voice_calling_server.py

import socket
import threading

# === Configuration ===
PORT = 50008
CHUNK_SIZE = 1024 * 2

# === Server Setup ===
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.bind(("0.0.0.0", PORT))
print(f"[SERVER] Voice relay server started on port {PORT}")

# === Shared State ===
clients = {}            # name -> (ip, port)
call_map = {}           # caller -> target
connected_pairs = set() # (caller, target) pairs with both clients registered

lock = threading.Lock()

# === Main Handler Loop ===
def handle_client():
    while True:
        try:
            data, addr = sock.recvfrom(4096)
            print(f"[SERVER] Packet received from {addr}")

            # === Registration Message ===
            if data.startswith(b"REGISTER:"):
                try:
                    message = data.decode('utf-8')
                    print(f"[SERVER] Registration message received: {message}")

                    parts = message.strip().split(":")
                    if len(parts) < 3:
                        print("[SERVER] Invalid registration format")
                        continue

                    name = parts[1]
                    target = parts[2]

                    with lock:
                        clients[name] = addr
                        call_map[name] = target
                        print(f"[SERVER] Registered client '{name}' at {addr} wants to call '{target}'")

                        # Check if target already registered
                        if target in clients:
                            print(f"[SERVER] Target '{target}' is online.")
                            connected_pairs.add((name, target))
                            if call_map.get(target) == name:
                                connected_pairs.add((target, name))
                                print(f"[SERVER] Bi-directional call ready between '{name}' and '{target}'")
                        else:
                            print(f"[SERVER] Target '{target}' not yet online.")

                except Exception as e:
                    print(f"[SERVER] Error during registration: {e}")

            # === Audio Packet ===
            else:
                sender_name = None
                with lock:
                    for name, client_addr in clients.items():
                        if client_addr == addr:
                            sender_name = name
                            break

                if sender_name is None:
                    print("[SERVER] Sender not recognized. Ignoring packet.")
                    continue

                with lock:
                    target_name = call_map.get(sender_name)
                    if not target_name:
                        print(f"[SERVER] No target set for '{sender_name}'")
                        continue

                    # Check if the connection is active
                    if (sender_name, target_name) in connected_pairs:
                        target_addr = clients.get(target_name)
                        if target_addr:
                            sock.sendto(data, target_addr)
                            print(f"[SERVER] Forwarded audio from '{sender_name}' to '{target_name}'")
                        else:
                            print(f"[SERVER] Target '{target_name}' address not found.")
                    else:
                        print(f"[SERVER] '{sender_name}' is waiting for '{target_name}' to come online.")

        except Exception as e:
            print(f"[SERVER] General error: {e}")

# === Start Server ===
handle_client()