using Godot;

namespace WorldSim;

/// <summary>Domains of practical knowledge (SPEC §5 — deliberately few).</summary>
public enum KnowledgeDomain { Forage, Woodcraft, Masonry }

/// <summary>
/// What a person knows how to do (SPEC §5). Not an object in the world —
/// it lives in people, spreads by proximity, grows by practice, and dies
/// with its holder unless it was passed on. Every death is a small library
/// burning; a teaching culture is a culture of copies.
///
/// Capacity is personal and randomized: some people can hold more than
/// others, and what fills first is what they lived.
/// </summary>
public class Knowledge
{
    public const int DomainCount = 3;

    /// <summary>0–1 per domain.</summary>
    public float[] Skill = new float[DomainCount];

    /// <summary>Total learning this mind can hold, across all domains.</summary>
    public float Capacity = 1.5f;

    public float Total => Skill[0] + Skill[1] + Skill[2];
    public float Headroom => Mathf.Max(0f, Capacity - Total);

    public float this[KnowledgeDomain d] => Skill[(int)d];

    /// <summary>Learn, limited by personal capacity.</summary>
    public void Gain(KnowledgeDomain d, float amount)
    {
        if (amount <= 0f || Headroom <= 0f) return;
        float a = Mathf.Min(amount, Headroom);
        Skill[(int)d] = Mathf.Clamp(Skill[(int)d] + a, 0f, 1f);
    }

    /// <summary>Which domain a material teaches and benefits from.</summary>
    public static KnowledgeDomain DomainFor(MaterialKind kind) => kind switch
    {
        MaterialKind.Food => KnowledgeDomain.Forage,
        MaterialKind.Herb => KnowledgeDomain.Forage,     // gathering the living land
        MaterialKind.Wood => KnowledgeDomain.Woodcraft,
        _                 => KnowledgeDomain.Masonry,    // stone, clay, ore — builder's craft
    };
}