// 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 <gtest/gtest.h>
#include <random>
#include "paddle/fluid/lite/core/compatible_tensor.h"
#include "paddle/fluid/lite/core/op_registry.h"

namespace paddle {
namespace lite {

void pool_avg(const int padding_height, const int padding_width,
              const int stride_height, const int stride_width,
              const int ksize_height, const int ksize_width,
              const float* input_data, const DDim& in_dim, float* output_data,
              const DDim& out_dim) {
  const int batch_size = in_dim[0];
  const int input_height = in_dim[2];
  const int input_width = in_dim[3];
  const int output_channels = out_dim[1];
  const int output_height = out_dim[2];
  const int output_width = out_dim[3];

  const size_t input_spatial_size = input_height * input_width;
  const size_t output_spatial_size = output_height * output_width;

  for (int i = 0; i < batch_size; i++) {
    for (int c = 0; c < output_channels; ++c) {
      int channel = i * output_channels + c;
      const float* input_ptr = input_data + channel * input_spatial_size;
      float* output_ptr = output_data + channel * output_spatial_size;

      for (int ph = 0; ph < output_height; ++ph) {
        int hstart = ph * stride_height - padding_height;
        int hend = std::min(hstart + ksize_height, input_height);
        hstart = std::max(hstart, 0);
        for (int pw = 0; pw < output_width; ++pw) {
          int wstart = pw * stride_width - padding_width;
          int wend = std::min(wstart + ksize_width, input_width);
          wstart = std::max(wstart, 0);

          float val = 0.f;
          int count = 0;
          for (int h = hstart; h < hend; ++h) {
            for (int w = wstart; w < wend; ++w) {
              val += input_ptr[h * input_width + w];
              ++count;
            }
          }
          output_ptr[ph * output_width + pw] =
              (count > 0) ? val * (1.f / count) : 0.f;
        }
      }
    }
  }
}

TEST(pool2d, init) {
  LOG(INFO) << "to get kernel ...";
  auto kernels = KernelRegistry::Global().Create(
      "pool2d", TARGET(kOpenCL), PRECISION(kFloat), DATALAYOUT(kNCHW));
  ASSERT_FALSE(kernels.empty());

  auto kernel = std::move(kernels.front());

  LOG(INFO) << "get kernel";

  lite::Tensor x, out;
  operators::PoolParam param;
  param.x = &x;
  param.output = &out;
  param.global_pooling = true;
  param.pooling_type = "avg";
  param.paddings = std::vector<int>{0, 0};
  param.strides = std::vector<int>{1, 1};
  param.ksize = std::vector<int>{7, 7};

  std::unique_ptr<KernelContext> context(new KernelContext);
  context->As<OpenClContext>().InitOnce();

  kernel->SetParam(param);
  kernel->SetContext(std::move(context));

  const DDim in_dim = DDim(std::vector<DDim::value_type>{4, 1024, 7, 7});
  const DDim out_dim = DDim(std::vector<DDim::value_type>{4, 1024, 1, 1});
  x.Resize(in_dim);
  out.Resize(out_dim);

  auto* x_data = x.mutable_data<float>();
  auto* out_data = out.mutable_data<float>();

  std::default_random_engine engine;
  std::uniform_real_distribution<float> dist(-5, 5);

  for (int i = 0; i < 4 * 1024 * 7 * 7; i++) {
    x_data[i] = dist(engine);
  }

  kernel->Launch();

  std::unique_ptr<float[]> out_ref(new float[4 * 1024 * 1 * 1]);
  pool_avg(0, 0, 1, 1, 7, 7, x_data, in_dim, out_ref.get(), out_dim);

  for (int i = 0; i < 4 * 1024 * 1 * 1; i++) {
    EXPECT_NEAR(out_data[i], out_ref[i], 1e-6);
  }
}

}  // namespace lite
}  // namespace paddle

USE_LITE_KERNEL(pool2d, kOpenCL, kFloat, kNCHW, def);