#!/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
#   Docker:     Žiga Kralj, S50ZK
#   GUI:        Žiga Kralj, S50ZK
#
######################################################

from socket import (
    socket,
    AF_INET,
    SOCK_STREAM,
    SOCK_DGRAM,
    IPPROTO_UDP,
    SOL_SOCKET,
    SO_BROADCAST,
)
from select import select

def connect_proxy(server, 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")
            return 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...")
            return 0
        

if __name__ == "__main__":
    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"))
        
    sys.exit(connect_proxy(SERVER, PORT))