;;
;; Copyright 2022, Jaidyn Levesque <jadedctrl@posteo.at>
;;
;; 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 program. If not, see <https://www.gnu.org/licenses/>.
;;

(import scheme
		(chicken file) (chicken file posix) (chicken io) (chicken keyword)
		(chicken pretty-print) (chicken process-context)
		(chicken process-context posix) (chicken string)
		srfi-1 srfi-13 srfi-69 srfi-180
		ircc
		getopt-long)


;; Write a to-be-JSON alist to the appropriate output
(define (chatd-json-write conn alist)
  (let* ([configured-output? (hash-table-exists? conn 'output)]
		 [output (if configured-output?
					 (open-output-file (hash-table-ref conn 'output))
					 (open-output-file* fileno/stdout))])
	(json-write alist output)
	(write-string "\n" #f output)
	(if configured-output?
		(close-output-port output))))


;; Return a user-info in chatd-friendly alist-format, by its alist
(define (user-alist conn nick)
  (let* ([ircc-alist (irc:user-alist conn nick)]
		 [hostmask (alist-ref 'hostmask ircc-alist)])
	(if (not hostmask)
		(list (cons 'name nick))
		(list (cons 'name nick)
			  (cons 'id (irc:hostmask-userhost hostmask))))))


;; Return an IRC room in chatd-amicable alist-format, using its hashtable
(define (channel-alist conn channel)
  (let ([channel-table (irc:channel-table conn channel)])
	(filter
	 (lambda (item) item)
	 (list
	  (cons 'id channel)
	  (cons 'name channel)
	  (cons 'topic (if (hash-table-exists? channel-table 'topic)
					   (hash-table-ref channel-table 'topic)
					   #f))
	  (cons 'users
			(map
			 (lambda (nick)
			   (cons 'user (user-alist conn nick)))
			 (hash-table-ref channel-table 'users)))))))


;; Returns a channel's chatd-friendly alist format, but solely with ID
(define (channel-alist-short conn channel)
  (list
   (cons 'id channel)
   (cons 'name channel)))


;; Used for creating chatd-format messages
;; The optional args are key-value pairs, as follows:
;; #:text #:id #:user #:channel #:long-channel #:additional
(define (compose-event-alist conn event . args)
  (let ([text (get-keyword #:text args)]
		[user (get-keyword #:user args)]
		[channel (get-keyword #:channel args)]
		[additional (get-keyword #:additional args)])
  (filter
   (lambda (item) (not (eq? #f item)))
;;	(if additional additional list)
	(list (cons 'event event)
;;		  (if additional additional #f)
		  (if text
			  (cons 'content
					(list (cons 'type "plain/text")
						  (cons 'body text)))
			  #f)
		  (if user
			  (cons 'user (user-alist conn user))
			  #f)
		  (if channel
			  (if (get-keyword #:long-channel args)
				   (cons 'channel (channel-alist conn channel))
				   (cons 'channel (channel-alist-short conn channel)))
			  #f)))))


;; Hook function for irc:loop; handles all IRC commands
(define (on-command conn cmd params #!optional sender)
  (cond
   [(and (string=? cmd "PRIVMSG")
		 (string? sender)
		 (irc:hostmask? sender))
	(let ([target (if (irc:user-is-self? conn (car params))
					  (irc:hostmask-nick sender)
					  (car params))])
	  (chatd-json-write conn
	   (compose-event-alist conn "message" #:channel target
							#:text (last params) #:user (irc:hostmask-nick sender))))]

   [(or (string=? cmd "NOTICE")
		(and (string=? cmd "PRIVMSG")
			 (or (string-null? sender) (not (irc:hostmask? sender)))))
	(chatd-json-write conn
	  (compose-event-alist conn "server-message"
						   #:text (last params)))]

   [(string=? cmd "JOIN")
	(chatd-json-write conn
	 (compose-event-alist conn "room-join" #:channel (car params)
						  #:user (irc:hostmask-nick sender)))]
   [(string=? cmd "NICK")
	(chatd-json-write conn
	 (compose-event-alist conn "user-info" #:user (last params)))])
)



;; Hook function for irc:loop; handles all IRC errors and replies
(define (on-reply conn reply params #!optional sender)
  (cond
      [(eq? reply RPL_WELCOME)
	   (irc:write-cmd conn "JOIN" "#thevoid")]

	  ;; After receiving a user-list or topic update, tell the user!
	  [(let ([channel (second params)])
		 (and (irc:channel? channel)
			  (or (eq? reply RPL_TOPIC)
				  (eq? reply RPL_TOPICWHOTIME)
				  (and (irc:capability? conn 'userhost-in-names)
					   (eq? reply RPL_ENDOFNAMES))
				  (eq? reply RPL_ENDOFWHO))))
	   (chatd-json-write conn
		(compose-event-alist conn "room-info" #:channel (second params) #:long-channel #t))])
  (chatd-json-write conn
   (compose-event-alist conn "server-message" #:text (last params))))


(define *help-msg*
  (string-append
   "usage: irc-chatd [-h] [-n nick] [-u user] [-p password] hostname\n\n"
   "`chatd` is a standard format for chat client-daemons; the goal being that a\n"
   "chat client should be able to work with any chat protocol (IRC, XMPP, etc)\n"
   "just by reading and writing to files served by a `chatd` daemon, without\n"
   "having to worry about the protocol in use.\n\n"
   "irc-chatd is a `chatd`-compliant IRC client-daemon, that outputs all messages\n"
   "from the server in parseable format to an output file, and receives input\n"
   "from a FIFO File.\n".))


(define *opts*
  '((help
	 "Print a usage message"
	 (single-char #\h))
	(nickname
	 "Your preferred nickname. Default is your system username."
	 (single-char #\n)
	 (value (required NICK)))
	(username
	 "Username of the connection. Default is your system username."
	 (single-char #\u)
	 (value (required USERNAME)))
	(password
	 "The password optionally used in connection."
	 (single-char #\p)
	 (value (required PASSWORD)))
	(name
	 "Set the realname of your connection."
	 (value (required NAME)))
	(output
	 "Output path for messages. Defaults to standard output."
	 (single-char #\o)
	 (value (required PATH)))))


;; Prints cli usage to stderr.
(define (help)
  (write-string *help-msg* #f (open-output-file* fileno/stderr))
  (write-string (usage *opts*) #f (open-output-file* fileno/stderr))
  (exit 1))


;; The `main` procedure that should be called to run feedsnake-unix for use as script.
(define (main)
  (let* ([args (getopt-long (command-line-arguments) *opts*)]
		 [free-args (alist-ref '@ args)])
	(if (or (null? free-args) (alist-ref 'help args))
		(help))

	(let*
		([username (or (alist-ref 'username args)
					   (current-effective-user-name))]
		 [password (alist-ref 'password args)]
		 [nickname (or (alist-ref 'nickname args)
					   (current-effective-user-name))]
		 [fullname (alist-ref 'name args)]
		 [server (last free-args)]
		 [hostname (first (string-split server ":"))]
		 [port (or (string->number (last (string-split server ":")))
				   6697)]
		 [output (alist-ref 'output args)]
		 [connection (if server
						 (irc:connect server port username nickname password fullname)
						 #f)])

	  (unless connection
		(help))

	  (if output
		  (hash-table-set! connection 'output output))

	  (irc:loop connection
				on-command
				on-reply))))


(main)