/**
 * \file dnn/src/common/algo_base.h
 * MegEngine is Licensed under the Apache License, Version 2.0 (the "License")
 *
 * Copyright (c) 2014-2021 Megvii Inc. All rights reserved.
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied.
 */

#pragma once

#include <functional>
#include <string>
#include <tuple>

#include "megdnn/oprs/base.h"
#include "src/common/utils.h"

namespace megdnn {

#define MEGDNN_DECL_ALGO_TYPE(_type)                              \
    uint32_t type() const override {                              \
        return static_cast<std::underlying_type<AlgoType>::type>( \
                AlgoType::_type);                                 \
    }

#define MEGDNN_FB_DECL_GET_ALGO_FROM_DESC(_opr)          \
    static fallback::_opr::AlgoBase* get_algo_from_desc( \
            const AlgorithmDesc& desc)

#define MEGDNN_FB_DEF_GET_ALGO_FROM_DESC(_opr)                  \
    fallback::_opr::AlgoBase* _opr::get_algo_from_desc(         \
            const AlgorithmDesc& desc) {                        \
        megdnn_assert(algo_pack().all_algos_map().find(desc) != \
                      algo_pack().all_algos_map().end());       \
        return algo_pack().all_algos_map().at(desc);            \
    }

#define MEGDNN_DEF_GET_ALGO_FROM_DESC(_opr)                     \
    _opr::Algorithm* _opr::get_algorithm_from_desc(             \
            const AlgorithmDesc& desc) {                        \
        megdnn_assert(algo_pack().all_algos_map().find(desc) != \
                      algo_pack().all_algos_map().end());       \
        return algo_pack().all_algos_map().at(desc);            \
    }

#define MEGDNN_FOREACH_ALGO_ATTRIBUTE_INHERITABLE(cb) \
    cb(AlgoAttribute::ACCURACY_DEPEND_ON_BATCH)

/**
 * \brief construct algo from AlgorithmDesc
 */
template <typename AlgoBase>
class AlgoConstructMixin {
private:
    std::vector<std::unique_ptr<AlgoBase>> m_refhold;
protected:
    typename AlgoBase::Mapper m_all_algos_map;

public:

    //! construct the algo which described by desc, and return the instance
    AlgoBase* construct_and_get_algo(
            const detail::Algorithm::Info::Desc& desc) {
        auto iter = m_all_algos_map.find(desc);
        if (iter != m_all_algos_map.end()) {
            return m_all_algos_map.at(desc);
        }
        std::string serialized_bin;
        AlgoBase::serialize_write_pod(desc.type, serialized_bin);
        serialized_bin += desc.param;
        m_refhold.emplace_back(AlgoBase::deserialize(serialized_bin));
        m_all_algos_map.emplace(desc, m_refhold.back().get());
        return m_refhold.back().get();
    }

    void clear() {
        m_all_algos_map.clear();
        m_refhold.clear();
    }

    const typename AlgoBase::Mapper& all_algos_map() const {
        return m_all_algos_map;
    }
};

template <std::size_t I = 0, typename Opr, typename... Tp>
inline typename std::enable_if<I == sizeof...(Tp), void>::type
set_sub_execution_policy(const Opr*, std::tuple<Tp...>&) {}

template <std::size_t I = 0, typename Opr, typename... Tp>
        inline typename std::enable_if <
        I<sizeof...(Tp), void>::type set_sub_execution_policy(
                const Opr* opr, std::tuple<Tp...>& t) {
    std::get<I>(t)->execution_policy() = opr->execution_policy().sub_policy[I];
    set_sub_execution_policy<I + 1, Opr, Tp...>(opr, t);
}

template <typename Opr, typename... SubOpr>
void set_execution_policy(const Opr* opr, SubOpr... sub_oprs) {
    if (opr->execution_policy().algo.valid() &&
        !opr->execution_policy().sub_policy.empty()) {
        megdnn_assert(opr->execution_policy().sub_policy.size() ==
                      sizeof...(sub_oprs));
        auto&& sub = std::make_tuple(sub_oprs...);
        set_sub_execution_policy<0, Opr, SubOpr...>(opr, sub);
    }
}

}  // namespace megdnn

namespace std {
template <>
struct hash<megdnn::detail::Algorithm::Info::Desc> {
    std::size_t operator()(
            const megdnn::detail::Algorithm::Info::Desc& desc) const {
        return megdnn::hash_combine<size_t>(
                megdnn::hash_combine<size_t>(
                        std::hash<std::string>()(desc.name),
                        megdnn::hash_combine<size_t>(
                                std::hash<std::string>()(desc.param),
                                std::hash<uint32_t>()(desc.type))),
                std::hash<uint32_t>()(static_cast<uint32_t>(desc.handle_type)));
    }
};
}  // namespace std

// vim: syntax=cpp.doxygen