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

namespace BoundaryLab.Domain;

public sealed class Basket
{
    private readonly int capacity;
    public Basket(int capacity) { if (capacity < 0) throw new ArgumentOutOfRangeException(nameof(capacity)); this.capacity = capacity; }
    public int Units { get; private set; }
    public bool TryAdd(int units)
    {
        if (units < 1 || units > capacity - Units) return false;
        Units += units; return true;
    }
}
public static class Shipping { public static bool NeedsFreight(Basket basket) => basket.Units >= 4; }