using UnityEngine;

namespace Gameplay.Player
{
    /// <summary>
    /// 通用第一人称射线检测，获取玩家注视的 GameObject。
    /// </summary>
    public class FirstPersonRaycaster : MonoBehaviour
    {
        [Header("Raycast Settings")]
        [SerializeField] private float rayLength = 15f;
        [SerializeField] private LayerMask layerMask = ~0; // 默认检测所有层
        [SerializeField] private Camera playerCamera;
        [SerializeField] private bool drawGizmos = true;

        /// <summary>
        /// 当前玩家注视的 GameObject（只读）。
        /// </summary>
        public GameObject CurrentLookAtObject { get; private set; }

        void Awake()
        {
            if (playerCamera == null)
            {
                var camObj = GameObject.FindWithTag("MainCamera");
                if (camObj != null)
                    playerCamera = camObj.GetComponent<Camera>();
            }
        }

        void Update()
        {
            UpdateLookAtObject();
        }

        private void UpdateLookAtObject()
        {
            if (playerCamera == null)
            {
                CurrentLookAtObject = null;
                return;
            }
            Ray ray = new Ray(playerCamera.transform.position, playerCamera.transform.forward);
            if (Physics.Raycast(ray, out RaycastHit hit, rayLength, layerMask))
            {
                CurrentLookAtObject = hit.collider.gameObject;
            }
            else
            {
                CurrentLookAtObject = null;
            }
        }

        void OnDrawGizmos()
        {
            if (!drawGizmos) return;
            Camera cam = playerCamera;
            if (cam == null && Application.isPlaying == false)
            {
                var camObj = GameObject.FindWithTag("MainCamera");
                if (camObj != null)
                    cam = camObj.GetComponent<Camera>();
            }
            if (cam == null) return;
            Gizmos.color = Color.cyan;
            Vector3 origin = cam.transform.position;
            Vector3 dir = cam.transform.forward * rayLength;
            Gizmos.DrawLine(origin, origin + dir);
        }
    }
}