/* 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. */

#pragma once
#include <functional>
#include <map>
#include <string>
#include <unordered_map>
#include <vector>

#include "paddle/fluid/framework/attribute.h"
#include "paddle/fluid/framework/no_need_buffer_vars_inference.h"
#include "paddle/fluid/framework/type_defs.h"
#include "paddle/fluid/platform/macros.h"

namespace paddle {
namespace framework {

class InferShapeBase {
 public:
  virtual ~InferShapeBase() = default;
  virtual void operator()(InferShapeContext*) const = 0;
};

struct OpInfo {
  OpCreator creator_;
  GradOpMakerFN grad_op_maker_;
  proto::OpProto* proto_{nullptr};
  OpAttrChecker* checker_{nullptr};
  InferVarTypeFN infer_var_type_;
  InferShapeFN infer_shape_;
  InferInplaceOpFN infer_inplace_;
  InferNoNeedBufferVarsFN infer_no_need_buffer_vars_;

  // NOTE(zjl): this flag is added to check whether
  // the grad maker is the default one.
  bool use_default_grad_op_desc_maker_{false};

  bool HasOpProtoAndChecker() const {
    return proto_ != nullptr && checker_ != nullptr;
  }

  const proto::OpProto& Proto() const {
    PADDLE_ENFORCE_NOT_NULL(proto_, "Operator Proto has not been registered");
    PADDLE_ENFORCE(proto_->IsInitialized(),
                   "Operator Proto must be initialized in op info");
    return *proto_;
  }

  const OpCreator& Creator() const {
    PADDLE_ENFORCE_NOT_NULL(creator_,
                            "Operator Creator has not been registered");
    return creator_;
  }

  const GradOpMakerFN& GradOpMaker() const {
    PADDLE_ENFORCE_NOT_NULL(grad_op_maker_,
                            "Operator GradOpMaker has not been registered.");
    return grad_op_maker_;
  }

  const OpAttrChecker* Checker() const { return checker_; }

  const InferNoNeedBufferVarsFN& NoNeedBufferVarsInferer() const {
    return infer_no_need_buffer_vars_;
  }
};

class OpInfoMap {
 public:
  static OpInfoMap& Instance();

  bool Has(const std::string& op_type) const {
    return map_.find(op_type) != map_.end();
  }

  void Insert(const std::string& type, const OpInfo& info) {
    PADDLE_ENFORCE(!Has(type), "Operator %s has been registered", type);
    map_.insert({type, info});
  }

  const OpInfo& Get(const std::string& type) const {
    auto op_info_ptr = GetNullable(type);
    PADDLE_ENFORCE_NOT_NULL(op_info_ptr, "Operator %s has not been registered",
                            type);
    return *op_info_ptr;
  }

  const OpInfo* GetNullable(const std::string& type) const {
    auto it = map_.find(type);
    if (it == map_.end()) {
      return nullptr;
    } else {
      return &it->second;
    }
  }

  const std::unordered_map<std::string, OpInfo>& map() const { return map_; }

  std::unordered_map<std::string, OpInfo>* mutable_map() { return &map_; }

  std::vector<std::string> GetUseDefaultGradOpDescMakerOps() const;

 private:
  OpInfoMap() = default;
  std::unordered_map<std::string, OpInfo> map_;

  DISABLE_COPY_AND_ASSIGN(OpInfoMap);
};

}  // namespace framework
}  // namespace paddle