// 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/segment/segment_loader.h"

#include <butil/time.h>

#include "common/config.h"

#include "common/status.h"

#include "storage/olap_define.h"

#include "storage/rowset/beta_rowset.h"

#include "util/stopwatch.hpp"

namespace doris {

SegmentLoader* SegmentLoader::instance() {

    return ExecEnv::GetInstance()->segment_loader();

}

bool SegmentCache::lookup(const SegmentCache::CacheKey& key, SegmentCacheHandle* handle) {

    auto* lru_handle = LRUCachePolicy::lookup(key.encode());

    if (lru_handle == nullptr) {

        return false;

    }

    handle->push_segment(this, lru_handle);

    return true;

}

void SegmentCache::insert(const SegmentCache::CacheKey& key, SegmentCache::CacheValue& value,

                          SegmentCacheHandle* handle) {

    auto* lru_handle =

            LRUCachePolicy::insert(key.encode(), &value, value.segment->meta_mem_usage(),

                                   value.segment->meta_mem_usage(), CachePriority::NORMAL);

    handle->push_segment(this, lru_handle);

}

void SegmentCache::erase(const SegmentCache::CacheKey& key) {

    LRUCachePolicy::erase(key.encode());

}

Status SegmentLoader::load_segment(const BetaRowsetSharedPtr& rowset, int64_t segment_id,

                                   SegmentCacheHandle* cache_handle, bool use_cache,

                                   bool need_load_pk_index_and_bf,

                                   OlapReaderStatistics* index_load_stats) {

    auto start = MonotonicMicros();

    SegmentCache::CacheKey cache_key(rowset->rowset_id(), segment_id);

    if (_segment_cache->lookup(cache_key, cache_handle)) {

        // Has to check the segment status here, because the segment in cache may has something wrong during

        // load index or create column reader.

        // Not merge this if logic with previous to make the logic more clear.

        if (cache_handle->pop_unhealthy_segment() == nullptr) {

            if (index_load_stats != nullptr) {

                index_load_stats->rowset_reader_load_segments_timer_ns +=

                        (MonotonicMicros() - start) * 1000;

            }

            return Status::OK();

        }

    }

    // If the segment is not healthy, then will create a new segment and will replace the unhealthy one in SegmentCache.

    segment_v2::SegmentSharedPtr segment;

    RETURN_IF_ERROR(rowset->load_segment(segment_id, index_load_stats, &segment));

    if (need_load_pk_index_and_bf) {

        RETURN_IF_ERROR(segment->load_pk_index_and_bf(index_load_stats));

    }

    if (use_cache && !config::disable_segment_cache) {

        // memory of SegmentCache::CacheValue will be handled by SegmentCache

        auto* cache_value = new SegmentCache::CacheValue(segment);

        _cache_mem_usage += segment->meta_mem_usage();

        _segment_cache->insert(cache_key, *cache_value, cache_handle);

    } else {

        cache_handle->push_segment(std::move(segment));

    }

    if (index_load_stats != nullptr) {

        index_load_stats->rowset_reader_load_segments_timer_ns +=

                (MonotonicMicros() - start) * 1000;

    }

    return Status::OK();

}

Status SegmentLoader::load_segments(const BetaRowsetSharedPtr& rowset,

                                    SegmentCacheHandle* cache_handle, bool use_cache,

                                    bool need_load_pk_index_and_bf,

                                    OlapReaderStatistics* index_load_stats) {

    if (cache_handle->is_inited()) {

        return Status::OK();

    }

    for (int64_t i = 0; i < rowset->num_segments(); i++) {

        RETURN_IF_ERROR(load_segment(rowset, i, cache_handle, use_cache, need_load_pk_index_and_bf,

                                     index_load_stats));

    }

    cache_handle->set_inited();

    return Status::OK();

}

void SegmentLoader::erase_segment(const SegmentCache::CacheKey& key) {

    _segment_cache->erase(key);

}

void SegmentLoader::erase_segments(const RowsetId& rowset_id, int64_t num_segments) {

    for (int64_t i = 0; i < num_segments; i++) {

        erase_segment(SegmentCache::CacheKey(rowset_id, i));

    }

}

} // namespace doris