// 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 "io/fs/file_meta_cache.h"

#include <utility>

#include "common/config.h"

#include "common/logging.h"

#include "util/stopwatch.hpp"

namespace doris {

namespace {

void update_profile_counter(int64_t* counter, int64_t value = 1) {

    if (counter != nullptr) {

        *counter += value;

    }

}

} // namespace

FileMetaCache::FileMetaCache(int64_t capacity,

                             std::unique_ptr<FileMetaPersistentCache> persistent_cache)

        : _cache(capacity), _persistent_cache(std::move(persistent_cache)) {}

std::string FileMetaCache::get_key(const std::string file_name, int64_t modification_time,

                                   int64_t file_size) {

    std::string meta_cache_key;

    meta_cache_key.resize(file_name.size() + sizeof(int64_t));

    memcpy(meta_cache_key.data(), file_name.data(), file_name.size());

    if (modification_time != 0) {

        memcpy(meta_cache_key.data() + file_name.size(), &modification_time, sizeof(int64_t));

    } else {

        memcpy(meta_cache_key.data() + file_name.size(), &file_size, sizeof(int64_t));

    }

    return meta_cache_key;

}

std::string FileMetaCache::get_key(io::FileReaderSPtr file_reader,

                                   const io::FileDescription& _file_description) {

    return FileMetaCache::get_key(

            file_reader->path().native(), _file_description.mtime,

            _file_description.file_size == -1 ? file_reader->size() : _file_description.file_size);

}

bool FileMetaCache::is_persistent_cache_enabled() {

    return config::enable_external_file_meta_disk_cache &&

           config::external_file_meta_disk_cache_max_entry_bytes > 0;

}

bool FileMetaCache::is_persistent_cache_payload_size_allowed(uint64_t payload_size) {

    const int64_t max_entry_bytes = config::external_file_meta_disk_cache_max_entry_bytes;

    return config::enable_external_file_meta_disk_cache && max_entry_bytes > 0 &&

           payload_size <= static_cast<uint64_t>(max_entry_bytes);

}

FileMetaCacheLookupResult FileMetaCache::lookup(const FileMetaCacheContext& context,

                                                ObjLRUCache::CacheHandle* handle,

                                                std::string* serialized_meta,

                                                FileMetaCacheProfile* profile) {

    DCHECK(handle != nullptr);

    DCHECK(serialized_meta != nullptr);

    if (context.enable_memory_cache && lookup(context.key, handle)) {

        serialized_meta->clear();

        if (profile != nullptr) {

            update_profile_counter(profile->hit_cache);

            update_profile_counter(profile->hit_memory_cache);

        }

        return {.state = FileMetaCacheLookupState::MEMORY_HIT};

    }

    FileMetaCacheLookupResult result;

    int64_t persisted_read_time = 0;

    if (lookup_persistent_cache(context, serialized_meta, &persisted_read_time)) {

        result.state = FileMetaCacheLookupState::PERSISTED_HIT;

        if (profile != nullptr) {

            update_profile_counter(profile->hit_cache);

            update_profile_counter(profile->hit_disk_cache);

            update_profile_counter(profile->read_disk_cache_time, persisted_read_time);

        }

    } else if (is_persistent_cache_enabled() && profile != nullptr) {

        update_profile_counter(profile->miss_disk_cache);

    }

    return result;

}

void FileMetaCache::invalidate_persistent_cache(const FileMetaCacheContext& context) {

    if (_persistent_cache != nullptr) {

        _persistent_cache->remove(context.format, context.key);

    }

}

bool FileMetaCache::lookup_persistent_cache(const FileMetaCacheContext& context,

                                            std::string* payload, int64_t* read_time) {

    DCHECK(payload != nullptr);

    DCHECK(read_time != nullptr);

    payload->clear();

    *read_time = 0;

    if (!is_persistent_cache_enabled() || _persistent_cache == nullptr) {

        return false;

    }

    MonotonicStopWatch watch;

    watch.start();

    Status status = _persistent_cache->read(context.format, context.key, context.modification_time,

                                            context.file_size, payload);

    *read_time = watch.elapsed_time();

    if (!status.ok()) {

        payload->clear();

        VLOG_DEBUG << "lookup file meta persistent cache failed: " << status;

        return false;

    }

    return true;

}

bool FileMetaCache::insert_persistent_cache(const FileMetaCacheContext& context,

                                            std::string_view payload, int64_t* write_time) {

    DCHECK(write_time != nullptr);

    *write_time = 0;

    if (!is_persistent_cache_payload_size_allowed(static_cast<uint64_t>(payload.size())) ||

        _persistent_cache == nullptr) {

        return false;

    }

    MonotonicStopWatch watch;

    watch.start();

    Status status = _persistent_cache->write(context.format, context.key, context.modification_time,

                                             context.file_size, payload);

    *write_time = watch.elapsed_time();

    if (!status.ok()) {

        VLOG_DEBUG << "insert file meta persistent cache failed: " << status;

        return false;

    }

    return true;

}

} // namespace doris