// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you 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 "rowset/segment_v2/common.h"

#include "vec/columns/column.h"

namespace doris {

#include "common/compile_check_begin.h"

using ScoreMap = phmap::flat_hash_map<segment_v2::rowid_t, float>;

using ScoreMapIterator = ScoreMap::const_iterator;

enum class OrderType {

    ASC,

    DESC,

};

class CollectionSimilarity {

public:

    CollectionSimilarity() { _bm25_scores.reserve(1024); }

    ~CollectionSimilarity() = default;

    void collect(segment_v2::rowid_t row_id, float score);

    void get_bm25_scores(roaring::Roaring* row_bitmap, vectorized::IColumn::MutablePtr& scores,

                         std::unique_ptr<std::vector<uint64_t>>& row_ids) const;

    void get_topn_bm25_scores(roaring::Roaring* row_bitmap, vectorized::IColumn::MutablePtr& scores,

                              std::unique_ptr<std::vector<uint64_t>>& row_ids, OrderType order_type,

                              size_t top_k) const;

private:

    template <OrderType order, typename Compare>

    void find_top_k_scores(const roaring::Roaring* row_bitmap, const ScoreMap& all_scores,

                           size_t top_k, Compare comp,

                           std::vector<std::pair<uint32_t, float>>& top_k_results) const;

    ScoreMap _bm25_scores;

};

using CollectionSimilarityPtr = std::shared_ptr<CollectionSimilarity>;

#include "common/compile_check_end.h"

} // namespace doris