// 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 <gen_cpp/Types_types.h>

#include <cstdint>

#include <map>

#include <memory>

#include <string>

#include <vector>

#include "common/status.h"

#include "olap/tablet_fwd.h"

namespace doris {

namespace io {

class RemoteFileSystem;

} // namespace io

class DataDir;

class TRemoteTabletSnapshot;

class StorageEngine;

struct FileStat {

    std::string name;

    std::string md5;

    int64_t size;

};

class ExecEnv;

/*

 * Upload:

 * upload() will upload the specified snapshot

 * to remote storage via broker.

 * Each call of upload() is responsible for several tablet snapshots.

 *

 * It will try to get the existing files in remote storage,

 * and only upload the incremental part of files.

 *

 * Download:

 * download() will download the remote tablet snapshot files

 * to local snapshot dir via broker.

 * It will also only download files which does not exist in local dir.

 *

 * Move:

 * move() is the final step of restore process. it will replace the

 * old tablet data dir with the newly downloaded snapshot dir.

 * and reload the tablet header to take this tablet on line.

 *

 */

class SnapshotLoader {

    friend class SnapshotHttpDownloader;

public:

    SnapshotLoader(StorageEngine& engine, ExecEnv* env, int64_t job_id, int64_t task_id,

                   const TNetworkAddress& broker_addr = {},

                   const std::map<std::string, std::string>& broker_prop = {});

    ~SnapshotLoader();

    Status init(TStorageBackendType::type type, const std::string& location);

    Status upload(const std::map<std::string, std::string>& src_to_dest_path,

                  std::map<int64_t, std::vector<std::string>>* tablet_files);

    Status download(const std::map<std::string, std::string>& src_to_dest_path,

                    std::vector<int64_t>* downloaded_tablet_ids);

    Status remote_http_download(const std::vector<TRemoteTabletSnapshot>& remote_tablets,

                                std::vector<int64_t>* downloaded_tablet_ids);

    Status move(const std::string& snapshot_path, TabletSharedPtr tablet, bool overwrite);

    int64_t get_http_download_files_num() const { return _http_download_files_num; }

private:

    Status _get_tablet_id_and_schema_hash_from_file_path(const std::string& src_path,

                                                         int64_t* tablet_id, int32_t* schema_hash);

    Status _check_local_snapshot_paths(const std::map<std::string, std::string>& src_to_dest_path,

                                       bool check_src);

    Status _get_existing_files_from_local(const std::string& local_path,

                                          std::vector<std::string>* local_files);

    Status _replace_tablet_id(const std::string& file_name, int64_t tablet_id,

                              std::string* new_file_name);

    Status _get_tablet_id_from_remote_path(const std::string& remote_path, int64_t* tablet_id);

    Status _report_every(int report_threshold, int* counter, int finished_num, int total_num,

                         TTaskType::type type);

    Status _list_with_checksum(const std::string& dir, std::map<std::string, FileStat>* md5_files);

    void _set_http_download_files_num(int64_t num) { _http_download_files_num = num; }

private:

    StorageEngine& _engine;

    ExecEnv* _env = nullptr;

    int64_t _job_id;

    int64_t _task_id;

    const TNetworkAddress _broker_addr;

    const std::map<std::string, std::string> _prop;

    std::shared_ptr<io::RemoteFileSystem> _remote_fs;

    // for test remote_http_download

    size_t _http_download_files_num;

};

} // end namespace doris