C# .NET TimeSpan Rounding and Display

TimeSpanExtensions.cs

using System;

namespace Utils {
    
    public static class TimeSpanExtensions
    {
        public static TimeSpan Round(this TimeSpan span, TimeSpanRoundingType type, MidpointRounding mode = MidpointRounding.ToEven) =>
            type switch
            {
                TimeSpanRoundingType.QuarterMinute => TimeSpan.FromSeconds(Math.Round(span.TotalSeconds / 15, 0, mode) * 15),
                TimeSpanRoundingType.HalfMinute => TimeSpan.FromSeconds(Math.Round(span.TotalSeconds / 30, 0, mode) * 30),
                TimeSpanRoundingType.Minute => TimeSpan.FromSeconds(Math.Round(span.TotalSeconds / 60, 0, mode) * 60),
                TimeSpanRoundingType.QuarterHour => TimeSpan.FromMinutes(Math.Round(span.TotalMinutes / 15, 0, mode) * 15),
                TimeSpanRoundingType.HalfHour => TimeSpan.FromMinutes(Math.Round(span.TotalMinutes / 30, 0, mode) * 30),
                TimeSpanRoundingType.Hour => TimeSpan.FromMinutes(Math.Round(span.TotalMinutes / 60, 0, mode) * 60),
                _ => throw new ArgumentOutOfRangeException(nameof(type), type, null)
            };

        public static string ToPrettyString(this TimeSpan span, TimeSpanPrettyDepth depth = TimeSpanPrettyDepth.Seconds)
        {
            static string AddS(int i) => i > 1 ? "s" : string.Empty;

            if (span == TimeSpan.Zero) return "no time";
            var sb = new StringBuilder();
            if (span.Days > 0 && depth >= TimeSpanPrettyDepth.Days)
                sb.Append($"{span.Days} day{AddS(span.Days)} ");
            if (span.Hours > 0 && depth >= TimeSpanPrettyDepth.Hours)
                sb.Append($"{span.Hours} hour{AddS(span.Hours)} ");
            if (span.Minutes > 0 && depth >= TimeSpanPrettyDepth.Minutes)
                sb.Append($"{span.Minutes} minute{AddS(span.Minutes)} ");
            if (span.Seconds > 0 && depth >= TimeSpanPrettyDepth.Seconds)
                sb.Append($"{span.Seconds} second{AddS(span.Seconds)} ");
            if (span.Milliseconds > 0 && depth >= TimeSpanPrettyDepth.Milliseconds)
                sb.Append($"{span.Milliseconds} millisecond{AddS(span.Milliseconds)} ");
            return sb.Remove(sb.Length - 1, 1).ToString();
        }
    }

    public enum TimeSpanRoundingType
    {
        QuarterMinute,
        HalfMinute,
        Minute,
        QuarterHour,
        HalfHour,
        Hour,
    }

    public enum TimeSpanPrettyDepth
    {
        Days = 1,
        Hours = 2,
        Minutes = 3,
        Seconds = 4,
        Milliseconds = 5
    }
}