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// Benchmark utils
#include "../../bench_utils/bench_utils.hpp"

// rocThrust
#include <thrust/device_vector.h>
#include <thrust/execution_policy.h>
#include <thrust/random.h>
#include <thrust/shuffle.h>

// Google Benchmark
#include <benchmark/benchmark.h>

// STL
#include <cstddef>
#include <string>
#include <vector>

struct basic
{
  template <typename T, typename Policy>
  float64_t run(thrust::device_vector<T>& data, const std::string rng_engine, Policy policy)
  {
    auto do_engine = [&](auto&& engine_constructor) {
      thrust::shuffle(policy, data.begin(), data.end(), engine_constructor());

      bench_utils::gpu_timer d_timer;

      d_timer.start(0);
      thrust::shuffle(policy, data.begin(), data.end(), engine_constructor());
      d_timer.stop(0);

      return d_timer.get_duration();
    };

    if (rng_engine == "minstd")
    {
      return do_engine([] {
        return thrust::random::minstd_rand{};
      });
    }
    else if (rng_engine == "ranlux24")
    {
      return do_engine([] {
        return thrust::random::ranlux24{};
      });
    }
    else if (rng_engine == "ranlux48")
    {
      return do_engine([] {
        return thrust::random::ranlux48{};
      });
    }
    else if (rng_engine == "taus88")
    {
      return do_engine([] {
        return thrust::random::taus88{};
      });
    }

    return -1;
  }
};

template <class Benchmark, class T>
void run_benchmark(
  benchmark::State& state, const std::size_t elements, const std::string /*seed_type*/, const std::string rng_engine)
{
  // Benchmark object
  Benchmark benchmark{};

  // GPU times
  std::vector<double> gpu_times;

  // Generate input
  thrust::device_vector<T> data(elements);

  bench_utils::caching_allocator_t alloc{};
  thrust::detail::device_t policy{};

  for (auto _ : state)
  {
    float64_t duration = benchmark.template run<T>(data, rng_engine, policy(alloc));
    state.SetIterationTime(duration);
    gpu_times.push_back(duration);
  }

  // BytesProcessed include read and written bytes, so when the BytesProcessed/s are reported
  // it will actually be the global memory bandwidth gotten.
  state.SetBytesProcessed(state.iterations() * 2 * elements * sizeof(T));
  state.SetItemsProcessed(state.iterations() * elements);

  const double gpu_cv         = bench_utils::StatisticsCV(gpu_times);
  state.counters["gpu_noise"] = gpu_cv;
}

#define CREATE_BENCHMARK(T, RngEngine, Elements)                                      \
  benchmark::RegisterBenchmark(                                                       \
    bench_utils::bench_naming::format_name(                                           \
      "{algo:shuffle,subalgo:" + name + ",input_type:" #T + ",rng_engine:" #RngEngine \
      + ",elements:" + bench_utils::format_pow2(Elements))                            \
      .c_str(),                                                                       \
    run_benchmark<Benchmark, T>,                                                      \
    Elements,                                                                         \
    seed_type,                                                                        \
    RngEngine)

#define BENCHMARK_RNG_ENGINE(type, rng_engine)                             \
  for (size_t size : bench_utils::sizes)                                   \
  {                                                                        \
    if (sizeof(type) * size <= bench_utils::system.devProp.totalGlobalMem) \
      bs.push_back(CREATE_BENCHMARK(type, rng_engine, size));              \
  }

#define BENCHMARK_TYPE(type)             \
  BENCHMARK_RNG_ENGINE(type, "minstd")   \
  BENCHMARK_RNG_ENGINE(type, "ranlux24") \
  BENCHMARK_RNG_ENGINE(type, "ranlux48") \
  BENCHMARK_RNG_ENGINE(type, "taus88")

template <class Benchmark>
void add_benchmarks(
  const std::string& name, std::vector<benchmark::internal::Benchmark*>& benchmarks, const std::string seed_type)
{
  std::vector<benchmark::internal::Benchmark*> bs;
  BENCHMARK_TYPE(int8_t)
  BENCHMARK_TYPE(int16_t)
  BENCHMARK_TYPE(int32_t)
  BENCHMARK_TYPE(int64_t)
#if THRUST_BENCHMARKS_HAVE_INT128_SUPPORT
  BENCHMARK_TYPE(int128_t)
#endif

  benchmarks.insert(benchmarks.end(), bs.begin(), bs.end());
}

int main(int argc, char* argv[])
{
  cli::Parser parser(argc, argv);
  parser.set_optional<std::string>("name_format", "name_format", "human", "either: json,human,txt");
  parser.set_optional<std::string>("seed", "seed", "random", bench_utils::get_seed_message());
  parser.run_and_exit_if_error();

  // Parse argv
  benchmark::Initialize(&argc, argv);
  bench_utils::bench_naming::set_format(parser.get<std::string>("name_format")); /* either: json,human,txt */
  const std::string seed_type = parser.get<std::string>("seed");

  // Benchmark info
  bench_utils::add_common_benchmark_info();
  benchmark::AddCustomContext("seed", seed_type);

  // Add benchmark
  std::vector<benchmark::internal::Benchmark*> benchmarks;
  add_benchmarks<basic>("basic", benchmarks, seed_type);

  // Use manual timing
  for (auto& b : benchmarks)
  {
    b->UseManualTime();
    b->Unit(benchmark::kMicrosecond);
    b->MinTime(0.4); // in seconds
  }

  // Run benchmarks
  benchmark::RunSpecifiedBenchmarks(bench_utils::ChooseCustomReporter());

  // Finish
  benchmark::Shutdown();
  return 0;
}