use ecs::error::Error;
use ecs::event::component::{Changed, EventMatchExt};
use ecs::pair::Pair;
use ecs::phase::UPDATE;
use ecs::query::Query;
use ecs::system::observer::Observe;
use ecs::{Component, World, error};
use tracing::level_filters::LevelFilter;
use tracing_subscriber::EnvFilter;
use tracing_subscriber::fmt::time::ChronoLocal;
use tracing_subscriber::layer::SubscriberExt;
use tracing_subscriber::util::SubscriberInitExt;

#[derive(Component)]
struct State
{
    value: u32,
}

fn do_something_fallible(query: Query<(&mut State,)>) -> Result<(), Error>
{
    for (mut state,) in &query {
        state.value += 1;

        state.set_changed();

        if state.value > 3 {
            return Err(error!("Invalid state value {}", state.value));
        }
    }

    Ok(())
}

fn handle_state_changed(observe: Observe<Pair<Changed, State>>) -> Result<(), Error>
{
    for evt_match in &observe {
        let state = evt_match.get_ent_target_comp();

        if state.value > 3 {
            return Err(error!("Invalid state value {}", state.value));
        }

        tracing::info!("State has valid value {}", state.value);
    }

    Ok(())
}

fn main()
{
    tracing_subscriber::registry()
        .with(
            tracing_subscriber::fmt::layer()
                .with_timer(ChronoLocal::new("%T%.6f".to_string())),
        )
        .with(
            EnvFilter::builder()
                .with_default_directive(LevelFilter::DEBUG.into())
                .from_env()
                .unwrap(),
        )
        .init();

    let mut world = World::new();

    world.set_err_handler(ecs::error::err_handler_log_error);

    world.create_entity((State { value: 0 },));

    world.register_system(*UPDATE, do_something_fallible);

    world.register_observer(handle_state_changed);

    world.step();
    world.step();
    world.step();
    world.step();
}