using System;
using Sirenix.OdinInspector;
using UnityEngine;

namespace Game.Component
{
    public class Tentacle2D : MonoBehaviour
    {
        public int          length;   //节点数量
        public LineRenderer lineRend; //线段绘制器

        private Vector3[] segmentPoses; //节点状态
        private Vector3[] _segmentV;
        private Transform _targetDir;
        public  float     targetDist; //单位距离

        [Header ("柔韧度，越大越柔韧") , Range (0 , 100)]
        public float _smoothSpeed;

        [Header ("拖尾速度")] public float trailSpeed;

        [BoxGroup ("wiggle"), Header ("波形运动器")]
        public bool wiggle;

        [BoxGroup ("wiggle"), ShowIf ("wiggle")]
        public float wiggleSpeed;

        [BoxGroup ("wiggle"), ShowIf ("wiggle")]
        public float wiggleMagnitude;
        
        //是否固定长度
        public bool HasFixedLength = false;
        
        public bool AutoPlay;


        private Vector3 _defaultAngle;

        private void Start ()
        {
            Init ();
        }

        private void Update ()
        {
            UpdateLineRend ();
        }

        public void Init ()
        {
            this._targetDir             = this.transform;
            this.lineRend.positionCount = this.length;
            this.segmentPoses           = new Vector3[this.length];
            this._segmentV              = new Vector3[this.length];
            this._defaultAngle          = this._targetDir.localRotation.eulerAngles;
            ResetPos ();
        }


        public void UpdateLineRend ()
        {
            if (this.wiggle)
            {
                this._targetDir.localRotation = Quaternion.Euler (this._defaultAngle.x , this._defaultAngle.y ,
                    this._defaultAngle.z + Mathf.Sin (Time.time * this.wiggleSpeed) * this.wiggleMagnitude);
            }

            var smoothSpeed = this._smoothSpeed * 0.01f;
            this.segmentPoses[0] = this._targetDir.position;
            for (int i = 1; i < this.length; i++)
            {
                
                if (trailSpeed > 0)
                {
                    this.segmentPoses[i] = Vector3.SmoothDamp (this.segmentPoses[i] ,
                        this.segmentPoses[i - 1] - this._targetDir.up * this.targetDist , ref this._segmentV[i] ,
                        smoothSpeed              + i                  / this.trailSpeed);
                }
                else
                {
                    Vector3 targetPos = this.segmentPoses[i - 1] + (this.segmentPoses[i] - this.segmentPoses[i - 1]).normalized * this.targetDist;
                    this.segmentPoses[i] = Vector3.SmoothDamp (this.segmentPoses[i] , targetPos , ref this._segmentV[i] , smoothSpeed);
                }

                if (HasFixedLength)
                {
                    this.segmentPoses[i] = this.segmentPoses[i -1] + (this.segmentPoses[i] - this.segmentPoses[i -1]).normalized * (this.targetDist);
                }
            }

            this.lineRend.SetPositions (this.segmentPoses);
        }

        private void ResetPos ()
        {
            this._targetDir.localRotation = Quaternion.Euler (this._defaultAngle);
            this.segmentPoses[0]          = this._targetDir.position;
            for (int i = 1; i < this.length; i++) this.segmentPoses[i] = this.segmentPoses[i - 1] - this._targetDir.up * this.targetDist;
            this.lineRend.SetPositions (this.segmentPoses);
        }
    }
}