(require 'gnus)
(autoload 'gnus-group-topic "gnus-topic")

(require 'org-gnus)

(setq gnus-home-directory "~/.gnus.d/"
      gnus-directory gnus-home-directory
      gnus-article-save-directory (expand-file-name "saved/" gnus-directory)
      gnus-kill-files-directory (expand-file-name "scores/" gnus-directory))

(setq gnus-startup-file (expand-file-name "newsrc" gnus-home-directory)
      gnus-init-file (expand-file-name "gnus" gnus-home-directory)
      gnus-save-newsrc-file nil
      gnus-read-newsrc-file nil)

(setq sendmail-program "/usr/bin/msmtp"
      gnus-gcc-mark-as-read t
      gnus-visible-headers '("^From" "^Subject" "^Date" "^To" "^Cc" "^User-Agent")
      gnus-confirm-mail-reply-to-news t)

(setq imap-shell-program "/usr/lib/dovecot/imap -c ~/.dovecotrc"
      gnus-select-method '(nnimap "dov" (nnimap-stream shell))
      gnus-secondary-select-methods '((nntp "news.gmane.org")))

(setq gnus-agent-go-online t
      gnus-agent-synchronize-flags t)

(setq mm-discouraged-alternatives '("text/html" "text/richtext"))
(setq gnus-interactive-exit nil)

(add-hook 'kill-emacs-hook 'gnus-grace-exit-before-kill-emacs)

(defun km/sync-mail ()
  (interactive)
  (let ((bufname (get-buffer-create "*Mail sync*"))
        (default-directory "~/")
        (process "mail-sync"))
    (with-current-buffer bufname
      (view-mode 1)
      (goto-char (point-max)))
    (display-buffer bufname)
    (if (process-live-p process)
        (message "Mail sync process is already running")
      (start-process process bufname km/sync-mail-cmd))))

(defvar km/sync-mail-cmd "sync-mail"
  "Run sync mail script.")

;; http://www.emacswiki.org/emacs/GnusSync
(defun gnus-grace-exit-before-kill-emacs ()
  (if (and (fboundp 'gnus-alive-p)
           (gnus-alive-p))
      (let ((noninteractive t))
        (gnus-group-exit))))

(define-prefix-command 'km/mail-map)
(global-set-key (kbd "C-x m") 'km/mail-map)

(define-key km/mail-map "g" 'gnus)
(define-key km/mail-map "p" 'gnus-plugged)
(define-key km/mail-map "u" 'gnus-unplugged)
(define-key km/mail-map "s" 'km/sync-mail)


;;; Gnus group buffer

(setq gnus-topic-display-empty-topics nil
      gnus-group-list-inactive-groups nil)

(setq gnus-group-use-permanent-levels t)

(setq gnus-group-sort-function '(km/gnus-group-sort-by-topic
                                 gnus-group-sort-by-level))

(defun km/gnus-group-sort-by-topic (info1 info2)
  "Sort alphabetically by group topic.
This allows groups to be ordered by topics even when topic mode
is off."
  (string< (gnus-group-topic (gnus-info-group info1))
           (gnus-group-topic (gnus-info-group info2))))

(define-key gnus-group-mode-map "e" 'gnus-group-select-group)


;;; Gnus summary and article buffer

(setq gnus-summary-line-format "%U%R %&user-date;%-20= %-15,15f  %B %S \n"
      gnus-sum-thread-tree-indent "  "
      gnus-sum-thread-tree-root "."
      gnus-sum-thread-tree-false-root "o "
      gnus-sum-thread-tree-single-indent ""
      gnus-sum-thread-tree-leaf-with-other "+-> "
      gnus-sum-thread-tree-vertical "| "
      gnus-sum-thread-tree-single-leaf "`-> ")

(setq gnus-auto-select-next 'quietly)

(setq gnus-thread-hide-subtree t
      gnus-thread-sort-functions '(gnus-thread-sort-by-most-recent-number))

(add-hook 'gnus-summary-mode-hook 'km/gnus-setup-local-ace-jump)

