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

namespace BaseGames.Combat.StatusEffects
{
    /// <summary>
    /// 状态效果管理器。
    /// 
    /// 架构 06_CombatModule §11：
    ///   - 双结构：List（Update 遍历）+ Dictionary（O(1) 类型查找）
    ///   - 实现 IStatusEffectable，接受来自 HurtBox 的 DamageType 并映射到具体效果
    ///   - DealDotDamage：StatusEffect 子类通过 Owner 调用，绕过无敌帧造成 DoT
    ///   - CleanseEffect：净化指定类型效果（道具/技能使用）
    /// </summary>
    [RequireComponent(typeof(SpriteRenderer))]
    public class StatusEffectManager : MonoBehaviour, IStatusEffectable
    {
        [Header("事件频道（可选）")]
        [SerializeField] private StatusEffectEventChannelSO _onStatusEffectApplied;
        [SerializeField] private StatusEffectEventChannelSO _onStatusEffectExpired;

        // ── 双结构 ─────────────────────────────────────────────────────────
        private readonly List<StatusEffect>                          _activeList  = new();
        private readonly Dictionary<StatusEffectType, StatusEffect>  _activeIndex = new();

        // ── Shader 渲染（MaterialPropertyBlock，不修改共享材质）─────────
        private SpriteRenderer      _renderer;
        private MaterialPropertyBlock _propBlock;
        // 缓存 Shader 属性 ID，避免每次调用 SetShaderParam 都做字符串哈希查找
        private readonly Dictionary<string, int> _shaderPropIds = new();

        // ── DoT 伤害代理（由 StatusEffect.OnTick 通过 Owner 调用）──────────
        private IDamageable _damageable;

        // ── 效果工厂字典（可在 Awake 后动态注册）─────────────────────
        private readonly Dictionary<DamageType, Func<StatusEffect>> _effectFactories = new();

        private void Awake()
        {
            _renderer   = GetComponent<SpriteRenderer>();
            _propBlock  = new MaterialPropertyBlock();
            _damageable = GetComponentInParent<IDamageable>();

            // 默认标准效果注册（子类或外部模块可调用 RegisterEffectFactory 覆盖或扩展）
            RegisterEffectFactory(DamageType.Fire,   () => new FireEffect());
            RegisterEffectFactory(DamageType.Poison, () => new PoisonEffect());
        }

        private void Update()
        {
            float delta = Time.deltaTime;

            // 逆序遍历，避免移除时索引错位
            for (int i = _activeList.Count - 1; i >= 0; i--)
            {
                StatusEffect effect = _activeList[i];
                effect.Update(delta);

                if (effect.IsExpired)
                    RemoveAt(i, effect);
            }
        }

        // ── IStatusEffectable 实现 ─────────────────────────────────────────

        /// <summary>
        /// HurtBox 调用入口：将 DamageType 映射为具体 StatusEffect 实例并施加。
        /// </summary>
        public void ApplyStatusEffect(DamageType type)
        {
            StatusEffect effect = CreateEffect(type);
            if (effect != null)
                ApplyEffect(effect);
        }
        /// <summary>
        /// 注册或覆盖一个 DamageType 对应的效果工厂。
        /// Boss 或特殊游玩法式可在运行时注册自定义效果。
        /// </summary>
        public void RegisterEffectFactory(DamageType type, Func<StatusEffect> factory)
            => _effectFactories[type] = factory;
        // ── 公开 API ───────────────────────────────────────────────────────

        /// <summary>直接施加一个具体效果（供技能/Boss 使用）。</summary>
        public void ApplyEffect(StatusEffect effect)
        {
            // 检查是否被现有效果阻断
            foreach (var blockerType in effect.BlockedBy)
                if (_activeIndex.ContainsKey(blockerType)) return;

            // 净化与新效果互斥的现有效果
            foreach (var excludedType in effect.MutualExclusions)
                if (_activeIndex.ContainsKey(excludedType))
                    CleanseEffect(excludedType);

            if (_activeIndex.TryGetValue(effect.EffectType, out StatusEffect existing))
            {
                existing.OnStack();
                BroadcastApplied(existing);
            }
            else
            {
                effect.OnApply(this);
                _activeList.Add(effect);
                _activeIndex[effect.EffectType] = effect;
                BroadcastApplied(effect);
            }
        }

        /// <summary>净化指定类型效果（净化道具/技能调用）。</summary>
        public void CleanseEffect(StatusEffectType type)
        {
            if (!_activeIndex.TryGetValue(type, out StatusEffect effect)) return;

            effect.OnExpire();
            _activeIndex.Remove(type);
            _activeList.Remove(effect);
            BroadcastExpired(effect);
        }

        /// <summary>查询是否存在指定类型效果（供状态机/UI 轮询）。</summary>
        public bool HasEffect(StatusEffectType type) => _activeIndex.ContainsKey(type);

        /// <summary>获取指定类型效果（可为 null）。</summary>
        public StatusEffect GetEffect(StatusEffectType type)
            => _activeIndex.TryGetValue(type, out var e) ? e : null;

        /// <summary>
        /// DoT 伤害代理（架构 06 §10）。StatusEffect.OnTick() 调用此方法，传入已构建好的 DamageInfo。
        /// </summary>
        public void ApplyDirectDamage(DamageInfo info)
        {
            _damageable?.TakeDamage(info);
        }

        /// <summary>设置 Sprite Shader 参数（MaterialPropertyBlock，不修改共享材质）。</summary>
        public void SetShaderParam(string param, float value)
        {
            if (_renderer == null) return;
            if (!_shaderPropIds.TryGetValue(param, out int propId))
            {
                propId = Shader.PropertyToID(param);
                _shaderPropIds[param] = propId;
            }
            _renderer.GetPropertyBlock(_propBlock);
            _propBlock.SetFloat(propId, value);
            _renderer.SetPropertyBlock(_propBlock);
        }

        /// <summary>净化所有状态效果（存档点激活 / 返回城镇等调用）。</summary>
        public void CleanseAll()
        {
            foreach (var e in _activeList) e.OnExpire();
            _activeList.Clear();
            _activeIndex.Clear();
        }

        // ── 私有辅助 ───────────────────────────────────────────────────────

        private StatusEffect CreateEffect(DamageType type)
            => _effectFactories.TryGetValue(type, out var factory) ? factory() : null;

        private void RemoveAt(int index, StatusEffect effect)
        {
            effect.OnExpire();
            _activeList.RemoveAt(index);
            _activeIndex.Remove(effect.EffectType);
            BroadcastExpired(effect);
        }

        private void BroadcastApplied(StatusEffect effect)
        {
            _onStatusEffectApplied?.Raise(new StatusEffectEvent
            {
                EffectType        = effect.EffectType,
                StackCount        = effect.StackCount,
                RemainingDuration = effect.Duration,
            });
        }

        private void BroadcastExpired(StatusEffect effect)
        {
            _onStatusEffectExpired?.Raise(new StatusEffectEvent
            {
                EffectType        = effect.EffectType,
                StackCount        = 0,
                RemainingDuration = 0f,
            });
        }
    }
}