// Copyright (c) CypherCore <http://github.com/CypherCore> All rights reserved.
// Licensed under the GNU GENERAL PUBLIC LICENSE. See LICENSE file in the project root for full license information.

using System;
using System.Numerics;

namespace Framework.GameMath
{
    public class Box
    {
        public Vector3[] _edgeVector = new Vector3[3];
        public Vector3 _center;
        public float _area;
        public float _volume;

        public Box(Vector3 min, Vector3 max)
        {
            _center = (max + min) * 0.5f;

            Vector3 bounds = new Vector3(max.X - min.X, max.Y - min.Y, max.Z - min.Z);
            _edgeVector[0] = new Vector3(bounds.X, 0, 0);
            _edgeVector[1] = new Vector3(0, bounds.Y, 0);
            _edgeVector[2] = new Vector3(0, 0, bounds.Z);
            bool finiteExtent = true;

            for (int i = 0; i < 3; ++i)
            {
                if (!float.IsFinite(_edgeVector[i].Length()))
                {
                    finiteExtent = false;
                    // If the extent is infinite along an axis, make the center zero to avoid NaNs
                    _center.SetAt(0.0f, i);
                }
            }


            if (finiteExtent)
            {
                _volume = bounds.X * bounds.Y * bounds.Z;
            }
            else
            {
                _volume = float.PositiveInfinity;
            }

            _area = 2 *
                (bounds.X * bounds.Y +
                 bounds.Y * bounds.Z +
                 bounds.Z * bounds.X);
        }

        public bool Contains(Vector3 point)
        {
            Vector3 u = _edgeVector[2];
            Vector3 v = _edgeVector[1];
            Vector3 w = _edgeVector[0];

            Matrix4x4 M = new(u.X, v.X, w.X, 0.0f, u.Y, v.Y, w.Y, 0.0f, u.Z, v.Z, w.Z, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f);

            // M^-1 * (point - _corner[0]) = point in unit cube's object space
            // compute the inverse of M
            Matrix4x4.Invert(M, out M);
            Vector3 osPoint = M.Multiply(point - Corner(0));

            return (osPoint.X >= 0) && (osPoint.Y >= 0) && (osPoint.Z >= 0) &&
                (osPoint.X <= 1) && (osPoint.Y <= 1) && (osPoint.Z <= 1);
        }

        Vector3 Corner(int i)
        {
            switch (i)
            {
                case 0: return _center + (0.5f * (-_edgeVector[0] - _edgeVector[1] - _edgeVector[2]));
                case 1: return _center + (0.5f * (_edgeVector[0] - _edgeVector[1] - _edgeVector[2]));
                case 2: return _center + (0.5f * (-_edgeVector[0] + _edgeVector[1] - _edgeVector[2]));
                case 3: return _center + (0.5f * (_edgeVector[0] + _edgeVector[1] - _edgeVector[2]));
                case 4: return _center + (0.5f * (-_edgeVector[0] - _edgeVector[1] + _edgeVector[2]));
                case 5: return _center + (0.5f * (_edgeVector[0] - _edgeVector[1] + _edgeVector[2]));
                case 6: return _center + (0.5f * (-_edgeVector[0] + _edgeVector[1] + _edgeVector[2]));
                default: return _center + (0.5f * (_edgeVector[0] + _edgeVector[1] + _edgeVector[2]));//case 7
            }
        }

        public bool isFinite()
        {
            return float.IsFinite(_volume);
        }
    }
}