/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://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. */

#include "paddle/fluid/inference/tensorrt/convert/op_converter.h"

namespace nvinfer1 {
class IScaleLayer;
}  // namespace nvinfer1
namespace paddle {
namespace framework {
class Scope;

namespace proto {
class OpDesc;
}  // namespace proto
}  // namespace framework
}  // namespace paddle

namespace paddle {
namespace inference {
namespace tensorrt {

class BatchNormOpConverter : public OpConverter {
 public:
  void operator()(const framework::proto::OpDesc& op,
                  const framework::Scope& scope, bool test_mode) override {
    VLOG(3) << "convert a fluid batch norm op to tensorrt batch_norm";

    framework::OpDesc op_desc(op, nullptr);
    auto* X = engine_->GetITensor(op_desc.Input("X").front());
    // Declare weights
    auto* Bias_v = scope.FindVar(op_desc.Input("Bias").front());
    auto* Mean_v = scope.FindVar(op_desc.Input("Mean").front());
    auto* Scale_v = scope.FindVar(op_desc.Input("Scale").front());
    auto* Variance_v = scope.FindVar(op_desc.Input("Variance").front());
    const float eps = BOOST_GET_CONST(float, op_desc.GetAttr("epsilon"));

    PADDLE_ENFORCE_NOT_NULL(
        Bias_v,
        platform::errors::NotFound(
            "Variable of Bias of batch_norm TRT converter is not found."));
    PADDLE_ENFORCE_NOT_NULL(
        Mean_v,
        platform::errors::NotFound(
            "Variable of Mean of batch_norm TRT converter is not found."));
    PADDLE_ENFORCE_NOT_NULL(
        Scale_v,
        platform::errors::NotFound(
            "Variable of Scale of batch_norm TRT converter is not found."));
    PADDLE_ENFORCE_NOT_NULL(
        Variance_v,
        platform::errors::NotFound(
            "Variable of Variance of batch_norm TRT converter is not found."));

    // get tensor
    auto* Bias_t = Bias_v->GetMutable<framework::LoDTensor>();
    auto* Mean_t = Mean_v->GetMutable<framework::LoDTensor>();
    auto* Scale_t = Scale_v->GetMutable<framework::LoDTensor>();
    auto* Variance_t = Variance_v->GetMutable<framework::LoDTensor>();

    // create temp tensor for weights
    framework::LoDTensor bias_tensor;
    framework::LoDTensor mean_tensor;
    framework::LoDTensor scale_tensor;
    framework::LoDTensor variance_tensor;

    bias_tensor.Resize(Bias_t->dims());
    mean_tensor.Resize(Mean_t->dims());
    scale_tensor.Resize(Scale_t->dims());
    variance_tensor.Resize(Variance_t->dims());

    platform::CPUPlace cpu_place;
    // copy data from gpu to cpu
    TensorCopySync((*Bias_t), cpu_place, &bias_tensor);
    TensorCopySync((*Mean_t), cpu_place, &mean_tensor);
    TensorCopySync((*Scale_t), cpu_place, &scale_tensor);
    TensorCopySync((*Variance_t), cpu_place, &variance_tensor);

    auto* bias_data = bias_tensor.mutable_data<float>(platform::CPUPlace());
    auto* mean_data = mean_tensor.mutable_data<float>(platform::CPUPlace());
    auto* scale_data = scale_tensor.mutable_data<float>(platform::CPUPlace());
    auto* variance_data =
        variance_tensor.mutable_data<float>(platform::CPUPlace());

    std::unique_ptr<framework::LoDTensor> combile_scale_tensor(
        new framework::LoDTensor());
    std::unique_ptr<framework::LoDTensor> combile_bias_tensor(
        new framework::LoDTensor());

    combile_scale_tensor->Resize(scale_tensor.dims());
    combile_bias_tensor->Resize(bias_tensor.dims());

    auto* combile_scale_data =
        combile_scale_tensor->mutable_data<float>(platform::CPUPlace());
    auto* combile_bias_data =
        combile_bias_tensor->mutable_data<float>(platform::CPUPlace());

    size_t ele_num = combile_scale_tensor->memory_size() / sizeof(float);

    for (size_t i = 0; i < ele_num; i++) {
      float scale = scale_data[i];
      float bias = bias_data[i];
      float mean = mean_data[i];
      float variance = variance_data[i];
      combile_scale_data[i] = scale / sqrtf(variance + eps);
      combile_bias_data[i] = bias - mean * combile_scale_data[i];
    }

    TensorRTEngine::Weight scale_weights{
        nvinfer1::DataType::kFLOAT, static_cast<void*>(combile_scale_data),
        combile_scale_tensor->memory_size() / sizeof(float)};
    TensorRTEngine::Weight shift_weights{
        nvinfer1::DataType::kFLOAT, static_cast<void*>(combile_bias_data),
        combile_bias_tensor->memory_size() / sizeof(float)};
    TensorRTEngine::Weight power_weights{nvinfer1::DataType::kFLOAT, nullptr,
                                         0};

    int dynamic_shape_offset = engine_->with_dynamic_shape() ? 1 : 0;
    nvinfer1::ILayer* layer = nullptr;
    nvinfer1::IShuffleLayer* expand_layer = nullptr;
    nvinfer1::IShuffleLayer* squeeze_layer = nullptr;

    auto x_dim = X->getDimensions();
    if (x_dim.nbDims < 3 + dynamic_shape_offset) {
      nvinfer1::Dims expand_shape;
      expand_shape.nbDims = 3 + dynamic_shape_offset;
      for (int i = 0; i < 3 + dynamic_shape_offset; i++) {
        if (i < x_dim.nbDims) {
          expand_shape.d[i] = x_dim.d[i] < 0 ? 0 : x_dim.d[i];
        } else {
          expand_shape.d[i] = 1;
        }
      }
      expand_layer = TRT_ENGINE_ADD_LAYER(engine_, Shuffle, *X);
      expand_layer->setReshapeDimensions(expand_shape);
      X = expand_layer->getOutput(0);
    }

    layer = TRT_ENGINE_ADD_LAYER(engine_, ScaleNd, *X,
                                 nvinfer1::ScaleMode::kCHANNEL,
                                 shift_weights.get(), scale_weights.get(),
                                 power_weights.get(), dynamic_shape_offset);

    auto output_name = op_desc.Output("Y").front();
    engine_->SetWeights(op_desc.Input("Bias").front(),
                        std::move(combile_bias_tensor));
    engine_->SetWeights(op_desc.Input("Scale").front(),
                        std::move(combile_scale_tensor));
    if (x_dim.nbDims < 3 + dynamic_shape_offset) {
      nvinfer1::Dims squeeze_shape;
      squeeze_shape.nbDims = x_dim.nbDims;
      for (int i = 0; i < squeeze_shape.nbDims; i++) {
        squeeze_shape.d[i] = x_dim.d[i] < 0 ? 0 : x_dim.d[i];
      }
      squeeze_layer =
          TRT_ENGINE_ADD_LAYER(engine_, Shuffle, *(layer->getOutput(0)));
      squeeze_layer->setReshapeDimensions(squeeze_shape);
      layer = static_cast<nvinfer1::ILayer*>(squeeze_layer);
    }
    RreplenishLayerAndOutput(layer, "batchnorm_add_scale", {output_name},
                             test_mode);
  }
};

}  // namespace tensorrt
}  // namespace inference
}  // namespace paddle

REGISTER_TRT_OP_CONVERTER(batch_norm, BatchNormOpConverter);
