using UnityEngine;
using System;
using BaseGames.Core.Events;

namespace BaseGames.Combat
{
    /// <summary>
    /// 护盾组件。实现 IShieldable 接口供 HurtBox 注入。
    /// 护盾参数通过 ShieldConfigSO 集中配置。
    /// </summary>
    public class ShieldComponent : MonoBehaviour, IShieldable
    {
        [Header("配置资产")]
        [SerializeField] private ShieldConfigSO _config;

        [Header("VFX 事件频道")]
        [SerializeField] private VoidEventChannelSO _onShieldBrokenChannel;   // 护盾破碎 → 播放破碎 VFX
        [SerializeField] private VoidEventChannelSO _onShieldRestoredChannel; // 护盾恢复 → 播放恢复 VFX

        // ── 运行时属性 ────────────────────────────────────────────────────────
        public int  MaxShieldHP     => _config.MaxShieldHP;
        public int  CurrentShieldHP { get; private set; }
        /// <summary>当前是否能吸收伤害（护盾 HP > 0 且不在破碎惩罚期）。</summary>
        public bool HasShield       => CurrentShieldHP > 0 && _brokenPenaltyTimer <= 0f;

        private float AbsorptionRatio    => _config.DamageAbsorptionRatio;
        private float RechargeDelay      => _config.RechargeDelay;
        private float RechargeRate       => _config.RechargeRate;
        private float BrokenPenaltyDur   => _config.BrokenPenaltyDuration;
        private float ParryRestoreRatio  => _config.ParryRestoreRatio;

        public event Action<int, int> OnShieldChanged;  // (current, max)
        public event Action           OnShieldBroken;

        private float _regenDelayTimer;
        private float _brokenPenaltyTimer;

        private void Awake()
        {
            Debug.Assert(_config != null, "[ShieldComponent] _config 未赋值，请在 Inspector 中指定 ShieldConfigSO。", this);
            CurrentShieldHP = MaxShieldHP;
        }

        private void Update()
        {
            int maxHP = MaxShieldHP;
            if (maxHP <= 0) return;

            // 破碎惩罚计时
            if (_brokenPenaltyTimer > 0f)
            {
                _brokenPenaltyTimer -= Time.deltaTime;
                // 破碎惩罚结束 → 广播护盾恢复事件（VFX 钩子）
                if (_brokenPenaltyTimer <= 0f)
                    _onShieldRestoredChannel?.Raise();
                return;
            }

            if (CurrentShieldHP >= maxHP) return;
            if (RechargeRate <= 0f) return;

            if (_regenDelayTimer > 0f)
            {
                _regenDelayTimer -= Time.deltaTime;
                return;
            }

            int prev = CurrentShieldHP;
            CurrentShieldHP = Mathf.Min(CurrentShieldHP + Mathf.CeilToInt(RechargeRate * Time.deltaTime), maxHP);
            if (CurrentShieldHP != prev)
                OnShieldChanged?.Invoke(CurrentShieldHP, maxHP);
        }

        /// <summary>
        /// 尝试以护盾吸收伤害。返回穿透量（0=全部吸收，>0=穿透量继续走 TakeDamage 流程）。
        /// </summary>
        public int AbsorbDamage(int amount)
        {
            if (!HasShield) return amount;

            _regenDelayTimer = RechargeDelay;

            int maxHP = MaxShieldHP;
            // 按吸收比例计算实际由护盾承担的伤害
            int toAbsorb = Mathf.FloorToInt(amount * AbsorptionRatio);
            toAbsorb = Mathf.Min(toAbsorb, CurrentShieldHP);
            int passthrough = amount - toAbsorb;

            CurrentShieldHP -= toAbsorb;
            OnShieldChanged?.Invoke(CurrentShieldHP, maxHP);

            if (CurrentShieldHP <= 0)
            {
                CurrentShieldHP = 0;
                _brokenPenaltyTimer = BrokenPenaltyDur;
                OnShieldBroken?.Invoke();
                _onShieldBrokenChannel?.Raise();  // VFX 钩子：播放护盾破碎特效
            }

            return passthrough;
        }

        /// <summary>存档点 / 复活时调用：完全恢复护盾并清除惩罚状态。</summary>
        public void FullRecharge()
        {
            bool wasBroken = _brokenPenaltyTimer > 0f || CurrentShieldHP <= 0;
            _brokenPenaltyTimer = 0f;
            _regenDelayTimer    = 0f;
            CurrentShieldHP     = MaxShieldHP;
            OnShieldChanged?.Invoke(CurrentShieldHP, MaxShieldHP);
            if (wasBroken)
                _onShieldRestoredChannel?.Raise();  // VFX 钩子：护盾已满血恢复
        }

        /// <summary>弹反成功时调用：按 ParryRestoreRatio 恢复护盾（会清除惩罚状态）。</summary>
        public void OnParrySuccess()
        {
            int maxHP = MaxShieldHP;
            if (maxHP <= 0) return;

            _brokenPenaltyTimer = 0f;
            _regenDelayTimer    = 0f;
            int restore = Mathf.CeilToInt(maxHP * ParryRestoreRatio);
            CurrentShieldHP = Mathf.Min(CurrentShieldHP + restore, maxHP);
            OnShieldChanged?.Invoke(CurrentShieldHP, maxHP);
        }

        /// <summary>Inspector / 道具系统调用：设置最大护盾并重置当前值。</summary>
        public void SetMaxShieldHP(int max)
        {
            _maxShieldHP        = Mathf.Max(0, max);
            _brokenPenaltyTimer = 0f;
            CurrentShieldHP     = MaxShieldHP;
            OnShieldChanged?.Invoke(CurrentShieldHP, MaxShieldHP);
        }
    }
}