;;; lirc.el --- Lambdalabs irc client  -*- lexical-binding:t -*-

;; Copyright (C) 2021 Tim Vaughan

;; Author: Tim Vaughan <timv@ughan.xyz>
;; Created: 14 June 2021
;; Version: 1.0
;; Keywords: network
;; Homepage: http://thelambdalab.xyz/erc
;; Package-Requires: ((emacs "26"))

;; This file is not part of GNU Emacs.

;; This program is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this file.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

(provide 'lerc)

;;; Customizations
;;

(defgroup lirc nil
  "Lightweight IRC client."
  :group 'network)

(defcustom lirc-nick "plugd"
  "Default nick.")
(defcustom lirc-full-name "plugd"
  "Default full name.")
(defcustom lirc-user-name "plugd"
  "Default user name.")
(defcustom lirc-host "localhost"
  "Default server.")
(defcustom lirc-port 6667
  "Default port.")

(defcustom lirc-prompt "> "
  "Prompt.")

(defvar lirc-response "")

(defun lirc-filter (proc string)
  (dolist (line (split-string (concat lirc-response string) "\n"))
    (if (string-suffix-p "\r" line)
        (lirc-process-msg-string (string-trim line))
      (setq lirc-response line))))

(defun lirc-get-process ()
  (let ((proc (get-process "lirc")))
    (if (and proc (eq (process-status proc) 'open))
        proc
      (make-network-process :name "lirc"
                            :host lirc-host
                            :service lirc-port
                            :filter #'lirc-filter
                            :nowait t
                            :buffer "*lirc*"))))

(defun lirc-as-string (obj)
  (if obj
      (with-output-to-string (princ obj))
    nil))

(defun lirc-msg (tags src cmd &rest params)
  (list (lirc-as-string tags)
        (lirc-as-string src)
        (upcase (lirc-as-string cmd))
        (mapcar #'lirc-as-string params)))

(defun lirc-msg-tags (msg) (elt msg 0))
(defun lirc-msg-src (msg) (elt msg 1))
(defun lirc-msg-cmd (msg) (elt msg 2))
(defun lirc-msg-params (msg) (elt msg 3))

(defvar lirc-msg-regex
  (rx
   (opt (: "@" (group (* (not (or "\n" "\r" ";" " ")))))
        (* whitespace))
   (opt (: ":" (group (* (not (or "\n" "\r" " ")))))
        (* whitespace))
   (group (: (* (not whitespace))))
   (* whitespace)
   (opt (group (+ not-newline)))))

(defun lirc-string->msg (string)
  (if (string-match lirc-msg-regex string)
      (let* ((tags (match-string 1 string))
             (src (match-string 2 string))
             (cmd (upcase (match-string 3 string)))
             (params-str (match-string 4 string))
             (params
              (if params-str
                  (let* ((idx (cl-search ":" params-str))
                         (l (split-string (string-trim (substring params-str 0 idx))))
                         (r (if idx (list (substring params-str (+ 1 idx))) nil)))
                    (append l r))
                nil)))
        (apply #'lirc-msg (append (list tags src cmd) params)))
    (error "Failed to parse string " string)))

(defun lirc-msg->string (msg)
  (let ((tags (lirc-msg-tags msg))
        (src (lirc-msg-src msg))
        (cmd (lirc-msg-cmd msg))
        (params (lirc-msg-params msg)))
    (concat
     (if tags (concat "@" tags " ") "")
     (if src (concat ":" src " ") "")
     cmd " "
     (if (> (length params) 1)
         (string-join (seq-take params (- (length params) 1)) " ")
       "")
     (if (> (length params) 0)
         (concat " :" (elt params (- (length params) 1)))))))

(defun lirc-display-string (string)
  (with-current-buffer "*lirc*"
    (let ((inhibit-read-only t))
      (save-excursion
        (goto-char (point-max))
        (insert string "\n")))))

(defun lirc-process-msg-string (string)
  (let ((msg (lirc-string->msg string)))
    (cond
     ((equal (lirc-msg-cmd msg) "PING")
      (lirc-send-msg
       (lirc-msg nil nil "PONG" (lirc-msg-params msg))))
     (t
      (lirc-display-string (lirc-msg->string msg))))))

(defun lirc-connect ()
  (lirc-send-msg (lirc-msg nil nil "USER" lirc-user-name 0 "*" lirc-full-name))
  (lirc-send-msg (lirc-msg nil nil "NICK" lirc-nick)))

(defun lirc-send-msg (msg)
  (let ((proc (lirc-get-process)))
    (process-send-string proc (concat (lirc-msg->string msg) "\r\n"))))
  

(defun lirc ()
  "Switch to *lirc* buffer."
  (interactive)
  (pop-to-buffer-same-window "*lirc*")
  (lirc-mode)
  (lirc-connect))

(define-derived-mode lirc-mode text-mode "lirc"
  "Major mode for LIRC.")


;;; lirc.el ends here
:bs-mbpr348.d.ethz.ch