/*
 * 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 System.Diagnostics;
using HumanoidRetargeter.Core.Formats.Mmd.Bullet.LinearMath;

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

internal class ConvexHullShape : PolyhedralConvexAabbCachingShape
{
	public ConvexHullShape(IList<IndexedVector3> points, int numPoints)
	{
		m_unscaledPoints = new List<IndexedVector3>(numPoints);
		m_shapeType = BroadphaseNativeTypes.CONVEX_HULL_SHAPE_PROXYTYPE;
		for (int i = 0; i < numPoints; ++i)
		{
			m_unscaledPoints.Add(points[i]);
		}

		RecalcLocalAabb();
	}

	public ConvexHullShape(IList<float> points, int numPoints)
	{
		m_unscaledPoints = new List<IndexedVector3>(numPoints);
		m_shapeType = BroadphaseNativeTypes.CONVEX_HULL_SHAPE_PROXYTYPE;
		for (int i = 0; i < numPoints / 3; ++i)
		{
			m_unscaledPoints.Add(new IndexedVector3(points[i * 3], points[i * 3] + 1, points[i * 3] + 2));
		}

		RecalcLocalAabb();
	}

	public void AddPoint(ref IndexedVector3 point)
	{
		m_unscaledPoints.Add(point);
		RecalcLocalAabb();
	}

	public IList<IndexedVector3> GetUnscaledPoints()
	{
		return m_unscaledPoints;
	}

	public IndexedVector3 GetScaledPoint(int i)
	{
		return m_unscaledPoints[i] * m_localScaling;
	}

	public int GetNumPoints()
	{
		return m_unscaledPoints.Count;
	}

	public override IndexedVector3 LocalGetSupportingVertexWithoutMargin(ref IndexedVector3 vec)
	{
		IndexedVector3 supVec = IndexedVector3.Zero;
		float newDot, maxDot = float.MinValue;
		for (int i = 0; i < m_unscaledPoints.Count; i++)
		{
			IndexedVector3 vtx = m_unscaledPoints[i] * m_localScaling;
			newDot = IndexedVector3.Dot(vec, vtx);
			if (newDot > maxDot)
			{
				maxDot = newDot;
				supVec = vtx;
			}
		}

		return supVec;
	}

	public override IndexedVector3 LocalGetSupportingVertex(ref IndexedVector3 vec)
	{
		IndexedVector3 supVertex = LocalGetSupportingVertexWithoutMargin(ref vec);
		if (GetMargin() != 0f)
		{
			IndexedVector3 vecnorm = vec;
			if (vecnorm.LengthSquared() < (MathUtil.SIMD_EPSILON * MathUtil.SIMD_EPSILON))
			{
				vecnorm = new IndexedVector3(-1f);
			}

			vecnorm.Normalize();
			supVertex += GetMargin() * vecnorm;
		}

		return supVertex;
	}

	public override void BatchedUnitVectorGetSupportingVertexWithoutMargin(IndexedVector3[] vectors, IndexedVector4[] supportVerticesOut, int numVectors)
	{
		float newDot;
		//use 'w' component of supportVerticesOut?
		{
			for (int i = 0; i < numVectors; i++)
			{
				IndexedVector4 temp = supportVerticesOut[i];
				temp.W = -MathUtil.BT_LARGE_FLOAT;
				supportVerticesOut[i] = temp;
			}
		}

		for (int i = 0; i < m_unscaledPoints.Count; i++)
		{
			IndexedVector3 vtx = GetScaledPoint(i);
			for (int j = 0; j < numVectors; j++)
			{
				IndexedVector3 vec = vectors[j];
				newDot = IndexedVector3.Dot(vec, vtx);
				if (newDot > supportVerticesOut[j].W)
				{
					//WARNING: don't swap next lines, the w component would get overwritten!
					supportVerticesOut[j] = new IndexedVector4(vtx, newDot);
				}
			}
		}
	}

	//debugging
	public override String GetName()
	{
		return "Convex";
	}

	public override int GetNumVertices()
	{
		return m_unscaledPoints.Count;
	}

	public override int GetNumEdges()
	{
		return m_unscaledPoints.Count;
	}

	public override void GetEdge(int i, out IndexedVector3 pa, out IndexedVector3 pb)
	{
		int index0 = i % m_unscaledPoints.Count;
		int index1 = (i + 1) % m_unscaledPoints.Count;
		pa = GetScaledPoint(index0);
		pb = GetScaledPoint(index1);
	}

	public override void GetVertex(int i, out IndexedVector3 vtx)
	{
		vtx = GetScaledPoint(i);
	}

	public override int GetNumPlanes()
	{
		return 0;
	}

	public override void GetPlane(out IndexedVector3 planeNormal, out IndexedVector3 planeSupport, int i)
	{
		{
		}

		planeNormal = IndexedVector3.Zero;
		planeSupport = IndexedVector3.Zero;
	}

	public override bool IsInside(ref IndexedVector3 pt, float tolerance)
	{
		{
		}

		return false;
	}

	public override void SetLocalScaling(ref IndexedVector3 scaling)
	{
		m_localScaling = scaling;
		RecalcLocalAabb();
	}

	public void Project(ref IndexedMatrix trans, ref IndexedVector3 dir, ref float min, ref float max)
	{
		min = float.MaxValue;
		max = float.MinValue;
		IndexedVector3 witnesPtMin;
		IndexedVector3 witnesPtMax;
		int numVerts = m_unscaledPoints.Count;
		for (int i = 0; i < numVerts; i++)
		{
			IndexedVector3 vtx = m_unscaledPoints[i] * m_localScaling;
			IndexedVector3 pt = trans * vtx;
			float dp = pt.Dot(dir);
			if (dp < min)
			{
				min = dp;
				witnesPtMin = pt;
			}

			if (dp > max)
			{
				max = dp;
				witnesPtMax = pt;
			}
		}

		if (min > max)
		{
			float tmp = min;
			min = max;
			max = tmp;
		}
	}

	private IList<IndexedVector3> m_unscaledPoints;
}