// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

//! This set of benchmarks exercises the open systems simulator exclusively via
//! its C API, so as to gauge any potential issues for C-based consumers of the
//! simulator.

use criterion::{criterion_group, criterion_main, Criterion};
use qdk_sim::c_api;
use std::ffi::CString;

// Use include_str! to store test case JSON as a string into the compiled
// test executable.
static BENCHMARK_NOISE_MODEL_JSON: &str = include_str!("data/benchmark-noise-model.json");

fn with_test_suite<T: criterion::measurement::Measurement>(
    sim_id: usize,
    group: &mut criterion::BenchmarkGroup<T>,
) {
    group.bench_function("apply x", |b| {
        b.iter(|| {
            c_api::x(sim_id, 0);
        })
    });
    group.bench_function("apply z", |b| {
        b.iter(|| {
            c_api::z(sim_id, 0);
        })
    });
    group.bench_function("apply ry", |b| {
        b.iter(|| {
            c_api::ry(sim_id, 1.234, 1);
        })
    });
    group.bench_function("apply cnot", |b| {
        b.iter(|| {
            c_api::cnot(sim_id, 0, 1);
        })
    });
    group.bench_function("measure", |b| {
        b.iter(|| {
            let mut result: usize = 0;
            // NB: The C API is not in general safe.
            unsafe {
                c_api::m(sim_id, 0, &mut result);
            }
        })
    });
}

fn ideal(c: &mut Criterion) {
    let mut sim_id: usize = 0;
    unsafe {
        let repr = CString::new("mixed").unwrap();
        let _err = c_api::init(3, repr.as_ptr(), &mut sim_id);
    }
    let mut group = c.benchmark_group("ideal");
    with_test_suite(sim_id, &mut group);
    group.finish();
    c_api::destroy(sim_id);
}

fn noisy(c: &mut Criterion) {
    let mut sim_id: usize = 0;
    unsafe {
        let repr = CString::new("mixed").unwrap();
        let _err = c_api::init(3, repr.as_ptr(), &mut sim_id);
    }
    // NB: The C API is not in general safe.
    unsafe {
        let model = CString::new(BENCHMARK_NOISE_MODEL_JSON).unwrap();
        c_api::set_noise_model(sim_id, model.as_ptr());
    }
    let mut group = c.benchmark_group("noisy");
    with_test_suite(sim_id, &mut group);
    group.finish();
    c_api::destroy(sim_id);
}

criterion_group!(benches, ideal, noisy);
criterion_main!(benches);