// 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 <filesystem>

#include <memory>

#include <shared_mutex>

#include <string>

#include <utility>

#include <vector>

#include "common/status.h"

#include "io/fs/file_reader_writer_fwd.h"

#include "io/fs/path.h"

#include "io/fs/remote_file_system.h"

#include "util/s3_util.h"

namespace Aws::S3 {

class S3Client;

} // namespace Aws::S3

namespace Aws::Utils::Threading {

class PooledThreadExecutor;

} // namespace Aws::Utils::Threading

namespace doris::io {

class ObjStorageClient;

// In runtime, AK and SK may be modified, and the original `S3Client` instance will be replaced.

// The `S3FileReader` cached by the `Segment` must hold a shared `ObjClientHolder` in order to

// access S3 data with latest AK SK.

class ObjClientHolder {

public:

    explicit ObjClientHolder(S3ClientConf conf);

    ~ObjClientHolder();

    Status init();

    // Update s3 conf and reset client if `conf` is different. This method is threadsafe.

    Status reset(const S3ClientConf& conf);

    std::shared_ptr<ObjStorageClient> get() const {

        std::shared_lock lock(_mtx);

        return _client;

    }

    Result<int64_t> object_file_size(const std::string& bucket, const std::string& key) const;

    // For error msg

    std::string full_s3_path(std::string_view bucket, std::string_view key) const;

    const S3ClientConf& s3_client_conf() { return _conf; }

private:

    mutable std::shared_mutex _mtx;

    std::shared_ptr<ObjStorageClient> _client;

    S3ClientConf _conf;

};

// File system for S3 compatible object storage

// When creating S3FileSystem, all required info should be set in S3Conf,

// such as ak, sk, region, endpoint, bucket.

// And the root_path of S3FileSystem is s3_conf.prefix.

// When using S3FileSystem, it accepts 2 kinds of path:

//  1. Full path: s3://bucket/path/to/file.txt

//      In this case, the root_path is not used.

//  2. only key: path/to/file.txt

//      In this case, the final key will be "prefix + path/to/file.txt"

class S3FileSystem final : public RemoteFileSystem {

public:

    static Result<std::shared_ptr<S3FileSystem>> create(S3Conf s3_conf, std::string id);

    ~S3FileSystem() override;

    const std::shared_ptr<ObjClientHolder>& client_holder() const { return _client; }

    const std::string& bucket() const { return _bucket; }

    const std::string& prefix() const { return _prefix; }

    std::string generate_presigned_url(const Path& path, int64_t expiration_secs,

                                       bool is_public_endpoint) const;

protected:

    Status create_file_impl(const Path& file, FileWriterPtr* writer,

                            const FileWriterOptions* opts) override;

    Status open_file_internal(const Path& file, FileReaderSPtr* reader,

                              const FileReaderOptions& opts) override;

    Status create_directory_impl(const Path& dir, bool failed_if_exists = false) override;

    Status delete_file_impl(const Path& file) override;

    Status delete_directory_impl(const Path& dir) override;

    Status batch_delete_impl(const std::vector<Path>& files) override;

    Status exists_impl(const Path& path, bool* res) const override;

    Status file_size_impl(const Path& file, int64_t* file_size) const override;

    Status list_impl(const Path& dir, bool only_file, std::vector<FileInfo>* files,

                     bool* exists) override;

    Status rename_impl(const Path& orig_name, const Path& new_name) override;

    Status upload_impl(const Path& local_file, const Path& remote_file) override;

    Status batch_upload_impl(const std::vector<Path>& local_files,

                             const std::vector<Path>& remote_files) override;

    Status download_impl(const Path& remote_file, const Path& local_file) override;

    Status absolute_path(const Path& path, Path& abs_path) const override {

        if (path.string().find("://") != std::string::npos) {

            // the path is with schema, which means this is a full path like:

            // s3://bucket/path/to/file.txt

            // so no need to concat with prefix

            abs_path = path;

        } else {

            // path with no schema

            abs_path = _prefix / path;

        }

        return Status::OK();

    }

private:

    S3FileSystem(S3Conf s3_conf, std::string id);

    Status init();

    // For error msg

    std::string full_s3_path(std::string_view key) const;

    std::string _bucket;

    std::string _prefix;

    std::shared_ptr<ObjClientHolder> _client;

};

} // namespace doris::io