#lang racket/base
;; A more different trivial example program demonstrating os2-tcp.rkt.

(require racket/string)
(require racket/set)
(require racket/match)
(require "os2.rkt")
(require "os2-tcp.rkt")

(define ((connection-handler local-addr remote-addr) self-pid)
  (transition 'no-state
    (send-tcp-mode remote-addr local-addr 'lines)
    (send-tcp-credit remote-addr local-addr 1)
    (role 'echoer (topic-subscriber (tcp-channel remote-addr local-addr (wild)))
      #:state state
      [(tcp-channel remote _ (? bytes? line))
       (transition state
	 (send-tcp-credit remote-addr local-addr 1)
	 (send-message
	  (tcp-channel local-addr remote-addr (bytes-append #"You said: " line #"\n"))))]
      [(tcp-channel remote _ (? eof-object?))
       (transition state
	 (kill))])))

(define (listener local-addr)
  (transition 'no-state
    (role 'inbound-handler (topic-subscriber (tcp-channel (wild) local-addr (wild)) #:virtual? #t)
      #:state state
      #:topic t
      #:on-presence (match t
		      [(topic 'publisher (tcp-channel remote-addr (== local-addr) _) #t)
		       ;; Ignore virtual flows. They just mean there's
		       ;; someone willing to supply connections to us
		       ;; at some point in the future.
		       state]
		      [(topic 'publisher (tcp-channel remote-addr (== local-addr) _) #f)
		       (transition state (spawn (connection-handler local-addr remote-addr)))]))))

(define (main port)
  (ground-vm
   (transition 'none
     (spawn tcp-spy)
     (spawn tcp-driver)
     (spawn (listener (tcp-listener port))))))

(main 5999)