// 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 <map>

#include <vector>

#include "core/custom_allocator.h"

#include "storage/olap_common.h"

#include "storage/utils.h"

namespace doris {

// Simple verion of rowid conversion, for segcompaction

// convert rows from several segments to rows in 1 segment

class SimpleRowIdConversion {

public:

    SimpleRowIdConversion(const RowsetId& rowset_id) : _rowst_id(rowset_id) {};

    ~SimpleRowIdConversion() = default;

    // resize segment rowid map to its rows num

    void reset_segment_map(const std::map<uint32_t, uint32_t>& num_rows) {

        _cur_dst_segment_rowid = 0;

        for (auto seg_rows : num_rows) {

            _segments_rowid_map.emplace(seg_rows.first,

                                        DorisVector<uint32_t>(seg_rows.second, UINT32_MAX));

        }

    }

    // add row id to the map

    void add(const std::vector<RowLocation>& rss_row_ids) {

        for (auto& item : rss_row_ids) {

            if (item.row_id == -1) {

                continue;

            }

            DCHECK(_segments_rowid_map.find(item.segment_id) != _segments_rowid_map.end() &&

                   _segments_rowid_map[item.segment_id].size() > item.row_id);

            _segments_rowid_map[item.segment_id][item.row_id] = _cur_dst_segment_rowid++;

        }

    }

    // get destination RowLocation

    // return non-zero if the src RowLocation does not exist

    int get(const RowLocation& src) const {

        auto it = _segments_rowid_map.find(src.segment_id);

        if (it == _segments_rowid_map.end()) {

            return -1;

        }

        const auto& rowid_map = it->second;

        if (src.row_id >= rowid_map.size() || UINT32_MAX == rowid_map[src.row_id]) {

            return -1;

        }

        return rowid_map[src.row_id];

    }

private:

    // key:   index indicates src segment.

    // value: index indicates row id of source segment, value indicates row id of destination

    //        segment. UINT32_MAX indicates current row not exist.

    DorisMap<uint32_t, DorisVector<uint32_t>> _segments_rowid_map;

    // dst rowset id

    RowsetId _rowst_id;

    // current rowid of dst segment

    std::uint32_t _cur_dst_segment_rowid = 0;

};

} // namespace doris