namespace InnovEnergy.Lib.Units;

public abstract class Unit
{
    protected Unit(Double value) => Value = value;

    public abstract String Symbol { get; }
    public Double Value { get;  }

    public override String ToString() => $"{Value} {Symbol}";

    public String ToDisplayString()
    {
        if (Value == 0)
            return $"0 {Symbol}";

        var a = Math.Abs(Value);
        var s = Math.Sign(Value);

        var i = 8;

        while (a >= 10000)
        {
            a /= 1000;
            i++;
        }
        while (a < 10)
        {
            a *= 1000;
            i--;
        }

        var r = a < 100
            ? Math.Floor(a * 10) / 10
            : Math.Floor(a);

        return $"{r * s} {Prefix[i]}{Symbol}";
    }

    private static readonly IReadOnlyList<String> Prefix = new[] { "y", "z", "a", "f", "p", "n", "µ", "m", "", "k", "M", "G", "T", "P", "E", "Y" };
}