// region.go -can be created

// attempting to load the AWS region from multiple sources
// in order of precedence: explicit config -> AWS config/env vars ->IMDS.
// Returns empty string (not error) if region cannot be determined, allowing
// the caller to decide whether to fail or use a default.
func loadRegionWithFallback(ctx context.Context, explicitRegion string) (string, error) {
    if explicitRegion != "" {
        return explicitRegion, nil
    }
    
    cfg, err := awsConfig.LoadDefaultConfig(ctx)
    if err != nil {
        return "", fmt.Errorf("failed to load AWS config: %w", err)
    }
    
    if cfg.Region != "" {
        return cfg.Region, nil
    }
    // Fallback (may fail in non-AWS environments)
    imdsClient := imds.NewFromConfig(cfg)
    region, err := imdsClient.GetRegion(ctx, &imds.GetRegionInput{})
    if err != nil {
        return "", fmt.Errorf("failed to get region from IMDS: %w", err)
    }
    
    return region.Region, nil
}