// Copyright (c) OpenMMLab. All rights reserved
#include "pytorch_cpp_helper.hpp"

#ifdef MMCV_WITH_CUDA
void ROIPoolForwardCUDAKernelLauncher(Tensor input, Tensor rois, Tensor output,
                                      Tensor argmax, int pooled_height,
                                      int pooled_width, float spatial_scale);

void ROIPoolBackwardCUDAKernelLauncher(Tensor grad_output, Tensor rois,
                                       Tensor argmax, Tensor grad_input,
                                       int pooled_height, int pooled_width,
                                       float spatial_scale);

void roi_pool_forward_cuda(Tensor input, Tensor rois, Tensor output,
                           Tensor argmax, int pooled_height, int pooled_width,
                           float spatial_scale) {
  ROIPoolForwardCUDAKernelLauncher(input, rois, output, argmax, pooled_height,
                                   pooled_width, spatial_scale);
}

void roi_pool_backward_cuda(Tensor grad_output, Tensor rois, Tensor argmax,
                            Tensor grad_input, int pooled_height,
                            int pooled_width, float spatial_scale) {
  ROIPoolBackwardCUDAKernelLauncher(grad_output, rois, argmax, grad_input,
                                    pooled_height, pooled_width, spatial_scale);
}
#endif

void roi_pool_forward(Tensor input, Tensor rois, Tensor output, Tensor argmax,
                      int pooled_height, int pooled_width,
                      float spatial_scale) {
  if (input.device().is_cuda()) {
#ifdef MMCV_WITH_CUDA
    CHECK_CUDA_INPUT(input);
    CHECK_CUDA_INPUT(rois);
    CHECK_CUDA_INPUT(output);
    CHECK_CUDA_INPUT(argmax);

    roi_pool_forward_cuda(input, rois, output, argmax, pooled_height,
                          pooled_width, spatial_scale);
#else
    AT_ERROR("RoIPool is not compiled with GPU support");
#endif
  } else {
    AT_ERROR("RoIPool is not implemented on CPU");
  }
}

void roi_pool_backward(Tensor grad_output, Tensor rois, Tensor argmax,
                       Tensor grad_input, int pooled_height, int pooled_width,
                       float spatial_scale) {
  if (grad_output.device().is_cuda()) {
#ifdef MMCV_WITH_CUDA
    CHECK_CUDA_INPUT(grad_output);
    CHECK_CUDA_INPUT(rois);
    CHECK_CUDA_INPUT(argmax);
    CHECK_CUDA_INPUT(grad_input);

    roi_pool_backward_cuda(grad_output, rois, argmax, grad_input, pooled_height,
                           pooled_width, spatial_scale);
#else
    AT_ERROR("RoIPool is not compiled with GPU support");
#endif
  } else {
    AT_ERROR("RoIPool is not implemented on CPU");
  }
}
