unread" "NOT tag:Spam")
  (+notmuch-define-saved-search "inbox" "i" 'tree
    "tag:inbox" "NOT tag:Spam")
  (+notmuch-define-saved-search "lists+unread" "l" 'tree
    "tag:/List/" "tag:unread")
  (+notmuch-define-saved-search "lists" "L" 'tree
    "tag:/List/")
  (+notmuch-define-saved-search "unread" "u" 'tree
    "tag:unread" "NOT tag:Spam")
  (+notmuch-define-saved-search "flagged" "f" 'tree
    "tag:flagged")
  (+notmuch-define-saved-search "sent" "t" 'tree
    "tag:sent")
  (+notmuch-define-saved-search "drafts" "d" 'tree
    "tag:draft")
  (+notmuch-define-saved-search "all mail" "a" 'tree "*")
  ;; Hooks and advice
  (add-hook 'message-send-hook #'+message-send-set-variables)
  (add-hook 'message-send-hook #'email-pre-send-check-attachment)
  (add-hook 'message-setup-hook #'+message-signature-setup)
  (autoload 'visual-fill-column-mode "visual-fill-column" nil t)
  (add-hook 'notmuch-message-mode-hook #'visual-fill-column-mode)
  (add-hook 'notmuch-show-mode-hook #'visual-fill-column-mode)

  (define-advice notmuch-bury-or-kill-this-buffer (:after (&rest _) poll-async)
    (notmuch-async-poll))

  (define-advice notmuch-address-selection-function
      (:override (prompt collection _) no-initial-input)
    "Call `completing-read' with `notmuch-address-history'.
This version doesn't add any initial-input."
    (completing-read prompt collection nil nil nil 'notmuch-address-history))

  (add-to-list 'notmuch-message-headers "List-Post" :append #'equal)
  (define-advice notmuch-mua-new-reply (:around (orig &rest r) list-aware)
    "Make `notmuch-mua-new-reply' list-aware."
    (let ((ml (notmuch-show-get-header :List-Post)))
      (apply orig r)
      (require 'message)
      (when ml
        (with-buffer-modified-unmodified
         (message-remove-header "To")
         (message-add-header
          (format "To: %s" (replace-regexp-in-string "<mailto:\\(.*\\)>" "\\1"
                                                     ml)))
         (message-goto-body)))))

  (define-advice notmuch-tag (:filter-args (args) trim)
    "Trim whitespace from ends of tags."
    (list (car args) (mapcar #'string-trim (cadr args))))
  ;; Load init file
  (load notmuch-init-file :noerror))

(use-package notmuch-tags
  :load-path "~/src/emacs/notmuch-tags.el/"
  :commands (notmuch-tags-mode))

(provide 'acdw-mail)
;;; acdw-mail.el ends here