/*******************************************************************************
 * Copyright (c) 2015-2018 Skymind, Inc.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Apache License, Version 2.0 which is available at
 * https://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 * SPDX-License-Identifier: Apache-2.0
 ******************************************************************************/

//
// @author saudet
// @author raver119@gmail.com
//

#include <ops/declarable/PlatformHelper.h>
#include <ops/declarable/OpRegistrator.h>
#include <platform_boilerplate.h>

#include <helpers/MKLDNNStream.h>
#include "mkldnnUtils.h"
#include <ops/declarable/helpers/convolutions.h>

using namespace dnnl;

namespace nd4j      {
namespace ops       {
namespace platforms {

//////////////////////////////////////////////////////////////////////////
PLATFORM_IMPL(maxpool2d, ENGINE_CPU) {
    auto input = INPUT_VARIABLE(0);

    REQUIRE_TRUE(input->rankOf() == 4, 0, "Input should have rank of 4, but got %i instead",
                 input->rankOf());

    // 0,1 - kernel Height/Width; 2,3 - stride Height/Width; 4,5 - pad Height/Width; 6,7 - dilation Height/Width; 8 - same mode;
    auto argI = *(block.getIArguments());
    auto output = OUTPUT_VARIABLE(0);

    const auto kH = INT_ARG(0);
    const auto kW = INT_ARG(1);
    const auto sH = INT_ARG(2);
    const auto sW = INT_ARG(3);
    int pH = INT_ARG(4);
    int pW = INT_ARG(5);
    const auto dH = INT_ARG(6);
    const auto dW = INT_ARG(7);
    const auto isSameMode = static_cast<bool>(INT_ARG(8));

    REQUIRE_TRUE(dH != 0 && dW != 0, 0, "AVGPOOL2D op: dilation must not be zero, but got instead {%i, %i}",
                 dH, dW);

    int oH = 0;
    int oW = 0;

    int isNCHW = block.getIArguments()->size() > 10 ? !INT_ARG(10) : 1;       // INT_ARG(10): 0-NCHW, 1-NHWC

    const int iH = static_cast<int>(isNCHW ? input->sizeAt(2) : input->sizeAt(1));
    const int iW = static_cast<int>(isNCHW ? input->sizeAt(3) : input->sizeAt(2));

    if (!isNCHW) {
        input = new NDArray(
                input->permute({0, 3, 1, 2}));                // [bS, iH, iW, iC] -> [bS, iC, iH, iW]
        output = new NDArray(
                output->permute({0, 3, 1, 2}));               // [bS, oH, oW, iC] -> [bS, iC, oH, oW]
    }

    ConvolutionUtils::calcOutSizePool2D(oH, oW, kH, kW, sH, sW, pH, pW, dH, dW, iH, iW, isSameMode);

    if (isSameMode)
        ConvolutionUtils::calcPadding2D(pH, pW, oH, oW, iH, iW, kH, kW, sH, sW, dH, dW);

    const int bS = input->sizeAt(0);
    const int iC = input->sizeAt(1);
    const int oC = output->sizeAt(1);

    auto poolingMode = PoolingType::MAX_POOL;
    int extraParam0 = 1;

    dnnl_memory_desc_t empty;
    dnnl::memory::desc pool_src_md(empty), pool_dst_md(empty);
    dnnl::memory::desc user_src_md(empty), user_dst_md(empty);
    dnnl::memory::dims pool_strides, pool_kernel, pool_padding, pool_padding_r;
    dnnl::algorithm algorithm;

    mkldnnUtils::getMKLDNNMemoryDescPool2d(kH, kW, sH, sW, pH, pW, dH, dW, poolingMode, extraParam0,
                                               true,
                                               bS, iC, iH, iW, oC, oH, oW, input, nullptr, output,
                                               algorithm,
                                               &pool_src_md, nullptr, &pool_dst_md, &user_src_md, nullptr,
                                               &user_dst_md,
                                               pool_strides, pool_kernel, pool_padding, pool_padding_r);

    auto pool_desc = pooling_forward::desc(prop_kind::forward_inference, algorithm, pool_src_md,
                                               pool_dst_md,
                                               pool_strides, pool_kernel, pool_padding, pool_padding_r);

    auto engine = mkldnnUtils::getEngine(LaunchContext::defaultContext()->engine());
    auto pool_prim_desc = pooling_forward::primitive_desc(pool_desc, engine);
    auto user_src_memory = dnnl::memory(user_src_md, engine, input->buffer());
    auto user_dst_memory = dnnl::memory(user_dst_md, engine, output->buffer());

    auto pool_src_memory = user_src_memory;
    dnnl::stream stream(engine);
    if (pool_prim_desc.src_desc() != user_src_memory.get_desc()) {
        pool_src_memory = dnnl::memory(pool_prim_desc.src_desc(), engine);
        reorder(user_src_memory, pool_src_memory).execute(stream, user_src_memory, pool_src_memory);
    }

