Convert seconds to human readable format

HumanTimeFormat.cs

using System.Collections.Generic;
using System.Linq;

public class HumanTimeFormat
{
    protected class DateComponent
    {
        // One unit of current component
        public int InSeconds { get; }
        // String present of current component
        public string Unit { get; }
        public string UnitPlural => Unit + 's';

        public DateComponent(string unit, int inSeconds)
        {
            this.Unit = unit;
            this.InSeconds = inSeconds;
        }

        public string Format(int seconds)
        {
            if (seconds < InSeconds)
                return "";

            seconds -= seconds % InSeconds;
            int value = seconds / InSeconds;

            return value == 1 ? $"{value} {Unit}" : $"{value} {UnitPlural}";
        }

        // Number of seconds left after converting to current unit
        public int SecondsLeft(int seconds) => seconds % InSeconds;
    }

    static DateComponent[] components;
    
    static HumanTimeFormat()
    {
        components = new DateComponent[]
        {
            new DateComponent("year", 365 * 24 * 60 * 60),
            new DateComponent("day", 24 * 60 * 60),
            new DateComponent("hour", 60 * 60),
            new DateComponent("minute", 60),
            new DateComponent("second", 1)
        };
    }

    public static string FormatSeconds(int seconds)
    {
        if (seconds == 0)
            return "now";

        List<string> dateComponents = new List<string>();

        for (int i = 0; i < components.Length; i++)
        {
            dateComponents.Add(components[i].Format(seconds));
            seconds = components[i].SecondsLeft(seconds);
        }

        dateComponents = dateComponents.Where(x => !string.IsNullOrWhiteSpace(x)).ToList();

        if (dateComponents.Count == 1)
            return dateComponents[0];

        var last = dateComponents.Last();
        dateComponents.RemoveAt(dateComponents.Count - 1);

        return string.Join(", ", dateComponents) + $" and {last}";
    }
}