//! Append CPU cost while every record fits in the write buffer.

use crate::{PAGE_SIZE, REPLAY_BUFFER, WRITE_BUFFER};
use commonware_runtime::{
    Supervisor as _,
    benchmarks::{context, tokio},
    buffer::paged::CacheRef,
};
use commonware_storage::journal::contiguous::{
    Many,
    fixed::{Config, Journal},
};
use commonware_utils::{NZU64, NZUsize, sequence::FixedBytes};
use criterion::{Criterion, criterion_group};
use std::{
    hint::black_box,
    time::{Duration, Instant},
};

fn bench_size<const SIZE: usize>(c: &mut Criterion) {
    let runner = tokio::Runner::default();
    let items = 320 * 1024 / SIZE;
    for prepared in [false, true] {
        c.bench_function(
            &format!(
                "{}/items={items} size={SIZE} prepared={prepared}",
                module_path!()
            ),
            |b| {
                b.to_async(&runner).iter_custom(|iters| async move {
                    let ctx = context::get::<commonware_runtime::tokio::Context>();
                    let cache = CacheRef::new(PAGE_SIZE, NZUsize!(32));
                    let item = FixedBytes::new([0xAB; SIZE]);
                    let mut elapsed = Duration::ZERO;
                    for _ in 0..iters {
                        let mut journal = Journal::init(
                            ctx.child("storage"),
                            Config {
                                partition: "fixed_append_buffered".into(),
                                items_per_blob: NZU64!(1_000_000),
                                write_buffer: WRITE_BUFFER,
                                replay_buffer: REPLAY_BUFFER,
                                page_cache: cache.clone(),
                            },
                        )
                        .await
                        .unwrap();

                        // Warm the tip allocation outside the timed region. Neither these
                        // appends nor the timed appends fill the tip or rotate the blob.
                        (journal, _) = journal.append(&item).await.unwrap();
                        let start = Instant::now();
                        for _ in 0..items {
                            if prepared {
                                let batch = journal.prepare_append(Many::Flat(
                                    std::slice::from_ref(black_box(&item)),
                                ));
                                (journal, _) = journal.append_prepared(batch).await.unwrap();
                            } else {
                                (journal, _) = journal.append(black_box(&item)).await.unwrap();
                            }
                        }
                        black_box(&journal);
                        elapsed += start.elapsed();
                        journal.destroy().await.unwrap();
                    }
                    elapsed
                });
            },
        );
    }
}

fn bench(c: &mut Criterion) {
    bench_size::<32>(c);
    bench_size::<256>(c);
}

criterion_group! {
    name = benches;
    config = Criterion::default().sample_size(20);
    targets = bench
}