    auto pool_dst_memory = user_dst_memory;
    if (pool_prim_desc.dst_desc() != user_dst_memory.get_desc()) {
        pool_dst_memory = dnnl::memory(pool_prim_desc.dst_desc(), engine);
    }

    pooling_forward(pool_prim_desc).execute(stream, {{DNNL_ARG_SRC, pool_src_memory},
                                                         {DNNL_ARG_DST, pool_dst_memory}});

    if (pool_prim_desc.dst_desc() != user_dst_memory.get_desc()) {
        reorder(pool_dst_memory, user_dst_memory).execute(stream, pool_dst_memory, user_dst_memory);
    }

    stream.wait();

    if (!isNCHW) {
        delete input;
        delete output;
    }

    return Status::OK();
}

//////////////////////////////////////////////////////////////////////////
PLATFORM_CHECK(maxpool2d, ENGINE_CPU) {
    auto input = INPUT_VARIABLE(0);
    auto output = OUTPUT_VARIABLE(0);

    return block.isUseMKLDNN() && nd4j::MKLDNNStream::isSupported({input, output});
}

//////////////////////////////////////////////////////////////////////////
PLATFORM_IMPL(maxpool2d_bp, ENGINE_CPU) {

    auto input = INPUT_VARIABLE(0);                          // [bS, iH, iW, iC] (NHWC) or [bS, iC, iH, iW] (NCHW)
    auto gradO = INPUT_VARIABLE(1);                          // [bS, oH, oW, oC] (NHWC) or [bS, oC, oH, oW] (NCHW), epsilon_next
    auto gradI = OUTPUT_VARIABLE(0);                         // [bS, iH, iW, iC] (NHWC) or [bS, iC, iH, iW] (NCHW), epsilon

    int kH = INT_ARG(0);                                                        // filter(kernel) height
    int kW = INT_ARG(1);                                                        // filter(kernel) width
    int sH = INT_ARG(2);                                                        // strides height
    int sW = INT_ARG(3);                                                        // strides width
    int pH = INT_ARG(4);                                                        // paddings height
    int pW = INT_ARG(5);                                                        // paddings width
    int dH = INT_ARG(6);                                                        // dilations height
    int dW = INT_ARG(7);                                                        // dilations width
    int isSameMode = INT_ARG(8);                                                // 0-VALID, 1-SAME
    int extraParam0 = INT_ARG(9);
    int isNCHW =
            block.getIArguments()->size() > 10 ? !INT_ARG(10) : 1;         // INT_ARG(10): 0-NCHW, 1-NHWC

    REQUIRE_TRUE(input->rankOf() == 4, 0,
                 "AVGPOOL2D_BP op: input should have rank of 4, but got %i instead", input->rankOf());
    REQUIRE_TRUE(dH != 0 && dW != 0, 0,
                 "AVGPOOL2D_BP op: dilation must not be zero, but got instead {%i, %i}", dH, dW);

    int bS, iC, iH, iW, oC, oH, oW;                             // batch size, input channels, input height/width, output channels, output height/width;
    int indIOioC, indIiH, indWoC, indWiC, indWkH, indOoH;       // corresponding indexes
    ConvolutionUtils::getSizesAndIndexesConv2d(isNCHW, *input, *gradO, bS, iC, iH, iW, oC, oH, oW, indIOioC,
                                               indIiH, indWiC, indWoC, indWkH, indOoH);

    std::string expectedGradOShape = ShapeUtils::shapeAsString(
            ShapeUtils::composeShapeUsingDimsAndIdx({bS, iC, oH, oW, 0, indIOioC, indIiH, indIiH + 1}));
    std::string expectedGradIShape = ShapeUtils::shapeAsString(
            ShapeUtils::composeShapeUsingDimsAndIdx({bS, iC, iH, iW, 0, indIOioC, indIiH, indIiH + 1}));
    REQUIRE_TRUE(expectedGradOShape == ShapeUtils::shapeAsString(gradO), 0,
                 "AVGPOOL2D_BP op: wrong shape of output's gradients array (next epsilon), expected is %s, but got %s instead !",
                 expectedGradOShape.c_str(), ShapeUtils::shapeAsString(gradO).c_str());
    REQUIRE_TRUE(expectedGradIShape == ShapeUtils::shapeAsString(gradI), 0,
                 "AVGPOOL2D_BP op: wrong shape of input's gradients array (epsilon), expected is %s, but got %s instead !",
                 expectedGradIShape.c_str(), ShapeUtils::shapeAsString(gradI).c_str());


    if (!isNCHW) {
        input = new NDArray(input->permute(
                {0, 3, 1, 2}));                                   // [bS, iH, iW, iC] -> [bS, iC, iH, iW]
        gradI = new NDArray(gradI->permute(
                {0, 3, 1, 2}));                                   // [bS, iH, iW, iC] -> [bS, iC, iH, iW]
        gradO = new NDArray(gradO->permute(
                {0, 3, 1, 2}));                                   // [bS, oH, oW, iC] -> [bS, iC, oH, oW]
    }

