import datetime
import socket
import sys
from typing import Optional

from utils import mac_address, broadcast_address


class Frame:

    def __init__(self,
                 destination: bytes,
                 protocol: bytes,
                 message: str,
                 source: bytes = mac_address):
        self.destination: bytes = destination
        self.source: bytes = source
        self.protocol: bytes = protocol
        self.message: str = message


def decode_packet(packet_bytes: bytes) -> Optional[Frame]:
    protocol: bytes = packet_bytes[12:14]

    if protocol != b"\x60\x00":
        return None

    try:
        destination = packet_bytes[0:6]
        source = packet_bytes[6:12]
        message = packet_bytes[14:].decode("utf-8").rstrip("\x00")
        return Frame(destination=destination,
                     source=source,
                     protocol=protocol,
                     message=message)
    except:
        # print("[Error] Could not decode message.")
        return None


if __name__ == "__main__":

    print("Starting listener...")
    sys.stdout.flush()

    connection = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.ntohs(3))

    while True:
        byte_string, addr = connection.recvfrom(65536)

        frame = decode_packet(byte_string)

        if frame is not None \
                and (frame.destination == mac_address or frame.destination == broadcast_address):
            dt_string = datetime.datetime.now().strftime("%d/%m/%Y %H:%M:%S")
            print("----")
            print("Revcd from {} to {} @{}".format(frame.source, frame.destination, dt_string))

            if frame.message == "ZeusWPI is de max!":
                print("Congratulations, packet received correctly!")
            else:
                print("Wrong message, please check that you are sending \"ZeusWPI is de max!\"")

        sys.stdout.flush()