// 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 <functional>
#include <memory>
#include <string>
#include <unordered_map>
#include <vector>

#include "paddle/fluid/framework/operator.h"
#include "paddle/fluid/framework/program_desc.h"
#include "paddle/fluid/framework/scope.h"
#include "paddle/phi/common/place.h"
#include "paddle/phi/core/platform/device_context.h"

#include "paddle/fluid/framework/new_executor/interpreter/execution_config.h"
#include "paddle/fluid/framework/new_executor/interpretercore.h"

#include "paddle/pir/include/core/program.h"

namespace paddle {
namespace framework {

/*
 * Simple, intuitive and effective. Only single thread is supported, and
 * currently designed for inference.
 */
class ProgramDesc;
class Scope;

class PADDLE_API NaiveExecutor {
 public:
  using HookFunc = std::function<void(OperatorBase*, Scope*)>;

  using PirHookFunc =
      std::function<void(InstructionBase*, ValueExecutionInfo*, Scope*)>;

  explicit NaiveExecutor(const phi::Place& place) : place_(place) {}

  ~NaiveExecutor();

  // Create child scope.
  // Create variables.
  void Prepare(Scope* scope, const ProgramDesc& program_desc, int block_id);

  void Prepare(Scope* scope);

  void PrepareInterpreterCore(
      Scope* scope,
      const ProgramDesc& program_desc,
      const framework::interpreter::ExecutionConfig& execution_config =
          framework::interpreter::ExecutionConfig{});

  void PrepareInterpreterCore(
      Scope* scope,
      const pir::Program& pir_program,
      const framework::interpreter::ExecutionConfig& execution_config =
          framework::interpreter::ExecutionConfig{});

  // Create variables before head.
  // Create parameters if persistable is true, or create the temporary variables
  // instead.
  void CreateVariables(const ProgramDesc& desc,
                       int block_id,
                       bool persistable,
                       Scope* scope);

  // Run all the operators.
  void Run();

  void RunInterpreterCore(const std::vector<std::string>& feed_names = {},
                          bool need_fetch = false,
                          bool switch_stream = false);

  // Get an tensor to operating directly, without the need for feed_ops.
  DenseTensor* FindTensor(const std::string& name);

  Scope* GetScope() { return scope_; }

  void MakeReusePlan(
      const std::unordered_map<std::string, std::string>& reuse_table);

  void ResetTrtOps(int num);

  void RegisterOutputHook(const HookFunc& hookfunc);
  void RegisterInputHook(const HookFunc& hookfunc);
  void RegisterOutputHook(const PirHookFunc& hookfunc);
  void RegisterInputHook(const PirHookFunc& hookfunc);

 private:
  void CreateOps(const ProgramDesc& desc, int block_id);

 private:
  const phi::Place place_;
  // Catch the required resource to avoid recreate.
  std::vector<std::unique_ptr<OperatorBase>> ops_;
  Scope* scope_{nullptr};

  std::vector<HookFunc> output_hookfuncs_;
  std::vector<HookFunc> input_hookfuncs_;

  std::vector<PirHookFunc> pir_output_hookfuncs_;
  std::vector<PirHookFunc> pir_input_hookfuncs_;

  // Record information that tensor_a should ShareBufferWith tensor_b.
  std::unordered_map<OperatorBase*, std::unordered_map<DenseTensor*, int>>
      reuse_cache_;
  std::vector<DenseTensor*> cluster_buffer_;

  std::unique_ptr<framework::InterpreterCore> interpreter_core_;
};

}  // namespace framework
}  // namespace paddle