/* Copyright (c) 2016 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. */

#include "paddle/fluid/operators/elementwise/elementwise_mul_op.h"

#include <memory>
#include <string>

#include "paddle/fluid/operators/elementwise/elementwise_op.h"
#include "paddle/fluid/platform/complex.h"
#include "paddle/fluid/prim/api/composite_backward/composite_backward_api.h"
#include "paddle/fluid/prim/utils/static/composite_grad_desc_maker.h"
#include "paddle/fluid/prim/utils/static/desc_tensor.h"

namespace paddle {
namespace operators {
class ElementwiseMulOpMaker : public ElementwiseOpMaker {
 protected:
  std::string GetName() const override { return "Mul"; }
  std::string GetEquation() const override { return "Out = X \\\\odot Y"; }

  void AddInputX() override {
    AddInput(
        "X",
        "(Variable), Tensor or phi::DenseTensor of any dimensions. Its dtype "
        "should be int32, int64, float32, float64.");
  }

  void AddInputY() override {
    AddInput(
        "Y",
        "(Variable), Tensor or phi::DenseTensor of any dimensions. Its dtype "
        "should be int32, int64, float32, float64.");
  }

  std::string GetOpFunctionality() const override {
    return "Multiply two tensors element-wise";
  }
};

template <typename T>
class ElementwiseMulOpGradMaker : public framework::SingleGradOpMaker<T> {
 public:
  using framework::SingleGradOpMaker<T>::SingleGradOpMaker;

 protected:
  void Apply(GradOpPtr<T> op) const override {
    op->SetType("elementwise_mul_grad");
    op->SetInput("X", this->Input("X"));
    op->SetInput("Y", this->Input("Y"));
    op->SetInput(framework::GradVarName("Out"), this->OutputGrad("Out"));
    op->SetAttrMap(this->Attrs());
    op->SetOutput(framework::GradVarName("X"), this->InputGrad("X"));
    op->SetOutput(framework::GradVarName("Y"), this->InputGrad("Y"));
  }
};

class ElementwiseMulCompositeGradOpMaker
    : public prim::CompositeGradOpMakerBase {
  using prim::CompositeGradOpMakerBase::CompositeGradOpMakerBase;

 public:
  void Apply() override {
    auto x = this->GetSingleForwardInput("X");
    auto y = this->GetSingleForwardInput("Y");
    auto out_grad = this->GetSingleOutputGrad("Out");
    auto x_grad = this->GetSingleInputGrad("X");
    auto x_grad_p = this->GetOutputPtr(&x_grad);
    auto x_grad_name = this->GetOutputName(x_grad);
    auto y_grad = this->GetSingleInputGrad("Y");
    auto y_grad_p = this->GetOutputPtr(&y_grad);
    auto y_grad_name = this->GetOutputName(y_grad);
    int axis = static_cast<int>(this->Attr<int>("axis"));
    PADDLE_ENFORCE_EQ(
        axis,
        -1,
        phi::errors::InvalidArgument(
            "We only support axis = -1 in composite mul_grad but we got: ",
            axis));
    prim::multiply_grad<prim::DescTensor>(
        x, y, out_grad, axis, x_grad_p, y_grad_p);
    VLOG(6) << "Runing mul_grad composite func";
    this->RecoverOutputName(x_grad, x_grad_name);
    this->RecoverOutputName(y_grad, y_grad_name);
  }
};

template <typename T>
class ElementwiseMulDoubleGradMaker : public framework::SingleGradOpMaker<T> {
 public:
  using framework::SingleGradOpMaker<T>::SingleGradOpMaker;

 protected:
  void Apply(GradOpPtr<T> op) const override {
    op->SetType("elementwise_mul_grad_grad");
    op->SetInput("X", this->Input("X"));
    op->SetInput("Y", this->Input("Y"));
    op->SetInput("DOut", this->Input(framework::GradVarName("Out")));
    op->SetInput("DDX", this->OutputGrad(framework::GradVarName("X")));
    op->SetInput("DDY", this->OutputGrad(framework::GradVarName("Y")));

    op->SetAttrMap(this->Attrs());

    op->SetOutput("DDOut", this->InputGrad(framework::GradVarName("Out")));
    op->SetOutput(framework::GradVarName("X"), this->InputGrad("X"));
    op->SetOutput(framework::GradVarName("Y"), this->InputGrad("Y"));
  }
};

class ElementwiseMulCompositeDoubleGradOpMaker
    : public prim::CompositeGradOpMakerBase {
  using prim::CompositeGradOpMakerBase::CompositeGradOpMakerBase;

 public:
  void Apply() override {
    // get input
    paddle::Tensor x = this->GetSingleForwardInput("X");
    paddle::Tensor y = this->GetSingleForwardInput("Y");
    paddle::Tensor out_grad = this->GetSingleOutputGrad("Out");
    paddle::optional<paddle::Tensor> ddx =
        this->GetOptionalSingleOutputGrad(framework::GradVarName("X"));
    paddle::optional<paddle::Tensor> ddy =
        this->GetOptionalSingleOutputGrad(framework::GradVarName("Y"));

