// MIT License
//
// Copyright (c) 2021 Advanced Micro Devices, Inc. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#include "common_benchmark_header.hpp"

// HIP API
#include "hipcub/device/device_partition.hpp"

#include <chrono>
#include <vector>

#ifndef DEFAULT_N
constexpr size_t DEFAULT_N = 1024 * 1024 * 32;
#endif

constexpr unsigned int batch_size = 10;
constexpr unsigned int warmup_size = 5;

namespace {
template <typename T>
struct LessOp {
    HIPCUB_HOST_DEVICE LessOp(const T& pivot)
        : pivot_{pivot}
    {
    }

    HIPCUB_HOST_DEVICE bool operator()(const T& val) const {
        return val < pivot_; 
    }
private:
    T pivot_;
};
}

template <typename T>
void run_threeway(benchmark::State& state,
                  const hipStream_t stream,
                  const T small_threshold,
                  const T large_threshold,
                  const size_t size)
{
    const auto input =
        benchmark_utils::get_random_data<T>(size, static_cast<T>(0), static_cast<T>(100));

    T* d_input             = nullptr;
    T* d_first_output      = nullptr;
    T* d_second_output     = nullptr;
    T* d_unselected_output = nullptr;
    unsigned int* d_num_selected_output = nullptr;
    HIP_CHECK(hipMalloc(&d_input, input.size() * sizeof(T)));
    HIP_CHECK(hipMalloc(&d_first_output, input.size() * sizeof(T)));
    HIP_CHECK(hipMalloc(&d_second_output, input.size() * sizeof(T)));
    HIP_CHECK(hipMalloc(&d_unselected_output, input.size() * sizeof(T)));
    HIP_CHECK(hipMalloc(&d_num_selected_output, 2 * sizeof(unsigned int)));

    const auto select_first_part_op  = LessOp<T>{small_threshold};
    const auto select_second_part_op = LessOp<T>{large_threshold};

    // Allocate temporary storage
    void*  d_temp_storage     = nullptr;
    size_t temp_storage_bytes = 0;
    HIP_CHECK(
        hipcub::DevicePartition::If(
            nullptr,
            temp_storage_bytes,
            d_input,
            d_first_output,
            d_second_output,
            d_unselected_output,
            d_num_selected_output,
            static_cast<int>(input.size()),
            select_first_part_op,
            select_second_part_op,
            stream
        )
    );
    HIP_CHECK(hipMalloc(&d_temp_storage, temp_storage_bytes));

    // Warm-up
    HIP_CHECK(hipMemcpy(d_input, input.data(), input.size() * sizeof(T), hipMemcpyHostToDevice));
    for(unsigned int i = 0; i < warmup_size; ++i) {
        HIP_CHECK(
            hipcub::DevicePartition::If(
                d_temp_storage,
                temp_storage_bytes,
                d_input,
                d_first_output,
                d_second_output,
                d_unselected_output,
                d_num_selected_output,
                static_cast<int>(input.size()),
                select_first_part_op,
                select_second_part_op,
                stream
            )
        );
    }
    HIP_CHECK(hipDeviceSynchronize());

    // Run benchmark
    for(auto _ : state) {
        namespace chrono = std::chrono;
        using clock  = chrono::high_resolution_clock;

        const auto start = clock::now();
        for (unsigned int i = 0; i < batch_size; ++i) {
            HIP_CHECK(
                hipcub::DevicePartition::If(
                    d_temp_storage,
                    temp_storage_bytes,
                    d_input,
                    d_first_output,
                    d_second_output,
                    d_unselected_output,
                    d_num_selected_output,
                    static_cast<int>(input.size()),
                    select_first_part_op,
                    select_second_part_op,
                    stream
                )
            );
        }
        HIP_CHECK(hipDeviceSynchronize());

        const auto end = clock::now();
        using seconds_d = chrono::duration<double>;
        const auto elapsed_seconds = chrono::duration_cast<seconds_d>(end - start);

        state.SetIterationTime(elapsed_seconds.count());
    }

    state.SetItemsProcessed(state.iterations() * batch_size * input.size());
    state.SetBytesProcessed(
        static_cast<int64_t>(state.iterations() * batch_size * input.size() * sizeof(input[0])));

    HIP_CHECK(hipFree(d_input));
    HIP_CHECK(hipFree(d_first_output));
    HIP_CHECK(hipFree(d_second_output));
    HIP_CHECK(hipFree(d_unselected_output));
    HIP_CHECK(hipFree(d_num_selected_output));
}

#define CREATE_BENCHMARK(T, SMALL_T, LARGE_T)                                        \
benchmark::RegisterBenchmark(                                                        \
    "parition_three_way<" #T ">(" #SMALL_T "%, " #LARGE_T "%)",                       \
    &run_threeway<T>, stream, static_cast<T>(SMALL_T), static_cast<T>(LARGE_T), size \
)

#define BENCHMARK_TYPE(type)        \
    CREATE_BENCHMARK(type, 33, 66), \
    CREATE_BENCHMARK(type, 10, 66), \
    CREATE_BENCHMARK(type, 50, 60), \
    CREATE_BENCHMARK(type, 50, 90)

void add_benchmarks(std::vector<benchmark::internal::Benchmark*>& benchmarks,
                    const hipStream_t                             stream,
                    const size_t                                  size)
{
    using custom_float2 = benchmark_utils::custom_type<float, float>;
    using custom_double2 = benchmark_utils::custom_type<double, double>;

    const auto add = {
        BENCHMARK_TYPE(int8_t),
        BENCHMARK_TYPE(int),
        BENCHMARK_TYPE(float),
        BENCHMARK_TYPE(long long),
        BENCHMARK_TYPE(double),
        BENCHMARK_TYPE(custom_float2),
        BENCHMARK_TYPE(custom_double2)
    };
    benchmarks.insert(benchmarks.end(), add.begin(), add.end());
}

int main(int argc, char *argv[])
{
    cli::Parser parser(argc, argv);
    parser.set_optional<size_t>("size", "size", DEFAULT_N, "number of values");
    parser.set_optional<int>("trials", "trials", -1, "number of iterations");
    parser.run_and_exit_if_error();

    // Parse argv
    benchmark::Initialize(&argc, argv);
    const size_t size = parser.get<size_t>("size");
    const int trials = parser.get<int>("trials");

    // HIP
    const hipStream_t stream = 0; // default
    {
        hipDeviceProp_t devProp;
        int device_id = 0;
        HIP_CHECK(hipGetDevice(&device_id));
        HIP_CHECK(hipGetDeviceProperties(&devProp, device_id));
        std::cout << "[HIP] Device name: " << devProp.name << std::endl;
    }

    // Add benchmarks
    std::vector<benchmark::internal::Benchmark*> benchmarks;
    add_benchmarks(benchmarks, stream, size);

    // Use manual timing
    for(auto& b : benchmarks)
    {
        b->UseManualTime();
        b->Unit(benchmark::kMillisecond);
    }

    // Force number of iterations
    if(trials > 0)
    {
        for(auto& b : benchmarks)
        {
            b->Iterations(trials);
        }
    }

    // Run benchmarks
    benchmark::RunSpecifiedBenchmarks();
    return 0;
}