YachtDice/Assets/Scripts/Dice/Dice.cs

using System;
using System.Collections.Generic;
using UnityEngine;

namespace YachtDice.Dice
{

public sealed class Dice : MonoBehaviour
{
    [Serializable]
    public struct Entry : IEquatable<Entry>
    {
        [SerializeField] private int value;
        [SerializeField] private Transform point;

        public int Value => value;
        public Transform Point => point;

        public bool Equals(Entry other) => point == other.point;
        public override bool Equals(object obj) => obj is Entry other && Equals(other);
        public override int GetHashCode() => point != null ? point.GetHashCode() : 0;
    }

    [SerializeField] private List<Entry> entries = new();

    private HashSet<Entry> entrySet;

    private void Awake() => RebuildSet();
    private void OnValidate() => RebuildSet();

    public void Test()
    {
        if (!TryGetTopValue(out var top) || !TryGetBottomValue(out var bottom))
            return;

        Debug.Log($"Top Value: {top}, Bottom Value: {bottom}");

        AlignToTopByLocalAngles();
    }

    private void RebuildSet()
    {
        entrySet = new HashSet<Entry>();
        if (entries == null) return;
        for (int i = 0; i < entries.Count; i++) entrySet.Add(entries[i]);
    }

    public bool TryGetTopValue(out int value) => TryGetExtremeValue(isTop: true, out value);
    public bool TryGetBottomValue(out int value) => TryGetExtremeValue(isTop: false, out value);

    public int AlignToTopByLocalAngles()
    {
        var e = GetExtremeEntryByWorldY(isTop: true);
        AlignByFaceLocalAngles(e.Point);
        return e.Value;
    }

    public int AlignToBottomByLocalAngles()
    {
        var e = GetExtremeEntryByWorldY(isTop: false);
        AlignByFaceLocalAngles(e.Point);
        return e.Value;
    }

    private bool TryGetExtremeValue(bool isTop, out int value)
    {
        value = default;

        if (entrySet == null || entrySet.Count == 0)
            return false;

        bool found = false;
        float bestY = isTop ? float.NegativeInfinity : float.PositiveInfinity;
        int best = default;

        foreach (var e in entrySet)
        {
            var p = e.Point;
            if (!p) continue;

            float y = p.position.y;
            if (!found || (isTop ? y > bestY : y < bestY))
            {
                found = true;
                bestY = y;
                best = e.Value;
            }
        }

        if (!found) return false;

        value = best;
        return true;
    }

    private Entry GetExtremeEntryByWorldY(bool isTop)
    {
        if (entrySet == null || entrySet.Count == 0)
            throw new InvalidOperationException("Dice: коллекция пуста.");

        bool found = false;
        float bestY = isTop ? float.NegativeInfinity : float.PositiveInfinity;
        Entry best = default;

        foreach (var e in entrySet)
        {
            var p = e.Point;
            if (!p) continue;

            float y = p.position.y;
            if (!found || (isTop ? y > bestY : y < bestY))
            {
                found = true;
                bestY = y;
                best = e;
            }
        }

        if (!found)
            throw new InvalidOperationException("Dice: все Transform == null.");

        return best;
    }

    private static float Norm180(float a)
    {
        a %= 360f;
        return a > 180f ? a - 360f : (a < -180f ? a + 360f : a);
    }

    private void AlignByFaceLocalAngles(Transform facePoint)
    {
        if (!facePoint) throw new InvalidOperationException("Dice: facePoint == null.");

        transform.localEulerAngles = Vector3.Scale(facePoint.localEulerAngles, new Vector3(-1f, -1f, -1f));

        var e = transform.localEulerAngles;
        transform.localEulerAngles = new Vector3(Norm180(e.x), Norm180(e.y), Norm180(e.z));
    }
}
}