using System.Collections.Generic;
using Cielonos.MainGame.Characters;
using SLSUtilities.General;
using SoftCircuits.Collections;
using UnityEngine;

namespace Cielonos.MainGame.Inventory
{
    /// <summary>
    /// 光环子模块。持续捕获指定半径内的角色，并通过 Enter / Stay / Exit 事件通知订阅方。
    /// 不使用 Data ScriptableObject，由道具在代码中直接构造。
    /// </summary>
    public class AuraSubmodule : SubmoduleBase<ItemBase>
    {
        /// <summary>
        /// 当前处于光环内的角色集合。
        /// </summary>
        public HashSet<CharacterBase> charactersInAura = new HashSet<CharacterBase>();

        /// <summary>
        /// 其他角色进入光环时触发，参数为进入的角色。
        /// </summary>
        public OrderedDictionary<string, PrioritizedAction<CharacterBase>> onOtherEnterAura = new();

        /// <summary>
        /// 其他角色持续处于光环内时触发（按 stayInterval 间隔），参数为在光环内的角色。
        /// </summary>
        public OrderedDictionary<string, PrioritizedAction<CharacterBase>> onOtherStayAura = new();

        /// <summary>
        /// 其他角色离开光环时触发，参数为离开的角色。
        /// </summary>
        public OrderedDictionary<string, PrioritizedAction<CharacterBase>> onOtherExitAura = new();

        /// <summary>
        /// 光环半径。
        /// </summary>
        public float auraRadius;

        /// <summary>
        /// Stay 计时器，到达 stayInterval 后对所有在光环内的角色触发 onOtherStayAura。
        /// </summary>
        public Timer stayTimer;

        /// <summary>
        /// 物理检测的 LayerMask。
        /// </summary>
        private readonly int _detectionLayerMask;

        private const int MaxDetectionCount = 32;
        private readonly Collider[] _overlapBuffer = new Collider[MaxDetectionCount];

        /// <summary>
        /// 用于比较前后帧角色集合的临时缓冲。
        /// </summary>
        private readonly HashSet<CharacterBase> _currentFrameCharacters = new HashSet<CharacterBase>();

        /// <summary>
        /// 构造光环子模块。
        /// </summary>
        /// <param name="owner">所属道具。</param>
        /// <param name="auraRadius">光环半径。</param>
        /// <param name="stayInterval">Stay 事件触发间隔（秒），默认 0.5 秒。</param>
        public AuraSubmodule(ItemBase owner, float auraRadius, float stayInterval = 0.5f) : base(owner)
        {
            this.auraRadius = auraRadius;

            stayTimer = new Timer(stayInterval, isInfinite: true);
            stayTimer.onComplete.Add(new PrioritizedAction(OnStayTimerComplete));

            _detectionLayerMask = LayerMask.GetMask("HurtBox");
        }

        /// <summary>
        /// 每帧调用，驱动物理检测和事件派发。
        /// </summary>
        public void Update(float deltaTime)
        {
            DetectCharacters();
            stayTimer.Update(deltaTime);
        }

        /// <summary>
        /// 清理所有追踪状态，对仍在光环内的角色触发 Exit 事件。
        /// </summary>
        public void Dispose()
        {
            foreach (var character in charactersInAura)
            {
                if (character != null)
                {
                    onOtherExitAura.Invoke(character);
                }
            }

            charactersInAura.Clear();
        }

        /// <summary>
        /// 执行球形物理检测，比较前后帧角色集合，触发 Enter / Exit 事件。
        /// </summary>
        private void DetectCharacters()
        {
            _currentFrameCharacters.Clear();

            Vector3 center = owner.player.transform.position;
            int hitCount = Physics.OverlapSphereNonAlloc(center, auraRadius, _overlapBuffer, _detectionLayerMask);

            for (int i = 0; i < hitCount; i++)
            {
                CharacterBase character = _overlapBuffer[i].GetComponentInParent<CharacterBase>();
                if (character == null || character == owner.player) continue;

                _currentFrameCharacters.Add(character);
            }

            // 检测新进入光环的角色
            foreach (var character in _currentFrameCharacters)
            {
                if (charactersInAura.Add(character))
                {
                    onOtherEnterAura.Invoke(character);
                }
            }

            // 检测离开光环的角色（从旧集合中移除不在当前帧的角色）
            charactersInAura.RemoveWhere(character =>
            {
                if (_currentFrameCharacters.Contains(character)) return false;

                if (character != null)
                {
                    onOtherExitAura.Invoke(character);
                }

                return true;
            });
        }

        /// <summary>
        /// Stay 计时器到期时，对所有在光环内的角色触发 onOtherStayAura。
        /// </summary>
        private void OnStayTimerComplete()
        {
            foreach (var character in charactersInAura)
            {
                if (character != null)
                {
                    onOtherStayAura.Invoke(character);
                }
            }
        }
    }
}