h-school/src/HSchool.Simulation/PersonInsulation.cs

using HSchool.Content;
using HSchool.People;

namespace HSchool.Simulation;

/// <summary>
/// Worn insulation in °C-equivalent points, summed from apparel currently on the body.
/// Tests that need a bare frost set <see cref="Naked"/> on the entity explicitly.
/// </summary>
public readonly record struct PersonInsulation(float Value)
{
    public static PersonInsulation Naked { get; } = new(0f);

    public static PersonInsulation FromWorn(DefCatalog catalog, params string[] defNames)
    {
        ArgumentNullException.ThrowIfNull(catalog);
        var sum = 0f;
        foreach (var name in defNames)
        {
            if (catalog.Things.TryGetValue(name, out var thing) && thing.Layers.Count > 0)
            {
                sum += thing.Insulation;
            }
        }

        return new PersonInsulation(sum);
    }

    public static PersonInsulation FromPerson(Person person, DefCatalog? catalog)
    {
        ArgumentNullException.ThrowIfNull(person);
        if (catalog is null)
        {
            return Naked;
        }

        var worn = new List<string>();
        foreach (var item in person.Items)
        {
            if (item.Location.Equals(ItemLocations.Worn, StringComparison.Ordinal))
            {
                worn.Add(item.Def);
            }
        }

        return worn.Count == 0 ? Naked : FromWorn(catalog, [.. worn]);
    }
}