// Copyright (c) 2023 Huawei Technologies Co., Ltd
// All rights reserved.
//
// Licensed under the BSD 3-Clause License  (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://opensource.org/licenses/BSD-3-Clause
//
// 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 <torch/csrc/autograd/custom_function.h>

#include "op_plugin/AclOpsInterface.h"
#include "op_plugin/utils/OpAdapter.h"

namespace acl_op {
using torch::autograd::Function;
using torch::autograd::AutogradContext;
using npu_preparation = at_npu::native::OpPreparation;
using npu_utils = at_npu::native::NpuUtils;

namespace {

at::Tensor& silu_out_npu_nocheck(at::Tensor& result, const at::Tensor& self)
{
    at_npu::native::OpCommand cmd;
    cmd.Name("Swish")
        .Input(self)
        .Output(result)
        .Attr("scale", static_cast<float>(1.0))
        .Run();
    return result;
}

at::Tensor& silu_out_npu(const at::Tensor& self, at::Tensor& result)
{
    npu_preparation::CheckOut(
        {self},
        result,
        self);

    if (!npu_utils::check_match(&result)) {
        at::Tensor contiguous_result = npu_utils::format_contiguous(result);
        silu_out_npu_nocheck(contiguous_result, self);
        npu_utils::format_fresh_view(result, contiguous_result);
    } else {
        silu_out_npu_nocheck(result, self);
    }

    return result;
}

at::Tensor silu_kernel_npu(const at::Tensor& self)
{
    at::Tensor result = npu_preparation::apply_tensor(self);

    silu_out_npu_nocheck(result, self);

    return result;
}

at::Tensor& silu_backward_out_npu_nocheck(
    at::Tensor& result,
    const at::Tensor& grad_output,
    const at::Tensor& x0,
    const at::Tensor& x1)
{
    at_npu::native::OpCommand cmd;
    cmd.Name("SwishGrad")
        .Input(grad_output)
        .Input(x0)
        .Input(x1)
        .Output(result)
        .Run();

    return result;
}

} // namespace

at::Tensor& npu_silu_(at::Tensor& self)
{
    silu_out_npu(self, self);
    return self;
}

at::Tensor npu_silu_backward(const at::Tensor& grad_output, const at::Tensor& x0, const at::Tensor& x1)
{
    at::Tensor grad_input = npu_preparation::apply_tensor(grad_output);
    silu_backward_out_npu_nocheck(grad_input, grad_output, x0, x1);

    return grad_input;
}

at::Tensor npu_silu(const at::Tensor& self)
{
    return silu_kernel_npu(self);
}

at::Tensor& silu_out(const at::Tensor& self, at::Tensor& out)
{
    silu_out_npu(self, out);
    return out;
}

at::Tensor silu(const at::Tensor& self)
{
    return silu_kernel_npu(self);
}

at::Tensor& silu_(at::Tensor& self)
{
    at::Tensor result = silu_kernel_npu(self);
    self.copy_(result);
    return self;
}

} // namespace acl_op