// SPDX-License-Identifier: MIT
// Copyright (c) 2018-2022, Advanced Micro Devices, Inc. All rights reserved.

#pragma once

#include <iostream>
#include <sstream>

#include "ck/tensor_operation/gpu/device/device_base.hpp"

#include "ck/library/utility/host_tensor.hpp"

namespace ck {
namespace tensor_operation {
namespace host {

template <ck::index_t NDimSpatial,
          typename InLayout,
          typename WeiLayout,
          typename OutLayout,
          typename InDataType,
          typename WeiDataType,
          typename OutDataType,
          typename InElementwiseOperation,
          typename WeiElementwiseOperation,
          typename OutElementwiseOperation,
          typename std::enable_if<NDimSpatial >= 1 && NDimSpatial <= 3, bool>::type = false>
struct ReferenceConvBwdData : public device::BaseOperator
{
    // Argument
    struct Argument : public device::BaseArgument
    {
        Argument(Tensor<InDataType>& input,
                 const Tensor<WeiDataType>& weight,
                 const Tensor<OutDataType>& output,
                 std::vector<ck::index_t> conv_filter_strides,
                 std::vector<ck::index_t> conv_filter_dilations,
                 std::vector<ck::index_t> input_left_pads,
                 std::vector<ck::index_t> input_right_pads,
                 InElementwiseOperation in_element_op,
                 WeiElementwiseOperation wei_element_op,
                 OutElementwiseOperation out_element_op)
            : input_{input},
              weight_{weight},
              output_{output},
              conv_strides_{conv_filter_strides},
              conv_dilations_{conv_filter_dilations},
              in_left_pads_{input_left_pads},
              in_right_pads_{input_right_pads},
              in_element_op_{in_element_op},
              wei_element_op_{wei_element_op},
              out_element_op_{out_element_op}
        {
        }

        Tensor<InDataType>& input_;
        const Tensor<WeiDataType>& weight_;
        const Tensor<OutDataType>& output_;

        std::vector<index_t> conv_strides_;
        std::vector<index_t> conv_dilations_;
        std::vector<index_t> in_left_pads_;
        std::vector<index_t> in_right_pads_;

        InElementwiseOperation in_element_op_;
        WeiElementwiseOperation wei_element_op_;
        OutElementwiseOperation out_element_op_;
    };

    // Invoker
    struct Invoker : public device::BaseInvoker
    {
        using Argument = ReferenceConvBwdData::Argument;

        // FIXME: properly implement "TensorView" for doing transpose or refer to dimension by name
        float Run(const Argument& arg)
        {
            // tensor descriptor in NCHW/KXYC/NKHW dimensional order
            HostTensorDescriptor in_desc  = arg.input_.mDesc;
            HostTensorDescriptor wei_desc = arg.weight_.mDesc;
            HostTensorDescriptor out_desc = arg.output_.mDesc;

            // input
            if constexpr(is_same_v<InLayout, ck::tensor_layout::convolution::NWC>)
            {
                in_desc = transpose_host_tensor_descriptor_given_new2old(
                    in_desc, std::vector<std::size_t>{0, 2, 1});
            }
            else if constexpr(is_same_v<InLayout, ck::tensor_layout::convolution::NHWC>)
            {
                in_desc = transpose_host_tensor_descriptor_given_new2old(
                    in_desc, std::vector<std::size_t>{0, 3, 1, 2});
            }
            else if constexpr(is_same_v<InLayout, ck::tensor_layout::convolution::NDHWC>)
            {
                in_desc = transpose_host_tensor_descriptor_given_new2old(
                    in_desc, std::vector<std::size_t>{0, 4, 1, 2, 3});
            }

            // weight
            if constexpr(is_same_v<WeiLayout, ck::tensor_layout::convolution::KXC>)
            {
                wei_desc = transpose_host_tensor_descriptor_given_new2old(
                    wei_desc, std::vector<std::size_t>{0, 2, 1});
            }
            else if constexpr(is_same_v<WeiLayout, ck::tensor_layout::convolution::KYXC>)
            {
                wei_desc = transpose_host_tensor_descriptor_given_new2old(
                    wei_desc, std::vector<std::size_t>{0, 3, 1, 2});
            }
            else if constexpr(is_same_v<WeiLayout, ck::tensor_layout::convolution::KZYXC>)
            {
                wei_desc = transpose_host_tensor_descriptor_given_new2old(
                    wei_desc, std::vector<std::size_t>{0, 4, 1, 2, 3});
            }

