private void EnsureLocalConflictByConflictFile(string conflictFilePath)
        {
            var conflict = _context.Conflicts.FirstOrDefault(current => current.ConflictFilePath == conflictFilePath);

            // conflict does not exist in database
            // actions: add new entity
            if (conflict == null)
            {
                _logger.LogDebug($"Conflict entity does not exist. Actions(s): Add new entity.");
                var originalFilePath = _regex_replace.Replace(conflictFilePath, string.Empty);

                conflict = new Conflict()
                {
                    OriginalFilePath = originalFilePath,
                    ConflictFilePath = conflictFilePath
                };

                _context.Conflicts.Add(conflict);
            }
            else
            {
                _logger.LogDebug($"Conflict entity already exists. Actions(s): do nothing.");
            }
        }
        private async Task <bool> CheckConflict(Conflict conflict)
        {
            var remoteItem        = _context.RemoteStates.FirstOrDefault(current => current.GetItemPath() == conflict.OriginalFilePath);
            var originalDriveItem = conflict.OriginalFilePath.ToDriveItem(DriveItemType.File);

            // original file exists locally
            if (await _localDrive.ExistsAsync(originalDriveItem))
            {
                _logger.LogDebug($"Original file exists locally.");
                var conflictDriveItem = conflict.ConflictFilePath.ToDriveItem(DriveItemType.File);

                // conflict file exists locally
                // actions: do nothing - user must delete or rename conflict file manually
                if (await _localDrive.ExistsAsync(conflictDriveItem))
                {
                    _logger.LogDebug($"Conflict file exists locally. Action(s): do nothing.");
                }

                // conflict file does not exist locally, i.e. conflict is solved
                else
                {
                    _logger.LogDebug($"Conflict file does not exist locally.");

                    // remote file is tracked in database
                    if (remoteItem != null)
                    {
                        _logger.LogDebug($"Remote file is tracked in database.");

                        // hashes are equal
                        // actions: do nothing
                        if (await _localDrive.GetHashAsync(originalDriveItem) == remoteItem.QuickXorHash)
                        {
                            _logger.LogDebug($"File is unchanged. Action(s): do nothing.");
                        }

                        // actions: upload file and replace remote version
                        else
                        {
                            _logger.LogInformation($"File was modified. Action(s): upload and replace file.");

                            originalDriveItem = await _localDrive.ToFullDriveItem(originalDriveItem);

                            var driveItem = await _remoteDrive.CreateOrUpdateAsync(originalDriveItem);

                            _context.RemoteStates.Add(driveItem.ToRemoteState());
                        }
                    }

                    // remote file is not tracked in database (e.g. upload failed previously)
                    // actions: upload file
                    else
                    {
                        _logger.LogInformation($"Remote file is not tracked in database. Action(s): upload file.");

                        originalDriveItem = await _localDrive.ToFullDriveItem(originalDriveItem);

                        var driveItem = await _remoteDrive.CreateOrUpdateAsync(originalDriveItem);

                        _context.RemoteStates.Add(driveItem.ToRemoteState());
                    }

                    return(true);
                }
            }

            // original file does not exist locally
            // actions: do nothing - user must delete or rename conflict file manually
            else
            {
                _logger.LogDebug($"Original file does not exist locally. Action(s): do nothing.");
            }

            return(false);
        }