using System;
using System.Collections;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using Animancer;
using AYellowpaper.SerializedCollections;
using BITFALL.Scene;
using BITKit;
using BITKit.Entities;
using BITKit.StateMachine;
using Unity.Mathematics;
using UnityEngine;
using UnityEngine.AI;
using UnityEngine.Splines;

namespace BITFALL.Movement.MotionBased.States
{
	public abstract class MotionBasedState:IMotionBasedState
	{
		[Inject] protected NavMeshAgent agent;
		[Inject] protected MotionBasedMovement movement;
		[Inject] protected AnimancerComponent animancerComponent;
		[Inject] protected IHealth health;
	

		protected Vector3 MotionVelocity { get; private set; }
		protected Vector3 MotionAngularVelocity { get; private set; }
		protected Quaternion MotionDeltaRotation { get; private set; }
		public virtual bool Enabled { get; set; }
		public virtual void Initialize()
		{
			
		}

		public virtual void OnStateEntry(IState old)
		{
		}

		public virtual void OnStateUpdate(float deltaTime)
		{
		
		}

		public virtual void OnStateExit(IState old, IState newState)
		{
		}

		public virtual void UpdateVelocity(ref Vector3 currentVelocity, float deltaTime)
		{
		}

		public virtual void UpdateRotation(ref Quaternion currentRotation, float deltaTime)
		{
		}

		public virtual void BeforeUpdateMovement(float deltaTime)
		{
		}

		public virtual void AfterUpdateMovement(float deltaTime)
		{
		}

		public virtual void ExecuteCommand<T>(T command)
		{
		}

		public virtual void OnAnimatorMove()
		{
			MotionVelocity = animancerComponent.Animator.velocity;
			MotionAngularVelocity = animancerComponent.Animator.angularVelocity;
			MotionDeltaRotation = animancerComponent.Animator.deltaRotation;
		}
	}

	[Serializable]
	public sealed class Empty : MotionBasedState
	{
		public override void OnStateEntry(IState old)
		{
			base.OnStateEntry(old);
			animancerComponent.Layers[0].Stop();
		}
	}
	[Serializable]
	public sealed class Idle : MotionBasedState
	{
		[SerializeField] private AnimationClip clip;
		public override void OnStateEntry(IState old)
		{
			base.OnStateEntry(old);
			animancerComponent.Play(clip,0.2f);
		}

		public override void OnStateUpdate(float deltaTime)
		{
			base.OnStateUpdate(deltaTime);

			var transform = agent.transform;

			if (!(agent.remainingDistance > 0.1f)) return;
			if(MathV.IsForward(transform.position, transform.forward, agent.steeringTarget))
			{
				movement.TransitionState<Walk>();
			}
			else
			{
				movement.TransitionState<IdleTurn>();
			}
		}
		public override void UpdateVelocity(ref Vector3 currentVelocity, float deltaTime)
		{
			base.UpdateVelocity(ref currentVelocity, deltaTime);
			currentVelocity = default;
		}
	}

	[Serializable]
	public sealed class IdleTurn : MotionBasedState
	{
		[SerializeField] private AnimationClip clip;
		private AnimancerState _state;

		private Quaternion entryRotation;
		Quaternion targetRotation;

		public override void OnStateEntry(IState old)
		{
			base.OnStateEntry(old);

			if (clip)
				_state = animancerComponent.Play(clip, 0.2f);

			entryRotation = movement.Rotation;
			var direction = agent.steeringTarget - movement.Position;

			if (direction.sqrMagnitude > 0.1f)
			{
				targetRotation =
					Quaternion.LookRotation(
						Vector3.ProjectOnPlane(agent.steeringTarget - agent.transform.position, Vector3.up)
					);
			}
			else
			{
				targetRotation = entryRotation;
			}

			if (clip)
				_state.Events.OnEnd += movement.TransitionState<Idle>;
		}

		public override void OnStateExit(IState old, IState newState)
		{
			base.OnStateExit(old, newState);
				agent.transform.rotation = targetRotation;
				_state = null;
		}

		public override void OnStateUpdate(float deltaTime)
		{
			base.OnStateUpdate(deltaTime);
			if (Quaternion.Angle(movement.Rotation, targetRotation) < 1)
			{
				movement.TransitionState<Idle>();
				return;
			}

			if (clip)
			{
				if (_state.Time > clip.length)
				{
					movement.TransitionState<Idle>();
					return;
				}
			}
			
