bevy-expedition-demo/src/layout/stairs.rs

use bevy::{ecs::relationship::RelatedSpawner, prelude::*};
use bevy_rapier2d::prelude::*;

use crate::{meters, player::Player};

use super::*;

const STAIRS_SPRITE_PATH: &'static str = "sprites/interactive/stairs.png";

#[derive(Component, Debug, PartialEq, Eq, Default, Clone, Copy, Reflect)]
#[reflect(Component, Debug, PartialEq, Default, Clone)]
#[require(InteractiveObject, Collider, Sensor)]
pub enum StairCollider {
    #[default]
    Up,
    Down,
}

#[derive(Component, Clone, Copy, Default, Reflect, Debug, PartialEq)]
#[reflect(Component, Clone, Default, Debug, PartialEq)]
#[require(Transform)]
pub struct Stairs {
    pub up: Option<Vec2>,
    pub down: Option<Vec2>,
}

pub fn on_stairs_interact(
    event: On<InteractionEvent>,
    collider_query: Query<(&ChildOf, &StairCollider)>,
    stairs_query: Query<&Stairs>,
    mut player_query: Query<&mut Transform, With<Player>>,
) {
    let Ok((parent, collider_type)) = collider_query.get(event.entity) else {
        return;
    };
    let Ok(stairs) = stairs_query.get(parent.0) else {
        error!("StairCollider does not have Stairs parent");
        return;
    };
    let Ok(mut player_transform) = player_query.single_mut() else {
        return;
    };
    
    let offset = match collider_type {
        StairCollider::Up => {
            let Some(offset) = stairs.up else {
                error!("StairCollider::Up triggered but Stairs.up is None");
                return;
            };
            offset
        },
        StairCollider::Down => {
            let Some(offset) = stairs.down else {
                error!("StairCollider::Down triggered but Stairs.down is None");
                return;
            };
            offset
        },
    };

    player_transform.translation.x += offset.x;
    player_transform.translation.y += offset.y;
}

pub fn stairs_bundle(
    asset_server: &Res<AssetServer>,
    position: Vec2,
    up_position: Option<Vec2>,
    down_position: Option<Vec2>,
) -> impl Bundle {
    let image = asset_server.load(STAIRS_SPRITE_PATH);
    let (has_up, has_down) = (up_position.is_some(), down_position.is_some());
    (
        Stairs {
            up: up_position,
            down: down_position,
        },
        Transform::from_xyz(position.x, position.y, -1.),
        InheritedVisibility::VISIBLE,
        Children::spawn((
            SpawnWith(move |parent: &mut RelatedSpawner<ChildOf>| {
                if has_up {
                    parent.spawn((
                        StairCollider::Up,
                        Collider::cuboid(meters(1.), meters(1.)),
                        Transform::from_xyz(meters(-1.), 0., 0.),
                    ));
                    parent.spawn((
                        Sprite::from_image(image),
                        Transform::from_xyz(0., meters(1.5), 0.),
                    ));
                }

                if has_down {
                    parent.spawn((
                        StairCollider::Down,
                        Collider::cuboid(meters(1.), meters(1.)),
                        Transform::from_xyz(meters(1.), 0., 0.),
                    ));
                }
            }),
        )),
        Name::new(format!("Stairs ({},{})", position.x, position.y))
    )
}