import traceback
import typing
import warnings

from source import packets
from source.behaviors import events
from source.error import UntrustedPeerException
from source.managers import Manager


class EventManager:
    """
    Responsible for receiving packets from other peers and handling them.
    """

    def __init__(self, manager: "Manager"):
        self.manager = manager

        # events
        self.event_handlers: dict[typing.Type[packets.base.BasePacket], events.base.BaseEvent] = {}

    def register_event_handler(self, packet_type: typing.Type[packets.base.BasePacket], event: events.base.BaseEvent) -> None:
        """
        Register a new event to react to a specific packet type
        :param packet_type: the type of packet to listen to
        :param event: the event handler
        """

        self.event_handlers[packet_type] = event

    def handle(self, packet: packets.base.BasePacket, address: tuple) -> None:
        """
        Handle the packet received
        :param packet: the packet to handle
        :param address: the address of the machine that sent the packet
        """

        # get the event handler of this kind of packet
        event_handler = self.event_handlers.get(type(packet))
        if event_handler is None:
            raise KeyError(f"Unrecognised packet type: {type(packet)}. Has it been registered ?")

        # use the event handler on the packet
        event_handler.handle(packet, address)

    def loop(self) -> None:
        """
        Handle events forever
        """

        while True:
            try:
                # wait for a new packet
                packet, address = self.manager.communication.receive()
                print(f"Received message from {address}: {packet}")
                # give it to the event handler
                self.manager.event.handle(packet, address)

            except UntrustedPeerException:
                print("Ignored: untrusted peer.")

            except Exception:  # NOQA
                warnings.warn(traceback.format_exc())