            // output
            if constexpr(is_same_v<OutLayout, ck::tensor_layout::convolution::NWK>)
            {
                out_desc = transpose_host_tensor_descriptor_given_new2old(
                    out_desc, std::vector<std::size_t>{0, 2, 1});
            }
            else if constexpr(is_same_v<OutLayout, ck::tensor_layout::convolution::NHWK>)
            {
                out_desc = transpose_host_tensor_descriptor_given_new2old(
                    out_desc, std::vector<std::size_t>{0, 3, 1, 2});
            }
            else if constexpr(is_same_v<OutLayout, ck::tensor_layout::convolution::NDHWK>)
            {
                out_desc = transpose_host_tensor_descriptor_given_new2old(
                    out_desc, std::vector<std::size_t>{0, 4, 1, 2, 3});
            }

            if constexpr(NDimSpatial == 1)
            {
                auto f_ncw = [&](auto n, auto c, auto wi) {
                    std::size_t K  = wei_desc.GetLengths()[0];
                    std::size_t X  = wei_desc.GetLengths()[2];
                    std::size_t Wo = out_desc.GetLengths()[2];

                    float v_acc = 0;

                    for(std::size_t x = 0; x < X; ++x)
                    {
                        auto w_tmp = ck::type_convert<ck::long_index_t>(wi) +
                                     ck::type_convert<ck::long_index_t>(arg.in_left_pads_[0]) -
                                     ck::type_convert<ck::long_index_t>(x * arg.conv_dilations_[0]);

                        if(w_tmp % arg.conv_strides_[0] == 0)
                        {
                            auto wo = ck::type_convert<ck::long_index_t>(w_tmp) /
                                      ck::type_convert<ck::long_index_t>(arg.conv_strides_[0]);

                            if(wo >= 0 && ck::type_convert<std::size_t>(wo) < Wo)
                            {
                                for(std::size_t k = 0; k < K; ++k)
                                {
                                    float v_out = 0;
                                    float v_wei = 0;

                                    // FIXME hacky
                                    arg.out_element_op_(
                                        v_out,
                                        ck::type_convert<float>(
                                            arg.output_.mData[out_desc.GetOffsetFromMultiIndex(
                                                n, k, wo)]));

                                    // FIXME hacky
                                    arg.wei_element_op_(
                                        v_wei,
                                        ck::type_convert<float>(
                                            arg.weight_
                                                .mData[wei_desc.GetOffsetFromMultiIndex(k, c, x)]));

                                    v_acc += v_out * v_wei;
                                }
                            }
                        }
                    }

                    float v_in;

                    arg.in_element_op_(v_in, v_acc);

                    // FIXME hacky
                    arg.input_.mData[in_desc.GetOffsetFromMultiIndex(n, c, wi)] =
                        ck::type_convert<InDataType>(v_acc);
                };

                make_ParallelTensorFunctor(f_ncw,
                                           in_desc.GetLengths()[0],
                                           in_desc.GetLengths()[1],
                                           in_desc.GetLengths()[2])(
                    std::thread::hardware_concurrency());

                return 0;
            }
            else if constexpr(NDimSpatial == 2)
            {
                auto f_nchw = [&](auto n, auto c, auto hi, auto wi) {
                    std::size_t K = wei_desc.GetLengths()[0];
                    std::size_t Y = wei_desc.GetLengths()[2];
                    std::size_t X = wei_desc.GetLengths()[3];

                    std::size_t Ho = out_desc.GetLengths()[2];
                    std::size_t Wo = out_desc.GetLengths()[3];

                    float v_acc = 0;

