// 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 <string>

#include <unordered_map>

#include "common/status.h"

#include "io/fs/file_system.h"

#include "io/fs/packed_file_manager.h"

namespace doris::io {

// FileSystem wrapper that handles packed file logic for small files

// When creating a file, it wraps the writer with PackedFileWriter

// When opening a file, it checks if the file is in a packed file and wraps with PackedFileReader

class PackedFileSystem final : public FileSystem {

public:

    PackedFileSystem(FileSystemSPtr inner_fs, PackedAppendContext append_info = {});

    PackedFileSystem(FileSystemSPtr inner_fs,

                     std::unordered_map<std::string, PackedSliceLocation> index_map,

                     PackedAppendContext append_info = {});

    ~PackedFileSystem() override = default;

    PackedFileSystem(const PackedFileSystem&) = delete;

    PackedFileSystem& operator=(const PackedFileSystem&) = delete;

protected:

    // Create file and wrap writer with PackedFileWriter

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

                            const FileWriterOptions* opts) override;

    // Open file and wrap reader with PackedFileReader if file is in packed file

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

                          const FileReaderOptions* opts) override;

    // Other operations not supported for PackedFileSystem

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

        return Status::InternalError("PackedFileSystem does not support create_directory");

    }

    Status delete_file_impl(const Path& file) override {

        return Status::InternalError("PackedFileSystem does not support delete_file");

    }

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

        return Status::InternalError("PackedFileSystem does not support batch_delete");

    }

    Status delete_directory_impl(const Path& dir) override {

        return Status::InternalError("PackedFileSystem does not support delete_directory");

    }

    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 {

        return Status::InternalError("PackedFileSystem does not support list");

    }

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

        return Status::InternalError("PackedFileSystem does not support rename");

    }

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

        abs_path = path;

        return Status::OK();

    }

private:

    FileSystemSPtr _inner_fs;

    // Map from small file path to packed file slice location

    std::unordered_map<std::string, PackedSliceLocation> _index_map;

    bool _index_map_initialized = false;

    PackedAppendContext _append_info;

};

} // namespace doris::io