    // get attr
    int axis = static_cast<int>(this->Attr<int>("axis"));
    PADDLE_ENFORCE_EQ(
        axis,
        -1,
        phi::errors::InvalidArgument("We only support axis = -1 in composite "
                                     "add_doubel_grad but we got: ",
                                     axis));

    // get output
    paddle::Tensor x_grad_t = this->GetSingleInputGrad("X");
    paddle::Tensor y_grad_t = this->GetSingleInputGrad("Y");
    paddle::Tensor grad_out_grad_t =
        this->GetSingleInputGrad(framework::GradVarName("Out"));

    // get output ptr
    paddle::Tensor* x_grad = this->GetOutputPtr(&x_grad_t);
    paddle::Tensor* y_grad = this->GetOutputPtr(&y_grad_t);
    paddle::Tensor* grad_out_grad = this->GetOutputPtr(&grad_out_grad_t);
    // get output orginal name
    std::string x_grad_name = this->GetOutputName(x_grad_t);
    std::string y_grad_name = this->GetOutputName(y_grad_t);
    std::string grad_out_grad_name = this->GetOutputName(grad_out_grad_t);

    VLOG(6) << "Runing multiply_double_grad composite func";
    prim::multiply_double_grad<prim::DescTensor>(
        x, y, out_grad, ddx, ddy, axis, x_grad, y_grad, grad_out_grad);

    // recover output name
    this->RecoverOutputName(x_grad_t, x_grad_name);
    this->RecoverOutputName(y_grad_t, y_grad_name);
    this->RecoverOutputName(grad_out_grad_t, grad_out_grad_name);
  }
};

template <typename T>
class ElementwiseMulTripleGradMaker : public framework::SingleGradOpMaker<T> {
 public:
  using framework::SingleGradOpMaker<T>::SingleGradOpMaker;

 protected:
  void Apply(GradOpPtr<T> op) const override {
    op->SetType("elementwise_mul_triple_grad");
    // get input from double grad
    op->SetInput("X", this->Input("X"));
    op->SetInput("Y", this->Input("Y"));
    op->SetInput("DOut", this->Input("DOut"));
    op->SetInput("DDX", this->Input("DDX"));
    op->SetInput("DDY", this->Input("DDY"));
    op->SetInput("D_DX", this->OutputGrad(framework::GradVarName("X")));
    op->SetInput("D_DY", this->OutputGrad(framework::GradVarName("Y")));
    op->SetInput("D_DDOut", this->OutputGrad("DDOut"));

    op->SetAttrMap(this->Attrs());

    // set outputs
    op->SetOutput("D_X", this->InputGrad("X"));
    op->SetOutput("D_Y", this->InputGrad("Y"));
    op->SetOutput("D_DOut", this->InputGrad("DOut"));
    op->SetOutput("D_DDX", this->InputGrad("DDX"));
    op->SetOutput("D_DDY", this->InputGrad("DDY"));
  }
};

}  // namespace operators
}  // namespace paddle

namespace ops = paddle::operators;
REGISTER_OPERATOR(elementwise_mul,
                  ops::ElementwiseMulOp,
                  ops::ElementwiseMulOpMaker,
                  ops::ElementwiseOpInferVarType,
                  ops::ElementwiseMulOpGradMaker<paddle::framework::OpDesc>,
                  ops::ElementwiseMulOpGradMaker<paddle::imperative::OpBase>,
                  ops::ElementwiseMulCompositeGradOpMaker);
REGISTER_OPERATOR(
    elementwise_mul_grad,
    ops::ElementwiseOpGrad,
    ops::ElementwiseMulDoubleGradMaker<paddle::framework::OpDesc>,
    ops::ElementwiseMulDoubleGradMaker<paddle::imperative::OpBase>,
    ops::ElementwiseMulCompositeDoubleGradOpMaker);

REGISTER_OPERATOR(
    elementwise_mul_grad_grad,
    ops::ElementwiseOpDoubleGrad,
    ops::ElementwiseDoubleGradOpInplaceInferer,
    ops::ElementwiseMulTripleGradMaker<paddle::framework::OpDesc>,
    ops::ElementwiseMulTripleGradMaker<paddle::imperative::OpBase>);

REGISTER_OPERATOR(elementwise_mul_triple_grad, ops::ElementwiseOpTripleGrad);

REGISTER_OP_VERSION(elementwise_mul)
    .AddCheckpoint(
        R"ROC(Register elementwise_mul for adding the attribute of Scale_y)ROC",
        paddle::framework::compatible::OpVersionDesc().NewAttr(
            "Scale_y",
            "In order to support the function of scaling the input Y when "
            "using the operator of elementwise_mul.",
            1.0f));