                    for(std::size_t y = 0; y < Y; ++y)
                    {
                        auto h_tmp = ck::type_convert<ck::long_index_t>(hi) +
                                     ck::type_convert<ck::long_index_t>(arg.in_left_pads_[0]) -
                                     ck::type_convert<ck::long_index_t>(y * arg.conv_dilations_[0]);
                        if(h_tmp % arg.conv_strides_[0] == 0)
                        {
                            auto ho = ck::type_convert<ck::long_index_t>(h_tmp) /
                                      ck::type_convert<ck::long_index_t>(arg.conv_strides_[0]);
                            if(ho >= 0 && ck::type_convert<std::size_t>(ho) < Ho)
                            {
                                for(std::size_t x = 0; x < X; ++x)
                                {
                                    auto w_tmp =
                                        ck::type_convert<ck::long_index_t>(wi) +
                                        ck::type_convert<ck::long_index_t>(arg.in_left_pads_[1]) -
                                        ck::type_convert<ck::long_index_t>(x *
                                                                           arg.conv_dilations_[1]);
                                    if(w_tmp % arg.conv_strides_[1] == 0)
                                    {
                                        auto wo = ck::type_convert<ck::long_index_t>(w_tmp) /
                                                  ck::type_convert<ck::long_index_t>(
                                                      arg.conv_strides_[1]);
                                        if(wo >= 0 && ck::type_convert<std::size_t>(wo) < Wo)
                                        {
                                            for(std::size_t k = 0; k < K; ++k)
                                            {
                                                float v_out = 0;
                                                float v_wei = 0;

                                                // FIXME hacky
                                                arg.out_element_op_(
                                                    v_out,
                                                    ck::type_convert<float>(
                                                        arg.output_
                                                            .mData[out_desc.GetOffsetFromMultiIndex(
                                                                n, k, ho, wo)]));

                                                // FIXME hacky
                                                arg.wei_element_op_(
                                                    v_wei,
                                                    ck::type_convert<float>(
                                                        arg.weight_
                                                            .mData[wei_desc.GetOffsetFromMultiIndex(
                                                                k, c, y, x)]));

                                                v_acc += v_out * v_wei;
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }

                    float v_in;

                    arg.in_element_op_(v_in, v_acc);

                    // FIXME hacky
                    arg.input_.mData[in_desc.GetOffsetFromMultiIndex(n, c, hi, wi)] =
                        ck::type_convert<InDataType>(v_acc);
                };

                make_ParallelTensorFunctor(f_nchw,
                                           in_desc.GetLengths()[0],
                                           in_desc.GetLengths()[1],
                                           in_desc.GetLengths()[2],
                                           in_desc.GetLengths()[3])(
                    std::thread::hardware_concurrency());

                return 0;
            }
            else if constexpr(NDimSpatial == 3)
            {
                auto f_ncdhw = [&](auto n, auto c, auto di, auto hi, auto wi) {
                    std::size_t K = wei_desc.GetLengths()[0];
                    std::size_t Z = wei_desc.GetLengths()[2];
                    std::size_t Y = wei_desc.GetLengths()[3];
                    std::size_t X = wei_desc.GetLengths()[4];

                    std::size_t Do = out_desc.GetLengths()[2];
                    std::size_t Ho = out_desc.GetLengths()[3];
                    std::size_t Wo = out_desc.GetLengths()[4];

                    float v_acc = 0;

                    for(std::size_t z = 0; z < Z; ++z)
                    {
                        auto d_tmp = ck::type_convert<ck::long_index_t>(di) +
                                     ck::type_convert<ck::long_index_t>(arg.in_left_pads_[0]) -
                                     ck::type_convert<ck::long_index_t>(z * arg.conv_dilations_[0]);
                        if(d_tmp % arg.conv_strides_[0] == 0)
                        {
                            auto do_ = ck::type_convert<ck::long_index_t>(d_tmp) /
                                       ck::type_convert<ck::long_index_t>(arg.conv_strides_[0]);
                            if(do_ >= 0 && ck::type_convert<std::size_t>(do_) < Do)
                            {
                                for(std::size_t y = 0; y < Y; ++y)
                                {
                                    auto h_tmp =
                                        ck::type_convert<ck::long_index_t>(hi) +
                                        ck::type_convert<ck::long_index_t>(arg.in_left_pads_[1]) -
                                        ck::type_convert<ck::long_index_t>(y *
                                                                           arg.conv_dilations_[1]);
                                    if(h_tmp % arg.conv_strides_[1] == 0)
                                    {
                                        auto ho = ck::type_convert<ck::long_index_t>(h_tmp) /
                                                  ck::type_convert<ck::long_index_t>(
                                                      arg.conv_strides_[1]);
                                        if(ho >= 0 && ck::type_convert<std::size_t>(ho) < Ho)
                                        {
                                            for(std::size_t x = 0; x < X; ++x)
                                            {
                                                auto w_tmp =
                                                    ck::type_convert<ck::long_index_t>(wi) +
                                                    ck::type_convert<ck::long_index_t>(
                                                        arg.in_left_pads_[2]) -
                                                    ck::type_convert<ck::long_index_t>(
                                                        x * arg.conv_dilations_[2]);

