// MIT License
//
// Copyright (c) 2017 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 <algorithm>
#include <functional>
#include <iostream>
#include <random>
#include <type_traits>
#include <vector>
#include <utility>

// Google Test
#include <gtest/gtest.h>
// HIP API
#include <hip/hip_runtime.h>
// rocPRIM API
#include <rocprim/rocprim.hpp>

#include "test_utils.hpp"

#define HIP_CHECK(error)         \
    ASSERT_EQ(static_cast<hipError_t>(error),hipSuccess)

namespace rp = rocprim;

template<
    class Input,
    class Output,
    class ReduceOp = ::rocprim::plus<Input>,
    int Init = 0, // as only integral types supported, int is used here even for floating point inputs
    unsigned int MinSegmentLength = 0,
    unsigned int MaxSegmentLength = 1000,
    // Tests output iterator with void value_type (OutputIterator concept)
    bool UseIdentityIterator = false
>
struct params
{
    using input_type = Input;
    using output_type = Output;
    using reduce_op_type = ReduceOp;
    static constexpr int init = Init;
    static constexpr unsigned int min_segment_length = MinSegmentLength;
    static constexpr unsigned int max_segment_length = MaxSegmentLength;
    static constexpr bool use_identity_iterator = UseIdentityIterator;
};

template<class Params>
class RocprimDeviceSegmentedReduce : public ::testing::Test {
public:
    using params = Params;
};

using custom_short2 = test_utils::custom_test_type<short>;
using custom_int2 = test_utils::custom_test_type<int>;
using custom_double2 = test_utils::custom_test_type<double>;

typedef ::testing::Types<
    params<unsigned char, unsigned int, rp::plus<unsigned int>>,
    params<int, int, rp::plus<int>, -100, 0, 10000>,
    params<double, double, rp::minimum<double>, 1000, 0, 10000>,
    params<int8_t, int8_t, rp::maximum<int8_t>, 0, 0, 2000>,
    params<uint8_t, uint8_t, rp::plus<uint8_t>, 10, 1000, 10000>,
    params<uint8_t, uint8_t, rp::maximum<uint8_t>, 50, 2, 10>,
    params<rp::half, rp::half, test_utils::half_maximum, 0, 1000, 2000>,
    params<rp::half, rp::half, test_utils::half_plus, 50, 2, 10>,
    params<custom_short2, custom_int2, rp::plus<custom_int2>, 10, 1000, 10000>,
    params<custom_double2, custom_double2, rp::maximum<custom_double2>, 50, 2, 10>,
    params<float, float, rp::plus<float>, 123, 100, 200>,
    params<unsigned char, long long, rp::plus<int>, 10, 3000, 4000>,
#ifndef __HIP__
    // hip-clang does not allow to convert half to float
    params<rp::half, float, rp::plus<float>, 0, 10, 300>,
#endif
    params<rp::half, rp::half, test_utils::half_minimum, 0, 1000, 30000>
> Params;

TYPED_TEST_CASE(RocprimDeviceSegmentedReduce, Params);

std::vector<size_t> get_sizes()
{
    std::vector<size_t> sizes = {
        1024, 2048, 4096, 1792,
        1, 10, 53, 211, 500,
        2345, 11001, 34567,
        100000,
        (1 << 16) - 1220
    };
    const std::vector<size_t> random_sizes = test_utils::get_random_data<size_t>(5, 1, 1000000);
    sizes.insert(sizes.end(), random_sizes.begin(), random_sizes.end());
    return sizes;
}

TYPED_TEST(RocprimDeviceSegmentedReduce, Reduce)
{
    using input_type = typename TestFixture::params::input_type;
    using output_type = typename TestFixture::params::output_type;
    using reduce_op_type = typename TestFixture::params::reduce_op_type;
    constexpr bool use_identity_iterator = TestFixture::params::use_identity_iterator;

    using result_type = output_type;
    using offset_type = unsigned int;

    const input_type init = TestFixture::params::init;
    const bool debug_synchronous = false;
    reduce_op_type reduce_op;

    std::random_device rd;
    std::default_random_engine gen(rd());
    std::uniform_int_distribution<size_t> segment_length_dis(
        TestFixture::params::min_segment_length,
        TestFixture::params::max_segment_length
    );

    for(size_t size : get_sizes())
    {
        SCOPED_TRACE(testing::Message() << "with size = " << size);

        hipStream_t stream = 0; // default

        // Generate data and calculate expected results
        std::vector<output_type> aggregates_expected;

        std::vector<input_type> values_input = test_utils::get_random_data<input_type>(size, 0, 100);

        std::vector<offset_type> offsets;
        unsigned int segments_count = 0;
        size_t offset = 0;
        while(offset < size)
        {
            const size_t segment_length = segment_length_dis(gen);
            offsets.push_back(offset);

            const size_t end = std::min(size, offset + segment_length);
            result_type aggregate = init;
            for(size_t i = offset; i < end; i++)
            {
                aggregate = reduce_op(aggregate, values_input[i]);
            }
            aggregates_expected.push_back(aggregate);

            segments_count++;
            offset += segment_length;
        }
        offsets.push_back(size);

        input_type * d_values_input;
        HIP_CHECK(hipMalloc(&d_values_input, size * sizeof(input_type)));
        HIP_CHECK(
            hipMemcpy(
                d_values_input, values_input.data(),
                size * sizeof(input_type),
                hipMemcpyHostToDevice
            )
        );

        offset_type * d_offsets;
        HIP_CHECK(hipMalloc(&d_offsets, (segments_count + 1) * sizeof(offset_type)));
        HIP_CHECK(
            hipMemcpy(
                d_offsets, offsets.data(),
                (segments_count + 1) * sizeof(offset_type),
                hipMemcpyHostToDevice
            )
        );

        output_type * d_aggregates_output;
        HIP_CHECK(hipMalloc(&d_aggregates_output, segments_count * sizeof(output_type)));

        size_t temporary_storage_bytes;

        HIP_CHECK(
            rp::segmented_reduce(
                nullptr, temporary_storage_bytes,
                d_values_input, d_aggregates_output,
                segments_count,
                d_offsets, d_offsets + 1,
                reduce_op, init,
                stream, debug_synchronous
            )
        );

        ASSERT_GT(temporary_storage_bytes, 0);

        void * d_temporary_storage;
        HIP_CHECK(hipMalloc(&d_temporary_storage, temporary_storage_bytes));

        HIP_CHECK(
            rp::segmented_reduce(
                d_temporary_storage, temporary_storage_bytes,
                d_values_input,
                test_utils::wrap_in_identity_iterator<use_identity_iterator>(d_aggregates_output),
                segments_count,
                d_offsets, d_offsets + 1,
                reduce_op, init,
                stream, debug_synchronous
            )
        );

        HIP_CHECK(hipFree(d_temporary_storage));

        std::vector<output_type> aggregates_output(segments_count);
        HIP_CHECK(
            hipMemcpy(
                aggregates_output.data(), d_aggregates_output,
                segments_count * sizeof(output_type),
                hipMemcpyDeviceToHost
            )
        );

        HIP_CHECK(hipFree(d_values_input));
        HIP_CHECK(hipFree(d_offsets));
        HIP_CHECK(hipFree(d_aggregates_output));

        ASSERT_NO_FATAL_FAILURE(test_utils::assert_near(aggregates_output, aggregates_expected, 0.01f));
    }
}