use std::{fs, path::PathBuf, sync::Arc};

use criterion::{BenchmarkId, Criterion, criterion_group, criterion_main};
use pumpkin_util::math::vector2::Vector2;
use pumpkin_world::{chunk::ChunkData, global_path, level::Level};
use tokio::{runtime::Runtime, sync::RwLock};

async fn test_reads(level: &Arc<Level>, positions: Vec<Vector2<i32>>) {
    let (send, mut recv) = tokio::sync::mpsc::unbounded_channel();
    let level = level.clone();
    tokio::spawn(async move { level.fetch_chunks(&positions, send).await });

    while let Some(x) = recv.recv().await {
        // Don't compile me away!
        let _ = x;
    }
}

/*
async fn test_reads_parallel(level: &Arc<Level>, positions: Vec<Vector2<i32>>, threads: usize) {
    let mut tasks = JoinSet::new();

    // we write non overlapping chunks to avoid conflicts or level cache
    // also we use `.rev()` to get the external radius first, avoiding
    // multiple files on the same request.
    for positions in positions.chunks(CHUNKS_ON_PARALLEL).rev().take(threads) {
        let level = level.clone();
        let positions = positions.to_vec();
        tasks.spawn(async move {
            test_reads(&level, positions.clone()).await;
        });
    }

    let _ = tasks.join_all().await;
}
*/

async fn test_writes(level: &Arc<Level>, chunks: Vec<(Vector2<i32>, Arc<RwLock<ChunkData>>)>) {
    level.write_chunks(chunks).await;
}

/*
async fn test_writes_parallel(
    level: &Arc<Level>,
    chunks: Vec<(Vector2<i32>, Arc<RwLock<ChunkData>>)>,
    threads: usize,
) {
    let mut tasks = JoinSet::new();

    // we write non overlapping chunks to avoid conflicts or level cache
    // also we use `.rev()` to get the external radius first, avoiding
    // multiple files on the same request.
    for chunks in chunks.chunks(CHUNKS_ON_PARALLEL).rev().take(threads) {
        let level = level.clone();
        let chunks = chunks.to_vec();
        tasks.spawn(async move {
            test_writes(&level, chunks).await;
        });
    }

    let _ = tasks.join_all().await;
}
*/

// -16..16 == 32 chunks, 32*32 == 1024 chunks
const MIN_CHUNK: i32 = -16;
const MAX_CHUNK: i32 = 16;

// How many chunks to use on parallel tests
//const CHUNKS_ON_PARALLEL: usize = 32;

fn initialize_level(
    async_handler: &Runtime,
    root_dir: PathBuf,
) -> Vec<(Vector2<i32>, Arc<RwLock<ChunkData>>)> {
    println!("Initializing data...");
    // Initial writes
    let mut chunks = Vec::new();
    async_handler.block_on(async {
        let (send, mut recv) = tokio::sync::mpsc::unbounded_channel();

        // Our data dir is empty, so we're generating new chunks here
        let level_to_save = Arc::new(Level::from_root_folder(root_dir.clone(), 123));
        println!("Level Seed is: {}", level_to_save.seed.0);

        let level_to_fetch = level_to_save.clone();
        tokio::spawn(async move {
            let chunks_to_generate = (MIN_CHUNK..MAX_CHUNK)
                .flat_map(|x| (MIN_CHUNK..MAX_CHUNK).map(move |z| Vector2::new(x, z)))
                .collect::<Vec<_>>();
            level_to_fetch.fetch_chunks(&chunks_to_generate, send).await;
        });

        while let Some((chunk, _)) = recv.recv().await {
            let pos = chunk.read().await.position;
            chunks.push((pos, chunk));
        }
        level_to_save.write_chunks(chunks.clone()).await;
    });

    // Sort by distance from origin to ensure a fair selection
    // when using a subset of the total chunks for the benchmarks
    chunks.sort_unstable_by_key(|chunk| (chunk.0.x * chunk.0.x) + (chunk.0.z * chunk.0.z));
    chunks
}