                                                if(w_tmp % arg.conv_strides_[2] == 0)
                                                {
                                                    auto wo =
                                                        ck::type_convert<ck::long_index_t>(w_tmp) /
                                                        ck::type_convert<ck::long_index_t>(
                                                            arg.conv_strides_[2]);
                                                    if(wo >= 0 &&
                                                       ck::type_convert<std::size_t>(wo) < Wo)
                                                    {
                                                        for(std::size_t k = 0; k < K; ++k)
                                                        {
                                                            float v_out = 0;
                                                            float v_wei = 0;

                                                            // FIXME hacky
                                                            arg.out_element_op_(
                                                                v_out,
                                                                ck::type_convert<float>(
                                                                    arg.output_.mData
                                                                        [out_desc
                                                                             .GetOffsetFromMultiIndex(
                                                                                 n,
                                                                                 k,
                                                                                 do_,
                                                                                 ho,
                                                                                 wo)]));

                                                            // FIXME hacky
                                                            arg.wei_element_op_(
                                                                v_wei,
                                                                ck::type_convert<float>(
                                                                    arg.weight_.mData
                                                                        [wei_desc
                                                                             .GetOffsetFromMultiIndex(
                                                                                 k, c, z, y, x)]));

                                                            v_acc += v_out * v_wei;
                                                        }
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }

                    float v_in;

                    arg.in_element_op_(v_in, v_acc);

                    // FIXME hacky
                    arg.input_.mData[in_desc.GetOffsetFromMultiIndex(n, c, wi)] =
                        ck::type_convert<InDataType>(v_acc);
                };

                make_ParallelTensorFunctor(f_ncdhw,
                                           in_desc.GetLengths()[0],
                                           in_desc.GetLengths()[1],
                                           in_desc.GetLengths()[2],
                                           in_desc.GetLengths()[3],
                                           in_desc.GetLengths()[4])(
                    std::thread::hardware_concurrency());

                return 0;
            }
        }

        float Run(const device::BaseArgument* p_arg,
                  const StreamConfig& /* stream_config */ = StreamConfig{}) override
        {
            return Run(*dynamic_cast<const Argument*>(p_arg));
        }
    };

    static constexpr bool IsValidCompilationParameter()
    {
        // TODO: properly implement this check
        return true;
    }

    bool IsSupportedArgument(const device::BaseArgument*) override { return true; }

    static auto MakeArgument(Tensor<InDataType>& input,
                             const Tensor<WeiDataType>& weight,
                             const Tensor<OutDataType>& output,
                             std::vector<ck::index_t> conv_filter_strides,
                             std::vector<ck::index_t> conv_filter_dilations,
                             std::vector<ck::index_t> input_left_pads,
                             std::vector<ck::index_t> input_right_pads,
                             InElementwiseOperation in_element_op,
                             WeiElementwiseOperation wei_element_op,
                             OutElementwiseOperation out_element_op)
    {
        return Argument{input,
                        weight,
                        output,
                        conv_filter_strides,
                        conv_filter_dilations,
                        input_left_pads,
                        input_right_pads,
                        in_element_op,
                        wei_element_op,
                        out_element_op};
    }

    static auto MakeInvoker() { return Invoker{}; }

    virtual std::unique_ptr<device::BaseInvoker> MakeInvokerPointer()
    {
        return std::make_unique<Invoker>(Invoker{});
    }

    std::string GetTypeString() const override
    {
        auto str = std::stringstream();

        // clang-format off
        str << "ReferenceConvBwdData"
            << std::endl;
        // clang-format on

        return str.str();
    }
};

} // namespace host
} // namespace tensor_operation
} // namespace ck
