#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-timer.rkt")
(require "os2-tcp.rkt")

(define ((connection-handler local-addr remote-addr) self-pid)
  (define (reader-role)
    (role 'echoer (topic-subscriber (tcp-channel remote-addr local-addr (wild)))
      #:state state
      [(tcp-channel remote _ (? bytes? bs))
       (transition state
	 (send-tcp-credit remote-addr local-addr 16)
	 (send-message (tcp-channel local-addr remote-addr bs)))]
      [(tcp-channel remote _ (? eof-object?))
       (transition state
	 (kill))]))

  (transition 'no-state
    (send-tcp-credit remote-addr local-addr 16)
    (reader-role)))

(define (listener local-addr)
  (transition 'no-state
    (role 'inbound-handler (topic-subscriber (tcp-channel (wild) local-addr (wild)) #:monitor? #t)
      #:state state
      #:topic t
      #:on-presence (match t
		      [(topic 'publisher (tcp-channel remote-addr (== local-addr) _) #f)
		       (transition state (spawn (connection-handler local-addr remote-addr)))]))))

(define (main port)
  (define (arm-timer)
    (role 'waiter (topic-subscriber (timer-expired (wild) (wild)))
      #:state state
      #:on-presence (transition state (send-message (set-timer 'label 500 'relative)))
      [(timer-expired _ _)
       (transition state (delete-role 'waiter) (arm-timer))]))
  (ground-vm
   (transition 'none
     (spawn tcp-spy)
     (spawn tcp-driver)
     (spawn timer-driver)
     (arm-timer)
     (spawn (listener (tcp-listener port))))))

(main 5999)