// 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.

#include "storage/index/indexed_column_reader.h"

#include <gen_cpp/segment_v2.pb.h>

#include <algorithm>

#include "common/status.h"

#include "io/io_common.h"

#include "storage/key_coder.h"

#include "storage/olap_common.h"

#include "storage/segment/encoding_info.h" // for EncodingInfo

#include "storage/segment/options.h"

#include "storage/segment/page_decoder.h"

#include "storage/segment/page_io.h"

#include "storage/types.h"

#include "util/block_compression.h"

#include "util/bvar_helper.h"

namespace doris {

using namespace ErrorCode;

namespace segment_v2 {

static bvar::Adder<uint64_t> g_index_reader_bytes("doris_pk", "index_reader_bytes");

static bvar::Adder<uint64_t> g_index_reader_compressed_bytes("doris_pk",

                                                             "index_reader_compressed_bytes");

static bvar::PerSecond<bvar::Adder<uint64_t>> g_index_reader_bytes_per_second(

        "doris_pk", "index_reader_bytes_per_second", &g_index_reader_bytes, 60);

static bvar::Adder<uint64_t> g_index_reader_pages("doris_pk", "index_reader_pages");

static bvar::PerSecond<bvar::Adder<uint64_t>> g_index_reader_pages_per_second(

        "doris_pk", "index_reader_pages_per_second", &g_index_reader_pages, 60);

static bvar::Adder<uint64_t> g_index_reader_cached_pages("doris_pk", "index_reader_cached_pages");

static bvar::PerSecond<bvar::Adder<uint64_t>> g_index_reader_cached_pages_per_second(

        "doris_pk", "index_reader_cached_pages_per_second", &g_index_reader_cached_pages, 60);

static bvar::Adder<uint64_t> g_index_reader_seek_count("doris_pk", "index_reader_seek_count");

static bvar::PerSecond<bvar::Adder<uint64_t>> g_index_reader_seek_per_second(

        "doris_pk", "index_reader_seek_per_second", &g_index_reader_seek_count, 60);

static bvar::Adder<uint64_t> g_index_reader_pk_pages("doris_pk", "index_reader_pk_pages");

static bvar::PerSecond<bvar::Adder<uint64_t>> g_index_reader_pk_bytes_per_second(

        "doris_pk", "index_reader_pk_pages_per_second", &g_index_reader_pk_pages, 60);

int64_t IndexedColumnReader::get_metadata_size() const {

    return sizeof(IndexedColumnReader) + _meta.ByteSizeLong();

}

Status IndexedColumnReader::load(bool use_page_cache, bool kept_in_memory,

                                 OlapReaderStatistics* index_load_stats) {

    _use_page_cache = use_page_cache;

    _kept_in_memory = kept_in_memory;

    _type_info = get_scalar_type_info((FieldType)_meta.data_type());

    if (_type_info == nullptr) {

        return Status::NotSupported("unsupported typeinfo, type={}", _meta.data_type());

    }

    RETURN_IF_ERROR(EncodingInfo::get(_type_info->type(), _meta.encoding(), {}, &_encoding_info));

    _value_key_coder = get_key_coder(_type_info->type());

    // read and parse ordinal index page when exists

    if (_meta.has_ordinal_index_meta()) {

        if (_meta.ordinal_index_meta().is_root_data_page()) {

            _sole_data_page = PagePointer(_meta.ordinal_index_meta().root_page());

        } else {

            RETURN_IF_ERROR(load_index_page(_meta.ordinal_index_meta().root_page(),

                                            &_ordinal_index_page_handle,

                                            _ordinal_index_reader.get(), index_load_stats));

            _has_index_page = true;

        }

    }

    // read and parse value index page when exists

    if (_meta.has_value_index_meta()) {

        if (_meta.value_index_meta().is_root_data_page()) {

            _sole_data_page = PagePointer(_meta.value_index_meta().root_page());

        } else {

            RETURN_IF_ERROR(load_index_page(_meta.value_index_meta().root_page(),

                                            &_value_index_page_handle, _value_index_reader.get(),

                                            index_load_stats));

            _has_index_page = true;

        }

    }

    _num_values = _meta.num_values();

    update_metadata_size();

    return Status::OK();

}

Status IndexedColumnReader::load_index_page(const PagePointerPB& pp, PageHandle* handle,

