from backend.events.schema import create_event
from backend.events.clock import GlobalClock


class EventBus:

    def __init__(self):
        self.subscribers = []

    def subscribe(self, fn):
        self.subscribers.append(fn)

    def emit(self, event_type, **kwargs):

        event = create_event(
            type=event_type,
            timestamp=GlobalClock.tick(),
            **kwargs
        )

        # fan-out to all listeners
        for sub in self.subscribers:
            sub(event)

        return event