//! One slice's event sweep.
//!
//! Written against the public API rather than against `TimeSlice` directly.
//! It used to reach for `TimeSlice`, `KeyTable`, `CompetitorStore`,
//! `Competitor` and `EventKind`, and was the *only* thing outside `src/`
//! that did — so a benchmark was dictating five public types that no test,
//! example or consumer could otherwise obtain.
//!
//! A single-slice history's `converge` calls exactly the same per-slice sweep,
//! so capping at one iteration measures the same code path.

use criterion::{Criterion, criterion_group, criterion_main};
use smallvec::smallvec;
use trueskill_tt::{
    ConstantDrift, ConvergenceOptions, Event, History, Member, Outcome, Team,
};

fn criterion_benchmark(criterion: &mut Criterion) {
    let build = || {
        let mut h = History::builder()
            .convergence(ConvergenceOptions {
                max_iter: 1,
                epsilon: 0.0,
                alpha: 1.0,
            })
            .drift(ConstantDrift::new(0.0))
            .build();

        // 100 events, all at one time, so the history has a single slice.
        let events: Vec<Event<i64, &'static str>> = (0..100)
            .map(|_| Event {
                time: 1,
                teams: smallvec![
                    Team::with_members([Member::new("a")]),
                    Team::with_members([Member::new("b")]),
                ],
                outcome: Outcome::winner(0, 2),
            })
            .collect();
        h.add_events(events).expect("fixture ingests");
        h
    };

    criterion.bench_function("slice_sweep_100_events", |b| {
        b.iter_batched(
            build,
            |mut h| {
                // `converge_partial`, not `converge`: one iteration is
                // deliberately short of convergence and `converge` reports that
                // as an error.
                let _ = h.converge_partial();
            },
            criterion::BatchSize::SmallInput,
        );
    });
}

criterion_group!(benches, criterion_benchmark);
criterion_main!(benches);