using System;
using System.Collections.Generic;
using System.Linq;
using BoundaryLab.Domain;

namespace BoundaryLab.Application;

public interface IRateSource { int GetRate(); }
public sealed class QuoteService(IRateSource rates)
{
    public int Total(int units)
    {
        if (!UnitRule.Valid(units)) throw new ArgumentOutOfRangeException(nameof(units));
        return checked(units * rates.GetRate());
    }
}