#![feature(test)]

extern crate test;

use legion::prelude::*;
use legion_transform::{local_to_world_system, prelude::*};
use test::Bencher;

#[bench]
fn local_to_world_update_without_change(b: &mut Bencher) {
    let _ = env_logger::builder().is_test(true).try_init();

    let mut world = Universe::new().create_world();
    let system = local_to_world_system::build(&mut world);

    let ltw = LocalToWorld::identity();
    let t = Translation::new(1.0, 2.0, 3.0);
    let r = Rotation::from_euler_angles(1.0, 2.0, 3.0);
    let s = Scale(2.0);
    let nus = NonUniformScale::new(1.0, 2.0, 3.0);

    // Add N of every combination of transform types.
    let n = 1000;
    let _translation = *world.insert((), vec![(ltw, t); n]).first().unwrap();
    let _rotation = *world.insert((), vec![(ltw, r); n]).first().unwrap();
    let _scale = *world.insert((), vec![(ltw, s); n]).first().unwrap();
    let _non_uniform_scale = *world.insert((), vec![(ltw, nus); n]).first().unwrap();
    let _translation_and_rotation = *world.insert((), vec![(ltw, t, r); n]).first().unwrap();
    let _translation_and_scale = *world.insert((), vec![(ltw, t, s); n]).first().unwrap();
    let _translation_and_nus = *world.insert((), vec![(ltw, t, nus); n]).first().unwrap();
    let _rotation_scale = *world.insert((), vec![(ltw, r, s); n]).first().unwrap();
    let _rotation_nus = *world.insert((), vec![(ltw, r, nus); n]).first().unwrap();
    let _translation_rotation_scale = *world.insert((), vec![(ltw, t, r, s); n]).first().unwrap();
    let _translation_rotation_nus = *world.insert((), vec![(ltw, t, r, nus); n]).first().unwrap();

    // Run the system once outside the test (which should compute everything and it shouldn't be
    // touched again).
    system.run(&mut world);
    system.command_buffer_mut().write(&mut world);

    // Then time the already-computed updates.
    b.iter(|| {
        system.run(&mut world);
        system.command_buffer_mut().write(&mut world);
    });
}