// 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/cache/file_block.h"

#include <glog/logging.h>

// IWYU pragma: no_include <bits/chrono.h>

#include <chrono> // IWYU pragma: keep

#include <sstream>

#include <string>

#include <thread>

#include "common/status.h"

#include "cpp/sync_point.h"

#include "io/cache/block_file_cache.h"

namespace doris {

namespace io {

std::ostream& operator<<(std::ostream& os, const FileBlock::State& value) {

    os << FileBlock::state_to_string(value);

    return os;

}

FileBlock::FileBlock(const FileCacheKey& key, size_t size, BlockFileCache* mgr,

                     State download_state)

        : _block_range(key.offset, key.offset + size - 1),

          _download_state(download_state),

          _mgr(mgr),

          _key(key) {

    /// On creation, file block state can be EMPTY, DOWNLOADED, SKIP_CACHE.

    switch (_download_state) {

    case State::DOWNLOADING: {

        DCHECK(false) << "Can create cell with either EMPTY, DOWNLOADED, SKIP_CACHE ";

        break;

    }

    default: {

        break;

    }

    }

}

FileBlock::State FileBlock::state() const {

    std::lock_guard block_lock(_mutex);

    return _download_state;

}

FileBlock::State FileBlock::state_unsafe() const {

    return _download_state;

}

uint64_t FileBlock::get_caller_id() {

    uint64_t id;

#if defined(__APPLE__)

    // On macOS, use pthread_threadid_np to get the thread ID

    pthread_threadid_np(nullptr, &id);

#else

    id = static_cast<uint64_t>(pthread_self());

#endif

    DCHECK(id != 0);

    return id;

}

void FileBlock::set_cache_type(FileCacheType new_type) {

    std::lock_guard block_lock(_mutex);

    _key.meta.type = new_type;

}

uint64_t FileBlock::get_or_set_downloader() {

    std::lock_guard block_lock(_mutex);

    if (_downloader_id == 0 && _download_state != State::DOWNLOADED) {

        DCHECK(_download_state != State::DOWNLOADING);

        _downloader_id = get_caller_id();

        _download_state = State::DOWNLOADING;

    } else if (_downloader_id == get_caller_id()) {

        LOG(INFO) << "Attempt to set the same downloader for block " << range().to_string()

                  << " for the second time";

    }

    return _downloader_id;

}

void FileBlock::reset_downloader(std::lock_guard<std::mutex>& block_lock) {

    DCHECK(_downloader_id != 0) << "There is no downloader";

    DCHECK(get_caller_id() == _downloader_id) << "Downloader can be reset only by downloader";

    reset_downloader_impl(block_lock);

}

void FileBlock::reset_downloader_impl(std::lock_guard<std::mutex>& block_lock) {

    if (_downloaded_size == range().size()) {

        Status st = set_downloaded(block_lock);

        if (!st.ok()) {

            LOG(WARNING) << "reset downloader error" << st;

        }

    } else {

        _downloaded_size = 0;

        _download_state = State::EMPTY;

        _downloader_id = 0;

    }

}

Status FileBlock::set_downloaded(std::lock_guard<std::mutex>& /* block_lock */) {

    DCHECK(_download_state != State::DOWNLOADED);

    if (_downloaded_size == 0) {

        _download_state = State::EMPTY;

        _downloader_id = 0;

        return Status::InternalError("Try to set empty block {} as downloaded",

                                     _block_range.to_string());

    }

    Status status = _mgr->_storage->finalize(_key, this->_block_range.size());

    if (status.ok()) [[likely]] {

        _download_state = State::DOWNLOADED;

    } else {

        _download_state = State::EMPTY;

        _downloaded_size = 0;

    }

    _downloader_id = 0;

    return status;

}

uint64_t FileBlock::get_downloader() const {

    std::lock_guard block_lock(_mutex);

    return _downloader_id;

}

bool FileBlock::is_downloader() const {

    std::lock_guard block_lock(_mutex);

    return get_caller_id() == _downloader_id;

}

bool FileBlock::is_downloader_impl(std::lock_guard<std::mutex>& /* block_lock */) const {

    return get_caller_id() == _downloader_id;

}

Status FileBlock::append(Slice data) {

    DCHECK(data.size != 0) << "Writing zero size is not allowed";

    RETURN_IF_ERROR(_mgr->_storage->append(_key, data));

    _downloaded_size += data.size;

    return Status::OK();

}

Status FileBlock::finalize() {

    if (_downloaded_size == 0) {

        std::lock_guard block_lock(_mutex);

        _download_state = State::EMPTY;

        _downloader_id = 0;

        _cv.notify_all();

        return Status::InternalError("Try to finalize an empty file block {}",

                                     _block_range.to_string());

    }

    if (_downloaded_size != _block_range.size()) {

        SCOPED_CACHE_LOCK(_mgr->_mutex, _mgr);

        size_t old_size = _block_range.size();

