package main

import (
	"log"
	"net"
	"time"
)

func main() {
	listenerAddr, err := net.ResolveTCPAddr("tcp4", ":6699")
	if err != nil {
		log.Fatalf("could not resolve listenAddr: %v", err)
	}

	listener, err := net.ListenTCP("tcp", listenerAddr)
	if err != nil {
		log.Fatalf("could not listen on address '%s': %v", listenerAddr.String(), err)
	}

	for {
		conn, err := listener.Accept()
		if err != nil {
			log.Printf("failed to accept new incoming connection: %v", err) // if logging facility has latency this will block
			continue
		}
		go connHandler(conn) // branch off into goroutine so we're not blocking
	}
}

func connHandler(conn net.Conn) {
	log.Printf("accepted new connection from: %s", conn.RemoteAddr().String())

	conn.SetReadDeadline(time.Now().Add(time.Second))

	for {

		buf := make([]byte, 128)
		bytesRead, err := conn.Read(buf)
		if err == nil && bytesRead > 0 {
			log.Printf("Incoming message over socket '%s': %s", conn.RemoteAddr().String(), string(buf))
		}

		_, err = conn.Write([]byte("1"))
		if err != nil {
			log.Printf("failed writing to connection '%s': %v", conn.RemoteAddr().String(), err)
			conn.Close()
			break
		}

		time.Sleep(time.Second)
	}

}