#!/usr/bin/python3

######################################################
#   FlexRadio discovery Proxy CLIENT
######################################################
#
#   This script connects to the FlexRadio discovery
#   proxy and re-broadcasts all received packets.
#
#   Author:     Jakob Kordež, S52KJ
#
######################################################

from socket import (
    socket,
    AF_INET,
    SOCK_STREAM,
    SOCK_DGRAM,
    IPPROTO_UDP,
    SOL_SOCKET,
    SO_BROADCAST,
)
from select import select
import sys
from argparse import ArgumentParser
import re

SERVER = "localhost"
PORT = 4996


# Argument parsing
serverRegex = r"^(?P<host>[^:]+)(:(?P<port>\d+))?$"

parser = ArgumentParser(
    prog="FlexRadio discovery proxy client",
    description="Connect to a FlexRadio discovery proxy and re-broadcast all received packets",
    epilog="Author: Jakob Kordež, S52KJ",
)
parser.add_argument(
    "server",
    metavar="SERVER",
    type=str,
    nargs="?",
    default=SERVER,
    help="Server address (default: %(default)s)",
)

args = parser.parse_args()
sp = re.fullmatch(serverRegex, args.server)
if not sp:
    print("Invalid server address")
    sys.exit(1)

SERVER = sp.group("host")
if sp.group("port"):
    PORT = int(sp.group("port"))


# Create broadcast socket
broadcastSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)
broadcastSocket.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)


# Connect to TCP server
with socket(AF_INET, SOCK_STREAM) as s:
    s.settimeout(5)
    print("Connecting to server...", (SERVER, PORT))

    # Try to connect to the server for 5 seconds
    try:
        s.connect((SERVER, PORT))
        print("Connected to server")
        print("\nPress Ctrl+C to exit...")
    except (ConnectionRefusedError, TimeoutError):
        print("Connection timed out")
        input("\nPress enter to exit...")
        sys.exit(1)

    s.setblocking(False)

    try:
        while True:
            r = select([s], [], [], 1)[0]
            if len(r) == 0:
                continue

            payload = s.recv(2048)
            if not payload:
                print("Server disconnected")
                break

            broadcastSocket.sendto(payload, ("255.255.255.255", 4992))
    except KeyboardInterrupt:
        print("\nExiting...")
        sys.exit(0)