use ecs::component::single::Single;
use ecs::event::{Event, Id as EventId};
use ecs::{Component, Query, World};

#[derive(Component)]
struct Ammo
{
    ammo_left: u32,
}

#[derive(Component, Default)]
struct AmmoCounter
{
    counter: u32,
}

fn count_ammo(query: Query<(Ammo,)>, mut ammo_counter: Single<AmmoCounter>)
{
    for (ammo,) in &query {
        println!("Found {} ammo", ammo.ammo_left);

        ammo_counter.counter += ammo.ammo_left;
    }
}

fn print_total_ammo_count(ammo_counter: Single<AmmoCounter>)
{
    println!("Total ammo count: {}", ammo_counter.counter);

    assert_eq!(ammo_counter.counter, 19);
}

#[derive(Debug)]
struct EventA;

impl Event for EventA
{
    fn id(&self) -> EventId
    {
        EventId::of::<Self>()
    }
}

#[derive(Debug)]
struct EventB;

impl Event for EventB
{
    fn id(&self) -> EventId
    {
        EventId::of::<Self>()
    }
}

fn main()
{
    let mut world = World::new();

    world.register_system(&EventA, count_ammo);
    world.register_system(&EventB, print_total_ammo_count);

    world.create_entity((Ammo { ammo_left: 4 },));
    world.create_entity((Ammo { ammo_left: 7 },));
    world.create_entity((Ammo { ammo_left: 8 },));

    world.add_single_component(AmmoCounter::default()).unwrap();

    world.emit(&EventA);

    world.emit(&EventB);
}