// Copyright (c) 2022 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 <string>
#include <algorithm>
#include <unordered_map>
#include <set>

#include "torch/script.h"
#include "iengine.h"
#include "poros_module.h"

namespace baidu {
namespace mirana {
namespace poros {

/**
 * @brief  compile graph
 *
 * @param [in] module : original module
 * @param [in] input_ivalues : prewarm datas
 * @param [in] options : Inference options
 * @return porosmodule
 * @retval !nullptr => succeed  nullptr => failed
 **/
std::unique_ptr<PorosModule> Compile(const torch::jit::Module& module,
        const std::vector<std::vector<c10::IValue> >& prewarm_datas,
        const PorosOptions& options);

class Compiler {
public:
    typedef std::unordered_map<const torch::jit::Node*, IEngine*> engine_map_t;
    typedef std::vector<std::vector<c10::IValue> > ivalue_vec_t;

    Compiler() : _origin_module(NULL) {}
    ~Compiler();

    /**
     * @brief initial Compiler
     *
     * @param [in] options : poros options
     * @return  int
     * @retval 0 => succeed  <0 => failed
    **/
    int init(const PorosOptions& options);

    /**
     * @brief compile whole graph
     *
     * @param [in] origin_module
     * @param [in] prewarm_datas : ivalue_vec_t, vector of IValue
     * @param [out] optimized_module : optimized graph
     * @return  int
     * @retval 0 => succeed  <0 => failed
    **/
    int compile(const torch::jit::Module& origin_module,
                const ivalue_vec_t& prewarm_datas,
                torch::jit::Module* optimized_module);

private:

    /**
     * @brief preprocess this calculation graph
     *
     * @param [in] prewarm_datas : ivalue_vec_t, vector of IValue
     * @param [out] graph : preprcessed graph
     * @return  int
     * @retval 0 => succeed  <0 => failed
    **/
    int preprocess_graph(const ivalue_vec_t& prewarm_datas, std::shared_ptr<torch::jit::Graph>& graph);

    /**
     * @brief segement this calculation graph
     *
     * @param [in/out] graph
     * @return  int
     * @retval 0 => succeed  <0 => failed
    **/
    int segment_graph(std::shared_ptr<torch::jit::Graph>& graph);

    // Split subgraph（block)
    // The divided subgraph, as a subgraph, is associated with the block
    int segment_block(torch::jit::Block& block, IEngine* engine, int current_depth);

    // Subgraph optimization
    /**
     * @brief Subgraph optimization
     *
     * @param [in] prewarm_datas : ivalue_vec_t, vector of IValue
     * @param [in] opt_graph : ivalue_vec_t, vector of IValue
     * @param [out] optimized_module : optimized graph
     * @return  int
     * @retval 0 => succeed  <0 => failed
    **/
    int optimize_subgraph(const ivalue_vec_t& prewarm_datas,
            const std::shared_ptr<torch::jit::Graph>& opt_graph,
            torch::jit::Module* optimized_module);

    // Subgraph optimization(block)
    int optimize_subblock(torch::jit::Block* block,
            torch::jit::Module* optimized_module);

    /**
     * @brief Compile the subgraph into a new graph based on the engine
     *
     * @param [in] engine : The engine used by the subgraph
     * @param [in] subgraph_node : Subgraph node
     * @return [out] module : Transformed model
     * @retval 0 => succeed  <0 => failed
    **/
    int transform(IEngine* engine, torch::jit::Node& subgraph_node,
            torch::jit::Module& module);

    /**
     * @brief Select engine based on subgraph and options
     *
     * @param [in] node : Jit Node
     * @return  int
     * @retval 0 => succeed  <0 => failed
    **/
    IEngine* select_engine(const torch::jit::Node* n);

    /**
     * @brief destory
     *
     * @return  void
    **/
    void close();

private:
    int _max_segment_depth{5};                    // Maximum subgraph segmentation depth
    ivalue_vec_t _prewarm_datas;                    // Prewarm datas
    PorosOptions _options;
    engine_map_t _engine_map;                       // The engine used to record the subgraph
    const torch::jit::Module* _origin_module;       // Origin_module
    std::atomic<int> _engine_index = {0};            // Record engine index
};

/**
 * @brief  compile graph, internal use
 *
 * @param [in] module : Origin module
 * @param [in] input_ivalues : Prewarm datas
 * @param [in] options : Inference options
 * @return optimized_module
 * @retval !nullptr => succeed  nullptr => failed
 **/
std::unique_ptr<torch::jit::Module> CompileGraph(const torch::jit::Module& module,
                                const std::vector<std::vector<c10::IValue> >& prewarm_datas,
                                const PorosOptions& options);

}  // namespace poros
}  // namespace mirana
}  // namespace baidu