going-rogue/erynrl/events.py

# Eryn Wells <eryn@erynwells.me>

'''Defines event handling mechanisms.'''

from typing import Optional, TYPE_CHECKING

import tcod

from . import log
from .actions.action import Action
from .actions.game import ExitAction, RegenerateRoomsAction, BumpAction, WaitAction
from .geometry import Direction, Point

if TYPE_CHECKING:
    from .engine import Engine


class EventHandler(tcod.event.EventDispatch[Action]):
    '''Abstract event handler class'''

    def __init__(self, engine: 'Engine'):
        super().__init__()
        self.engine = engine

    def handle_events(self, context: tcod.context.Context):
        '''Wait for events and handle them.'''
        for event in tcod.event.wait():
            context.convert_event(event)
            self.handle_event(event)

    def handle_event(self, event: tcod.event.Event):
        '''
        Handle an event by transforming it into an Action and processing it until it is completed. If the Action
        succeeds, also process actions from other Entities.

        Parameters
        ----------
        event : tcod.event.Event
            The event to handle
        '''
        action = self.dispatch(event)

        # Unhandled event. Ignore it.
        if not action:
            log.EVENTS.debug('Unhandled event: %s', event)
            return

        self.engine.process_input_action(action)

    def ev_quit(self, event: tcod.event.Quit) -> Optional[Action]:
        return ExitAction()


class MainGameEventHandler(EventHandler):
    '''
    Handler of `tcod` events for the main game.

    Receives input from the player and dispatches actions to the game engine to interat with the hero and other objects
    in the game.
    '''

    def ev_keydown(self, event: tcod.event.KeyDown) -> Optional[Action]:
        action: Optional[Action] = None

        hero = self.engine.hero

        is_shift_pressed = bool(event.mod & tcod.event.Modifier.SHIFT)

        sym = event.sym
        match sym:
            case tcod.event.KeySym.b:
                action = BumpAction(hero, Direction.SouthWest)
            case tcod.event.KeySym.h:
                action = BumpAction(hero, Direction.West)
            case tcod.event.KeySym.j:
                action = BumpAction(hero, Direction.South)
            case tcod.event.KeySym.k:
                action = BumpAction(hero, Direction.North)
            case tcod.event.KeySym.l:
                action = BumpAction(hero, Direction.East)
            case tcod.event.KeySym.n:
                action = BumpAction(hero, Direction.SouthEast)
            case tcod.event.KeySym.u:
                action = BumpAction(hero, Direction.NorthEast)
            case tcod.event.KeySym.y:
                action = BumpAction(hero, Direction.NorthWest)
            case tcod.event.KeySym.ESCAPE:
                action = ExitAction()
            case tcod.event.KeySym.SPACE:
                action = RegenerateRoomsAction()
            case tcod.event.KeySym.PERIOD:
                if not is_shift_pressed:
                    action = WaitAction(hero)

        return action

    def ev_mousemotion(self, event: tcod.event.MouseMotion) -> Optional[Action]:
        mouse_point = Point(event.tile.x, event.tile.y)
        if not self.engine.map.tile_is_in_bounds(mouse_point):
            mouse_point = None
        self.engine.update_mouse_point(mouse_point)


class GameOverEventHandler(EventHandler):
    '''When the game is over (the hero dies, the player quits, etc), this event handler takes over.'''

    def ev_keydown(self, event: tcod.event.KeyDown) -> Optional[Action]:
        action: Optional[Action] = None

        sym = event.sym
        match sym:
            case tcod.event.KeySym.ESCAPE:
                action = ExitAction()

        return action