server.py

import socket
import threading
import time
from rich import print
from rich.console import Console

HOST = "0.0.0.0"
PORT = 5555

clients = []      # list of client sockets
nicknames = []    # corresponding nicknames
lock = threading.Lock()
console = Console()

def broadcast(message, sender_socket=None):
    """Send message to all clients except the sender (optional)."""
    with lock:
        for client in clients[:]:
            if client != sender_socket:
                try:
                    client.send(message)
                except:
                    client.close()
                    remove_client(client)

def broadcast_userlist():
    """Send the current list of nicknames to all clients."""
    with lock:
        userlist = ",".join(nicknames)
        msg = f"##users##{userlist}".encode('utf-8')
        for client in clients:
            try:
                client.send(msg)
            except:
                client.close()
                remove_client(client)

def remove_client(client_socket):
    """Remove a dead client and notify others."""
    with lock:
        if client_socket in clients:
            idx = clients.index(client_socket)
            nick = nicknames[idx]
            clients.remove(client_socket)
            nicknames.pop(idx)
            console.print(f"[red]{nick} left the chat[/red]")
            broadcast(f"🔴 {nick} left the chat.".encode('utf-8'))
            broadcast_userlist()   # update everyone's user list

def handle_client(conn, addr):
    """Receive messages from one client."""
    try:
        nickname = conn.recv(1024).decode('utf-8').strip()
    except:
        conn.close()
        return

    with lock:
        clients.append(conn)
        nicknames.append(nickname)
    console.print(f"[green]{nickname} connected from {addr}[/green]")
    broadcast(f"🟢 {nickname} joined the chat.".encode('utf-8'))
    broadcast_userlist()   # send updated user list to everyone

    try:
        while True:
            data = conn.recv(1024)
            if not data:
                break
            message = data.decode('utf-8')
            console.print(f"[cyan]{nickname}:[/cyan] {message}")
            broadcast(f"{nickname}: {message}".encode('utf-8'), sender_socket=conn)
    except (ConnectionResetError, BrokenPipeError):
        pass
    finally:
        remove_client(conn)
        conn.close()

def main():
    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    server.bind((HOST, PORT))
    server.listen()
    console.print(f"[green]Server listening on {HOST}:{PORT}[/green]")

    try:
        while True:
            server.settimeout(1.0)
            try:
                conn, addr = server.accept()
                threading.Thread(target=handle_client, args=(conn, addr), daemon=True).start()
            except socket.timeout:
                continue
    except KeyboardInterrupt:
        console.print("\n[yellow]Shutting down server...[/yellow]")
    finally:
        with lock:
            for c in clients:
                c.close()
        server.close()
        console.print("[bold red]Server stopped[/bold red]")

if __name__ == "__main__":
    main()