using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class CameraOcclusionDetector : MonoBehaviour
{
    public Transform player; // 主角的Transform
    public LayerMask obstacleLayer; // 障碍物层，例如：Default, Environment

    public List<GameObject> objectsToCheck; // 要检测是否被遮挡的物体列表
    public List<GameObject> OldhitObject=new List<GameObject>(); // 碰撞体的GameObject

    public Vector3 Offset; // 偏移量，用于修正碰撞体的位置
    public Vector3 OffsetCamera; // 偏移量，用于修正碰撞体的位置

    public float minDistance = 1.5f;
    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        foreach (var obj in objectsToCheck)
        {
            bool isOvvluded = IsPlayerOccluded(obj);
            //Debug.Log(obj.name + "是否被遮挡：" + isOvvluded);
            if (isOvvluded)
            {
                obj.SetActive(false);
                if (!OldhitObject.Contains(obj))
                    OldhitObject.Add(obj);
            }
        }

        if (OldhitObject.Count > 0)
        {
            // 恢复之前被遮挡但现在可见的物体
            for (int i = OldhitObject.Count - 1; i >= 0; i--)
            {
                float distance = GetDistanceToPlayer(OldhitObject[i]);
                //Debug.Log("距离：" + OldhitObject[i] + "距离：" + distance);
                if (distance > minDistance)
                {
                    OldhitObject[i].SetActive(true);
                    //OldhitObject.RemoveAt(i);
                }
            }
        }
    }
    /// <summary>
    /// 判断是否有物体遮挡了 "摄像机 -> 主角" 的视线
    /// </summary>
    /// <returns>被遮挡返回 true，视野清晰返回 false</returns>
    public bool IsPlayerOccluded(GameObject obj)
    {
        // 计算从主角指向摄像机的方向
        Vector3 _player = player.position + Offset;
        Vector3 _camera = transform.position + OffsetCamera;
        Vector3 directionToCamera = _camera - _player;
        float distance = directionToCamera.magnitude;
        // 从主角向摄像机发射射线，并渲染射线
        //Debug.DrawRay(_player, directionToCamera.normalized * distance, Color.red);
        // 关键点：从主角向摄像机发射射线
        if (Physics.Raycast(player.position, directionToCamera.normalized, out RaycastHit hit, distance, obstacleLayer))
        {
            // 1. 如果射线击中的距离非常近（几乎在主角身上），可能是主角自身的碰撞体，视为无遮挡
            // 2. 如果射线击中了非主角物体（距离正常），则是被遮挡了

            // 定义一个极小的距离阈值，用于忽略主角自身的碰撞体
            float minDistance = 0.1f;
            //Debug.Log("被遮挡了！击中物体：" + hit.collider.name + "，距离：" + hit.distance);
            if (hit.distance > minDistance && obj == hit.transform.gameObject)
            {
                //Debug.Log("被遮挡了！击中物体：" + hit.collider.name + "，距离：" + hit.distance);
                //hitObject= hit.transform.gameObject; // 记录碰撞体的GameObject
                return true; // 视野被遮挡
            }
        }

         //Debug.Log("视野清晰");
        return false; // 视野未被遮挡
    }

    /// <summary>
    /// 返回指定物体到玩家的距离
    /// </summary>
    /// <param name="obj">要检测距离的物体</param>
    /// <returns>物体到玩家的距离</returns>
    public float GetDistanceToPlayer(GameObject obj)
    {
        Vector3 objPosition = obj.transform.position;
        Vector3 playerPosition = player.position;
        return Vector3.Distance(objPosition, playerPosition);
    }
}