(defun km/gnus-setup-local-ace-jump ()
  (add-hook 'ace-jump-mode-end-hook (lambda () (gnus-summary-scroll-up 0))
            nil t))

(defun km/gnus-follow-last-message-link (arg)
  "Follow link at bottom of message.
When a prefix argument, move to and copy the link but don't
follow it."
  (interactive "P")
  (km/gnus-end-of-article-buffer)
  (widget-backward 1)
  (if arg
      (shr-copy-url)
    (widget-button-press (point))))

(defun km/gnus-open-github-patch ()
  "Open patch from github email.
A new buffer with the patch contents is opened in another window."
  (interactive)
  (km/gnus-end-of-article-buffer)
  (search-backward "patch")
  (let ((url (thing-at-point 'url))
        (patch-buffer (generate-new-buffer "*gnus-github-patch*")))
    (switch-to-buffer-other-window patch-buffer)
    (url-insert-file-contents url)
    (diff-mode)
    (view-mode 1)))

(defun km/gnus-end-of-article-buffer ()
  "Move point to the end of the article buffer."
  ;; The next 3 lines are from `gnus-summary-widget-forward'.
  (gnus-summary-select-article)
  (gnus-configure-windows 'article)
  (select-window (gnus-get-buffer-window gnus-article-buffer))
  (goto-char (point-max)))


;; From http://ivan.kanis.fr/ivan-gnus.el
(defun km/gnus-catchup-and-goto-next-group (&optional all)
  "Mark all articles in this group as read and select the next group.
If given a prefix, mark all articles, unread as well as ticked, as
read. Don't ask to confirm."
  (interactive "P")
  (save-excursion
    (gnus-summary-catchup all t))
  (gnus-summary-next-group))

;; From http://ivan.kanis.fr/ivan-gnus.el
(defadvice gnus-summary-next-group (before km/gnus-next-group activate)
  "Go to next group without selecting the first article."
  (ad-set-arg 0 t))

(define-key gnus-summary-mode-map
  (kbd "C-c j") 'km/gnus-follow-last-message-link)
(define-key gnus-summary-mode-map ";" 'gnus-summary-universal-argument)
;; This overrides `gnus-summary-post-news', which is also bound to
;; 'S p'.
(define-key gnus-summary-mode-map "c" 'km/gnus-catchup-and-goto-next-group)
(define-key gnus-summary-mode-map "e" 'gnus-summary-scroll-up)
(define-key gnus-summary-mode-map "j" 'ace-jump-mode)

(define-key gnus-article-mode-map
  (kbd "C-c j") 'km/gnus-follow-last-message-link)
(define-key gnus-article-mode-map "e" 'shr-browse-url)


;;; Message mode

(setq message-send-mail-function 'message-send-mail-with-sendmail
      message-sendmail-envelope-from 'header
      message-citation-line-function 'message-insert-formatted-citation-line
      message-citation-line-format "%f wrote:"
      message-kill-buffer-on-exit t
      footnote-section-tag "")

(add-hook 'message-send-hook 'km/message-confirm-sender)
(add-hook 'message-mode-hook
          (lambda () (flyspell-mode 1)))

(defun km/message-confirm-sender ()
  "Stop sending message from the wrong address."
  (unless (yes-or-no-p (format "Send message from %s?"
                               (message-field-value "From")))
    (user-error "Not sending message")))

;; Modified from
;; http://emacs-fu.blogspot.com/2008/12/some-simple-tricks-boxquote-footnote.html.
(defun km/snip-mail-quote (beg end &optional number quote-char)
  "Replace region lines with \"[...]\".
If prefix argument NUMBER is non-nil, add the number of lines
that were snipped.  The default QUOTE-CHAR is \">\".  Place text
following the snipped lines on a new line, and file the resulting
paragraph."
  (interactive "r\nP")
  (let ((nlines (count-lines beg end))
        (quote-char (or quote-char ">")))
    (delete-region beg end)
    (if number
        (insert (format "[%d line%s ...]" nlines (if (= 1 nlines) "" "s")))
      (insert (format "[...]")))
    (search-backward "[")
    (unless (bolp)
      (newline))
    (search-forward "]")
    (unless (eolp)
      (newline)
      (insert quote-char)
      (just-one-space)
      (fill-paragraph))))

