Create a valid NTFS Windows filename out of a string

FilenameHelpers.cs

    /// <summary>Creates a valid Windows filename from a string.</summary>
    /// <param name="filename">The filename candidate.</param>
    /// <param name="replaceInvalidCharsWith">What to replace invalid filename chars in <paramref name="filename"/> with.</param>
    /// <returns>
    /// A new <see cref="string"/>, equivalent to <paramref name="filename"/>, but modified to be a valid Windows filename if it
    /// <paramref name="filename"/> wasn't already.
    /// </returns>
    /// <exception cref="ArgumentException"/>
    /// <remarks>The length of the filename is not checked, and the casing is not modified.</remarks>
    public static string ToFilename(this string filename, string replaceInvalidCharsWith = "_")
        => string.IsNullOrWhiteSpace(filename)
             ? throw new ArgumentException($"Is null, empty, or whitespace.", nameof(filename))

         : string.IsNullOrEmpty(replaceInvalidCharsWith)
             ? throw new ArgumentException($"Is null or empty.", nameof(replaceInvalidCharsWith))

         : filename.All(c => c == '.')
             ? throw new ArgumentException($"Consists only of dots", nameof(filename))

         : replaceInvalidCharsWith.All(c => c == '.')
             ? throw new ArgumentException($"Consists only of dots.", nameof(replaceInvalidCharsWith))

         : replaceInvalidCharsWith.IndexOfAny(_invalidFileNameChars) != -1
             ? throw new ArgumentException($"Contains invalid filename chars.", nameof(replaceInvalidCharsWith))

         : Regex.Replace(filename.Trim(), $"[{Regex.Escape(new(_invalidFileNameChars))}]", replaceInvalidCharsWith,
                         RegexOptions.Compiled | RegexOptions.CultureInvariant);