		}

		public override void UpdateVelocity(ref Vector3 currentVelocity, float deltaTime)
		{
			base.UpdateVelocity(ref currentVelocity, deltaTime);
			currentVelocity = default;
		}

		public override void UpdateRotation(ref Quaternion currentRotation, float deltaTime)
		{
			base.UpdateRotation(ref currentRotation, deltaTime);
			if (clip)
			{
					currentRotation = Quaternion.Lerp(entryRotation, targetRotation, _state.NormalizedTime);
			}
			else
			{
				currentRotation = Quaternion.RotateTowards(currentRotation, targetRotation, 720 * deltaTime);
			}
		
		}
	}

	[Serializable]
	public sealed class Blocked : MotionBasedState
	{
		[RuntimeInitializeOnLoadMethod]
		private static void Reload()
		{
			BlockAreas.Clear();
		}
		internal static readonly ConcurrentDictionary<int, ISceneBlockArea> BlockAreas = new();

		internal static bool IsBlocked(Collider x)
		{
			var instanceId = x.GetInstanceID();
			var area = BlockAreas.GetOrAdd(instanceId, GetBlockArea);
			return area switch
			{
				not null => area.IsBlocked,
				_ => false,
			};
			ISceneBlockArea GetBlockArea(int id)
			{
				return x.GetComponent<ISceneBlockArea>();
			}
		}

		internal static bool DestinationIsBlocked(Collider x, Vector3 initialPosition,Vector3 direction)
		{
			if (IsBlocked(x) is false) return false;
			var block = BlockAreas[x.GetInstanceID()];
			var dir = Vector3.ProjectOnPlane(direction, Vector3.up).normalized;
			return block.InRange(initialPosition, dir);
		}


		[SerializeField] private AnimationClip clip;

		private Vector3 initialPosition;
		public override void OnStateEntry(IState old)
		{
			animancerComponent.Play(clip);
			initialPosition = movement.Position + movement.ViewCenter;
		}

		public override void UpdateVelocity(ref Vector3 currentVelocity, float deltaTime)
		{
			base.UpdateVelocity(ref currentVelocity, deltaTime);
			currentVelocity = default;
		}

		public override void OnStateUpdate(float deltaTime)
		{
			base.OnStateUpdate(deltaTime);
			if(movement.colliders.Length is 0)
			{
				movement.TransitionState<Idle>();
				return;
			}
			if(movement.colliders.Any(LocalDestinationIsBlocked))
			{
				
			}
			else
			{
				movement.TransitionState<Idle>();
			}
		}
		private bool LocalDestinationIsBlocked(Collider x)
		{
			var direction = agent.nextPosition - initialPosition;
			return DestinationIsBlocked(x, initialPosition, direction.normalized);
		}
		
	
	}
	[Serializable]
	public sealed class Walk : MotionBasedState
	{
		[SerializeField] private LinearMixerTransition _state;

		private AnimancerState _playingState;
		private float rot = 0;
		public override void OnStateEntry(IState old)
		{
			base.OnStateEntry(old);
			_playingState = animancerComponent.Play(_state);
		}

		public override void OnStateExit(IState old, IState newState)
		{
			base.OnStateExit(old, newState);
			_playingState = null;
		}

		public override void OnStateUpdate(float deltaTime)
		{
			base.OnStateUpdate(deltaTime);
			if (agent.remainingDistance < 0.1f)
			{
				movement.TransitionState<Idle>();
				return;
			}

			if (agent.isOnOffMeshLink)
			{
				movement.TransitionState<OffMeshLink>();
				return;
			}

			//if(colliders.Any(Blocked.IsBlocked))
			if (movement.colliders.Any(LocalDestinationIsBlocked))
			{
				movement.TransitionState<Blocked>();
				return;
				