        _block_range.right = _block_range.left + _downloaded_size - 1;

        size_t new_size = _block_range.size();

        DCHECK(new_size < old_size);

        _mgr->reset_range(_key.hash, _block_range.left, old_size, new_size, cache_lock);

    }

    std::lock_guard block_lock(_mutex);

    Status st = set_downloaded(block_lock);

    _cv.notify_all();

    return st;

}

Status FileBlock::read(Slice buffer, size_t read_offset) {

    return _mgr->_storage->read(_key, read_offset, buffer);

}

Status FileBlock::change_cache_type(FileCacheType new_type) {

    SCOPED_CACHE_LOCK(_mgr->_mutex, _mgr);

    return change_cache_type_lock(new_type, cache_lock);

}

Status FileBlock::change_cache_type_lock(FileCacheType new_type,

                                         std::lock_guard<std::mutex>& cache_lock) {

    std::lock_guard block_lock(_mutex);

    if (new_type == _key.meta.type) {

        return Status::OK();

    }

    if (_download_state == State::DOWNLOADED) {

        Status st;

        TEST_SYNC_POINT_CALLBACK("FileBlock::change_cache_type", &st);

        RETURN_IF_ERROR(_mgr->_storage->change_key_meta_type(_key, new_type, _block_range.size()));

    }

    _mgr->change_cache_type(_key.hash, _block_range.left, new_type, cache_lock);

    _key.meta.type = new_type;

    return Status::OK();

}

FileBlock::State FileBlock::wait() {

    std::unique_lock block_lock(_mutex);

    if (_downloader_id == 0) {

        return _download_state;

    }

    if (_download_state == State::DOWNLOADING) {

        DCHECK(_downloader_id != 0 && _downloader_id != get_caller_id());

        _cv.wait_for(block_lock, std::chrono::milliseconds(config::block_cache_wait_timeout_ms));

    }

    return _download_state;

}

void FileBlock::complete_unlocked(std::lock_guard<std::mutex>& block_lock) {

    if (is_downloader_impl(block_lock)) {

        reset_downloader(block_lock);

        _cv.notify_all();

    }

}

std::string FileBlock::get_info_for_log() const {

    std::lock_guard block_lock(_mutex);

    return get_info_for_log_impl(block_lock);

}

std::string FileBlock::get_info_for_log_impl(std::lock_guard<std::mutex>& block_lock) const {

    std::stringstream info;

    info << "File block: " << range().to_string() << ", ";

    info << "state: " << state_to_string(_download_state) << ", ";

    info << "size: " << _block_range.size() << ", ";

    info << "downloader id: " << _downloader_id << ", ";

    info << "caller id: " << get_caller_id();

    return info.str();

}

FileBlock::State FileBlock::state_unlock(std::lock_guard<std::mutex>&) const {

    return _download_state;

}

std::string FileBlock::state_to_string(FileBlock::State state) {

    switch (state) {

    case FileBlock::State::DOWNLOADED:

        return "DOWNLOADED";

    case FileBlock::State::EMPTY:

        return "EMPTY";

    case FileBlock::State::DOWNLOADING:

        return "DOWNLOADING";

    case FileBlock::State::SKIP_CACHE:

        return "SKIP_CACHE";

    default:

        DCHECK(false);

        return "";

    }

}

std::string FileBlock::get_cache_file() const {

    return _mgr->_storage->get_local_file(this->_key);

}

FileBlocksHolder::~FileBlocksHolder() {

    for (auto file_block_it = file_blocks.begin(); file_block_it != file_blocks.end();) {

        auto current_file_block_it = file_block_it;

        auto& file_block = *current_file_block_it;

        BlockFileCache* _mgr = file_block->_mgr;

        {

            bool should_remove = false;

            {

                std::lock_guard block_lock(file_block->_mutex);

                file_block->complete_unlocked(block_lock);

                if (file_block.use_count() == 2 &&

                    (file_block->is_deleting() ||

                     file_block->state_unlock(block_lock) == FileBlock::State::EMPTY)) {

                    should_remove = true;

                }

            }

            if (should_remove) {

                SCOPED_CACHE_LOCK(_mgr->_mutex, _mgr);

                std::lock_guard block_lock(file_block->_mutex);

                if (file_block.use_count() == 2) {

                    DCHECK(file_block->state_unlock(block_lock) != FileBlock::State::DOWNLOADING);

                    // one in cache, one in here

                    if (file_block->is_deleting() ||

                        file_block->state_unlock(block_lock) == FileBlock::State::EMPTY) {

                        _mgr->remove(file_block, cache_lock, block_lock, false);

                    }

                }

            }

        }

        file_block_it = file_blocks.erase(current_file_block_it);

    }

}

} // namespace io

} // namespace doris