from __future__ import annotations

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from engine import Engine
    from entity import Entity


class Action:
    def perform(self, engine: Engine, entity: Entity) -> None:
        """Perform this action with the objects needed to determine its scope

        'engine' is the scope this action is being perfrmed in.

        'entity is the object performing the action.

        This method must be overridden by Action subclasses
        """
        raise NotImplementedError()

class EscapeAction(Action):
    def perform(self, engine: Engine, entity: Entity) -> None:
        raise SystemExit()

class MovementAction(Action):
    def __init__(self, dx: int, dy: int):
        super().__init__()

        self.dx = dx
        self.dy = dy

    def perform(self, engine: Engine, entity: Entity) -> None:
        dest_x = entity.x + self.dx
        dest_y = entity.y + self.dy

        if not engine.game_map.in_bounds(dest_x, dest_y):
            return  # Destination is out of bounds.
        if not engine.game_map.tiles["walkable"][dest_x, dest_y]:
            return  # Destination is blocked by a tile

        entity.move(self.dx, self.dy)