// 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 <memory>
#include <random>
#include "lite/backends/opencl/target_wrapper.h"
#include "lite/core/op_registry.h"
#include "lite/core/tensor.h"
#include "lite/kernels/opencl/test_helper.h"

#define FP16_MAX_DIFF (5e-1)

namespace paddle {
namespace lite {

void gird_sampler_ref(const float* din,
                      const DDim& in_dims,
                      const float* grid,
                      float* output) {
  int num = in_dims[0];
  int channel = in_dims[1];
  int height = in_dims[2];
  int width = in_dims[3];
  int spatial_size = height * width;

  auto inbound = [](int x, int y, float x_max, float y_max) {
    if (x < 0 || x > x_max || y < 0 || y > y_max) {
      return false;
    }
    return true;
  };

  for (int n = 0; n < num; ++n) {
    const float* x_n = din + n * channel * height * width;
    float* out_n = output + n * channel * height * width;
    const float* grid_n = grid + n * height * width * 2;
    for (int c = 0; c < channel; ++c) {
      const float* x_c = x_n + c * spatial_size;
      float* out_c = out_n + c * spatial_size;
      for (int s = 0; s < spatial_size; ++s) {
        float x = grid_n[s * 2];
        float y = grid_n[s * 2 + 1];
        float xwf = (x + 1.f) * 0.5 * (width - 1);
        float ynf = (y + 1.f) * 0.5 * (height - 1);
        int xw = floor(xwf);
        int xe = xw + 1;
        int yn = floor(ynf);
        int ys = yn + 1;

        float dw = xwf - xw;
        float de = xe - xwf;
        float dn = ynf - yn;
        float ds = ys - ynf;

        float wn = inbound(xw,
                           yn,
                           static_cast<float>(width - 1),
                           static_cast<float>(height - 1))
                       ? x_c[yn * width + xw]
                       : 0.f;
        float en = inbound(xe,
                           yn,
                           static_cast<float>(width - 1),
                           static_cast<float>(height - 1))
                       ? x_c[yn * width + xe]
                       : 0.f;
        float ws = inbound(xw,
                           ys,
                           static_cast<float>(width - 1),
                           static_cast<float>(height - 1))
                       ? x_c[ys * width + xw]
                       : 0.f;
        float es = inbound(xe,
                           ys,
                           static_cast<float>(width - 1),
                           static_cast<float>(height - 1))
                       ? x_c[ys * width + xe]
                       : 0.f;

        out_c[s] = wn * de * ds + en * dw * ds + ws * de * dn + es * dw * dn;
      }
    }
  }
}
// #define GRID_FP16_LOOP_TEST
// #define GRID_FP16_PRINT_RESULT
TEST(grid_samler_image2d, compute) {
#ifdef GRID_FP16_LOOP_TEST
  for (int n = 1; n <= 100; n += 33) {
    for (auto c : {1, 3, 8, 23, 32}) {
      for (int h = 12; h <= 100; h += 13) {
        for (int w = 12; w <= 100; w += 25) {
#else
  const int n = 1;
  const int c = 2;
  const int h = 3;
  const int w = 4;
#endif  // GRID_FP16_LOOP_TEST

          LOG(INFO) << "======== input shape[n,c,h,w]:" << n << " " << c << " "
                    << h << " " << w << " ========";

          auto kernels =
              KernelRegistry::Global().Create("grid_sampler",
                                              TARGET(kOpenCL),
                                              PRECISION(kFP16),
                                              DATALAYOUT(kImageDefault));
          ASSERT_FALSE(kernels.empty());
          auto kernel = std::move(kernels.front());
          LOG(INFO) << "get kernel:" << kernel->doc();

          lite::Tensor x, grid, out;
          operators::GridSamplerParam param;
          param.x = &x;
          param.grid = &grid;
          param.out = &out;

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

          kernel->SetParam(param);
          std::unique_ptr<KernelContext> grid_context(new KernelContext);
          context->As<OpenCLContext>().CopySharedTo(
              &(grid_context->As<OpenCLContext>()));
          kernel->SetContext(std::move(grid_context));

          const DDim in_dim = DDim(std::vector<DDim::value_type>{n, c, h, w});
          const DDim grid_dim = DDim(std::vector<DDim::value_type>{n, h, w, 2});
          const DDim out_dim = DDim(std::vector<DDim::value_type>{n, c, h, w});
          x.Resize(in_dim);
          grid.Resize(grid_dim);
          out.Resize(out_dim);

          std::default_random_engine engine;
          std::uniform_real_distribution<float> dist(-1, 1);
          int sum = n * c * h * w;
          int sum2 = n * h * w * 2;
          std::vector<float> input_v(sum);
          std::vector<float> grid_v(sum2);
          for (auto& i : input_v) {
            i = dist(engine);
          }
          for (auto& i : grid_v) {
            i = dist(engine);
          }

