#!/usr/bin/env python3
"""stdin/stdout <-> TCP relay: the SUT executable an ETSI adapter forks inside WSL, forwarding
the hex-line protocol to sut_bridge.py --listen on the Windows side (which owns the COM port).

  run_etsi.py ... --sut /usr/bin/python3 --sut-args "/root/sut_tcp_relay.py --connect 172.x.x.x:7788"
"""
import argparse
import socket
import sys


def main():
    p = argparse.ArgumentParser(description=__doc__)
    p.add_argument('--connect', required=True, help='host:port of sut_bridge.py --listen')
    args = p.parse_args()
    host, port = args.connect.rsplit(':', 1)
    with socket.create_connection((host, int(port))) as connection:
        reader = connection.makefile('rb')
        for line in sys.stdin:
            line = line.strip()
            if not line:
                continue
            connection.sendall(line.encode() + b'\n')
            reply = reader.readline()
            if not reply:
                sys.exit(2)
            sys.stdout.write(reply.decode().strip() + '\n')
            sys.stdout.flush()


if __name__ == '__main__':
    main()