// Copyright (c) 2024 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.

#pragma once

#include "paddle/phi/core/dense_tensor.h"
#include "paddle/phi/core/device_context.h"
#include "paddle/phi/kernels/full_kernel.h"
namespace phi {

template <typename T, typename Context>
void SwiGLUKernelImpl(
    const Context &dev_ctx, const T *x, const T *y, T *z, int64_t m, int64_t n);

template <typename T, typename Context>
void SwiGLUKernel(const Context &dev_ctx,
                  const DenseTensor &x,
                  const optional<DenseTensor> &y,
                  DenseTensor *z) {
  // If either x or y has a numel 0, the numel of z is 0.
  if (z->numel() == 0) {
    dev_ctx.template Alloc<T>(z);
    return;
  }

  const auto *x_ptr = x.data<T>();
  auto *z_ptr = dev_ctx.template Alloc<T>(z);
  const auto &dims = x.dims();

  if (y) {
    const auto &y_tensor = y.get();
    const auto &y_dims = y_tensor.dims();
    PADDLE_ENFORCE_EQ(y_dims,
                      dims,
                      common::errors::InvalidArgument(
                          "The shape of Input(Y):[%s] must be equal "
                          "to the shape of Input(X):[%s].",
                          y_dims,
                          dims));
    SwiGLUKernelImpl<T, Context>(
        dev_ctx, x_ptr, y_tensor.data<T>(), z_ptr, x.numel(), 1);
  } else {
    auto dims_2d = flatten_to_2d(dims, dims.size() - 1);
    int64_t m = dims_2d[0], n = dims_2d[1];
    PADDLE_ENFORCE_EQ(n % 2,
                      0,
                      common::errors::InvalidArgument(
                          "The last dim of Input(X) should be exactly divided "
                          "by 2 when Input(Y) is None, but got %d",
                          n));
    SwiGLUKernelImpl<T, Context>(dev_ctx, x_ptr, nullptr, z_ptr, m, n / 2);
  }
}

}  // namespace phi