#pragma once

#include <Backups/BackupEntryWithChecksumCalculation.h>


namespace DB
{

/// Represents a file prepared to be included in a backup, assuming that until this backup entry is destroyed
/// the file can be appended with new data, but the bytes which are already in the file won't be changed.
class BackupEntryFromAppendOnlyFile : public BackupEntryWithChecksumCalculation<IBackupEntry>
{
public:
    /// The constructor is allowed to not set `file_size_`, in that case it will be calculated from the data.
    BackupEntryFromAppendOnlyFile(
        const DiskPtr & disk_,
        const String & file_path_,
        bool copy_encrypted_ = false,
        const std::optional<UInt64> & file_size_ = {});

    ~BackupEntryFromAppendOnlyFile() override;

    std::unique_ptr<SeekableReadBuffer> getReadBuffer(const ReadSettings & read_settings) const override;
    UInt64 getSize() const override { return size; }

    DataSourceDescription getDataSourceDescription() const override { return data_source_description; }
    bool isEncryptedByDisk() const override { return copy_encrypted; }

    bool isFromFile() const override { return true; }
    DiskPtr getDisk() const override { return disk; }
    String getFilePath() const override { return file_path; }

private:
    const DiskPtr disk;
    const String file_path;
    const DataSourceDescription data_source_description;
    const bool copy_encrypted;
    const UInt64 size;
};

}