// Copyright (C) 2019-2020 Zilliz. 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 "common/Json.h"
#include "query/PlanImpl.h"
#include "segcore/SegmentGrowing.h"
#include <utility>
#include "PlanNodeVisitor.h"
#include "plan/PlanNode.h"
#include "exec/QueryContext.h"

namespace milvus::query {

class ExecPlanNodeVisitor : public PlanNodeVisitor {
 public:
    void
    visit(FloatVectorANNS& node) override;

    void
    visit(BinaryVectorANNS& node) override;

    void
    visit(Float16VectorANNS& node) override;

    void
    visit(BFloat16VectorANNS& node) override;

    void
    visit(SparseFloatVectorANNS& node) override;

    void
    visit(Int8VectorANNS& node) override;

    void
    visit(RetrievePlanNode& node) override;

 public:
    ExecPlanNodeVisitor(const segcore::SegmentInterface& segment,
                        Timestamp timestamp,
                        const PlaceholderGroup* placeholder_group)
        : segment_(segment),
          timestamp_(timestamp),
          placeholder_group_(placeholder_group) {
    }

    ExecPlanNodeVisitor(const segcore::SegmentInterface& segment,
                        Timestamp timestamp)
        : segment_(segment), timestamp_(timestamp) {
        placeholder_group_ = nullptr;
    }

    SearchResult
    get_moved_result(PlanNode& node) {
        assert(!search_result_opt_.has_value());
        node.accept(*this);
        assert(search_result_opt_.has_value());
        auto ret = std::move(search_result_opt_).value();
        search_result_opt_.reset();
        search_result_opt_ = std::nullopt;
        return ret;
    }

    RetrieveResult
    get_retrieve_result(PlanNode& node) {
        assert(!retrieve_result_opt_.has_value());
        std::cout.flush();
        node.accept(*this);
        assert(retrieve_result_opt_.has_value());
        auto ret = std::move(retrieve_result_opt_).value();
        retrieve_result_opt_.reset();
        retrieve_result_opt_ = std::nullopt;
        return ret;
    }

    void
    SetExprUsePkIndex(bool use_pk_index) {
        expr_use_pk_index_ = use_pk_index;
    }

    bool
    GetExprUsePkIndex() {
        return expr_use_pk_index_;
    }

    static BitsetType
    ExecuteTask(plan::PlanFragment& plan,
                std::shared_ptr<milvus::exec::QueryContext> query_context);

 private:
    template <typename VectorType>
    void
    VectorVisitorImpl(VectorPlanNode& node);

 private:
    const segcore::SegmentInterface& segment_;
    Timestamp timestamp_;
    const PlaceholderGroup* placeholder_group_;

    SearchResultOpt search_result_opt_;
    RetrieveResultOpt retrieve_result_opt_;
    bool expr_use_pk_index_ = false;
};

// for test use only
inline BitsetType
ExecuteQueryExpr(std::shared_ptr<milvus::plan::PlanNode> plannode,
                 const milvus::segcore::SegmentInternalInterface* segment,
                 uint64_t active_count,
                 uint64_t timestamp) {
    auto plan_fragment = plan::PlanFragment(plannode);

    auto query_context = std::make_shared<milvus::exec::QueryContext>(
        DEAFULT_QUERY_ID, segment, active_count, timestamp);
    auto bitset =
        ExecPlanNodeVisitor::ExecuteTask(plan_fragment, query_context);

    // For test case, bitset 1 indicates true but executor is verse
    bitset.flip();
    return bitset;
}

}  // namespace milvus::query