          LOG(INFO) << "prepare input";
          CLImageConverterDefault* default_converter =
              new CLImageConverterDefault();
          DDim x_image_shape = default_converter->InitImageDimInfoWith(in_dim);
          LOG(INFO) << "x_image_shape = " << x_image_shape[0] << " "
                    << x_image_shape[1];
          std::vector<half_t> x_image_data(x_image_shape.production() *
                                           4);  // 4 : RGBA
          default_converter->NCHWToImage(
              input_v.data(), x_image_data.data(), in_dim);
          auto* x_image = x.mutable_data<half_t, cl::Image2D>(
              x_image_shape[0], x_image_shape[1], x_image_data.data());
          // LOG(INFO) << "x_image:" << x_image;

          DDim grid_image_shape =
              default_converter->InitImageDimInfoWith(grid_dim);
          LOG(INFO) << "grid_image_shape = " << grid_image_shape[0] << " "
                    << grid_image_shape[1];
          std::vector<half_t> grid_image_data(grid_image_shape.production() *
                                              4);  // 4 : RGBA
          default_converter->NCHWToImage(
              grid_v.data(), grid_image_data.data(), grid_dim);
          auto* grid_image = grid.mutable_data<half_t, cl::Image2D>(
              grid_image_shape[0], grid_image_shape[1], grid_image_data.data());
          // LOG(INFO) << "grid_image:" << grid_image;

          DDim out_image_shape =
              default_converter->InitImageDimInfoWith(out_dim);
          LOG(INFO) << "out_image_shape = " << out_image_shape[0] << " "
                    << out_image_shape[1];
          auto* out_image = out.mutable_data<half_t, cl::Image2D>(
              out_image_shape[0], out_image_shape[1]);
          // LOG(INFO) << "out_image:" << out_image;
          kernel->Launch();

          auto* wait_list = context->As<OpenCLContext>().cl_wait_list();
          auto* out_ptr = param.out->data<half_t, cl::Image2D>();
          auto it = wait_list->find(out_ptr);
          if (it != wait_list->end()) {
            VLOG(4) << "--- Find the sync event for the target cl tensor. ---";
            auto& event = *(it->second);
            event.wait();
          } else {
            LOG(FATAL)
                << "Could not find the sync event for the target cl tensor.";
          }

          std::unique_ptr<float[]> out_ref(new float[out_dim.production()]);
          gird_sampler_ref(
              input_v.data(), in_dim, grid_v.data(), out_ref.get());

          const size_t cl_image2d_row_pitch{0};
          const size_t cl_image2d_slice_pitch{0};
          half_t* out_image_data = new half_t[out_image_shape.production() * 4];
          TargetWrapperCL::ImgcpySync(out_image_data,
                                      out_image,
                                      out_image_shape[0],
                                      out_image_shape[1],
                                      cl_image2d_row_pitch,
                                      cl_image2d_slice_pitch,
                                      IoDirection::DtoH);
          float* out_data = new float[out_image_shape.production() * 4];
          default_converter->ImageToNCHW(
              out_image_data, out_data, out_image_shape, out_dim);
// result
#ifdef GRID_FP16_PRINT_RESULT
          LOG(INFO) << "---- print kernel result (input -> output) ----";
          for (int eidx = 0; eidx < in_dim.production(); ++eidx) {
            std::cout << input_v[eidx] << " -> " << out_data[eidx] << "\n";
          }
#endif  // GRID_FP16_PRINT_RESULT
          for (int i = 0; i < out_dim.production(); i++) {
            auto abs_diff = abs(out_data[i] - out_ref[i]);
            auto relative_diff = COMPUTE_RELATIVE_DIFF(out_data[i], out_ref[i]);
            EXPECT_EQ(
                (relative_diff <= FP16_MAX_DIFF) || (abs_diff <= FP16_MAX_DIFF),
                true);
            if ((relative_diff > FP16_MAX_DIFF) && (abs_diff > FP16_MAX_DIFF)) {
              LOG(ERROR) << "error idx:" << i << " out_data[" << i
                         << "]:" << out_data[i] << " "
                                                   "out_ref["
                         << i << "]:" << out_ref[i] << " abs_diff:" << abs_diff
                         << " relative_diff:" << relative_diff
                         << " FP16_MAX_DIFF:" << FP16_MAX_DIFF;
            }
          }
#ifdef GRID_FP16_LOOP_TEST
        }  // w
      }    // h
    }      // c
  }        // n
#else
// nothing to do.
#endif
}

}  // namespace lite
}  // namespace paddle

USE_LITE_KERNEL(grid_sampler, kOpenCL, kFP16, kImageDefault, ImageDefault);