/*
 * C# / XNA  port of Bullet (c) 2011 Mark Neale <[email protected]>
 *
 * Bullet Continuous Collision Detection and Physics Library
 * Copyright (c) 2003-2008 Erwin Coumans  http://www.bulletphysics.com/
 *
 * This software is provided 'as-is', without any express or implied warranty.
 * In no event will the authors be held liable for any damages arising from
 * the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */
// Adapted from BulletXNA 73b2e1b9: namespace isolation, no XNA rendering, one type per file.
#nullable disable
#pragma warning disable CS1591, CS0168, CS0219, CS0414, CS0660, CS0661, CS0659, CS0693, CS8981, CS0108, CS0114
using System;
using System.Collections.Generic;
using HumanoidRetargeter.Core.Formats.Mmd.Bullet.LinearMath;

namespace HumanoidRetargeter.Core.Formats.Mmd.Bullet.BulletCollision;

internal class MultiSphereShape : ConvexInternalAabbCachingShape
{
	public MultiSphereShape(IList<IndexedVector3> positions, IList<float> radi, int numSpheres)
	{
		m_shapeType = BroadphaseNativeTypes.MULTI_SPHERE_SHAPE_PROXYTYPE;
		//float startMargin = float.MaxValue;
		for (int i = 0; i < numSpheres; i++)
		{
			m_localPositionArray.Add(positions[i]);
			m_radiArray.Add(radi[i]);
		}

		RecalcLocalAabb();
	}

	public override void CalculateLocalInertia(float mass, out IndexedVector3 inertia)
	{
		IndexedVector3 localAabbMin;
		IndexedVector3 localAabbMax;
		GetCachedLocalAabb(out localAabbMin, out localAabbMax);
		IndexedVector3 halfExtents = (localAabbMax - localAabbMin) * 0.5f;
		float lx = 2f * (halfExtents.X);
		float ly = 2f * (halfExtents.Y);
		float lz = 2f * (halfExtents.Z);
		inertia = new IndexedVector3(mass / (12.0f) * (ly * ly + lz * lz), mass / (12.0f) * (lx * lx + lz * lz), mass / (12.0f) * (lx * lx + ly * ly));
	}

	public override IndexedVector3 LocalGetSupportingVertexWithoutMargin(ref IndexedVector3 vec0)
	{
		int i;
		IndexedVector3 supVec = IndexedVector3.Zero;
		float maxDot = float.MinValue;
		IndexedVector3 vec = vec0;
		float lenSqr = vec.LengthSquared();
		if (lenSqr < (MathUtil.SIMD_EPSILON * MathUtil.SIMD_EPSILON))
		{
			vec = new IndexedVector3(1, 0, 0);
		}
		else
		{
			float rlen = (1.0f) / (float)Math.Sqrt(lenSqr);
			vec *= rlen;
		//vec.Normalize();
		}

		IndexedVector3 vtx = IndexedVector3.Zero;
		float newDot;
		int numSpheres = m_localPositionArray.Count;
		for (i = 0; i < numSpheres; i++)
		{
			IndexedVector3 pos = m_localPositionArray[i];
			float rad = m_radiArray[i];
			vtx = (pos) + vec * m_localScaling * (rad) - vec * GetMargin();
			newDot = IndexedVector3.Dot(vec, vtx);
			if (newDot > maxDot)
			{
				maxDot = newDot;
				supVec = vtx;
			}
		}

		return supVec;
	}

	public override void BatchedUnitVectorGetSupportingVertexWithoutMargin(IndexedVector3[] vectors, IndexedVector4[] supportVerticesOut, int numVectors)
	{
		for (int j = 0; j < numVectors; j++)
		{
			float maxDot = float.MinValue;
			IndexedVector3 vec = vectors[j];
			IndexedVector3 vtx = IndexedVector3.Zero;
			float newDot;
			int numSpheres = m_localPositionArray.Count;
			for (int i = 0; i < numSpheres; i++)
			{
				IndexedVector3 pos = m_localPositionArray[i];
				float rad = m_radiArray[i];
				vtx = (pos) + vec * m_localScaling * (rad) - vec * GetMargin();
				newDot = IndexedVector3.Dot(vec, vtx);
				if (newDot > maxDot)
				{
					maxDot = newDot;
					supportVerticesOut[j] = new IndexedVector4(vtx, 0);
				}
			}
		}
	}

	public int GetSphereCount()
	{
		return m_localPositionArray.Count;
	}

	public IndexedVector3 GetSpherePosition(int index)
	{
		return m_localPositionArray[index];
	}

	public float GetSphereRadius(int index)
	{
		return m_radiArray[index];
	}

	public override String GetName()
	{
		return "MultiSphere";
	}

	private IList<IndexedVector3> m_localPositionArray = new List<IndexedVector3>();
	private IList<float> m_radiArray = new List<float>();
	private IndexedVector3 m_inertiaHalfExtents;
}