mediator.py

"""
https://www.djangospin.com/design-patterns-python/mediator/

Objects in a system communicate through a Mediator instead of directly with each other.
This reduces the dependencies between communicating objects, thereby reducing coupling.

*TL;DR
Encapsulates how a set of objects interact.
"""

from __future__ import annotations


class ChatRoom:
    """Mediator class"""

    def display_message(self, user: User, message: str) -> None:
        print(f"[{user} says]: {message}")


class User:
    """A class whose instances want to interact with each other"""

    def __init__(self, name: str) -> None:
        self.name = name
        self.chat_room = ChatRoom()

    def say(self, message: str) -> None:
        self.chat_room.display_message(self, message)

    def __str__(self) -> str:
        return self.name


def main():
    """
    >>> molly = User('Molly')
    >>> mark = User('Mark')
    >>> ethan = User('Ethan')

    >>> molly.say("Hi Team! Meeting at 3 PM today.")
    [Molly says]: Hi Team! Meeting at 3 PM today.
    >>> mark.say("Roger that!")
    [Mark says]: Roger that!
    >>> ethan.say("Alright.")
    [Ethan says]: Alright.
    """


if __name__ == "__main__":
    import doctest

    doctest.testmod()