#lang racket/base

(require racket/match)

(require "os2.rkt")
(require (prefix-in base: "os2-tcp.rkt"))

(provide (rename-out [base:tcp-driver tcp-driver])
	 (rename-out [base:tcp-spy tcp-spy])

	 tcp-listener
	 topic->tcp-connection

	 (rename-out [base:tcp-channel tcp-channel])
	 (rename-out [base:tcp-credit tcp-credit])
	 (rename-out [base:tcp-mode tcp-mode]))

;; Returns a topic that can be subscribed to in order to be told about
;; conversations coming and going relating to TCP connections arriving
;; at a local server socket. The server socket is created implicitly
;; as the result of subscribing to this topic.
(define (tcp-listener port)
  (topic-subscriber (base:tcp-channel (wild) (base:tcp-listener port) (wild))
		    #:monitor? #t))

;; Given the topic of a newly-arriving connection, creates helper
;; functions that create communication requests relating to that
;; connection, and also creates topics useful for hearing
;; communications relating to that connection.
(define (topic->tcp-connection new-topic)
  (match-define (topic _ (base:tcp-channel remote-addr local-addr _) _) new-topic)
  (define (cin feedback) (send-feedback (base:tcp-channel remote-addr local-addr feedback)))
  (define (cout data) (send-message (base:tcp-channel local-addr remote-addr data)))
  (define in-topic (topic-subscriber (base:tcp-channel remote-addr local-addr (wild))))
  (define out-topic (topic-publisher (base:tcp-channel local-addr remote-addr (wild))))
  (values cin cout in-topic out-topic))