use ecs::pair::Pair;
use ecs::phase::START as START_PHASE;
use ecs::{Component, Query, World};

#[derive(Component)]
struct Person
{
    name: String,
}

fn print_dog_likers(query: Query<(&Person, Pair<Likes, &Dogs>)>)
{
    for (person, liked_dogs) in &query {
        println!(
            "{} likes {} dogs!",
            person.name,
            if liked_dogs.large { "large" } else { "small" },
        );
    }
}

#[derive(Component)]
struct Likes;

#[derive(Component)]
struct Cats;

#[derive(Component)]
struct Dogs
{
    large: bool,
}

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

    world.register_system(*START_PHASE, print_dog_likers);

    world.create_entity((
        Person { name: "Irving".to_string() },
        Pair::new_with_comp_target::<Likes>(Dogs { large: true }),
    ));

    world.create_entity((
        Person { name: "Mark".to_string() },
        Pair::new_with_comp_target::<Likes>(Cats),
    ));

    world.create_entity((
        Person { name: "Helena".to_string() },
        Pair::new_with_comp_target::<Likes>(Dogs { large: false }),
    ));

    world.step();
}