;;; irc.el -*- lexical-binding: t; -*-
;;;
;;; Author:  Jakob L. Kreuze <zerodaysfordays@sdf.org>
;;; URL:     https://git.sr.ht/~jakob/.emacs.d/
;;;
;;; Configuration of ERC, as well as additional custom defuns for making an
;;; enjoyable IRC experience within Emacs.
;;;



;; Functions for connecting to and authenticating with my IRC bouncer.

(defun read-bouncer-password ()
  "Pull the password for my bouncer from authinfo"
  (let ((auth (auth-source-search :host "jakob.space" :user "jakob" :port 6697)))
    (unless auth
      (error "No auth entry for bouncer."))
    (let ((secretf (plist-get (car auth) :secret)))
      (unless secretf
        (error "No secret for bouncer's auth entry."))
      (funcall secretf))))

(defvar *bouncer-port-alist* '(("freenode" . 6697)
                               ("tildetown" . 6671)))

(defun connect-bouncer (server)
  "Connect to `SERVER' on the bouncer and rename the buffer"
  (let* ((port (cdr (assoc server *bouncer-port-alist*)))
         (buf (erc-tls :server "jakob.space"
                       :port port
                       :password (read-bouncer-password))))
    (erc-with-buffer (buf (rename-buffer server)))))

;; Interactive function for connecting to all of my bouncer's IRC servers.

(defvar irc-autoconnect-networks '("freenode" "tildetown")
  "List of networks to automatically connect to when 'irc' is invoked.")

(defun irc ()
  "Connect to every network in `irc-autoconnect-networks'."
  (interactive)
  (dolist (network irc-autoconnect-networks)
    (connect-bouncer network)))

(defun irc-quit ()
  "Disconnects from and kills all buffers associated with ERC."
  (interactive)
  (let ((server-buffers (cl-remove-if-not #'erc-server-buffer-p (erc-buffer-list))))
    (dolist (buffer server-buffers)
      (erc-with-buffer (buffer)
        (erc-quit-server (funcall erc-quit-reason nil))))))

(use-package erc
  :straight nil

  ;; Only load the modules I actually use. This list deviates from the default
  ;; by including truncate, but omitting autojoin.
  :config
  (setq erc-modules '(button completion fill
                      irccontrols list match
                      menu move-to-prompt netsplit
                      networks noncommands readonly
                      ring stamp track truncate))
  (erc-update-modules)

  ;; Configure personal details.
  :init
  (setq erc-nick '("jakob" "tsarfox")
        erc-user-full-name "Jakob <http://jakob.space>"
        erc-quit-reason (lambda (reason)
                          (or reason (concat "Program received signal "
                                             "SIGSEGV, Segmentation fault."))))

  ;; Display the current nick in the prompt.
  :init
  (setq erc-prompt (lambda () (format "%s>" (erc-current-nick))))

  ;; Center everything.
  :init
  (setq erc-fill-function 'erc-fill-static
        erc-fill-column 100
        erc-fill-static-center 22)

  ;; Enable MIRC and control sequences so I can partake in figlet spam,
  ;; objectively the best part of the IRC experience.
  :init
  (setq erc-interpret-controls-p t
        erc-interpret-mirc-color t)

  ;; Enable timestamps, and show them to the left of the messages.
  :init
  (setq erc-hide-timestamps nil
        erc-insert-timestamp-function 'erc-insert-timestamp-left)

  ;; Although 'log' is omitted from `erc-modules', I still explicitly disable
  ;; logging. I can just save the buffer if I want to save a conversation.
  :init
  (setq erc-enable-logging nil
        erc-save-buffer-on-part nil)

  ;; Similarly, 'autowaway' is omitted from `erc-modules', but I'm disabling it
  ;; anyway.
  :init
  (setq erc-auto-set-away nil
        erc-auto-discard-away nil)

  ;; Kill buffers when I disconnect.
  :init
  (setq erc-kill-buffer-on-part t
        erc-kill-queries-on-quit t
        erc-kill-server-buffer-on-quit t)

  ;; Don't get in my way by popping new windows when someone queries me, and
  ;; don't assault me with windows when I connect to my bouncer.
  :init
  (setq erc-auto-query 'bury
        erc-join-buffer 'bury)

  ;; Show CTCP requests. Not for any reason in particular, I just like seeing
  ;; when people ping me.
  :init
  (setq erc-paranoid t)

  ;; Hide JOIN/PART/QUIT messages from idlers.
  :init
  (setq erc-lurker-hide-list '("JOIN" "PART" "QUIT")
        erc-lurker-threshold-time 3600)

  ;; Configure `erc-track' to ignore the less interesting message types.
  :init
  (setq erc-track-exclude-server-buffer t
        erc-track-exclude-types '("JOIN" "NICK" "PART" "QUIT" "MODE"
                                  "324" "329" "332" "333" "353" "477"))

  ;; Enable channel tracking.
  :config
  (erc-track-minor-mode 1)
  (erc-track-mode 1)

  ;; Move to the prompt as soon as I begin typing. I've configured the buffer
  ;; text preceding it to be read-only, anyway.
  :config
  (erc-move-to-prompt-enable)

  ;; Bind a key for resetting =erc-track=, since I tend to get absolutely
  ;; bombarded upon reconnecting.
  :bind
  (:map erc-mode-map
    ("C-c f" . (lambda ()
                 (interactive)
                 (setq erc-modified-channels-alist nil)
                 (erc-modified-channels-update))))

  ;; Let `erc-fill' handle filling.
  :hook
  (erc-mode . (lambda () (auto-fill-mode 0))))

;; Configure 'erc-hl-nicks' to show names using pretty colors.

(use-package erc-hl-nicks
  :after erc
  :config
  (erc-hl-nicks-enable))

;; Display a bar delimiting read and unread messages. Adapted from [1].
;;
;; [1]: https://www.emacswiki.org/emacs/ErcBar

(defvar erc-bar-overlay nil
  "Overlay used to set bar")

(defvar erc-bar-threshold 1
  "The minimum number of messages required for the bar to be
displayed.")

(defun erc-bar-move-back (n)
  "Moves back n message lines. Ignores wrapping, and server
messages."
  (interactive "nHow many lines ? ")
  (re-search-backward "^.*<.*>" nil t n))

(defun erc-bar-update-overlay ()
  "Update the overlay for current buffer, based on the content of
erc-modified-channels-alist. Should be executed on window
change."
  (interactive)
  (let* ((info (assq (current-buffer) erc-modified-channels-alist))
         (count (cadr info)))
    (if (and info (> count erc-bar-threshold))
        (save-excursion
          (goto-char (point-max))
          (when (erc-bar-move-back count)
            (let ((inhibit-field-text-motion t))
              (move-overlay erc-bar-overlay
                            (line-beginning-position)
                            (line-end-position)
                            (current-buffer)))))
      (delete-overlay erc-bar-overlay))))

(with-eval-after-load 'erc
  ;; Run the hook before 'erc-modified-channels-update
  (defadvice erc-track-mode (after erc-bar-setup-hook
                                   (&rest args) activate)
    (remove-hook 'window-configuration-change-hook 'erc-bar-update-overlay)
    (add-hook 'window-configuration-change-hook 'erc-bar-update-overlay))

  (add-hook 'erc-send-completed-hook (lambda (str)
                                       (ignore str)
                                       (erc-bar-update-overlay))))

;; Display the bar as a highlight on the most recently unread message.

(with-palette
 (setq erc-bar-overlay (make-overlay 0 0))
 (overlay-put erc-bar-overlay 'face `(:background ,black-2)))