using System.Collections.Generic;
using UnityEngine;

namespace Cielonos.MainGame.Characters
{
    public partial class OcclusionFadeSubmodule
    {
        // --- 内部类：用于管理正在褪色的物体状态 ---
        private class FadingObject
        {
            public Renderer renderer;
            public MaterialPropertyBlock propBlock;
            public float currentAlpha;
            public float lastHitTime;

            public FadingObject(Renderer r)
            {
                renderer = r;
                propBlock = new MaterialPropertyBlock();
                // 初始获取当前可能的Fade值，默认为1
                currentAlpha = 1.0f;
                lastHitTime = Time.time;
            }
        }
    }

    public partial class OcclusionFadeSubmodule : SubmoduleBase<PlayerViewSubcontroller>
    {
        [Header("References")] [Tooltip("主角头部的Transform")]
        public Transform playerHead;

        [Tooltip("主角中心点的Transform")] public Transform playerCenter;
        [Tooltip("主角脚部的Transform")] public Transform playerFeet;
        [Tooltip("主摄像机，如果不填则自动获取MainCamera")] public Camera targetCamera;

        [Header("Settings")] [Tooltip("遮挡层级：只检测这些层级的物体（例如 Wall, Default）")]
        public LayerMask obstructionLayer;

        [Header("Fading Settings")] [Tooltip("物体变透明的速度 (建议快一点，比如 10-15)")]
        public float fadeOutSpeed = 5f;

        [Tooltip("物体恢复实体的速度 (建议慢一点，比如 2-5)")] public float fadeInSpeed = 2f;

        [Tooltip("被遮挡时的目标透明度")] [Range(0f, 1f)]
        public float targetAlpha = 0.5f;
        
        [Header("Stability")]
        [Tooltip("防抖动缓冲时间：当物体不再遮挡视线后，延迟多少秒才开始恢复实体？")]
        public float recoveryDelay = 0.1f;

        [Tooltip("射线球体半径：使用SphereCast代替Raycast可以让检测更宽容，防止细小缝隙穿帮")]
        public float checkRadius = 0.1f;

        // 字典：Renderer -> 状态对象
        private Dictionary<Renderer, FadingObject> _fadingObjects = new Dictionary<Renderer, FadingObject>();

        // 缓存 ID
        private static readonly int FadeID = Shader.PropertyToID("_Fade");

        // 射线检测缓存数组 (NonAlloc优化，避免每帧GC)
        private RaycastHit[] _hitsBuffer = new RaycastHit[20];
        
        private List<LineRenderer> _debugLines = new List<LineRenderer>();

        public OcclusionFadeSubmodule(PlayerViewSubcontroller owner) : base(owner)
        {
            obstructionLayer = LayerMask.GetMask("FadableEnvironment");
            targetCamera = owner.playerCamera;
            playerHead = owner.player.bodyPartsSc.head;
            playerCenter = owner.player.bodyPartsSc.flexibleCenterPoint;
            playerFeet = owner.player.bodyPartsSc.footPoint;
        }

        public void Update()
        {
            if (playerHead == null || playerCenter == null || playerFeet == null || targetCamera == null) return;
            
            // 2. 执行射线检测
            Vector3 cameraPos = targetCamera.transform.position;

            // 检测头部路径
            CastRayAndMark(cameraPos, playerHead.position);
            

            // 检测中心路径
            CastRayAndMark(cameraPos, playerCenter.position);

            // 检测脚部路径
            CastRayAndMark(cameraPos, playerFeet.position);

            // 3. 处理淡入淡出逻辑
            ProcessFading();
        }

        private void CastRayAndMark(Vector3 start, Vector3 end)
        {
            Vector3 direction = end - start;
            float distance = direction.magnitude;

            int hitCount = Physics.SphereCastNonAlloc(
                start,
                checkRadius,
                direction.normalized,
                _hitsBuffer,
                distance,
                obstructionLayer,
                QueryTriggerInteraction.Ignore
            );

            for (int i = 0; i < hitCount; i++)
            {
                RaycastHit hit = _hitsBuffer[i];
                Renderer r = hit.collider.GetComponent<Renderer>();

                if (r == null || hit.transform.root == playerHead.root) continue;

                // 如果是新物体，加入字典
                if (!_fadingObjects.ContainsKey(r))
                {
                    if (r.sharedMaterial != null && r.sharedMaterial.HasProperty(FadeID))
                    {
                        _fadingObjects.Add(r, new FadingObject(r));
                    }
                }

                // 更新击中时间
                if (_fadingObjects.TryGetValue(r, out FadingObject obj))
                {
                    obj.lastHitTime = Time.time; // 刷新时间戳
                }
            }
        }

        private void ProcessFading()
        {
            List<Renderer> keysToRemove = new List<Renderer>();
            float currentTime = Time.time;

            foreach (var kvp in _fadingObjects)
            {
                FadingObject obj = kvp.Value;
                Renderer r = obj.renderer;

                if (r == null)
                {
                    keysToRemove.Add(kvp.Key);
                    continue;
                }

                // --- 核心逻辑修改 ---

                // 判断是否处于"遮挡状态"或"缓冲期"
                // 只要当前时间 < 最后击中时间 + 延迟时间，就认为它还应该保持透明
                bool isObstructedOrBuffered = currentTime < (obj.lastHitTime + recoveryDelay);

                float target = isObstructedOrBuffered ? targetAlpha : 1.0f;

                // 根据目标选择速度：变透明用快速度，恢复用慢速度
                float speed = isObstructedOrBuffered ? fadeOutSpeed : fadeInSpeed;

                // 执行插值
                obj.currentAlpha = Mathf.MoveTowards(obj.currentAlpha, target, Time.deltaTime * speed);
                // 应用属性
                r.GetPropertyBlock(obj.propBlock);
                obj.propBlock.SetFloat(FadeID, obj.currentAlpha);
                r.SetPropertyBlock(obj.propBlock);

                // 清理逻辑：只有当完全恢复，且早已过了缓冲期才移除
                if (!isObstructedOrBuffered && Mathf.Approximately(obj.currentAlpha, 1.0f))
                {
                    keysToRemove.Add(r);
                }
            }

            foreach (var key in keysToRemove)
            {
                _fadingObjects.Remove(key);
            }
        }
    }
}