// FileBackup.hpp
//
// Copyright (C) 2011 ARM Research Labs, LLC.
// See www.armresearch.com for the copyright terms.
//
// This file defines the interface used by the FileBackup class.
//

#ifndef FileBackuphpp_included
#define FileBackuphpp_included

#include <string>
#include <map>

/// FileBackup class.
//
// This class provides capability to manage the backup and restore of
// disk files.
//
//////////////////////////////////////////////////////////////////////////////////////////////////////////
class FileBackup {

public:

    /// Create a backup of the specified file.
    //
    // This method first removes any .failed files, and then creates a
    // backup of the specified file.  The name of the backup file is
    // the name of the file appended by the BackupSuffix data member.
    //
    // The file can be restored from the backup by RestoreFromBackup.
    //
    // \param[in] File is the file name to create a backup for.
    //
    // \throws std::runtime_error if an error is encountered.
    //
    // \see RestoreAllFilesFromBackup().
    //
    void CreateBackupFile(std::string File);

    /// Remove the backups of all the specified files.
    //
    // This method removes the backup of the files specified by the
    // CreateBackup() method.
    //
    // \throws std::runtime_error if an error is encountered.
    //
    void RemoveAllBackupFiles();

    /// Restore the all the specified files from the backup.
    //
    // This method restores the backup of the files specified by the
    // CreateBackupFile() method.
    //
    // The new file that is overwritten is first copied to the file
    // with a suffix ".failed".  Then, if the original file existed,
    // it is restored.
    //
    // \throws std::runtime_error if an error is encountered.
    //
    // \see CreateBackupFile().
    //
    void RestoreAllFilesFromBackup();

    /// Get the name of the backup file.
    //
    // \param[in] File is the name of the file to back up.
    //
    // \returns the name of the backup file.
    //
    static std::string GetBackupFileName(std::string File);

    /// Get the name of the failed file.
    //
    // \param[in] File is the name of the file that contains the
    // configuration that failed (i.e. resulted in an error).
    //
    // \returns the name of the failed file.
    //
    static std::string GetFailedFileName(std::string File);

    /// Check if a file exists.
    //
    // \returns true if the file exists, false otherwise.
    //
    static bool FileExists(std::string File);

private:

    /// Copy a file.
    //
    // \param[in] From is the name of the file to copy from.
    //
    // \param[in] To is the name of the file to copy to.
    //
    // \throws runtime_error in case of error.
    //
    void CopyFile(std::string From, std::string To);

    /// Suffix to append to the file name to obtain the backup file
    /// name.
    static const std::string BackupSuffix;

    /// Suffix to append to the file name to obtain the failed file
    /// name.
    static const std::string FailedSuffix;

    /// Typedef for container of names of files.
    //
    // The key is the name of the file to back up.  The value is true
    // if the file to back up exists, false otherwise.
    typedef std::map<std::string, bool> FilenameContainer;

    /// Container of files that have backups.
    FilenameContainer OriginalFileExists;

};

#endif