;;; email/mu4e/config.el -*- lexical-binding: t; -*-

(defvar +mu4e-backend 'mbsync
  "Which backend to use. Can either be offlineimap, mbsync or nil (manual).")


;;
;;; Packages

(add-to-list 'auto-mode-alist '("\\.\\(?:offlineimap\\|mbsync\\)rc\\'" . conf-mode))


(use-package! mu4e
  :commands mu4e mu4e-compose-new
  :init
  (provide 'html2text) ; disable obsolete package
  (setq mu4e-maildir "~/.mail"
        mu4e-attachment-dir "~/.mail/.attachments"
        mu4e-user-mail-address-list nil)
  :config
  (pcase +mu4e-backend
    (`mbsync
     (setq mu4e-get-mail-command "mbsync -a"
           mu4e-change-filenames-when-moving t))
    (`offlineimap
     (setq mu4e-get-mail-command "offlineimap -o -q")))

  (setq mu4e-update-interval nil
        mu4e-compose-format-flowed t ; visual-line-mode + auto-fill upon sending
        mu4e-view-show-addresses t
        mu4e-sent-messages-behavior 'sent
        mu4e-hide-index-messages t
        ;; try to show images
        mu4e-view-show-images t
        mu4e-view-image-max-width 800
        ;; configuration for sending mail
        message-send-mail-function #'smtpmail-send-it
        smtpmail-stream-type 'starttls
        message-kill-buffer-on-exit t ; close after sending
        ;; start with the first (default) context;
        mu4e-context-policy 'pick-first
        ;; compose with the current context, or ask
        mu4e-compose-context-policy 'ask-if-none
        ;; use helm/ivy
        mu4e-completing-read-function
        (cond ((featurep! :completion ivy) #'ivy-completing-read)
              ((featurep! :completion helm) #'completing-read)
              (t #'ido-completing-read))
        ;; no need to ask
        mu4e-confirm-quit nil
        ;; remove 'lists' column
        mu4e-headers-fields
        '((:account . 12)
          (:human-date . 12)
          (:flags . 4)
          (:from . 25)
          (:subject)))

  ;; set mail user agent
  (setq mail-user-agent 'mu4e-user-agent)

  ;; Use fancy icons
  (setq mu4e-headers-has-child-prefix '("+" . "")
        mu4e-headers-empty-parent-prefix '("-" . "")
        mu4e-headers-first-child-prefix '("\\" . "")
        mu4e-headers-duplicate-prefix '("=" . "")
        mu4e-headers-default-prefix '("|" . "")
        mu4e-headers-draft-mark '("D" . "")
        mu4e-headers-flagged-mark '("F" . "")
        mu4e-headers-new-mark '("N" . "")
        mu4e-headers-passed-mark '("P" . "")
        mu4e-headers-replied-mark '("R" . "")
        mu4e-headers-seen-mark '("S" . "")
        mu4e-headers-trashed-mark '("T" . "")
        mu4e-headers-attach-mark '("a" . "")
        mu4e-headers-encrypted-mark '("x" . "")
        mu4e-headers-signed-mark '("s" . "")
        mu4e-headers-unread-mark '("u" . ""))

  ;; Add a column to display what email account the email belongs to.
  (add-to-list 'mu4e-header-info-custom
               '(:account
                 :name "Account"
                 :shortname "Account"
                 :help "Which account this email belongs to"
                 :function
                 (lambda (msg)
                   (let ((maildir (mu4e-message-field msg :maildir)))
                     (format "%s" (substring maildir 1 (string-match-p "/" maildir 1)))))))

  (defadvice! +mu4e--refresh-current-view-a (&rest _)
    :after #'mu4e-mark-execute-all (mu4e-headers-rerun-search))

  (when (featurep! :tools flyspell)
    (add-hook 'mu4e-compose-mode-hook #'flyspell-mode))

  ;; Wrap text in messages
  (setq-hook! 'mu4e-view-mode-hook truncate-lines nil)

  (when (fboundp 'imagemagick-register-types)
    (imagemagick-register-types))

  (set-evil-initial-state!
    '(mu4e-main-mode
      mu4e-view-mode
      mu4e-headers-mode
      mu4e-compose-mode
      mu4e~update-mail-mode)
    'normal)

  (map! :localleader
        :map mu4e-compose-mode-map
        :desc "send and exit" "s" #'message-send-and-exit
        :desc "kill buffer"   "d" #'message-kill-buffer
        :desc "save draft"    "S" #'message-dont-send
        :desc "attach"        "a" #'mail-add-attachment))


(use-package! mu4e-maildirs-extension
  :after mu4e
  :config
  (mu4e-maildirs-extension)
  (setq mu4e-maildirs-extension-title nil))


(use-package! org-mu4e
  :hook (mu4e-compose-mode . org-mu4e-compose-org-mode)
  :config
  (setq org-mu4e-link-query-in-headers-mode nil
        org-mu4e-convert-to-html t)

  ;; Only render to html once. If the first send fails for whatever reason,
  ;; org-mu4e would do so each time you try again.
  (add-hook! 'message-send-hook
    (setq-local org-mu4e-convert-to-html nil)))


;;
;;; Gmail integration

(when (featurep! +gmail)
  (after! mu4e
    ;; don't save message to Sent Messages, Gmail/IMAP takes care of this
    (setq mu4e-sent-messages-behavior 'delete

          ;; don't need to run cleanup after indexing for gmail
          mu4e-index-cleanup nil

          ;; because gmail uses labels as folders we can use lazy check since
          ;; messages don't really "move"
          mu4e-index-lazy-check t)

    ;; In my workflow, emails won't be moved at all. Only their flags/labels are
    ;; changed. Se we redefine the trash and refile marks not to do any moving.
    ;; However, the real magic happens in `+mu4e|gmail-fix-flags'.
    ;;
    ;; Gmail will handle the rest.
    (defun +mu4e--mark-seen (docid _msg target)
      (mu4e~proc-move docid (mu4e~mark-check-target target) "+S-u-N"))

    (delq! 'delete mu4e-marks #'assq)
    (setf (alist-get 'trash mu4e-marks)
          (list :char '("d" . "▼")
                :prompt "dtrash"
                :dyn-target (lambda (_target msg) (mu4e-get-trash-folder msg))
                :action #'+mu4e--mark-seen)
          ;; Refile will be my "archive" function.
          (alist-get 'refile mu4e-marks)
          (list :char '("d" . "▼")
                :prompt "dtrash"
                :dyn-target (lambda (_target msg) (mu4e-get-trash-folder msg))
                :action #'+mu4e--mark-seen))

    ;; This hook correctly modifies gmail flags on emails when they are marked.
    ;; Without it, refiling (archiving), trashing, and flagging (starring) email
    ;; won't properly result in the corresponding gmail action, since the marks
    ;; are ineffectual otherwise.
    (add-hook! 'mu4e-mark-execute-pre-hook
      (defun +mu4e-gmail-fix-flags-h (mark msg)
        (pcase mark
          (`trash  (mu4e-action-retag-message msg "-\\Inbox,+\\Trash,-\\Draft"))
          (`refile (mu4e-action-retag-message msg "-\\Inbox"))
          (`flag   (mu4e-action-retag-message msg "+\\Starred"))
          (`unflag (mu4e-action-retag-message msg "-\\Starred")))))))