(define-key message-mode-map (kbd "C-c m s") 'km/snip-mail-quote)


;;; Select and bury

;; Modified from http://www.xsteve.at/prg/gnus/

(defun km/gnus-select-or-bury ()
  "Start, select, or bury gnus."
  (interactive)
  (let ((bufname (buffer-name)))
    (if (or (string-equal "*Group*" bufname)
            (string-match "\*Summary" bufname)
            (string-match "\*Article" bufname))
        (km/bury-gnus)
      (if (get-buffer "*Group*")
          (km/unbury-gnus)
        (gnus-unplugged)))))

(defvar gnus-bury-window-configuration nil)

(defun km/unbury-gnus ()
  (let (dead-frame-p
        (windows-saved-p
         (and (boundp 'gnus-bury-window-configuration)
              gnus-bury-window-configuration)))
    (when windows-saved-p
      (unless (set-window-configuration gnus-bury-window-configuration)
        (setq dead-frame-p t)))
    (when (or dead-frame-p (not windows-saved-p))
      (switch-to-buffer "*Group*"))))

(defun km/bury-gnus ()
  (let ((buf nil)
        (bufname nil))
    (setq gnus-bury-window-configuration nil)
    (dolist (buf (buffer-list))
      (setq bufname (buffer-name buf))
      (when (or (string-equal "*Group*" bufname)
                (string-match "\*Summary" bufname)
                (string-match "\*Article" bufname))
        (unless gnus-bury-window-configuration
          (setq gnus-bury-window-configuration (current-window-configuration)))
        (delete-other-windows)
        (if (eq (current-buffer) buf)
            (bury-buffer)
          (bury-buffer buf))))))

(define-key km/mail-map "b" 'km/gnus-select-or-bury)


;;; Notmuch

(require 'notmuch)
(require 'org-notmuch)

(setq org-gnus-prefer-web-links t)

(setq notmuch-fcc-dirs nil
      notmuch-search-oldest-first nil)

(add-hook 'km/org-store-link-hook 'km/gnus-goto-message-in-notmuch)

(defun km/notmuch-file-to-group (file)
  "Calculate the Gnus group name from the given file name."
  (let ((group (file-name-directory (directory-file-name (file-name-directory file)))))
    (setq group (replace-regexp-in-string ".*/mail/" "nnimap+dov:" group))
    (setq group (replace-regexp-in-string "/$" "" group))
    (if (string-match ":$" group)
        (concat group "INBOX")
      (replace-regexp-in-string ":\\." ":" group))))

(defun km/notmuch-goto-message-in-gnus ()
  "Open a summary buffer containing the current notmuch article."
  (interactive)
  (let ((group (km/notmuch-file-to-group (notmuch-show-get-filename)))
        (message-id (replace-regexp-in-string
                     "^id:" "" (notmuch-show-get-message-id))))
    (setq message-id (replace-regexp-in-string "\"" "" message-id))
    (if (and group message-id)
        (progn
          (switch-to-buffer "*Group*")
          (org-gnus-follow-link group message-id))
      (message "Couldn't get relevant infos for switching to Gnus."))))

(defun km/gnus-goto-message-in-notmuch ()
  "Show message in notmuch."
  (interactive)
  (when (and (memq major-mode '(gnus-summary-mode gnus-article-mode))
             (string= (cadr (gnus-find-method-for-group gnus-newsgroup-name))
                      "dov"))
    (let* ((header (with-current-buffer gnus-summary-buffer
                     (gnus-summary-article-header)))
           (message-id (org-remove-angle-brackets (mail-header-id header))))
      (notmuch-show (concat "id:" message-id)))))

(define-key notmuch-show-mode-map (kbd "C-c C-c") 'km/notmuch-goto-message-in-gnus)
(define-key gnus-group-mode-map "GG" 'notmuch-search)

(define-key km/mail-map "n" 'notmuch-search)

(provide 'init-gnus)