//! Criterion bench for [`SpectrogramComputer::compute_aggregate`] — the
//! hot per-chunk path. Guards the zero-alloc-after-construction property:
//! a future change that reintroduces allocation into this loop should
//! show up here as a clear regression.
#![allow(clippy::expect_used, clippy::unwrap_used)]

use std::hint::black_box;

use clawaudio_dsp::{SpectrogramComputer, SpectrogramConfig};
use criterion::{Criterion, criterion_group, criterion_main};

fn sine(freq: f32, sample_rate: u32, n: usize) -> Vec<f32> {
    (0..n)
        .map(|i| (std::f32::consts::TAU * freq * i as f32 / sample_rate as f32).sin())
        .collect()
}

fn bench_compute_aggregate(c: &mut Criterion) {
    let cfg = SpectrogramConfig {
        sample_rate: 16_000,
        fft_size: 512,
        hop_size: 256,
        mel_bins: 16,
        f_low_hz: 80.0,
        f_high_hz: 8_000.0,
    };
    let mut sc = SpectrogramComputer::new(cfg).expect("valid config");
    // ~0.5s chunk at 16kHz, a realistic single-chunk size.
    let mono = sine(440.0, 16_000, 8_000);
    let mut out = vec![0.0f32; sc.mel_bins()];

    let mut group = c.benchmark_group("dsp");
    group.bench_function("compute_aggregate_16khz_500ms_16mel", |b| {
        b.iter(|| {
            sc.compute_aggregate(black_box(&mono), black_box(&mut out))
                .expect("compute_aggregate");
            black_box(&out);
        });
    });
    group.finish();
}

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