using System;
using System.Runtime.CompilerServices;

namespace MTAssets.UltimateLODSystem.MeshSimplifier.Internal
{
	internal struct Triangle : IEquatable<Triangle>
	{
		public int index;

		public int v0;

		public int v1;

		public int v2;

		public int subMeshIndex;

		public int va0;

		public int va1;

		public int va2;

		public double err0;

		public double err1;

		public double err2;

		public double err3;

		public bool deleted;

		public bool dirty;

		public Vector3d n;

		public int this[int index]
		{
			[MethodImpl(MethodImplOptions.AggressiveInlining)]
			get
			{
				return index switch
				{
					1 => v1, 
					0 => v0, 
					_ => v2, 
				};
			}
			[MethodImpl(MethodImplOptions.AggressiveInlining)]
			set
			{
				switch (index)
				{
				case 0:
					v0 = value;
					break;
				case 1:
					v1 = value;
					break;
				case 2:
					v2 = value;
					break;
				default:
					throw new ArgumentOutOfRangeException("index");
				}
			}
		}

		[MethodImpl(MethodImplOptions.AggressiveInlining)]
		public Triangle(int index, int v0, int v1, int v2, int subMeshIndex)
		{
			this.index = index;
			this.v0 = v0;
			this.v1 = v1;
			this.v2 = v2;
			this.subMeshIndex = subMeshIndex;
			va0 = v0;
			va1 = v1;
			va2 = v2;
			err0 = (err1 = (err2 = (err3 = 0.0)));
			deleted = (dirty = false);
			n = default(Vector3d);
		}

		[MethodImpl(MethodImplOptions.AggressiveInlining)]
		public void GetAttributeIndices(int[] attributeIndices)
		{
			attributeIndices[0] = va0;
			attributeIndices[1] = va1;
			attributeIndices[2] = va2;
		}

		[MethodImpl(MethodImplOptions.AggressiveInlining)]
		public void SetAttributeIndex(int index, int value)
		{
			switch (index)
			{
			case 0:
				va0 = value;
				break;
			case 1:
				va1 = value;
				break;
			case 2:
				va2 = value;
				break;
			default:
				throw new ArgumentOutOfRangeException("index");
			}
		}

		[MethodImpl(MethodImplOptions.AggressiveInlining)]
		public void GetErrors(double[] err)
		{
			err[0] = err0;
			err[1] = err1;
			err[2] = err2;
		}

		public override int GetHashCode()
		{
			return index;
		}

		public override bool Equals(object obj)
		{
			if (obj is Triangle triangle)
			{
				return index == triangle.index;
			}
			return false;
		}

		public bool Equals(Triangle other)
		{
			return index == other.index;
		}
	}
}