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

#[derive(Component)]
struct Sword
{
    attack_strength: u32,
}

#[derive(Component)]
struct Player;

#[derive(Component)]
struct Health
{
    health: u32,
}

#[derive(Component)]
struct Holding;

fn print_player_stats(player_query: Query<(&Player, &Health, Pair<Holding, Wildcard>)>)
{
    for (_, health, sword_relationship) in &player_query {
        println!("Player health: {}", health.health);

        if let Some(sword_ent) = sword_relationship.get_target_entity() {
            let sword = sword_ent
                .get::<Sword>()
                .expect("Sword entity is missing sword component");

            println!("Player sword attack strength: {}", sword.attack_strength);
        }
    }
}

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

    world.register_system(*START_PHASE, print_player_stats);

    let sword_uid = world.create_entity((Sword { attack_strength: 17 },));

    world.create_entity((
        Player,
        Health { health: 180 },
        Pair::new::<Holding>(sword_uid),
    ));

    world.step();
}