from .wrapper_util import threaded
import logging, traceback

class Event(object):
    def __init__(self):
        self.source = self

class Observable(object):
    """
    A simple publish-subscribe system.
    """

    def __init__(self, events = []):
        self.events: dict[str, list] = {}
        for event in events:
            self.register_event(event)
    
    def register_event(self, event):
        if(event not in self.events):
            self.events[event] = []
    
    def subscribe_event(self, event, callback):
        if(event not in self.events):
            self.register_event(event)
        self.events[event].append(callback)
    
    @threaded
    def fire_event(self, event, **kwargs):
        e = Event()
        e.source = self
        for k, v in kwargs.items():
            setattr(e, k, v)
        if(event in self.events):
            for fn in self.events[event]:
                self.call_observer(fn, e)
        else:
            logging.warning(f"Event {event} without callback")
    
    @threaded
    def call_observer(self, function, event):
        try:
            function(event)
        except Exception as ex:
            logging.exception(f'Error in event {event} to function {function.__name__}')