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

use bevy::{
    ecs::query::QueryFilter,
    prelude::*,
};

use bevy_rapier2d::prelude::*;

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

use super::*;

fn get_interactive_id<F: QueryFilter>(
    tested_id: Entity,
    interactive_query: Query<(), F>,
    parent_query: Query<&ChildOf, With<Collider>>,
) -> Option<Entity> {
    if interactive_query.get(tested_id).is_ok() {
        return Some(tested_id);
    }
    let Ok(parent_id) = parent_query.get(tested_id) else {
        return None;
    };
    match interactive_query.get(parent_id.0) {
        Ok(_) => Some(parent_id.0),
        Err(_) => None,
    }
}

fn interact_collisions_inner<F: QueryFilter>(
    first: Entity,
    second: Entity,
    interactive_query: Query<(), F>,
    player_query: Query<(), With<Player>>,
    parent_query: Query<&ChildOf, With<Collider>>,
) -> Option<Entity> {
    let Some(interactive_id) = get_interactive_id(first, interactive_query, parent_query) else {
        return None;
    };
    if player_query.get(second).is_err() {
        return None;
    }
    Some(interactive_id)
}

pub fn detect_interact_collisions(
    mut commands: Commands,
    mut collision_events: MessageReader<CollisionEvent>,
    player_query: Query<(), With<Player>>,
    interactive_query1: Query<(), (With<InteractiveObject>, Without<MayInteract>)>,
    interactive_query2: Query<(), (With<InteractiveObject>, With<MayInteract>)>,
    parent_query: Query<&ChildOf, With<Collider>>,
) {
    for collision_event in collision_events.read() {
        match collision_event {
            CollisionEvent::Started(first, second, _) => {
                if let Some(interactive_id) = interact_collisions_inner(*first, *second, interactive_query1, player_query, parent_query) {
                    commands.entity(interactive_id).insert(MayInteract);
                }
                if let Some(interactive_id) = interact_collisions_inner(*second, *first, interactive_query1, player_query, parent_query) {
                    commands.entity(interactive_id).insert(MayInteract);
                }
            },
            CollisionEvent::Stopped(first, second, _) => {
                if let Some(interactive_id) = interact_collisions_inner(*first, *second, interactive_query2, player_query, parent_query) {
                    commands.entity(interactive_id).remove::<MayInteract>();
                }
                if let Some(interactive_id) = interact_collisions_inner(*second, *first, interactive_query2, player_query, parent_query) {
                    commands.entity(interactive_id).remove::<MayInteract>();
                }
            },
        }
    }
}

pub fn lock_door(
    mut commands: Commands,
    query: Query<&ChildOf, Added<lock::Padlock>>,
) {
    for parent in query {
        commands.entity(parent.0).insert(Locked);
    }
}

pub fn setup_world(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
) {
    let level_handle = asset_server.load("levels/level.toml");
    commands.insert_resource(LevelAssetHandle(level_handle));
}