// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
use bencher::Bencher;
use deno_core::v8;
use deno_core::Extension;
use deno_core::JsRuntime;
use deno_core::RuntimeOptions;

use crate::profiling::is_profiling;

pub fn create_js_runtime(setup: impl FnOnce() -> Vec<Extension>) -> JsRuntime {
  JsRuntime::new(RuntimeOptions {
    extensions: setup(),
    ..Default::default()
  })
}

fn loop_code(iters: u64, src: &str) -> String {
  format!(r#"for(let i=0; i < {}; i++) {{ {} }}"#, iters, src,)
}

pub fn bench_js_sync(
  b: &mut Bencher,
  src: &str,
  setup: impl FnOnce() -> Vec<Extension>,
) {
  let mut runtime = create_js_runtime(setup);
  let scope = &mut runtime.handle_scope();

  // Increase JS iterations if profiling for nicer flamegraphs
  let inner_iters = 1000 * if is_profiling() { 10000 } else { 1 };
  // Looped code
  let looped_src = loop_code(inner_iters, src);

  let code = v8::String::new(scope, looped_src.as_ref()).unwrap();
  let script = v8::Script::compile(scope, code, None).unwrap();

  // Run once if profiling, otherwise regular bench loop
  if is_profiling() {
    script.run(scope).unwrap();
  } else {
    b.iter(|| {
      script.run(scope).unwrap();
    });
  }
}

pub fn bench_js_async(
  b: &mut Bencher,
  src: &str,
  setup: impl FnOnce() -> Vec<Extension>,
) {
  let mut runtime = create_js_runtime(setup);
  let tokio_runtime = tokio::runtime::Builder::new_current_thread()
    .enable_all()
    .build()
    .unwrap();

  // Looped code
  let looped = loop_code(1000, src);
  let src = looped.as_ref();

  if is_profiling() {
    for _ in 0..10000 {
      tokio_runtime.block_on(inner_async(src, &mut runtime));
    }
  } else {
    b.iter(|| {
      tokio_runtime.block_on(inner_async(src, &mut runtime));
    });
  }
}

async fn inner_async(src: &str, runtime: &mut JsRuntime) {
  runtime.execute_script("inner_loop", src).unwrap();
  runtime.run_event_loop(false).await.unwrap();
}