using System.Collections;
using UnityEngine;
using Animancer;
using BaseGames.Core;
using BaseGames.Core.Pool;

namespace BaseGames.Enemies.Abilities
{
    /// <summary>
    /// 敌人能力抽象基类（架构 07_EnemyModule §8.4）。
    /// 责任：生命周期管理、冷却计时、中断分发。子类只实现 <see cref="ExecuteCoroutine"/>。
    ///
    /// 设计要点：
    /// - 单一执行实例：同一能力同时只有一个协程在跑。
    /// - 协程内 yield WaitForSeconds 复用 <see cref="EnemyAbilityWaits"/>（无 GC）。
    /// - 受击/死亡时由 <see cref="EnemyBase"/> 调用 <see cref="Interrupt"/>。
    /// </summary>
    [DisallowMultipleComponent]
    public abstract class EnemyAbilityBase : MonoBehaviour
    {
        [Header("配置 SO")]
        [SerializeField] protected EnemyAbilitySO _config;

        // 缓存依赖（Awake 填入，热路径无 GetComponent）
        protected EnemyBase           _enemy;
        protected AnimancerComponent  _animancer;
        protected Transform           _transform;

        private Coroutine _runner;
        private float     _cooldownEndTime = -1f;
        private bool      _isRunning;

        // ── 公共状态 ─────────────────────────────────────────────────────
        public EnemyAbilitySO Config            => _config;
        public bool           IsRunning         => _isRunning;
        public AbilityRunState Phase            { get; protected set; } = AbilityRunState.Idle;
        public float          CooldownRemaining => Mathf.Max(0f, _cooldownEndTime - Time.time);
        public bool           IsOnCooldown      => CooldownRemaining > 0f;

        /// <summary>能力被外部中断时触发（BD Task / 状态机订阅用）。</summary>
        public event System.Action<InterruptReason> Interrupted;

        /// <summary>BD 任务统一查询入口：当前是否可用（冷却完毕且未执行中）。</summary>
        public virtual bool CanUse => !_isRunning && !IsOnCooldown && _enemy != null && _enemy.IsAlive;

        protected virtual void Awake()
        {
            _enemy     = GetComponentInParent<EnemyBase>();
            _animancer = _enemy != null ? _enemy.Animancer : GetComponentInParent<AnimancerComponent>();
            _transform = transform;
            if (_enemy == null)
                Debug.LogError($"[EnemyAbilityBase] {GetType().Name} 找不到 EnemyBase。", this);
            if (_animancer == null)
                Debug.LogWarning($"[EnemyAbilityBase] {GetType().Name} 找不到 AnimancerComponent，动画能力将无法播放动画。", this);
        }

        protected virtual void OnDisable()
        {
            if (_isRunning) Interrupt(InterruptReason.ExternalRequest);
        }

        // ── 执行 ─────────────────────────────────────────────────────────
        /// <summary>
        /// 启动能力。重复调用、冷却中或已运行将返回 false。
        /// 若 <see cref="EnemyAbilitySO.exclusionGroup"/> 非空，会先中断同组其他能力（互斥）。
        /// </summary>
        public bool Execute()
        {
            if (!CanUse) return false;

            // 互斥组：启动前中断同组正在运行的其他能力
            if (_config != null && !string.IsNullOrEmpty(_config.exclusionGroup))
                _enemy?.Abilities.InterruptGroup(_config.exclusionGroup, InterruptReason.ExternalRequest);

            _runner    = StartCoroutine(RunInternal());
            return true;
        }

        /// <summary>
        /// 强制启动能力，忽略冷却检查（连段语义：外部组合技调用子能力时使用）。
        /// 若能力正在运行则先中断再重启。
        /// </summary>
        public bool ForceExecute()
        {
            if (_enemy == null || !_enemy.IsAlive) return false;
            if (_isRunning) Interrupt(InterruptReason.ExternalRequest);
            _runner = StartCoroutine(RunInternal());
            return true;
        }

        private IEnumerator RunInternal()
        {
            _isRunning = true;
            Phase      = AbilityRunState.Telegraph;
            try
            {
                if (_config != null && _config.telegraphDuration > 0f)
                    yield return TelegraphRoutine();

                Phase = AbilityRunState.Windup;
                yield return ExecuteCoroutine();
                Phase = AbilityRunState.Recovery;
            }
            finally
            {
                _isRunning       = false;
                _runner          = null;
                _cooldownEndTime = Time.time + (_config != null ? _config.cooldown : 0f);
                if (Phase != AbilityRunState.Interrupted) Phase = AbilityRunState.Idle;
                OnAbilityEnded();
            }
        }

        /// <summary>子类实现：能力主体。可分多段、含 HitBox 激活/弹幕生成/物理推进等。</summary>
        protected abstract IEnumerator ExecuteCoroutine();

        /// <summary>预警阶段（默认生成 VFX 后等待 telegraphDuration）。子类可重写。</summary>
        protected virtual IEnumerator TelegraphRoutine()
        {
            if (!string.IsNullOrEmpty(_config.telegraphVfxKey))
            {
                var pool = ServiceLocator.GetOrDefault<IObjectPoolService>();
                pool?.Spawn(_config.telegraphVfxKey, _transform.position, Quaternion.identity);
            }
            yield return EnemyAbilityWaits.Get(_config.telegraphDuration);
        }

        /// <summary>能力结束钩子（被中断或正常结束都会调用）。</summary>
        protected virtual void OnAbilityEnded() { }

        /// <summary>中断当前执行。冷却仍会按配置计入。</summary>
        public void Interrupt(InterruptReason reason)
        {
            if (!_isRunning) return;
            if (_config != null)
            {
                if (reason == InterruptReason.Hurt    && !_config.interruptOnHurt)    return;
                if (reason == InterruptReason.Stagger && !_config.interruptOnStagger) return;
            }
            if (_runner != null) StopCoroutine(_runner);
            _runner    = null;
            _isRunning = false;
            Phase      = AbilityRunState.Interrupted;
            OnInterrupted(reason);
            Interrupted?.Invoke(reason);
            OnAbilityEnded();
            _cooldownEndTime = Time.time + (_config != null ? _config.cooldown * 0.5f : 0f);
        }

        protected virtual void OnInterrupted(InterruptReason reason) { }

        /// <summary>子类辅助：朝向目标（写入输入信号，下一 FixedUpdate 由 EnemyMovement 消费）。</summary>
        protected void FaceTarget(Transform target)
        {
            if (target == null || _enemy == null) return;
            _enemy.FaceTarget(target.position);
        }
    }

    /// <summary>WaitForSeconds 池（架构 §10 GC 优化）。能力协程统一通过此获取等待指令。</summary>
    internal static class EnemyAbilityWaits
    {
        private const int MaxCacheSize = 64;

        private static readonly System.Collections.Generic.Dictionary<float, WaitForSeconds> _cache
            = new System.Collections.Generic.Dictionary<float, WaitForSeconds>(32);
        public static WaitForSeconds Get(float seconds)
        {
            if (seconds <= 0f) return null;
            if (!_cache.TryGetValue(seconds, out var w))
            {
                if (_cache.Count < MaxCacheSize)
                {
                    w = new WaitForSeconds(seconds);
                    _cache[seconds] = w;
                }
                else
                {
                    return new WaitForSeconds(seconds);
                }
            }
            return w;
        }
    }
}