using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.AI;
using UnityStandardAssets.Vehicles.Car;
using XFramework;


// 基于NavMesh 扩展现有AI功能   
public class CarAIExtendCtrl : MonoBehaviour
{
    UnityEngine.AI.NavMeshAgent thisAgent;
    [SerializeField]
    private Transform target;
    CarAIControl carAIControl;
    [SerializeField]
    MoveType moveType;
    [SerializeField]
    Vector3[] wayPoints;
    int curentIndex;
    [SerializeField]
    public float fllowKeepDis = 100;//跟随时保持的距离
    bool stopDriving=true;
    Vector3 initialPos;
    // Start is called before the first frame update
    void Awake()
    {
        thisAgent = this.transform.GetComponentInChildren<UnityEngine.AI.NavMeshAgent>();
        carAIControl = this.GetComponent<CarAIControl>();
        initialPos = thisAgent.transform.localPosition;
        //SetFllowTarget(target);
        // SetWayPoint(wayPoints);
    }

    //设置目标点位  此后本车辆按照跟随模式移动
    public void SetFllowTarget(Transform transform)
    {
        moveType = MoveType.fllow;
        target = transform;
        stopDriving = false;
    }

    //设置路径点位 此后本车辆按照路径点循环移动 默认从第一个点位开始移动   也可设置单个点位
    public void SetWayPoint(Vector3 [] postion,int startIndex=0)
    {
        moveType = MoveType.wayPoints;
        wayPoints = postion;
        curentIndex = startIndex;
        stopDriving = false;
    }

    //改变控制模式  停止移动 等待设置目标点或跟随物体
    public void ChangeCtrlType(MoveType moveType)
    {
        this.moveType = moveType;
        StopAIMove();
    }

    //暂停后恢复移动
    public void StartAIMove()
    {
        stopDriving = false;
    }

    //暂停移动  
    public void StopAIMove()
    {
        stopDriving = true;
        carAIControl.StopMove();
    }

    float timer = 0.2f;

    Vector3[] naveMeshPathPoints;//通过寻路组件计算获得的细节路径点
 
    // Update is called once per frame
    void Update()
    {
        thisAgent.transform.localPosition = initialPos;
        thisAgent.transform.localRotation = Quaternion.identity;
        if (stopDriving) return;//暂停模式不在设置路点
        timer -= Time.unscaledTime;
        if (timer > 0) return;//0.2f执行一次即可  节省一定的运算性能
        timer = 0.2f;
        bool hasPath =false;
        NavMeshPath navMeshPath = new NavMeshPath();
        if (thisAgent.isOnNavMesh)
        {
            switch (moveType)
            {
                case MoveType.fllow:
                    hasPath = thisAgent.SetDestination(target.position);
                    break;
                case MoveType.wayPoints:
                    if (Vector3.Distance(this.transform.position, wayPoints[curentIndex]) < 3 && curentIndex < wayPoints.Length - 1)
                    {
                        curentIndex++;
                    }
                    hasPath = thisAgent.SetDestination(wayPoints[curentIndex]);
                    break;
                default:
                    break;
            }
            if (hasPath && thisAgent.path.corners.Length > 1)
            {
                naveMeshPathPoints = thisAgent.path.corners;
            }
            else
            {
                naveMeshPathPoints = null;
            }

            if (naveMeshPathPoints != null)
            {
                switch (moveType)
                {
                    case MoveType.fllow://跟随模式计算路径距离 并保持跟随距离
                        float pathDistance = 0;
                        for (int i = 0; i < naveMeshPathPoints.Length - 1; i++)
                        {
                            pathDistance += Vector3.Distance(naveMeshPathPoints[i], naveMeshPathPoints[i + 1]);
                        }
                        if (pathDistance > fllowKeepDis)//超出保持距离时 保持移动
                            MoveToPostion(naveMeshPathPoints[1]);
                        else
                            carAIControl.StopMove();
                        break;
                    case MoveType.wayPoints://即将到达最后一个点位时 不在发送移动命令  避免因刹车制动过慢导致无法停车
                        if (Vector3.Distance(this.transform.position, wayPoints[wayPoints.Length - 1]) < 5)
                        {
                            if (!stopDriving)
                            {
                                StopAIMove();
                                Debug.Log("arrive points");
                                EventCenter.Instance.EventTrigger("ArriveDestination");
                            }
                        }
                        else
                            MoveToPostion(naveMeshPathPoints[1]);
                        break;
                    default:
                        break;
                }
            }
            //  Debug.Log(tempDist);
            //Speed_Order = Mathf.Lerp(Min_Speed_Rate, Max_Speed_Rate, tempDist / 50.0f); // Slow down the speed within 50m.
        }
        else
        {
            thisAgent.Warp(this.transform.position);
        }
    }

    //给AI控制器设置移动目标点位
    void MoveToPostion(Vector3 targetPos)
    {
        carAIControl.StartMove(targetPos);
    }

    private void OnEnable()
    {
        if (carAIControl)
            carAIControl.enabled = true;
    }

    private void OnDisable()
    {
        if (carAIControl)
            carAIControl.enabled = false;
    }
}

public enum MoveType
{
    fllow,
    wayPoints,
}