#include "pytorch_cpp_helper.hpp"

#ifdef MMCV_WITH_CUDA
void ROIAlignForwardCUDAKernelLauncher(Tensor input, Tensor rois, Tensor output,
                                       Tensor argmax_y, Tensor argmax_x,
                                       int aligned_height, int aligned_width,
                                       float spatial_scale, int sampling_ratio,
                                       int pool_mode, bool aligned);

void ROIAlignBackwardCUDAKernelLauncher(Tensor grad_output, Tensor rois,
                                        Tensor argmax_y, Tensor argmax_x,
                                        Tensor grad_input, int aligned_height,
                                        int aligned_width, float spatial_scale,
                                        int sampling_ratio, int pool_mode,
                                        bool aligned);

void roi_align_forward_cuda(Tensor input, Tensor rois, Tensor output,
                            Tensor argmax_y, Tensor argmax_x,
                            int aligned_height, int aligned_width,
                            float spatial_scale, int sampling_ratio,
                            int pool_mode, bool aligned) {
  ROIAlignForwardCUDAKernelLauncher(
      input, rois, output, argmax_y, argmax_x, aligned_height, aligned_width,
      spatial_scale, sampling_ratio, pool_mode, aligned);
}

void roi_align_backward_cuda(Tensor grad_output, Tensor rois, Tensor argmax_y,
                             Tensor argmax_x, Tensor grad_input,
                             int aligned_height, int aligned_width,
                             float spatial_scale, int sampling_ratio,
                             int pool_mode, bool aligned) {
  ROIAlignBackwardCUDAKernelLauncher(
      grad_output, rois, argmax_y, argmax_x, grad_input, aligned_height,
      aligned_width, spatial_scale, sampling_ratio, pool_mode, aligned);
}
#endif

void roi_align_forward(Tensor input, Tensor rois, Tensor output,
                       Tensor argmax_y, Tensor argmax_x, int aligned_height,
                       int aligned_width, float spatial_scale,
                       int sampling_ratio, int pool_mode, bool aligned) {
  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_y);
    CHECK_CUDA_INPUT(argmax_x);

    roi_align_forward_cuda(input, rois, output, argmax_y, argmax_x,
                           aligned_height, aligned_width, spatial_scale,
                           sampling_ratio, pool_mode, aligned);
#else
    AT_ERROR("RoIAlign is not compiled with GPU support");
#endif
  } else {
    AT_ERROR("RoIAlign is not implemented on CPU");
  }
}

void roi_align_backward(Tensor grad_output, Tensor rois, Tensor argmax_y,
                        Tensor argmax_x, Tensor grad_input, int aligned_height,
                        int aligned_width, float spatial_scale,
                        int sampling_ratio, int pool_mode, bool aligned) {
  if (grad_output.device().is_cuda()) {
#ifdef MMCV_WITH_CUDA
    CHECK_CUDA_INPUT(grad_output);
    CHECK_CUDA_INPUT(rois);
    CHECK_CUDA_INPUT(argmax_y);
    CHECK_CUDA_INPUT(argmax_x);
    CHECK_CUDA_INPUT(grad_input);

    roi_align_backward_cuda(grad_output, rois, argmax_y, argmax_x, grad_input,
                            aligned_height, aligned_width, spatial_scale,
                            sampling_ratio, pool_mode, aligned);
#else
    AT_ERROR("RoIAlign is not compiled with GPU support");
#endif
  } else {
    AT_ERROR("RoIAlign is not implemented on CPU");
  }
}