                                            IndexPageReader* reader,

                                            OlapReaderStatistics* index_load_stats) {

    Slice body;

    PageFooterPB footer;

    BlockCompressionCodec* local_compress_codec;

    RETURN_IF_ERROR(get_block_compression_codec(_meta.compression(), &local_compress_codec));

    RETURN_IF_ERROR(read_page(PagePointer(pp), handle, &body, &footer, INDEX_PAGE,

                              local_compress_codec, false, index_load_stats));

    RETURN_IF_ERROR(reader->parse(body, footer.index_page_footer()));

    _mem_size += body.get_size();

    return Status::OK();

}

Status IndexedColumnReader::read_page(const PagePointer& pp, PageHandle* handle, Slice* body,

                                      PageFooterPB* footer, PageTypePB type,

                                      BlockCompressionCodec* codec, bool pre_decode,

                                      OlapReaderStatistics* stats) const {

    OlapReaderStatistics tmp_stats;

    OlapReaderStatistics* stats_ptr = stats != nullptr ? stats : &tmp_stats;

    PageReadOptions opts(io::IOContext {.is_index_data = true,

                                        .file_cache_stats = &stats_ptr->file_cache_stats});

    opts.use_page_cache = _use_page_cache;

    opts.kept_in_memory = _kept_in_memory;

    opts.pre_decode = pre_decode;

    opts.type = type;

    opts.file_reader = _file_reader.get();

    opts.page_pointer = pp;

    opts.codec = codec;

    opts.stats = stats_ptr;

    opts.encoding_info = _encoding_info;

    if (_is_pk_index) {

        opts.type = PRIMARY_KEY_INDEX_PAGE;

    }

    auto st = PageIO::read_and_decompress_page(opts, handle, body, footer);

    g_index_reader_compressed_bytes << pp.size;

    g_index_reader_bytes << footer->uncompressed_size();

    g_index_reader_pages << 1;

    g_index_reader_cached_pages << tmp_stats.cached_pages_num;

    return st;

}

IndexedColumnReader::~IndexedColumnReader() = default;

///////////////////////////////////////////////////////////////////////////////

Status IndexedColumnIterator::_read_data_page(const PagePointer& pp) {

    Status status;

    // there is not init() for IndexedColumnIterator, so do it here

    if (!_compress_codec) {

        RETURN_IF_ERROR(get_block_compression_codec(_reader->get_compression(), &_compress_codec));

    }

    PageHandle handle;

    Slice body;

    PageFooterPB footer;

    RETURN_IF_ERROR(_reader->read_page(pp, &handle, &body, &footer, DATA_PAGE, _compress_codec,

                                       true, _stats));

    // parse data page

    // note that page_index is not used in IndexedColumnIterator, so we pass 0

    PageDecoderOptions opts;

    opts.need_check_bitmap = false;

    status = ParsedPage::create(std::move(handle), body, footer.data_page_footer(),

                                _reader->encoding_info(), pp, 0, &_data_page, opts);

    if (!status.ok()) {

        LOG(WARNING) << "failed to create ParsedPage in IndexedColumnIterator, file="

                     << _reader->_file_reader->path().native() << ", page_offset=" << pp.offset

                     << ", page_size=" << pp.size << ", error=" << status;

    }

    DCHECK(_reader->_meta.ordinal_index_meta().is_root_data_page()

                   ? _reader->_meta.num_values() == _data_page.num_rows

                   : true);

    return status;

}

Status IndexedColumnIterator::seek_to_ordinal(ordinal_t idx) {

    DCHECK(idx <= _reader->num_values());

    if (!_reader->support_ordinal_seek()) {

        return Status::NotSupported("no ordinal index");

    }

    // it's ok to seek past the last value

    if (idx == _reader->num_values()) {

        _current_ordinal = idx;

        _seeked = true;

        return Status::OK();

    }

    if (!_data_page || !_data_page.contains(idx)) {

        // need to read the data page containing row at idx

        if (_reader->_has_index_page) {

            std::string key;

            KeyCoderTraits<FieldType::OLAP_FIELD_TYPE_UNSIGNED_BIGINT>::full_encode_ascending(&idx,

                                                                                              &key);

            RETURN_IF_ERROR(_ordinal_iter.seek_at_or_before(key));

            RETURN_IF_ERROR(_read_data_page(_ordinal_iter.current_page_pointer()));

