simpleclient.py

#!/usr/bin/python3

import socket
import threading

SERVER_IP = '::1'     # Change if server is on another machine
SERVER_PORT = 1999
USERNAME = input("Enter your username: ")

client_socket = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
client_socket.settimeout(2)

response_received = threading.Event()

# Send JOIN request
join_msg = f"JOIN {USERNAME}"
client_socket.sendto(join_msg.encode('utf-8'), (SERVER_IP, SERVER_PORT))

def listen():
    while True:
        try:
            data, addr = client_socket.recvfrom(1024)
            print("\n" + data.decode('utf-8'))
            response_received.set()
        except socket.timeout:
            continue

threading.Thread(target=listen, daemon=True).start()

# Message loop
while True:

    response_received.wait()
    
    sendToFriend = str(input("Do you want to send a msg to a friend Y/N:"))
    
    response_received.clear()
    if (sendToFriend == "Y"):
        to_user = input("\nSend to: ")
        message = input("Message: ")
        msg = f"MSG {to_user} {message}"
    else:
        msg = input()
    client_socket.sendto(msg.encode('utf-8'), (SERVER_IP, SERVER_PORT))