    if (isSameMode)                       // SAME
        ConvolutionUtils::calcPadding2D(pH, pW, oH, oW, iH, iW, kH, kW, sH, sW, dH, dW);

    auto poolingMode = PoolingType::MAX_POOL;

    dnnl_memory_desc_t empty;
    dnnl::memory::desc pool_src_md(empty), pool_diff_src_md(empty), pool_dst_md(empty);
    dnnl::memory::desc user_src_md(empty), user_diff_src_md(empty), user_dst_md(empty);
    dnnl::memory::dims pool_strides, pool_kernel, pool_padding, pool_padding_r;
    dnnl::algorithm algorithm;

    mkldnnUtils::getMKLDNNMemoryDescPool2d(kH, kW, sH, sW, pH, pW, dH, dW, poolingMode, extraParam0,
                                               true,
                                               bS, iC, iH, iW, oC, oH, oW, input, gradI, gradO, algorithm,
                                               &pool_src_md, &pool_diff_src_md, &pool_dst_md, &user_src_md,
                                               &user_diff_src_md, &user_dst_md,
                                               pool_strides, pool_kernel, pool_padding, pool_padding_r);

    // input is sometimes null, so we can't rely on pool_src_md being valid
    auto pool_desc = pooling_forward::desc(prop_kind::forward, algorithm,
                                               input->buffer() != nullptr ? pool_src_md : pool_diff_src_md,
                                               pool_dst_md, pool_strides, pool_kernel, pool_padding,
                                               pool_padding_r);

    auto engine = mkldnnUtils::getEngine(LaunchContext::defaultContext()->engine());
    dnnl::stream stream(engine);
    auto pool_prim_desc = pooling_forward::primitive_desc(pool_desc, engine);

    auto poolB_desc = pooling_backward::desc(algorithm, pool_diff_src_md, pool_dst_md,
                                                 pool_strides, pool_kernel, pool_padding, pool_padding_r);

    auto poolB_prim_desc = pooling_backward::primitive_desc(poolB_desc, engine, pool_prim_desc);
    auto userB_src_memory = dnnl::memory(user_src_md, engine, gradI->buffer());
    auto userB_dst_memory = dnnl::memory(user_dst_md, engine, gradO->buffer());

    auto poolB_src_memory = userB_src_memory;
    if (poolB_prim_desc.diff_src_desc() != userB_src_memory.get_desc()) {
        poolB_src_memory = dnnl::memory(poolB_prim_desc.diff_src_desc(), engine);
    }

    auto poolB_dst_memory = userB_dst_memory;
    if (poolB_prim_desc.diff_dst_desc() != userB_dst_memory.get_desc()) {
        poolB_dst_memory = dnnl::memory(poolB_prim_desc.diff_dst_desc(), engine);
        reorder(userB_dst_memory, poolB_dst_memory).execute(stream, userB_dst_memory, poolB_dst_memory);
    }

    auto user_src_memory = dnnl::memory(user_src_md, engine, input->buffer());
    auto pool_src_memory = user_src_memory;
    if (pool_prim_desc.src_desc() != user_src_memory.get_desc()) {
        pool_src_memory = dnnl::memory(pool_prim_desc.src_desc(), engine);
        reorder(user_src_memory, pool_src_memory).execute(stream, user_src_memory, pool_src_memory);
    }

    auto pool_dst_memory = dnnl::memory(pool_prim_desc.dst_desc(), engine);
    auto pool_workspace_memory = dnnl::memory(pool_prim_desc.workspace_desc(), engine);

    pooling_forward(pool_prim_desc).execute(stream, {{DNNL_ARG_SRC,       pool_src_memory},
                                                         {DNNL_ARG_DST,       pool_dst_memory},
                                                         {DNNL_ARG_WORKSPACE, pool_workspace_memory}});
    // probably wrong, fix that
    pooling_backward(poolB_prim_desc).execute(stream, {{DNNL_ARG_DIFF_DST,  poolB_dst_memory},
                                                           {DNNL_ARG_WORKSPACE, pool_workspace_memory},
                                                           {DNNL_ARG_DIFF_SRC,  poolB_src_memory}});

    if (poolB_prim_desc.diff_src_desc() != userB_src_memory.get_desc()) {
        reorder(poolB_src_memory, userB_src_memory).execute(stream, poolB_src_memory, userB_src_memory);
    }

    stream.wait();

    if (!isNCHW) {
        delete input;
        delete gradI;
        delete gradO;
    }

    return Status::OK();
}

PLATFORM_CHECK(maxpool2d_bp, ENGINE_CPU) {
    auto input = INPUT_VARIABLE(0);
    auto output = OUTPUT_VARIABLE(0);

    return block.isUseMKLDNN() && nd4j::MKLDNNStream::isSupported({input, output});
}

}
}
}