"""Base classes for states."""

from __future__ import annotations

from typing import Protocol, TypeAlias

import attrs

import tcod.console

import tcod.event

class State(Protocol):

"""An abstract game state."""

__slots__ = ()

def on_event(self, event: tcod.event.Event) -> StateResult:

"""Called on events."""

def on_draw(self, console: tcod.console.Console) -> None:

"""Called when the state is being drawn."""

@attrs.define()

class Push:

"""Push a new state on top of the stack."""

state: State

@attrs.define()

class Pop:

"""Remove the current state from the stack."""

@attrs.define()

class Reset:

"""Replace the entire stack with a new state."""

state: State

StateResult: TypeAlias = "Push | Pop | Reset | None"

"""Union of state results."""