Gnus is one of the most extensible Email programs on the
planet. And it's not even made for email but NNTP.

#+BEGIN_SRC emacs-lisp
  (require 'gnus)
  (require 'gnus-msg)
  (require 'mail-source)
  (require 'message)
  (require 'nnfolder)
  (require 'sendmail)

  (require 'oni-helpers)
#+END_SRC

Store all Gnus-related data in my data directory.

#+BEGIN_SRC emacs-lisp
  (setq gnus-directory (oni:data-location "News")
        gnus-article-save-directory gnus-directory
        gnus-cache-directory gnus-directory
        gnus-kill-files-directory gnus-directory)
#+END_SRC

Store all Mail source-related data in my data directory.

#+BEGIN_SRC emacs-lisp
  (setq mail-source-directory (oni:data-location "Mail"))
#+END_SRC

Store all message-related data in the same place as the Mail source
data.

#+BEGIN_SRC emacs-lisp
  (setq message-directory (oni:data-location "Mail"))
#+END_SRC

Store all nnfolder-related data in the same place as the Mail
source data.

#+BEGIN_SRC emacs-lisp
  (setq nnfolder-directory (oni:data-location "Mail"))
#+END_SRC

Use msmtp to send mail.

#+BEGIN_SRC emacs-lisp
  (setq send-mail-function 'sendmail-send-it)
  (setq sendmail-program "/usr/bin/msmtp")
#+END_SRC

Tell Gnus I'm not a novice anymore. One of the features of Gnus I
use a lot is deleting messages and as long as Gnus thinks I'm a
novice it will ask me if I'm sure every single time.

#+BEGIN_SRC emacs-lisp
  (setq gnus-novice-user nil)
#+END_SRC

Add a keybinding to the Gnus summary mode to easily delete
messages.

#+BEGIN_SRC emacs-lisp
  (define-key gnus-summary-mode-map (kbd "M-d") 'oni-gnus-delete-forward)
#+END_SRC

* ryuslash.org

  Set my main email address as the primary select method for Gnus.

  #+BEGIN_SRC emacs-lisp
    (setq gnus-select-method
          '(nnmaildir "ryuslash" (directory "~/documents/mail/ryuslash/")))
  #+END_SRC

  When sending mail from the ryuslash inbox, use the ryuslash msmtp
  account.

  #+BEGIN_SRC emacs-lisp
    (add-to-list 'gnus-posting-styles
                 '(".*"
                   (address "tom@ryuslash.org")
                   (eval (setq message-sendmail-extra-arguments
                               '("-a" "ryuslash")))))
  #+END_SRC

* picturefix

  Add my work email account as a secondary select method.

  #+BEGIN_SRC emacs-lisp
    (add-to-list 'gnus-secondary-select-methods
                 '(nnmaildir "picturefix"
                             (directory "~/documents/mail/picturefix/")))
  #+END_SRC

  When sending mail from the picturefix account, use the picturefix
  msmtp account and set the proper name and email address.

  #+BEGIN_SRC emacs-lisp
    (add-to-list 'gnus-posting-styles
                 '("picturefix:"
                   (name "Tom Willemsen")
                   (address "tom@picturefix.nl")
                   (eval (setq message-sendmail-extra-arguments
                               '("-a" "picturefix")))))
  #+END_SRC

* gmail

  Add my other personal email as a secondary select method.

  #+BEGIN_SRC emacs-lisp
    (add-to-list 'gnus-secondary-select-methods
                 '(nnmaildir "gmail"
                             (directory "~/documents/mail/gmail/")))
  #+END_SRC

  When sending mail from the gmail account, use the gmail msmtp
  accound and set the proper email address.

  #+BEGIN_SRC emacs-lisp
    (add-to-list 'gnus-posting-styles
                 '("gmail:"
                   (name "Tom Willemse")
                   (address "ryuslash@gmail.com")
                   (eval (setq message-sendmail-extra-arguments
                               '("-a" "gmail")))))
  #+END_SRC