Time Ago in C#

public static string AsTimeAgo(this DateTime dateTime)
{
  TimeSpan timeSpan = DateTime.Now.Subtract(dateTime);

  return timeSpan.TotalSeconds switch
  {
    <= 60 => $"{timeSpan.Seconds} seconds ago",

    _ => timeSpan.TotalMinutes switch
    {
      <= 1 => "about a minute ago",
      < 60 => $"about {timeSpan.Minutes} minutes ago",
      _ => timeSpan.TotalHours switch
      {
        <= 1 => "about an hour ago",
        < 24 => $"about {timeSpan.Hours} hours ago",
        _ => timeSpan.TotalDays switch
        {
          <= 1 => "yesterday",
          <= 30 => $"about {timeSpan.Days} days ago",

          <= 60 => "about a month ago",
          < 365 => $"about {timeSpan.Days / 30} months ago",

          <= 365 * 2 => "about a year ago",
          _ => $"about {timeSpan.Days / 365} years ago"
        }
      }
    }
  };
}