# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
# All Rights Reserved. See LICENSE file for details.

from abc import ABC

from tfw.networking import Scope
from tfw.crypto import message_checksum

from .event_handler_base import EventHandlerBase


class BroadcastingEventHandler(EventHandlerBase, ABC):
    # pylint: disable=abstract-method
    """
    Abstract base class for EventHandlers which broadcast responses
    and intelligently ignore their own broadcasted messages they receive.
    """
    def __init__(self, key):
        super().__init__(key)
        self.own_message_hashes = []

    def event_handler_callback(self, message):
        message_hash = message_checksum(message)

        if message_hash in self.own_message_hashes:
            self.own_message_hashes.remove(message_hash)
            return

        response = self.dispatch_handling(message)
        if response:
            self.own_message_hashes.append(message_checksum(response))
            self.server_connector.send_message(response, Scope.BROADCAST)