use criterion::{black_box, criterion_group, criterion_main, Criterion};
use lazy_static::lazy_static;
use std::{env, rc::Rc, sync::Arc, time::Duration};
use tvix_build::buildservice::DummyBuildService;
use tvix_castore::{
    blobservice::{BlobService, MemoryBlobService},
    directoryservice::{DirectoryService, MemoryDirectoryService},
};
use tvix_eval::{builtins::impure_builtins, EvalIO};
use tvix_glue::{
    builtins::{add_derivation_builtins, add_fetcher_builtins},
    configure_nix_path,
    tvix_io::TvixIO,
    tvix_store_io::TvixStoreIO,
};
use tvix_store::pathinfoservice::{MemoryPathInfoService, PathInfoService};

lazy_static! {
    static ref BLOB_SERVICE: Arc<dyn BlobService> = Arc::new(MemoryBlobService::default());
    static ref DIRECTORY_SERVICE: Arc<dyn DirectoryService> =
        Arc::new(MemoryDirectoryService::default());
    static ref PATH_INFO_SERVICE: Arc<dyn PathInfoService> = Arc::new(MemoryPathInfoService::new(
        BLOB_SERVICE.clone(),
        DIRECTORY_SERVICE.clone(),
    ));
    static ref TOKIO_RUNTIME: tokio::runtime::Runtime = tokio::runtime::Runtime::new().unwrap();
}

fn interpret(code: &str) {
    // TODO: this is a bit annoying.
    // It'd be nice if we could set this up once and then run evaluate() with a
    // piece of code. b/262

    // We assemble a complete store in memory.
    let tvix_store_io = Rc::new(TvixStoreIO::new(
        BLOB_SERVICE.clone(),
        DIRECTORY_SERVICE.clone(),
        PATH_INFO_SERVICE.clone(),
        Arc::<DummyBuildService>::default(),
        TOKIO_RUNTIME.handle().clone(),
    ));

    let mut eval = tvix_eval::Evaluation::new(
        Box::new(TvixIO::new(tvix_store_io.clone() as Rc<dyn EvalIO>)) as Box<dyn EvalIO>,
        true,
    );

    eval.builtins.extend(impure_builtins());
    add_derivation_builtins(&mut eval, tvix_store_io.clone());
    add_fetcher_builtins(&mut eval, tvix_store_io);
    configure_nix_path(
        &mut eval,
        // The benchmark requires TVIX_BENCH_NIX_PATH to be set, so barf out
        // early, rather than benchmarking tvix returning an error.
        &Some(env::var("TVIX_BENCH_NIX_PATH").expect("TVIX_BENCH_NIX_PATH must be set")),
    );

    let result = eval.evaluate(code, None);

    assert!(result.errors.is_empty());
}

fn eval_nixpkgs(c: &mut Criterion) {
    c.bench_function("hello outpath", |b| {
        b.iter(|| {
            interpret(black_box("(import <nixpkgs> {}).hello.outPath"));
        })
    });
}

criterion_group!(
    name = benches;
    config = Criterion::default().measurement_time(Duration::from_secs(30)).sample_size(10);
    targets = eval_nixpkgs
);
criterion_main!(benches);