using HSchool.Content;

namespace HSchool.Ai;

/// <summary>
/// How much a lesson adds to one skill this step. Hungry learns worse; trait offsets scale the
/// rate. The world stores the running total — this is just the number.
/// </summary>
public static class LessonLearning
{
    public static float NeedFactor(float hunger) => Math.Clamp(0.25f + (0.75f * hunger), 0.25f, 1f);

    public static float TraitFactor(int offset) => Math.Max(0.1f, 1f + (offset / 100f));

    public static float Gain(
        float current,
        SkillDef skill,
        float share,
        float lessonSkillPerHour,
        float hours,
        float hunger,
        int traitOffset)
    {
        ArgumentNullException.ThrowIfNull(skill);
        var delta = share * lessonSkillPerHour * hours * NeedFactor(hunger) * TraitFactor(traitOffset);
        return Math.Clamp(current + delta, skill.Range.Min, skill.Range.Max);
    }
}