client.py

import socket
import threading
import os
import random


UDP_MAX_SIZE = 65535


COMMANDS=('/members',
'/connect',
'/exit',
'/help')

HELP_TEXT=""" 
/members- get active members
/connect <clientXXXX> -connect to member
/exit - disconnect from client"""


def listen(s: socket.socket, host:str , port: int):
    while True:
        msg,addr = s.recvfrom(UDP_MAX_SIZE)
        msg_port= addr[-1]
        msg= msg.decode('ascii')
        allowed_ports=threading.current_thread().allowed_ports
        if msg_port not in allowed_ports:
            continue

        if not msg:
            continue

        if '__' in msg:
            command, content = msg.split('__')
            if command =='members':
                for n, member in enumerate(content.split(';'), start=1):
                    print('\r\r' + f'{n}) {member}'+ '\n' + 'you: ', end='')
        else:
            peer_name=f'client{msg_port}'
            print('\r\r' + f'{peer_name}: ' + msg + '\n' + f'you: ', end='')


def start_listen(target,socket,host,port):
    th=threading.Thread(target=target,args=(socket,host,port),daemon=True)
    th.start()
    return th




def connect(host: str = '127.0.0.1', port: int = 8891):
    own_port=random.randint(8001,9000)
    s=socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    s.bind((host, own_port))

    listen_thread=start_listen(listen,s,host,port)
    allowed_ports =[port]
    listen_thread.allowed_ports=allowed_ports
    sendto=(host,port)
    s.sendto('__join'.encode('ascii'),sendto)

    while True:
        msg = input(f'you: ')

        command=msg.split(' ')[0]
        if command in COMMANDS:
            if msg=='/members':
                s.sendto('__members'.encode('ascii'),sendto)
            
            if msg=='/exit':
                peer_port=sendto[-1]
                allowed_ports.remove(peer_port)
                sendto=(host,port)
                print(f'Disconnect from client{peer_port}')

            if msg.startswith('/connect'):
                peer=msg.split(' ')[-1]
                peer_port=int(peer.replace('client', ''))
                allowed_ports.append(peer_port)
                sendto=(host,peer_port)
                print(f'Connect to client{peer_port}')

            if msg == '/help':
               print(HELP_TEXT)
        else:
            s.sendto(msg.encode('ascii'),sendto)

if __name__ == '__main__':
    os.system('clear')
    print('Welcome to chat!')
    connect()