// 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 "olap/olap_common.h"

#include "olap/utils.h"

namespace doris {

// For unique key merge on write table, we should update delete bitmap

// of destination rowset when compaction finished.

// Through the row id correspondence between the source rowset and the

// destination rowset, we can quickly update the delete bitmap of the

// destination rowset.

class RowIdConversion {

public:

    RowIdConversion() = default;

    ~RowIdConversion() = default;

    // resize segment rowid map to its rows num

    void init_segment_map(const RowsetId& src_rowset_id, const std::vector<uint32_t>& num_rows) {

        for (size_t i = 0; i < num_rows.size(); i++) {

            uint32_t id = _segments_rowid_map.size();

            _segment_to_id_map.emplace(std::pair<RowsetId, uint32_t> {src_rowset_id, i}, id);

            _id_to_segment_map.emplace_back(src_rowset_id, i);

            _segments_rowid_map.emplace_back(std::vector<std::pair<uint32_t, uint32_t>>(

                    num_rows[i], std::pair<uint32_t, uint32_t>(UINT32_MAX, UINT32_MAX)));

        }

    }

    // set dst rowset id

    void set_dst_rowset_id(const RowsetId& dst_rowset_id) { _dst_rowst_id = dst_rowset_id; }

    const RowsetId get_dst_rowset_id() { return _dst_rowst_id; }

    // add row id to the map

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

             const std::vector<uint32_t>& dst_segments_num_row) {

        for (auto& item : rss_row_ids) {

            if (item.row_id == -1) {

                continue;

            }

            uint32_t id = _segment_to_id_map.at(

                    std::pair<RowsetId, uint32_t> {item.rowset_id, item.segment_id});

            if (_cur_dst_segment_id < dst_segments_num_row.size() &&

                _cur_dst_segment_rowid >= dst_segments_num_row[_cur_dst_segment_id]) {

                _cur_dst_segment_id++;

                _cur_dst_segment_rowid = 0;

            }

            _segments_rowid_map[id][item.row_id] =

                    std::pair<uint32_t, uint32_t> {_cur_dst_segment_id, _cur_dst_segment_rowid++};

        }

    }

    // get destination RowLocation

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

    int get(const RowLocation& src, RowLocation* dst) const {

        auto iter = _segment_to_id_map.find({src.rowset_id, src.segment_id});

        if (iter == _segment_to_id_map.end()) {

            return -1;

        }

        const auto& rowid_map = _segments_rowid_map[iter->second];

        if (src.row_id >= rowid_map.size()) {

            return -1;

        }

        auto& [dst_segment_id, dst_rowid] = rowid_map[src.row_id];

        if (dst_segment_id == UINT32_MAX && dst_rowid == UINT32_MAX) {

            return -1;

        }

        dst->rowset_id = _dst_rowst_id;

        dst->segment_id = dst_segment_id;

        dst->row_id = dst_rowid;

        return 0;

    }

    const std::vector<std::vector<std::pair<uint32_t, uint32_t>>>& get_rowid_conversion_map()

            const {

        return _segments_rowid_map;

    }

    const std::map<std::pair<RowsetId, uint32_t>, uint32_t>& get_src_segment_to_id_map() {

        return _segment_to_id_map;

    }

    std::pair<RowsetId, uint32_t> get_segment_by_id(uint32_t id) const {

        DCHECK_GT(_id_to_segment_map.size(), id);

        return _id_to_segment_map.at(id);

    }

    uint32_t get_id_by_segment(const std::pair<RowsetId, uint32_t>& segment) const {

        return _segment_to_id_map.at(segment);

    }

private:

    // the first level vector: index indicates src segment.

    // the second level vector: index indicates row id of source segment,

    // value indicates row id of destination segment.

    // <UINT32_MAX, UINT32_MAX> indicates current row not exist.

    std::vector<std::vector<std::pair<uint32_t, uint32_t>>> _segments_rowid_map;

    // Map source segment to 0 to n

    std::map<std::pair<RowsetId, uint32_t>, uint32_t> _segment_to_id_map;

    // Map 0 to n to source segment

    std::vector<std::pair<RowsetId, uint32_t>> _id_to_segment_map;

    // dst rowset id

    RowsetId _dst_rowst_id;

    // current dst segment id

    std::uint32_t _cur_dst_segment_id = 0;

    // current rowid of dst segment

    std::uint32_t _cur_dst_segment_rowid = 0;

};

} // namespace doris