#include <ATen/ATen.h>
#include <ATen/NativeFunctions.h>
#include <ATen/Config.h>


#if !AT_MKLDNN_ENABLED()

namespace at::native {

Tensor mkldnn_prelu(const Tensor& input, const Tensor& weight) {
  TORCH_CHECK(false, "mkldnn_prelu: ATen not compiled with MKLDNN support");
}

std::tuple<Tensor, Tensor> mkldnn_prelu_backward(const Tensor& grad_output, const Tensor& input, const Tensor& weight) {
  TORCH_CHECK(false, "mkldnn_prelu_backward: ATen not compiled with MKLDNN support");
}

}

#else // AT_MKLDNN_ENABLED

#include <ATen/native/mkldnn/MKLDNNCommon.h>
#include <ATen/native/mkldnn/Utils.h>

namespace at::native {

Tensor mkldnn_prelu(const Tensor& input, const Tensor& weight) {
  if (input.scalar_type() == ScalarType::BFloat16) {
    TORCH_CHECK(mkldnn_bf16_device_check(),
        "mkldnn_relu: bf16 path needs the cpu support avx512bw, avx512vl and avx512dq");
  }

  const ideep::tensor& x = itensor_from_mkldnn(input);
  const ideep::tensor& w = itensor_from_tensor(weight);

  ideep::tensor y;
  ideep::prelu_forward::compute(
      x, w, y, ideep::prop_kind::forward_training);
  return new_with_itensor_mkldnn(std::move(y), optTypeMetaToScalarType(input.options().dtype_opt()),
                                 input.options().device_opt());
}

std::tuple<Tensor, Tensor> mkldnn_prelu_backward(const Tensor& grad_output, const Tensor& input, const Tensor& weight) {
  const ideep::tensor& x = itensor_from_mkldnn(input);
  const ideep::tensor& w = itensor_from_tensor(weight);
  const ideep::tensor grady = itensor_from_mkldnn(grad_output);
  ideep::tensor gradx;
  ideep::tensor gradw;

  ideep::prelu_backward::compute(
      x, w, grady, gradx, gradw, ideep::prop_kind::backward);
  if (weight.is_mkldnn()) {
    return std::make_tuple(
        new_with_itensor_mkldnn(std::move(gradx),
                                optTypeMetaToScalarType(grad_output.options().dtype_opt()),
                                grad_output.options().device_opt()),
        new_with_itensor_mkldnn(std::move(gradw),
                                optTypeMetaToScalarType(weight.options().dtype_opt()),
                                weight.options().device_opt()));
  } else {
    return std::make_tuple(
        new_with_itensor_mkldnn(std::move(gradx),
                                optTypeMetaToScalarType(grad_output.options().dtype_opt()),
                                grad_output.options().device_opt()),
        mkldnn_to_dense(new_with_itensor_mkldnn(std::move(gradw),
                                                optTypeMetaToScalarType(weight.options().dtype_opt()),
                                                weight.options().device_opt())));
  }
}
}

#endif // AT_MKLDNN_ENABLED
