// Copyright (c) 2018 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 <map>
#include <string>
#include <unordered_set>
#include <vector>
#include "paddle/fluid/framework/details/memory_optimize_helper.h"
#include "paddle/fluid/framework/ir/graph.h"
#include "paddle/fluid/framework/ir/pass.h"

namespace paddle {
namespace framework {
namespace details {

class GraphView {
 public:
  GraphView() = default;

  void Build(ir::Graph* g);

  const std::vector<ir::Node*> AllOps();

  ir::Node* GetNodeByName(const std::string& name,
                          const std::vector<ir::Node*>& nodes) const;

  std::vector<ir::Node*> PendingOpsOnVar(ir::Node* var);

  bool OutConnectInputByCtrlVar(ir::Node* in_var, ir::Node* out_var);

 private:
  std::vector<ir::Node*> ops_;
};

class InplacePass : public ir::Pass {
 public:
  InplacePass();

 protected:
  std::unique_ptr<ir::Graph> ApplyImpl(
      std::unique_ptr<ir::Graph> graph) const override;

  void InitSSAGraphNodes() const;

 private:
  void InplaceModifyVar(const std::string& in_var, const std::string& out_var,
                        const size_t& idx, ir::Graph* graph) const;

  void InplaceModifyDesc(const std::string& in_var, const std::string& out_var,
                         const size_t& idx) const;

  void TryInplaceOpInputOutput(ir::Node* op, ir::Graph* graph) const;

  mutable std::map<std::string, std::vector<ir::Node*>> var_nodes_;

  mutable std::unordered_set<std::string> whitelist_;
  mutable GraphView view_;
};

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