// Copyright (c) 2021 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 <sstream>

#include "glog/logging.h"
#include "gtest/gtest.h"

#include "paddle/fluid/eager/accumulation/accumulation_node.h"
#include "paddle/fluid/eager/api/generated/eager_generated/backwards/scale_node.h"
#include "paddle/fluid/eager/api/utils/tensor_utils.h"
#include "paddle/fluid/eager/autograd_meta.h"
#include "paddle/fluid/eager/backward.h"
#include "paddle/fluid/eager/grad_node_info.h"

#include "paddle/fluid/eager/api/all.h"

#include "paddle/pten/core/dense_tensor.h"
#include "paddle/pten/core/tensor_meta.h"

#include "paddle/fluid/eager/tests/test_utils.h"

namespace egr {

TEST(CrossBatchAccumulation, SingleScaleNode) {
  eager_test::InitEnv(paddle::platform::CPUPlace());

  std::vector<paddle::experimental::Tensor> target_tensors;
  paddle::framework::DDim ddim = paddle::framework::make_ddim({4, 16, 16, 32});

  paddle::experimental::Tensor tensor = egr_utils_api::CreateTensorWithValue(
      ddim, paddle::platform::CPUPlace(), pten::DataType::FLOAT32,
      pten::DataLayout::NCHW, 1.0 /*value*/, false /*is_leaf*/);
  target_tensors.emplace_back(std::move(tensor));
  paddle::experimental::Tensor& target_tensor = target_tensors[0];

  paddle::experimental::Tensor leaf_tensor = paddle::experimental::Tensor();
  {
    auto scale_node_ptr = std::make_shared<GradNodeScale>(1, 1);
    scale_node_ptr->SetAttributes_scale(5.0 /*scale*/);

    scale_node_ptr->SetDefaultGradInOutMeta();

    auto acc_node_ptr = std::make_shared<GradNodeAccumulation>();

    AutogradMeta* auto_grad_meta = EagerUtils::autograd_meta(&target_tensor);
    auto_grad_meta->SetGradNode(
        std::dynamic_pointer_cast<GradNodeBase>(scale_node_ptr));
    auto_grad_meta->SetSingleOutRankWithSlot(0, 0);
    auto_grad_meta->SetStopGradient(false);
    egr_utils_api::RetainGradForTensor(target_tensor);  // result: 1.0

    auto meta = AutogradMeta();
    meta.SetSingleOutRankWithSlot(0, 0);
    meta.SetStopGradient(false);
    meta.SetGradNode(acc_node_ptr);
    std::vector<egr::AutogradMeta*> res = {&meta};
    scale_node_ptr->AddEdges(&res, 0);

    AutogradMeta* auto_grad_meta1 = EagerUtils::autograd_meta(&leaf_tensor);
    auto_grad_meta1->SetGradNode(
        std::dynamic_pointer_cast<GradNodeBase>(acc_node_ptr));
    auto_grad_meta1->SetSingleOutRankWithSlot(0, 0);
    egr_utils_api::RetainGradForTensor(leaf_tensor);
  }

  RunBackward(target_tensors, {});

  eager_test::CompareGradTensorWithValue<float>(target_tensor, 1.0);
  eager_test::CompareGradTensorWithValue<float>(leaf_tensor, 5.0);

  RunBackward(target_tensors, {});

  eager_test::CompareGradTensorWithValue<float>(target_tensor, 1.0);
  eager_test::CompareGradTensorWithValue<float>(leaf_tensor, 10.0);
}

}  // namespace egr
