#!/usr/bin/guile
!#

(use-modules (ice-9 rdelim)
             (ice-9 textual-ports)
             (ice-9 format))

(define +channels+ '("#tildetown" "#bots"))

(define (scdr lst)
  "Safe CDR. Returns CDR of lst, if it is a list. Returns lst otherwise."
  (if (not (pair? lst))
      lst
      (cdr lst)))

(define (scar lst)
  "Safe CAR, see scdr."
  (if (not (pair? lst))
      lst
      (car lst)))

(define (slist-ref lst index)
  "Safe list-ref, see scdr."
  (if (< (length lst) (+ index 1))
      '()
      (list-ref lst index)))

(define (slist-tail lst index)
  "Safe list-tail, see scdr."
  (if (< (length lst) (+ index 1))
      '()
      (list-tail lst index)))

(define (string-tail str index)
  "List-tail for strings."
  (list->string (list-tail (string->list str) index)))

(define (intersperse sep lst)
  "Returns a new list with sep between each element of lst."
  (cond
   ((or (null? lst)
        (null? (cdr lst))) lst)
   (else (cons (car lst)
               (cons sep
                     (intersperse sep (cdr lst)))))))

(define (make-connection host port)
  "Connect to irc server on host:port, returns a socket for reading and writing."
  (let* ((sock (socket PF_INET SOCK_STREAM 0))
         (con (connect sock
                       AF_INET
                       (car (vector-ref (gethost host) 4))
                       port)))
    sock))

(define (pong stream)
  (format stream "PONG :anna\r\n"))

(define (send-nick stream)
  (format stream "NICK anna\r\n"))

(define (send-user stream)
  (format stream "USER anna 0.0.0.0 anna :Anna\r\n"))

(define (join-channels stream)
  (for-each (lambda (chn)
              (format stream "JOIN ~a\r\n" chn))
            +channels+))


(define (send-message stream chn msg)
  (format stream "PRIVMSG ~a :~a\r\n" chn msg))

(define (send-action stream chn action)
  (format stream "PRIVMSG ~a :\x01ACTION ~a\x01\r\n" chn action))

(define (main-loop stream)
  (let* ((inl (read-line stream))
         (data (string-tokenize inl))
         (chn (scar (scdr (member "PRIVMSG" data)))))
    ;; debug print
    (format #t "~s~%" data)
    (cond
     ((equal? (car data) "PING")
      (pong stream))
     ((or (equal? ":!rollcall" (slist-ref data 3))
          (equal? ":!anna" (slist-ref data 3)))
      (send-message stream chn "Hello! I respond to !rollcall, !anna, and !eval <s-expr>."))
     ((equal? ":!eval" (slist-ref data 3))
      (let* ((expr (string-concatenate (intersperse " " (cdr (member ":!eval" data))))))
        (send-message stream chn (eval (read (open-input-string expr))
                                             (interaction-environment)))))
     ((and (= 7 (length data))
           (equal? (list-tail data 4) '("ACTION" "shoots" "anna")))
      (send-action stream chn "dies")
      (close-port stream)
      (exit)))
    (main-loop stream)))

(let* ((io (make-connection "127.0.0.1" 6667)))
  (send-nick io)
  (send-user io)
  (join-channels io)

  (main-loop io))