import json
import socket

def is_cone_napt(dest1, dest2, timeout=2):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.settimeout(timeout)
    sock.bind(("", 0))

    try:
        sock.sendto("judge_napt_type", dest1)
        data1, _ = sock.recvfrom(1024)
        sock.sendto("judge_napt_type", dest2)
        data2, _ = sock.recvfrom(1024)

        ip1, port1 = data1.split(":")
        ip2, port2 = data2.split(":")
        return ip1 == ip2 and int(port1) == int(port2)
    finally:
        sock.close()

def main():
    Server1 = "timd.cn", 8082
    Server2 = "timd.cn", 8083
    P2P_Server = "timd.cn", 8081
    MYNAME = "ClientB"

    can_make_hole = is_cone_napt(Server1, Server2)
    if not can_make_hole:
        raise RuntimeError("can't make hole")

    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

    try:
        sock.sendto(json.dumps({"op": "register",
            "name": MYNAME}), P2P_Server)
        data, _ = sock.recvfrom(1024)
        result = json.loads(data)
        if result["code"] != 0:
            raise RuntimeError("register failed")

        count = 1
        while True:
            data, addr = sock.recvfrom(1024)
            request = json.loads(data)
            op = request["op"]

            if op == "prepare":
                peer = tuple(request["peer"])
                sock.sendto(json.dumps({"op": "make_hole_for_you"}), peer)
                sock.sendto(json.dumps({"op": "prepare_ok",
                    "peer": peer}), P2P_Server)
            elif op == "get_data":
                print("%s:%d is getting data" % addr)
                sock.sendto(json.dumps({"code": 0,
                    "data": "%d. data from %s" % (count, MYNAME)}), addr)
                count = count + 1
    finally:
        sock.close()


if __name__ == "__main__":
    main()