// Depends on config options from `./config`
/*
// This doesn't really test anything...
fn bench_chunk_io_parallel(c: &mut Criterion) {
    // System temp dirs are in-memory, so we can't use temp_dir
    let root_dir = global_path!("./bench_root_tmp");
    let _ = fs::remove_dir_all(&root_dir); // delete if it exists
    fs::create_dir(&root_dir).unwrap(); // create the directory

    let async_handler = tokio::runtime::Builder::new_multi_thread().build().unwrap();

    let chunks = initialize_level(&async_handler, root_dir.clone());
    let positions = chunks.iter().map(|(pos, _)| *pos).collect::<Vec<_>>();

    let iters = [1, 2, 8, 32];

    let mut write_group_parallel = c.benchmark_group("write_chunks");
    for n_requests in iters {
        let root_dir = root_dir.clone();

        write_group_parallel.bench_with_input(
            BenchmarkId::new("Parallel", n_requests),
            &chunks,
            |b, parallel_chunks| {
                let chunks = parallel_chunks.to_vec();
                b.to_async(&async_handler).iter(async || {
                    let level = Arc::new(Level::from_root_folder(root_dir.clone()));
                    test_writes_parallel(&level, chunks.clone(), n_requests).await
                })
            },
        );
    }
    write_group_parallel.finish();

    let mut read_group = c.benchmark_group("read_chunks");
    for n_requests in iters {
        let root_dir = root_dir.clone();


        read_group.bench_with_input(
            BenchmarkId::new("Parallel", n_requests),
            &positions,
            |b, positions| {
                let positions = positions.to_vec();
                b.to_async(&async_handler).iter(async || {
                    let level = Arc::new(Level::from_root_folder(root_dir.clone()));
                    test_reads_parallel(&level, positions.clone(), n_requests).await
                })
            },
        );
    }
    read_group.finish();

    fs::remove_dir_all(&root_dir).unwrap(); // cleanup

}
*/

// Depends on config options from `./config`
fn bench_chunk_io(c: &mut Criterion) {
    // System temp dirs are in-memory, so we can't use temp_dir
    let root_dir = global_path!("./bench_root_tmp");
    let _ = fs::remove_dir_all(&root_dir); // delete it if it exists
    fs::create_dir(&root_dir).unwrap(); // create the directory

    let async_handler = tokio::runtime::Builder::new_current_thread()
        .build()
        .unwrap();

    let chunks = initialize_level(&async_handler, root_dir.clone());
    let positions = chunks.iter().map(|(pos, _)| *pos).collect::<Vec<_>>();

    let iters = [16, 64, 256, 512];
    // These test worst case: no caching done by `Level`
    // testing with 16, 64, 256 chunks
    let mut write_group = c.benchmark_group("write_chunks");
    for n_chunks in iters {
        let chunks = &chunks[..n_chunks];
        let root_dir = root_dir.clone();
        assert!(
            chunks.len() == n_chunks,
            "Expected {} chunks, got {}",
            n_chunks,
            chunks.len()
        );
        write_group.bench_with_input(
            BenchmarkId::new("Single", n_chunks),
            &chunks,
            |b, chunks| {
                b.to_async(&async_handler).iter(async || {
                    let level = Arc::new(Level::from_root_folder(root_dir.clone(), 123));
                    test_writes(&level, chunks.to_vec()).await
                })
            },
        );
    }
    write_group.finish();

    // These test worst case: no caching done by `Level`
    // testing with 16, 64, 256 chunks
    let mut read_group = c.benchmark_group("read_chunks");
    for n_chunks in iters {
        let positions = &positions[..n_chunks];
        let root_dir = root_dir.clone();
        assert!(
            positions.len() == n_chunks,
            "Expected {} chunks, got {}",
            n_chunks,
            positions.len()
        );

        read_group.bench_with_input(
            BenchmarkId::new("Single", n_chunks),
            &positions,
            |b, positions| {
                b.to_async(&async_handler).iter(async || {
                    let level = Arc::new(Level::from_root_folder(root_dir.clone(), 123));
                    test_reads(&level, positions.to_vec()).await
                })
            },
        );
    }
    read_group.finish();

    fs::remove_dir_all(&root_dir).unwrap(); // cleanup
}

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