# use bevy_app::prelude::*;
# use bevy_transform::prelude::*;
# #[cfg(feature = "sprite")]
# use bevy_sprite::Sprite;
use bevy_quadtree::{QuadTreePlugin, CollisionCircle, CollisionRect};

fn main() {
    #[cfg(feature = "sprite")]
    App::new()
        .add_plugins(QuadTreePlugin::<(
                (CollisionCircle, GlobalTransform), (CollisionRect, (GlobalTransform, Sprite)),
            ),
            8, 40, 100, 100, 20>::default()
        )
        // CollisionCircle follows GlobalTransform, CollisionRect follows Sprite and GlobalTransform
        // at most 40 entities in a node
        // at most 8 levels
        // 100 x 100 world size
        // 20 / 10 = 2 = outlet_boundary / inlet_boundary (for loose quadtree)
        .run();
}

// in systems
cmds.spawn((
    Sprite {
        color: Color::WHITE,
        custom_size: Some(CUSTOM_SIZE),
        ..Default::default()
    },
    // Spawn collision shape `CollisionRect` with `Sprite`,
    // the plugin will auto-update it following `Changed<GlobalTransform>` and `Changed<Sprite>`
    CollisionRect::from(Rect::from_center_size(pos, CUSTOM_SIZE)),
    Transform::from_xyz(pos.x, world_pos.y, 1.),
))

type MyQuadTree = QuadTree<40, 100, 100, 20>;

fn pick(
    mut gizmos: Gizmos,
    btn: Res<ButtonInput<MouseButton>>,
    key: Res<ButtonInput<KeyCode>>,
    quadtree: Res<MyQuadTree>,
    mut start: Local<Option<Vec2>>,
    ...
) {
    if !btn.pressed(MouseButton::Left) {
        *start = None;
        return;
    }
    let world_position = ...;
    let cancel_pick = key.any_pressed([KeyCode::ShiftLeft, KeyCode::ShiftRight]);
    match *start {
        Some(start) => {
            gizmos.rect_2d(
                (start + world_pos) / 2.,
                (start - world_pos).abs(),
                if cancel_pick { RED } else { WHITE },
            );
            let res = if start.x > world_pos.x {
                // left pick
                quadtree.query::<QOr<(Overlap, Contain)>>(&CollisionRect::from(
                    Rect::from_corners(start, world_pos),
                ))
            } else {
                // right pick
                quadtree
                    .query::<Contain>(&CollisionRect::from(Rect::from_corners(start, world_pos)))
            };
            if cancel_pick {
                ...
            } else {
                ...
            }
        }
        None => *start = Some(world_pos),
    }
}

xx.observe(
    |trigger: Trigger<TextRefreshEvent>,
     mut q_box: Query<(&mut Sprite, &mut CollisionRect)>| {
        if let Ok((mut s, mut c)) = q_box.get_mut(trigger.entity()) {
            let ev = trigger.event();
            let delta = Vec2::new(ev.width * FONT_WIDTH, (ev.height - 1.) * FONT_HEIGHT);
            s.custom_size = Some(CUSTOM_SIZE + delta);
            // the plugin default only track `Changed<GlobalTransform>`
            // without feature `sprite` enabled, you can also do this way.
            c.set_init_size(CUSTOM_SIZE + delta);
        }
    },
)