Command.py

from __future__ import annotations
from abc import ABC, abstractmethod


class Command(ABC):
    @abstractmethod
    def execute(self) -> None:
        pass


class SimpleCommand(Command):
    def __init__(self, payload: str) -> None:
        self._payload = payload

    def execute(self) -> None:
        print(f"SimpleCommand: Puedo hacer cosas simples como imprimir..."
              f"({self._payload})")


class ComplexCommand(Command):
    def __init__(self, receiver: Receiver, a: str, b: str) -> None:
        self._receiver = receiver
        self._a = a
        self._b = b

    def execute(self) -> None:
        print("ComplexCommand: Puedo hacer cosas complejas recibiendo objetos", end="")
        self._receiver.do_something(self._a)
        self._receiver.do_something_else(self._b)


class Receiver:
    def do_something(self, a: str) -> None:
        print(f"\nReceiver: Trabajando en ({a}.)", end="")

    def do_something_else(self, b: str) -> None:
        print(f"\nReceiver: Tambien trabajando en ({b}.)", end="")


class Invoker:
    _on_start = None
    _on_finish = None

    def set_on_start(self, command: Command):
        self._on_start = command

    def set_on_finish(self, command: Command):
        self._on_finish = command

    def do_something_important(self) -> None:
        print("Invoker: Apunto de empezar a recibir comandos")
        if isinstance(self._on_start, Command):
            self._on_start.execute()

        print("Invoker: ...Realizando una acción...")

        print("Invoker: Si no hay mas comandos deja de recibir comandos")
        if isinstance(self._on_finish, Command):
            self._on_finish.execute()


if __name__ == "__main__":
    invoker = Invoker()
    invoker.set_on_start(SimpleCommand("Di Hola!"))
    receiver = Receiver()
    invoker.set_on_finish(ComplexCommand(
        receiver, "Enviar correo", "Guardar reporte"))

    invoker.do_something_important()