#[macro_use]
extern crate criterion;
extern crate bincode;
extern crate tempfile;

use chgk_ledb_lib::db;
use std::path::PathBuf;

use db::{Reader, Writer, WriterOpts};

use criterion::{BatchSize, Criterion};
use tempfile::tempdir;

#[derive(bincode::Encode, bincode::Decode, Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
struct TestData {
    num: u128,
    test: String,
}

const N: usize = 4096;

fn gen_data(count: usize) -> impl Iterator<Item = TestData> {
    (0..count)
        .into_iter()
        .map(|i| 143 + i as u128)
        .map(|i| TestData {
            num: i,
            test: "test ---- Test ____".repeat(123 + i as usize % 15),
        })
}

fn prepare_db_writer(path: &PathBuf) -> Writer<TestData> {
    let opts = WriterOpts {
        compress_lvl: 1,
        data_buf_size: 100 * 1024 * 1024,
        out_buf_size: 100 * 1024 * 1024,
        current_buf_size: 10240,
    };

    Writer::new(path, opts).expect("new writer")
}

fn db_read(c: &mut Criterion) {
    let dir = tempdir().expect("tempdir");
    let tmpfile = dir.path().join("test.tmp");
    let mut writer = prepare_db_writer(&tmpfile);

    let mut items_iter = gen_data(N).collect::<Vec<TestData>>().into_iter();
    writer.load(&mut items_iter).unwrap();
    writer.finish().unwrap();

    c.bench_function("read", |b| {
        b.iter_batched(
            || {
                let reader: Reader<TestData> = Reader::new(&tmpfile, 2048).expect("new reader");
                reader
            },
            |mut reader| {
                let mut reader_iter = reader.iter();
                while let Some(item) = reader_iter.next() {
                    drop(item);
                }
            },
            BatchSize::SmallInput,
        )
    });
}

fn db_write(c: &mut Criterion) {
    let dir = tempdir().expect("tempdir");
    let tmpfile = dir.path().join("test.tmp");
    c.bench_function("write", |b| {
        b.iter_batched(
            || {
                let src = gen_data(N).collect::<Vec<TestData>>().into_iter();
                let writer = prepare_db_writer(&tmpfile);
                (src, writer)
            },
            |(mut src, mut writer)| {
                writer.load(&mut src).unwrap();
                writer.finish().unwrap();
            },
            BatchSize::SmallInput,
        )
    });
}

fn config() -> Criterion {
    Criterion::default().sample_size(40)
}

criterion_group! {name=benches; config = config(); targets = db_read, db_write}
criterion_main!(benches);