using TriangleNet.Geometry;

namespace TriangleNet.Topology
{
	public struct Otri
	{
		internal Triangle tri;

		internal int orient;

		private static readonly int[] plus1Mod3 = new int[3] { 1, 2, 0 };

		private static readonly int[] minus1Mod3 = new int[3] { 2, 0, 1 };

		public Triangle Triangle
		{
			get
			{
				return tri;
			}
			set
			{
				tri = value;
			}
		}

		public override string ToString()
		{
			if (tri == null)
			{
				return "O-TID [null]";
			}
			return $"O-TID {tri.hash}";
		}

		public void Sym(ref Otri ot)
		{
			ot.tri = tri.neighbors[orient].tri;
			ot.orient = tri.neighbors[orient].orient;
		}

		public void Sym()
		{
			int num = orient;
			orient = tri.neighbors[num].orient;
			tri = tri.neighbors[num].tri;
		}

		public void Lnext(ref Otri ot)
		{
			ot.tri = tri;
			ot.orient = plus1Mod3[orient];
		}

		public void Lnext()
		{
			orient = plus1Mod3[orient];
		}

		public void Lprev(ref Otri ot)
		{
			ot.tri = tri;
			ot.orient = minus1Mod3[orient];
		}

		public void Lprev()
		{
			orient = minus1Mod3[orient];
		}

		public void Onext(ref Otri ot)
		{
			ot.tri = tri;
			ot.orient = minus1Mod3[orient];
			int num = ot.orient;
			ot.orient = ot.tri.neighbors[num].orient;
			ot.tri = ot.tri.neighbors[num].tri;
		}

		public void Onext()
		{
			orient = minus1Mod3[orient];
			int num = orient;
			orient = tri.neighbors[num].orient;
			tri = tri.neighbors[num].tri;
		}

		public void Oprev(ref Otri ot)
		{
			ot.tri = tri.neighbors[orient].tri;
			ot.orient = tri.neighbors[orient].orient;
			ot.orient = plus1Mod3[ot.orient];
		}

		public void Oprev()
		{
			int num = orient;
			orient = tri.neighbors[num].orient;
			tri = tri.neighbors[num].tri;
			orient = plus1Mod3[orient];
		}

		public void Dnext(ref Otri ot)
		{
			ot.tri = tri.neighbors[orient].tri;
			ot.orient = tri.neighbors[orient].orient;
			ot.orient = minus1Mod3[ot.orient];
		}

		public void Dnext()
		{
			int num = orient;
			orient = tri.neighbors[num].orient;
			tri = tri.neighbors[num].tri;
			orient = minus1Mod3[orient];
		}

		public void Dprev(ref Otri ot)
		{
			ot.tri = tri;
			ot.orient = plus1Mod3[orient];
			int num = ot.orient;
			ot.orient = ot.tri.neighbors[num].orient;
			ot.tri = ot.tri.neighbors[num].tri;
		}

		public void Dprev()
		{
			orient = plus1Mod3[orient];
			int num = orient;
			orient = tri.neighbors[num].orient;
			tri = tri.neighbors[num].tri;
		}

		public void Rnext(ref Otri ot)
		{
			ot.tri = tri.neighbors[orient].tri;
			ot.orient = tri.neighbors[orient].orient;
			ot.orient = plus1Mod3[ot.orient];
			int num = ot.orient;
			ot.orient = ot.tri.neighbors[num].orient;
			ot.tri = ot.tri.neighbors[num].tri;
		}

		public void Rnext()
		{
			int num = orient;
			orient = tri.neighbors[num].orient;
			tri = tri.neighbors[num].tri;
			orient = plus1Mod3[orient];
			num = orient;
			orient = tri.neighbors[num].orient;
			tri = tri.neighbors[num].tri;
		}

		public void Rprev(ref Otri ot)
		{
			ot.tri = tri.neighbors[orient].tri;
			ot.orient = tri.neighbors[orient].orient;
			ot.orient = minus1Mod3[ot.orient];
			int num = ot.orient;
			ot.orient = ot.tri.neighbors[num].orient;
			ot.tri = ot.tri.neighbors[num].tri;
		}

		public void Rprev()
		{
			int num = orient;
			orient = tri.neighbors[num].orient;
			tri = tri.neighbors[num].tri;
			orient = minus1Mod3[orient];
			num = orient;
			orient = tri.neighbors[num].orient;
			tri = tri.neighbors[num].tri;
		}

		public Vertex Org()
		{
			return tri.vertices[plus1Mod3[orient]];
		}

		public Vertex Dest()
		{
			return tri.vertices[minus1Mod3[orient]];
		}

		public Vertex Apex()
		{
			return tri.vertices[orient];
		}

		public void Copy(ref Otri ot)
		{
			ot.tri = tri;
			ot.orient = orient;
		}

		public bool Equals(Otri ot)
		{
			if (tri == ot.tri)
			{
				return orient == ot.orient;
			}
			return false;
		}

		internal void SetOrg(Vertex v)
		{
			tri.vertices[plus1Mod3[orient]] = v;
		}

		internal void SetDest(Vertex v)
		{
			tri.vertices[minus1Mod3[orient]] = v;
		}

		internal void SetApex(Vertex v)
		{
			tri.vertices[orient] = v;
		}

		internal void Bond(ref Otri ot)
		{
			tri.neighbors[orient].tri = ot.tri;
			tri.neighbors[orient].orient = ot.orient;
			ot.tri.neighbors[ot.orient].tri = tri;
			ot.tri.neighbors[ot.orient].orient = orient;
		}

		internal void Dissolve(Triangle dummy)
		{
			tri.neighbors[orient].tri = dummy;
			tri.neighbors[orient].orient = 0;
		}

		internal void Infect()
		{
			tri.infected = true;
		}

		internal void Uninfect()
		{
			tri.infected = false;
		}

		internal bool IsInfected()
		{
			return tri.infected;
		}

		internal void Pivot(ref Osub os)
		{
			os = tri.subsegs[orient];
		}

		internal void SegBond(ref Osub os)
		{
			tri.subsegs[orient] = os;
			os.seg.triangles[os.orient] = this;
		}

		internal void SegDissolve(SubSegment dummy)
		{
			tri.subsegs[orient].seg = dummy;
		}

		internal static bool IsDead(Triangle tria)
		{
			return tria.neighbors[0].tri == null;
		}

		internal static void Kill(Triangle tri)
		{
			tri.neighbors[0].tri = null;
			tri.neighbors[2].tri = null;
		}
	}
}