#lang racket

(require "os-big-bang.rkt")
(require "os-udp.rkt")

(define (counter server-socket)
  (os-big-bang 0
    (subscribe 'packet-handler
      (message-handlers current-counter
	[(udp-packet source (== server-socket) #"get")
	 (transition (+ current-counter 1)
	   (send-message
	    (udp-packet server-socket source
			(integer->integer-bytes current-counter 8 #f))))]))))

(define main
  (os-big-bang 'no-state
    (send-message `(request create-echo-socket (udp new 5678 65536)))
    (subscribe/fresh sub
      (message-handlers w
	[`(reply create-echo-socket ,server-socket)
	 (transition w
	   (unsubscribe sub)
	   (spawn (counter server-socket)))]))))

(ground-vm
 (os-big-bang 'none
   (spawn udp-driver)
   (spawn main)))