use bevy::{
    prelude::*,
};

#[derive(Component,Debug)]
struct Pos(Vec2);
#[derive(Component,Debug)]
struct Ray(Vec2);
#[derive(Component,Debug)]
struct Col(Color);
#[derive(Component,Debug)]
struct Size(f32);

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
	.add_systems(Startup, setup)
	.add_systems(Update, (animate, rand_color, gizmos))
	.run()
}

fn setup(
    mut commands: Commands,
) {
    commands.spawn(Camera2dBundle {
	transform: Transform::from_xyz(250.0, 0.0, 0.0),
	..default()
    });
    
    commands.spawn((
	Pos(Vec2::new(0.0, 0.0)),
	Ray(Vec2::new(100.0, 5.0)),
	Col(Color::rgba(1.0, 0.0, 1.0, 1.0)),
	Size(10.0)
    ));

    commands.spawn((
	Pos(Vec2::new(0.0, 0.0)),
	Ray(Vec2::new(200.0, 1.0)),
	Col(Color::rgba(1.0, 1.0, 0.0, 1.0)),
	Size(20.0)
    ));

}

fn animate(
    time: Res<Time>,
    mut query: Query<(&mut Pos, &Ray)>
) {
    let t = time.elapsed_seconds();
    for (mut pos, ray) in &mut query {
	pos.0.x = (ray.0.y*t).cos() * ray.0.x;
	pos.0.y = (ray.0.y*t).sin() * ray.0.x;
    }
}

fn rand_color(
    time: Res<Time>,
    mut query: Query<&mut Col>
) {
    let t = time.delta_seconds();
    for mut col in &mut query {
	if let Color::Rgba{ ref mut red, .. } = col.0 {
	    *red += t;
	    if *red > 1.0 {
		*red = 0.0;
	    }
	}
    }
}

fn gizmos(
    mut gizmos: Gizmos,
    query: Query<(&Pos,&Col,&Size)>
) {
    for (Pos(pos), Col(color), Size(size)) in &query {
	gizmos.circle_2d(*pos, *size, *color);
    }
}