#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from typing import Self, Callable, Any

class EventsManager:

    def __init__(self:Self) -> None:
        self.__events:list[Callable[[Any|None], Any|None]] = []

    def execute(self:Self, *arguments:tuple[Any|None, ...]) -> tuple[Any|None]:
        
        results:tuple[Any|None] = ()

        for event in self.__events:
            if event is not None:
                results += (event(*arguments),)

        return results

    def add(self:Self, 
        event:Callable[[Any|None], Any|None]
    ) -> int|None:
        
        i:int|None = None

        if callable(event):

            l:int = len(self.__events)

            i = 0
            while i < l and self.__events[i] is not None:
                i += 1

            if i < l:
                self.__events[i] = event
            else:
                self.__events.append(event)

        return i
    
    def remove(self:Self, i:int) -> bool:
        if 0 <= i < len(self.__events) and self.__events[i] is not None:
            self.__events[i] = None
            return True
        return False