// 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/packed_file_reader.h"

#include <algorithm>

#include <utility>

#include "common/logging.h"

#include "common/status.h"

#include "io/fs/file_reader.h"

namespace doris::io {

PackedFileReader::PackedFileReader(FileReaderSPtr inner_reader, Path path, int64_t offset,

                                   int64_t size)

        : _inner_reader(std::move(inner_reader)),

          _path(std::move(path)),

          _packed_file_offset(offset),

          _file_size(size) {

    DCHECK(_inner_reader != nullptr);

}

PackedFileReader::~PackedFileReader() {

    if (!_closed) {

        static_cast<void>(close());

    }

}

Status PackedFileReader::read_at_impl(size_t offset, Slice result, size_t* bytes_read,

                                      const IOContext* io_ctx) {

    if (_closed) {

        return Status::InternalError("FileReader is already closed");

    }

    // Calculate the actual offset in packed file

    size_t actual_offset = _packed_file_offset + offset;

    // Calculate the maximum bytes we can read

    size_t max_read = std::min(result.get_size(), static_cast<size_t>(_file_size - offset));

    // Adjust result slice to the actual size we can read

    Slice adjusted_result(result.get_data(), max_read);

    // Read from packed file at the adjusted offset

    auto s = _inner_reader->read_at(actual_offset, adjusted_result, bytes_read, io_ctx);

    if (!s.ok()) {

        LOG(WARNING) << "failed to read packed file: " << _path.native() << ", offset: " << offset

                     << ", actual offset: " << actual_offset

                     << ", result size: " << adjusted_result.get_size()

                     << ", error: " << s.to_string()

                     << ", packed file offset: " << _packed_file_offset

                     << ", file size: " << _file_size;

        return s;

    }

    return Status::OK();

}

Status PackedFileReader::close() {

    if (_closed) {

        return Status::OK();

    }

    if (_inner_reader) {

        RETURN_IF_ERROR(_inner_reader->close());

    }

    _closed = true;

    return Status::OK();

}

} // namespace doris::io