// Copyright (c) 2019 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 "lite/operators/conv_transpose_op.h"
#include <memory>
#include "lite/core/op_lite.h"
#include "lite/core/op_registry.h"

namespace paddle {
namespace lite {
namespace operators {

bool ConvTransposeOpLite::CheckShape() const {
  CHECK_OR_FALSE(param_.x);
  CHECK_OR_FALSE(param_.filter);
  CHECK_OR_FALSE(param_.output);

  const auto in_dims = param_.x->dims();
  const auto filter_dims = param_.filter->dims();

  CHECK_OR_FALSE(in_dims.size() == 4 || in_dims.size() == 5);

  CHECK_EQ_OR_FALSE(in_dims.size(), filter_dims.size());
  CHECK_OR_FALSE(in_dims.size() - param_.strides.size() == 2U);

  CHECK_OR_FALSE(in_dims[1] % param_.groups == 0);
  CHECK_EQ_OR_FALSE(filter_dims.size(), 4UL);
  return true;
}

inline int ConvTransposeOutputSize(int input_size,
                                   int filter_size,
                                   int dilation,
                                   int pad_left,
                                   int pad_right,
                                   int stride) {
  const int dkernel = dilation * (filter_size - 1) + 1;
  int output_size = (input_size - 1) * stride - pad_left - pad_right + dkernel;

  return output_size;
}

inline void UpdatePaddingAndDilation(std::vector<int>* paddings,
                                     std::vector<int>* dilations,
                                     const std::vector<int>& strides,
                                     const std::string padding_algorithm,
                                     const lite::DDim data_dims,
                                     const lite::DDim& ksize) {
  // when padding_desc is "VALID" or "SAME"
  if (padding_algorithm == "SAME") {
    for (size_t i = 0; i < strides.size(); ++i) {
      int out_size = (data_dims[i + 2] + strides[i] - 1) / strides[i];
      int pad_sum = std::max(
          (out_size - 1) * strides[i] + ksize[i + 2] - data_dims[i + 2],
          (int64_t)0);
      int pad_0 = pad_sum / 2;
      int pad_1 = pad_sum - pad_0;
      // pad
      *(paddings->begin() + i * 2) = pad_0;
      *(paddings->begin() + i * 2 + 1) = pad_1;
      // dilation
      *(dilations->begin() + i) = 1;
    }
  } else if (padding_algorithm == "VALID") {
    for (auto& it : *paddings) {
      it = 0;
    }
  }
}

bool ConvTransposeOpLite::InferShape() const {
  const auto in_dims = param_.x->dims();
  const auto filter_dims = param_.filter->dims();

  UpdatePaddingAndDilation(param_.paddings.get(),
                           param_.dilations.get(),
                           param_.strides,
                           padding_algorithm_,
                           in_dims,
                           filter_dims);
  auto paddings = *param_.paddings;
  auto dilations = *param_.dilations;

  std::vector<int64_t> output_shape;
  output_shape.push_back(in_dims[0]);
  output_shape.push_back(filter_dims[1] * param_.groups);
  for (size_t i = 0; i < param_.strides.size(); ++i) {
    output_shape.push_back(ConvTransposeOutputSize(in_dims[i + 2],
                                                   filter_dims[i + 2],
                                                   dilations[i],
                                                   paddings[i * 2],
                                                   paddings[i * 2 + 1],
                                                   param_.strides[i]));
  }

  // Set output dims
  param_.output->Resize(lite::DDim(output_shape));
  return true;
}

// TODO(Superjomn) replace framework::OpDesc with a lite one.
bool ConvTransposeOpLite::AttachImpl(const cpp::OpDesc& op_desc,
                                     lite::Scope* scope) {
  auto X = op_desc.Input("Input").front();
  auto Filter = op_desc.Input("Filter").front();
  auto Out = op_desc.Output("Output").front();
  param_.x = scope->FindVar(X)->GetMutable<lite::Tensor>();
  param_.filter = scope->FindVar(Filter)->GetMutable<lite::Tensor>();
  param_.output = scope->FindVar(Out)->GetMutable<lite::Tensor>();

  param_.strides = op_desc.GetAttr<std::vector<int>>("strides");
  auto paddings = op_desc.GetAttr<std::vector<int>>("paddings");
  param_.groups = op_desc.GetAttr<int>("groups");
  auto dilations = op_desc.GetAttr<std::vector<int>>("dilations");

  if (op_desc.HasAttr("padding_algorithm")) {
    padding_algorithm_ = op_desc.GetAttr<std::string>("padding_algorithm");
  }
  // 2-pad to 4-pad
  if (paddings.size() == 2L) {
    for (size_t i = 0; i < 2L; ++i) {
      int copy_pad = *(paddings.begin() + 2 * i);
      paddings.insert(paddings.begin() + 2 * i + 1, copy_pad);
    }
  } else {
    if (paddings.size() != 4L) {
      LOG(FATAL)
          << "Paddings size should be the same or twice as the input size.";
    }
  }
  param_.paddings = std::make_shared<std::vector<int>>(paddings);
  param_.dilations = std::make_shared<std::vector<int>>(dilations);

  // optional params
  std::vector<std::string> input_arg_names = op_desc.InputArgumentNames();
  if (std::find(input_arg_names.begin(), input_arg_names.end(), "Bias") !=
      input_arg_names.end()) {
    auto bias_arguments = op_desc.Input("Bias");
    if (bias_arguments.size() > 0) {
      auto bias_var = scope->FindVar(bias_arguments.front());
      if (bias_var != nullptr) {
        param_.bias =
            const_cast<lite::Tensor*>(&(bias_var->Get<lite::Tensor>()));
      }
    }
  }
  if (op_desc.HasAttr("fuse_relu")) {
    param_.fuse_relu = op_desc.GetAttr<bool>("fuse_relu");
  }
  return true;
}

}  // namespace operators
}  // namespace lite
}  // namespace paddle

REGISTER_LITE_OP(conv2d_transpose,
                 paddle::lite::operators::ConvTransposeOpLite);