using System;
using UnityEngine;

namespace RootMotion.FinalIK
{
	[Serializable]
	public class IKSolverHeuristic : IKSolver
	{
		public Transform target;

		public float tolerance;

		public int maxIterations = 4;

		public bool useRotationLimits = true;

		public bool XY;

		public Bone[] bones = new Bone[0];

		protected Vector3 lastLocalDirection;

		protected float chainLength;

		protected virtual int minBones => 2;

		protected virtual bool boneLengthCanBeZero => true;

		protected virtual bool allowCommonParent => false;

		protected virtual Vector3 localDirection => bones[0].transform.InverseTransformDirection(bones[bones.Length - 1].transform.position - bones[0].transform.position);

		protected float positionOffset => Vector3.SqrMagnitude(localDirection - lastLocalDirection);

		public bool SetChain(Transform[] hierarchy, Transform root)
		{
			if (bones == null || bones.Length != hierarchy.Length)
			{
				bones = new Bone[hierarchy.Length];
			}
			for (int i = 0; i < hierarchy.Length; i++)
			{
				if (bones[i] == null)
				{
					bones[i] = new Bone();
				}
				bones[i].transform = hierarchy[i];
			}
			Initiate(root);
			return base.initiated;
		}

		public void AddBone(Transform bone)
		{
			Transform[] array = new Transform[bones.Length + 1];
			for (int i = 0; i < bones.Length; i++)
			{
				array[i] = bones[i].transform;
			}
			array[^1] = bone;
			SetChain(array, root);
		}

		public override void StoreDefaultLocalState()
		{
			for (int i = 0; i < bones.Length; i++)
			{
				bones[i].StoreDefaultLocalState();
			}
		}

		public override void FixTransforms()
		{
			if (base.initiated && !(IKPositionWeight <= 0f))
			{
				for (int i = 0; i < bones.Length; i++)
				{
					bones[i].FixTransform();
				}
			}
		}

		public override bool IsValid(ref string message)
		{
			if (bones.Length == 0)
			{
				message = "IK chain has no Bones.";
				return false;
			}
			if (bones.Length < minBones)
			{
				message = "IK chain has less than " + minBones + " Bones.";
				return false;
			}
			Bone[] array = bones;
			for (int i = 0; i < array.Length; i++)
			{
				if (array[i].transform == null)
				{
					message = "One of the Bones is null.";
					return false;
				}
			}
			Transform transform = IKSolver.ContainsDuplicateBone(bones);
			if (transform != null)
			{
				message = transform.name + " is represented multiple times in the Bones.";
				return false;
			}
			if (!allowCommonParent && !IKSolver.HierarchyIsValid(bones))
			{
				message = "Invalid bone hierarchy detected. IK requires for its bones to be parented to each other in descending order.";
				return false;
			}
			if (!boneLengthCanBeZero)
			{
				for (int j = 0; j < bones.Length - 1; j++)
				{
					if ((bones[j].transform.position - bones[j + 1].transform.position).magnitude == 0f)
					{
						message = "Bone " + j + " length is zero.";
						return false;
					}
				}
			}
			return true;
		}

		public override Point[] GetPoints()
		{
			return bones;
		}

		public override Point GetPoint(Transform transform)
		{
			for (int i = 0; i < bones.Length; i++)
			{
				if (bones[i].transform == transform)
				{
					return bones[i];
				}
			}
			return null;
		}

		protected override void OnInitiate()
		{
		}

		protected override void OnUpdate()
		{
		}

		protected void InitiateBones()
		{
			chainLength = 0f;
			for (int i = 0; i < bones.Length; i++)
			{
				if (i < bones.Length - 1)
				{
					bones[i].length = (bones[i].transform.position - bones[i + 1].transform.position).magnitude;
					chainLength += bones[i].length;
					Vector3 position = bones[i + 1].transform.position;
					bones[i].axis = Quaternion.Inverse(bones[i].transform.rotation) * (position - bones[i].transform.position);
					if (bones[i].rotationLimit != null)
					{
						if (XY && !(bones[i].rotationLimit is RotationLimitHinge))
						{
							Warning.Log("Only Hinge Rotation Limits should be used on 2D IK solvers.", bones[i].transform);
						}
						bones[i].rotationLimit.Disable();
					}
				}
				else
				{
					bones[i].axis = Quaternion.Inverse(bones[i].transform.rotation) * (bones[bones.Length - 1].transform.position - bones[0].transform.position);
				}
			}
		}

		protected Vector3 GetSingularityOffset()
		{
			if (!SingularityDetected())
			{
				return Vector3.zero;
			}
			Vector3 normalized = (IKPosition - bones[0].transform.position).normalized;
			Vector3 rhs = new Vector3(normalized.y, normalized.z, normalized.x);
			if (useRotationLimits && bones[bones.Length - 2].rotationLimit != null && bones[bones.Length - 2].rotationLimit is RotationLimitHinge)
			{
				rhs = bones[bones.Length - 2].transform.rotation * bones[bones.Length - 2].rotationLimit.axis;
			}
			return Vector3.Cross(normalized, rhs) * bones[bones.Length - 2].length * 0.5f;
		}

		private bool SingularityDetected()
		{
			if (!base.initiated)
			{
				return false;
			}
			Vector3 vector = bones[bones.Length - 1].transform.position - bones[0].transform.position;
			Vector3 vector2 = IKPosition - bones[0].transform.position;
			float magnitude = vector.magnitude;
			float magnitude2 = vector2.magnitude;
			if (magnitude < magnitude2)
			{
				return false;
			}
			if (magnitude < chainLength - bones[bones.Length - 2].length * 0.1f)
			{
				return false;
			}
			if (magnitude == 0f)
			{
				return false;
			}
			if (magnitude2 == 0f)
			{
				return false;
			}
			if (magnitude2 > magnitude)
			{
				return false;
			}
			if (Vector3.Dot(vector / magnitude, vector2 / magnitude2) < 0.999f)
			{
				return false;
			}
			return true;
		}
	}
}