			}
			return;
            bool LocalDestinationIsBlocked(Collider x)
			{
				var direction = agent.nextPosition - movement.Position;
				return Blocked.DestinationIsBlocked(x, movement.Position+movement.ViewCenter, direction.normalized);
			}
		}

		public override void AfterUpdateMovement(float deltaTime)
		{
			base.AfterUpdateMovement(deltaTime);
			movement.transform.position = agent.nextPosition;
		}

		public override void UpdateVelocity(ref Vector3 currentVelocity, float deltaTime)
		{
			base.UpdateVelocity(ref currentVelocity, deltaTime);
			
			currentVelocity = MotionVelocity;
		}

		public override void UpdateRotation(ref Quaternion currentRotation, float deltaTime)
		{
			base.UpdateRotation(ref currentRotation, deltaTime);

			var pathRotation = currentRotation;
			var lerpRotation = currentRotation;
			
			var direction = agent.steeringTarget - agent.transform.position;
			if(direction.sqrMagnitude>0.1f)
			{
				direction = Vector3.ProjectOnPlane(direction, Vector3.up);
				pathRotation = Quaternion.LookRotation(direction); 
				lerpRotation =
					Quaternion.RotateTowards(
						currentRotation,
						pathRotation,
						360 * deltaTime
						)
					;
			}
			
		
			if (_playingState is not null)	
			{
				var dir = pathRotation * Vector3.forward; //位置差，方向  
				var dot = Vector3.Dot(movement.Forward, dir.normalized);//点乘判断前后：dot >0在前，<0在后
				var dot1 = Vector3.Dot(movement.transform.right, dir.normalized);//点乘判断左右： dot1>0在右，<0在左
				var angle = Mathf.Acos(Vector3.Dot(movement.Forward.normalized, dir.normalized)) * Mathf.Rad2Deg;//通过点乘求出
				
				angle = dot1 > 0 ? angle : -angle;
				
				var clamp = Mathf.Clamp(angle/45, -1, 1);
				
				rot = Mathf.MoveTowards(rot, clamp, 8 * deltaTime);
				
				_state.State.Parameter =rot ;
				
				//Debug.Log($"angle:{angle} dot:{dot} dot1:{dot1} clamp:{clamp}");

			}
			currentRotation = lerpRotation;
		}
	}

	[Serializable]
	public sealed class OffMeshLink : MotionBasedState
	{
		[SerializeField] public AnimationClip[] clips;
		private AnimancerState _state;

		private Vector3 startPos;
		private Vector3 endPos;
		private Spline _spline;
		
		private (float progress,float increment) splineProgress;
		public override void OnStateEntry(IState old)
		{
			base.OnStateEntry(old);
			if (clips.TryGetElementAt(agent.currentOffMeshLinkData.offMeshLink.area, out var clip) && clip)
			{
				agent.autoTraverseOffMeshLink = false;
				_state = animancerComponent.Play(clip);
				_state.Events.OnEnd += movement.TransitionState<Idle>;

				_spline = agent.currentOffMeshLinkData.offMeshLink.TryGetComponent<SplineContainer>(out var splineContainer) ? splineContainer[0] : null;

				var currentOffMeshLinkData = agent.currentOffMeshLinkData;
				startPos = currentOffMeshLinkData.startPos;
				endPos = currentOffMeshLinkData.endPos;

				if (_spline is not null)
				{
					var offsetTransform= splineContainer.transform;
					var isStart =
						Vector3.Distance(
							movement.Position,
							offsetTransform.TransformPoint(splineContainer.Splines[0].Knots.First().Position)
						) <
						Vector3.Distance(
							movement.Position,
							offsetTransform.TransformPoint(splineContainer.Splines[0].Knots.Last().Position)
						);
					splineProgress = isStart ? (0, 1) : (1, -1);
				}
			}
			else
			{
				_state = null;
				agent.autoTraverseOffMeshLink = true;
				movement.TransitionState<Idle>();
			}
		}

		public override void OnStateUpdate(float deltaTime)
		{
			base.OnStateUpdate(deltaTime);
			try
			{
				if (_spline is not null)
				{
					splineProgress.progress += splineProgress.increment * deltaTime;
					var link = agent.currentOffMeshLinkData.offMeshLink.transform;
					movement.transform.position = 
						link.position + link.rotation *
						_spline.EvaluatePosition(splineProgress.progress);
				}
				else
				{
					var currentOffMeshLinkData = agent.currentOffMeshLinkData;
					movement.transform.position = Vector3.Lerp(
						currentOffMeshLinkData.startPos,
						currentOffMeshLinkData.endPos,
						_state.NormalizedTime
					);
				}
			}
			catch (Exception e)
			{
				Debug.LogException(e);
				movement.TransitionState<Idle>();
			}
		
		}

		public override void OnStateExit(IState old, IState newState)
		{
			base.OnStateExit(old, newState);
			agent.CompleteOffMeshLink();
		}
	}
}