//   Copyright (c) 2019 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/framework/details/fuse_sgd_op_pass.h"
#include <algorithm>
#include "paddle/fluid/framework/ir/graph_helper.h"
#include "paddle/fluid/framework/op_registry.h"

namespace paddle {
namespace framework {
namespace details {

const std::string FuseSgdOpPass::GetOpType() const { return "sgd"; }

const std::vector<std::string> FuseSgdOpPass::GetAuxiliaryVarNames() const {
  return {};
}

void FuseSgdOpPass::FuseOptimizerOps(
    const std::unordered_map<std::string, std::vector<std::string>>
        &aux_var_set,
    const std::unordered_map<std::string, std::string> &fused_vars_name,
    const std::vector<ir::Node *> &sgd_ops, ir::Graph *graph) const {
  FuseSgdOps(aux_var_set, fused_vars_name, sgd_ops, graph);
}

void FuseSgdOpPass::FuseSgdOps(
    const std::unordered_map<std::string, std::vector<std::string>> &vars_set,
    const std::unordered_map<std::string, std::string> &fused_vars_name,
    const std::vector<ir::Node *> &sgd_ops, ir::Graph *graph) const {
  PADDLE_ENFORCE_GT(sgd_ops.size(), static_cast<size_t>(0));

  // NOTE: fused_var is only exist in scope, so the graph doesn't have fused_var
  // node.

  int op_role = boost::get<int>(
      sgd_ops[0]->Op()->GetAttr(OpProtoAndCheckerMaker::OpRoleAttrName()));
  VLOG(10) << "Insert sgd to graph ";
  // Add fused scale
  OpDesc Sgd_desc(sgd_ops[0]->Op()->Block());
  Sgd_desc.SetType("sgd");
  Sgd_desc.SetInput(kParam, {fused_vars_name.at(kParam)});
  Sgd_desc.SetInput(kGrad, {fused_vars_name.at(kGrad)});
  Sgd_desc.SetOutput("ParamOut", {fused_vars_name.at(kParam)});

  // TODO(zcd): The LearningRate, Beta1Pow, Beta2Pow should be equal.
  Sgd_desc.SetInput(kLearningRate, sgd_ops[0]->Op()->Input(kLearningRate));

  // NOTE: multi_devices_pass requires that every op should have a role.
  Sgd_desc.SetAttr(OpProtoAndCheckerMaker::OpRoleAttrName(), op_role);

  auto sgd_node = graph->CreateOpNode(&Sgd_desc);

  InserInputAndOutputForOptOps(sgd_ops, sgd_node);
}

}  // namespace details
}  // namespace framework
}  // namespace paddle

REGISTER_PASS(fuse_sgd_op_pass, paddle::framework::details::FuseSgdOpPass)
    .RequirePassAttr(paddle::framework::details::kPlaces)
    .RequirePassAttr(paddle::framework::details::kLocalScopes);