import socket

def run_tcp_server():
    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    server.bind(("0.0.0.0", 10000))
    server.listen(1)
    print("TCP server started on port 10000")
    print("Waiting for connections...")

    try:
        while True:
            conn, addr = server.accept()
            print(f"Connection from {addr}")
            
            with conn:
                while True:
                    data = conn.recv(1024)
                    if not data:
                        break
                    
                    message = data.decode().strip()
                    print(f"Received: '{message}'")
                    
                    if message.upper() == 'EXIT':
                        conn.sendall(b"Server shutting down...")
                        print("Received EXIT command, shutting down")
                        return
                    
                    modified_message = f"ECHO: {message.upper()}"
                    conn.sendall(modified_message.encode())
                    print(f"Sent response: '{modified_message}'")
                    
    except KeyboardInterrupt:
        print("\nServer stopped by user")
    finally:
        server.close()
        print("Server socket closed")

if __name__ == "__main__":
    run_tcp_server()