using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using Animancer;
using BaseGames.Combat;
using BaseGames.Core.Events;

namespace BaseGames.Boss
{
    /// <summary>
    /// 挂在 Boss GameObject 上，接收 BossOrchestrator 的指令执行指定 BossSkillSO。
    /// 管理 VulnerabilityWindow 计时和 WeakPointSystem 激活。
    /// </summary>
    public class BossSkillExecutor : MonoBehaviour
    {
        [SerializeField] private HitBox[]                    _hitBoxes;
        [SerializeField] private WeakPointSystem             _weakPointSystem;
        [SerializeField] private AnimancerComponent          _animancer;
        [SerializeField] private string                      _bossId;
        [SerializeField] private BossSkillEventChannelSO     _onBossSkillStarted;
        [SerializeField] private BossSkillEventChannelSO     _onBossSkillEnded;
        /// <remarks>PlayerController 无 Instance（架构 05 §2），由 Inspector 指定。</remarks>
        [SerializeField] private Transform                   _playerTransform;

        private BossSkillSO    _currentSkill;
        private bool           _isExecuting;
        private Coroutine      _activeCoroutine;

        public bool IsExecuting => _isExecuting;

        /// <summary>
        /// 按 float 值复用 WaitForSeconds 实例，消除协程中每次 new WaitForSeconds 的 GC 分配。
        /// Domain Reload 禁用时静态缓存跨 PlayMode 会话保留，但 WaitForSeconds 是幂等值对象，
        /// 不会引发功能错误；[RuntimeInitializeOnLoadMethod] 确保每次进入 Play 时清空。
        /// </summary>
        private static readonly Dictionary<float, WaitForSeconds> _wfsCache = new();

        [UnityEngine.RuntimeInitializeOnLoadMethod(UnityEngine.RuntimeInitializeLoadType.SubsystemRegistration)]
        private static void ClearWFSCache() => _wfsCache.Clear();

        private static WaitForSeconds GetWFS(float t)
        {
            if (!_wfsCache.TryGetValue(t, out var wfs))
                _wfsCache[t] = wfs = new WaitForSeconds(t);
            return wfs;
        }

        // ── 公共 API ───────────────────────────────────────────────────────────

        /// <summary>
        /// 执行一个 Boss 技能。若当前已在执行中则直接返回。
        /// </summary>
        public void ExecuteSkill(BossSkillSO skill)
        {
            if (_isExecuting || skill == null) return;
            _activeCoroutine = StartCoroutine(ExecuteSkillCoroutine(skill));
        }

        /// <summary>
        /// 立即打断正在执行的技能（阶段切换时调用）。
        /// </summary>
        public void InterruptCurrentSkill()
        {
            if (_activeCoroutine != null)
            {
                StopCoroutine(_activeCoroutine);
                _activeCoroutine = null;
            }
            FinishExecution();
        }

        // ── 主协程 ─────────────────────────────────────────────────────────────

        private IEnumerator ExecuteSkillCoroutine(BossSkillSO skill)
        {
            _isExecuting  = true;
            _currentSkill = skill;
            _onBossSkillStarted?.Raise(new BossSkillEvent { BossId = _bossId, SkillId = skill.skillId });

            // 播放技能动画
            if (skill.skillAnimation != null)
                _animancer.Play(skill.skillAnimation);

            // 启动 VulnerabilityWindow 协程（与主序列并行）
            Coroutine vulnCoroutine = null;
            if (skill.vulnerabilityWindows != null && skill.vulnerabilityWindows.Length > 0)
                vulnCoroutine = StartCoroutine(ActivateVulnerabilityWindowsCoroutine(skill));

            // 执行攻击序列（优先 sequenceOnMiss 作为默认序列）
            if (skill.sequenceOnMiss != null)
                yield return ExecuteSequenceCoroutine(skill.sequenceOnMiss);

            // 若弱点协程还在运行则等待其结束（避免孤立协程）
            if (vulnCoroutine != null)
                yield return vulnCoroutine;

            FinishExecution();
        }

        private void FinishExecution()
        {
            _isExecuting = false;
            if (_currentSkill != null)
            {
                _onBossSkillEnded?.Raise(new BossSkillEvent { BossId = _bossId, SkillId = _currentSkill.skillId });
                _currentSkill = null;
            }
        }

        // ── 序列协程 ────────────────────────────────────────────────────────────

        private IEnumerator ExecuteSequenceCoroutine(SkillSequenceSO seq)
        {
            int repeatCount = 0;
            do
            {
                foreach (var step in seq.steps)
                {
                    if (step.delayBeforeStep > 0f)
                        yield return GetWFS(step.delayBeforeStep);

                    if (step.pattern != null)
                        yield return ExecutePatternCoroutine(step.pattern);
                }

                repeatCount++;

                if (seq.RepeatIfPlayerInRange && seq.RepeatDelay > 0f)
                    yield return GetWFS(seq.RepeatDelay);
            }
            while (seq.RepeatIfPlayerInRange
                   && (seq.MaxRepeatCount == 0 || repeatCount < seq.MaxRepeatCount)
                   && IsPlayerInRange());
        }

        private IEnumerator ExecutePatternCoroutine(AttackPatternSO pattern)
        {
            // 预备
            if (pattern.WindupDuration > 0f)
                yield return GetWFS(pattern.WindupDuration);

            // 激活 HitBox（架构 06 §4：Activate(DamageSourceSO, Transform)）
            foreach (var hb in _hitBoxes)
                hb.Activate(pattern.DamageSource, transform);

            if (pattern.ActiveDuration > 0f)
                yield return GetWFS(pattern.ActiveDuration);

            // 关闭 HitBox
            foreach (var hb in _hitBoxes)
                hb.Deactivate();

            // 后摇
            if (pattern.RecoveryDuration > 0f)
                yield return GetWFS(pattern.RecoveryDuration);
        }

        // ── VulnerabilityWindow 协程 ─────────────────────────────────────────────

        private IEnumerator ActivateVulnerabilityWindowsCoroutine(BossSkillSO skill)
        {
            foreach (var window in skill.vulnerabilityWindows)
            {
                if (window.TriggerDelay > 0f)
                    yield return GetWFS(window.TriggerDelay);

                bool activateSpecific = window.ActivateWeakPointHurtBox;
                _weakPointSystem?.SetActive(true, window.DamageMultiplier, activateSpecific);
                window.OpenFeedback?.Play();

                yield return GetWFS(window.Duration);

                _weakPointSystem?.SetActive(false, 1f, activateSpecific);
                window.CloseFeedback?.Play();
            }
        }

        // ── 工具 ───────────────────────────────────────────────────────────────

        private bool IsPlayerInRange() =>
            _playerTransform != null &&
            Vector2.Distance(transform.position, _playerTransform.position) < 8f;
    }
}