use flecs::*;

#[derive(Default, Debug, PartialEq)]
struct Position {
	x: f32,
	y: f32,
}

#[derive(Default, Debug, PartialEq)]
struct Velocity {
	x: f32,
	y: f32,
}

fn main() {
	let mut world = World::new();
	world.component::<Position>();
	world.component::<Velocity>();

	// Can wire a function into a system
	let system =
		world.system().expr("Position, Velocity").each_mut::<(Position, Velocity)>(|e, (p, v)| {
			p.x += v.x;
			p.y += v.y;
			println!("{}: {:?}, {:?}", e.name(), p, v);
		});

	world
		.entity()
		.named("e1")
		.set::<Position>(Position { x: 10.0, y: 20.0 })
		.set::<Velocity>(Velocity { x: 1.0, y: 2.0 });

	world
		.entity()
		.named("e2")
		.set::<Position>(Position { x: 10.0, y: 20.0 })
		.set::<Velocity>(Velocity { x: 3.0, y: 4.0 });

	// This entity will not match as it does not have Position, Velocity
	world.entity().named("e3").set::<Position>(Position { x: 10.0, y: 20.0 });

	system.run(0.333);
}

#[cfg(test)]
mod tests {
	#[test]
	fn flecs_systems_basics() {
		super::main();
	}
}