            _current_iter = &_ordinal_iter;

        } else {

            RETURN_IF_ERROR(_read_data_page(_reader->_sole_data_page));

        }

    }

    ordinal_t offset_in_page = idx - _data_page.first_ordinal;

    RETURN_IF_ERROR(_data_page.data_decoder->seek_to_position_in_page(offset_in_page));

    DCHECK(offset_in_page == _data_page.data_decoder->current_index());

    _data_page.offset_in_page = offset_in_page;

    _current_ordinal = idx;

    _seeked = true;

    return Status::OK();

}

Status IndexedColumnIterator::seek_at_or_after(const void* key, bool* exact_match) {

    if (!_reader->support_value_seek()) {

        return Status::NotSupported("no value index");

    }

    if (_reader->num_values() == 0) {

        return Status::Error<ErrorCode::ENTRY_NOT_FOUND>("value index is empty ");

    }

    g_index_reader_seek_count << 1;

    bool load_data_page = false;

    PagePointer data_page_pp;

    if (_reader->_has_index_page) {

        // seek index to determine the data page to seek

        std::string encoded_key;

        _reader->_value_key_coder->full_encode_ascending(key, &encoded_key);

        Status st = _value_iter.seek_at_or_before(encoded_key);

        if (st.is<ENTRY_NOT_FOUND>()) {

            // all keys in page is greater than `encoded_key`, point to the first page.

            // otherwise, we may missing some pages.

            // For example, the predicate is `col1 > 2`, and the index page is [3,5,7].

            // so the `seek_at_or_before(2)` will return Status::Error<ENTRY_NOT_FOUND>().

            // But actually, we expect it to point to page `3`.

            _value_iter.seek_to_first();

        } else if (!st.ok()) {

            return st;

        }

        data_page_pp = _value_iter.current_page_pointer();

        _current_iter = &_value_iter;

        if (!_data_page || _data_page.page_pointer != data_page_pp) {

            // load when it's not the same with the current

            load_data_page = true;

        }

    } else if (!_data_page) {

        // no index page, load data page for the first time

        load_data_page = true;

        data_page_pp = PagePointer(_reader->_sole_data_page);

    }

    if (load_data_page) {

        RETURN_IF_ERROR(_read_data_page(data_page_pp));

    }

    // seek inside data page

    Status st = _data_page.data_decoder->seek_at_or_after_value(key, exact_match);

    // return the first row of next page when not found

    if (st.is<ENTRY_NOT_FOUND>() && _reader->_has_index_page) {

        if (_value_iter.has_next()) {

            _seeked = true;

            *exact_match = false;

            _current_ordinal = _data_page.first_ordinal + _data_page.num_rows;

            // move offset to the end of the page

            _data_page.offset_in_page = _data_page.num_rows;

            return Status::OK();

        }

    }

    RETURN_IF_ERROR(st);

    _data_page.offset_in_page = _data_page.data_decoder->current_index();

    _current_ordinal = _data_page.first_ordinal + _data_page.offset_in_page;

    DCHECK(_data_page.contains(_current_ordinal));

    _seeked = true;

    return Status::OK();

}

Status IndexedColumnIterator::next_batch(size_t* n, MutableColumnPtr& dst) {

    DCHECK(_seeked);

    if (_current_ordinal == _reader->num_values()) {

        *n = 0;

        return Status::OK();

    }

    size_t remaining = *n;

    while (remaining > 0) {

        if (!_data_page.has_remaining()) {

            // trying to read next data page

            if (!_reader->_has_index_page) {

                break; // no more data page

            }

            bool has_next = _current_iter->move_next();

            if (!has_next) {

                break; // no more data page

            }

            RETURN_IF_ERROR(_read_data_page(_current_iter->current_page_pointer()));

        }

        size_t rows_to_read = std::min(_data_page.remaining(), remaining);

        size_t rows_read = rows_to_read;

        RETURN_IF_ERROR(_data_page.data_decoder->next_batch(&rows_read, dst));

        DCHECK(rows_to_read == rows_read);

        _data_page.offset_in_page += rows_read;

        _current_ordinal += rows_read;

        remaining -= rows_read;

    }

    *n -= remaining;

    _seeked = false;

    return Status::OK();

}

} // namespace segment_v2

} // namespace doris