;;; -*-emacs-lisp-*-
;;;
;;; ERC configuration

(setq erc-nick "mdw"
      erc-user-full-name "Mark Wooding")

(if (not (memq 'truncate erc-modules))
    (setq erc-modules (cons 'truncate erc-modules)))

(setq erc-fill-column 76
      erc-timestamp-right-column 68
      erc-fill-prefix "   "
      erc-max-buffer-size (* 60 3000))

(setq erc-track-exclude-types '("NICK" "JOIN" "PART"))

(setq erc-auto-query 'buffer)

(defun mdw-erc-turn-off-truncate-lines ()
  (setq truncate-lines nil
	truncate-partial-with-windows nil
	word-wrap t
	wrap-prefix (concat (propertize "    " 'face 'erc-prompt-face)
			    " ")))
(add-hook 'erc-mode-hook 'mdw-erc-turn-off-truncate-lines)

(setq erc-autojoin t
      erc-autojoin-domain-only nil
      erc-autojoin-channels-alist
      '(("chiark.greenend.org.uk" "#chiark")
	("irc.distorted.org.uk" "#distorted" "#jukebox")
	("irc.hstg.corp.good.com" "#hstg")))
(erc-autojoin-mode 1)

(defvar mdw-erc-auto-greet-bots-alist nil
  "*Alist of (SERVER-REGEXP BOT-NICK MESSAGE-FORM).
Evaluate MESSAGE-FORM and sent to BOT-NICK when connected to a server which
matches SERVER-REGEXP.")

(defvar mdw-erc-ircop-alist nil
  "*Alist of (SERVER-REGEXP ACCT PASSWD).
Login details for claiming server admin rights.")

(defun mdw-remprop-nondestructive (indic plist)
  "Return a plist like PLIST, only without the first entry for INDIC.
The PLIST is not itself modified."
  (if (getf plist indic)
      (let* ((head (cons nil nil))
	     (tail head))
	(while (and plist (not (eq (car plist) indic)))
	  (let* ((i (pop plist)) (v (pop plist))
		 (vv (cons v nil)) (ii (cons i vv)))
	    (rplacd tail ii)
	    (setq tail vv)))
	(rplacd tail (cddr plist))
	(cdr head))
    plist))

(defun* mdw-cons-replace
    (item list &rest keys &key (key '#'identity) &allow-other-keys)
  "Return LIST, with ITEM at the start, replacing any existing matching item.
Specifically, any item in the list satisfying the test are removed
\(nondestructively), and then the new ITEM is added to the front."
  (cons item (apply #'remove* (funcall key item) list :key key
		    (mdw-remprop-nondestructive :key keys))))

(defmacro* mdw-pushnew-replace (item place &rest keys)
  "Add ITEM to the list PLACE, replacing any existing matching item.
Specifically, any item in the list satisfying the test are removed
\(nondestructively), and then the new ITEM is added to the front.

Evaluation order for the keywords is a bit screwy: don't rely on it."
  (cond ((fboundp 'cl-callf2)
	 `(cl-callf2 mdw-cons-replace ,item ,place ,@keys))
	((fboundp 'cl-setf-do-modify)
	 ;; `cl-setf-do-modify' returns a list (LETS STORE FETCH).
	 (let ((setf-things (cl-setf-do-modify place (cons 'list keys))))
	   `(let (,@(car setf-things))
	      ,(cl-setf-do-store (cadr setf-things)
				 `(mdw-cons-replace ,item ,place
						    ,@keys)))))
	(t (error "Don't know how to hack places on this Emacs."))))

(defun mdw-define-bot-greeting (server bot greeting)
  "Define a new bot greeting."
  (mdw-pushnew-replace (list server bot greeting)
		       mdw-erc-auto-greet-bots-alist
		       :test #'string= :key #'car))
(defun mdw-add-ircop-credentials (server acct passwd)
  "Define a new set of `ircop' credentials."
  (mdw-pushnew-replace (list server acct passwd)
		       mdw-erc-ircop-alist
		       :test #'string= :key #'car))

(defun mdw-assoc-regexp (regexp alist)
  "Return the association in ALIST whose car matches REGEXP."
  (let ((answer nil))
    (dolist (l alist)
      (when (string-match (car l) regexp)
	(setq answer l)))
    answer))

(defun mdw-erc-auto-greet-bots (server nick)
  "Send greeting message to bots."
  (let ((a (mdw-assoc-regexp server mdw-erc-auto-greet-bots-alist)))
    (when a
      (let ((bot (cadr a))
	    (message (caddr a)))
	(erc-server-send (concat "PRIVMSG " bot " :" message))))))
(add-hook 'erc-after-connect 'mdw-erc-auto-greet-bots)

(defun erc-cmd-GREET ()
  "Send greeting messages, according to `mdw-erc-auto-greet-bots-alist'."
  (mdw-erc-auto-greet-bots erc-session-server (erc-current-nick)))

(defun erc-cmd-IRCOP ()
  "Claim `ircop' privileges."
  (let ((a (mdw-assoc-regexp erc-session-server mdw-erc-ircop-alist)))
    (when a
      (let ((acct (cadr a))
	    (passwd (caddr a)))
	(erc-server-send (concat "OPER " acct " " passwd))))))

(load "~/.erc-auth.el")
(load "~/.erc-local.el")