// 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 "paddle/fluid/lite/operators/pool_op.h"
#include "paddle/fluid/lite/core/op_registry.h"

namespace paddle {
namespace lite {
namespace operators {

int PoolOutputSize(int input_size, int filter_size, int padding, int stride,
                   bool ceil_mode) {
  int output_size;
  if (!ceil_mode) {
    output_size = (input_size - filter_size + 2 * padding) / stride + 1;
  } else {
    output_size =
        (input_size - filter_size + 2 * padding + stride - 1) / stride + 1;
  }
  CHECK_OR_FALSE(output_size > 0);
  return output_size;
}

bool PoolOpLite::CheckShape() const {
  CHECK_OR_FALSE(param_.x);
  CHECK_OR_FALSE(param_.output);
  return true;
}

bool PoolOpLite::InferShape() const {
  const auto input_dims = param_.x->dims();
  CHECK_OR_FALSE(input_dims.size() == 4 || input_dims.size() == 5);

  if (param_.global_pooling) {
    param_.ksize.resize(static_cast<size_t>(input_dims.size()) - 2);
    for (size_t i = 0; i < param_.ksize.size(); ++i) {
      param_.paddings[i] = 0;
      param_.ksize[i] = static_cast<int>(input_dims[i + 2]);
    }
  }

  CHECK_OR_FALSE(input_dims.size() - param_.ksize.size() == 2U);
  CHECK_EQ_OR_FALSE(param_.ksize.size(), param_.strides.size());
  CHECK_EQ_OR_FALSE(param_.ksize.size(), param_.paddings.size());

  std::vector<int64_t> output_shape({input_dims[0], input_dims[1]});
  if (param_.adaptive) {
    output_shape.insert(output_shape.end(), param_.ksize.begin(),
                        param_.ksize.end());
  } else {
    for (size_t i = 0; i < param_.ksize.size(); ++i) {
      output_shape.push_back(
          PoolOutputSize(input_dims[i + 2], param_.ksize[i], param_.paddings[i],
                         param_.strides[i], param_.ceil_mode));
    }
  }
  // share LoD
  // param_.output->set_lod(param_.input->lod());
  param_.output->Resize(lite::DDim(output_shape));
  return true;
}

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

REGISTER_LITE_OP(pool2d, paddle::lite::operators::PoolOpLite);