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

namespace BaseGames.Enemies.Abilities
{
    /// <summary>
    /// 闪烁突袭能力：消失后瞬移到目标侧后方/上方/侧翼，现身后衔接出手。
    ///
    /// 流程：
    /// 1. 选择闪烁目标点（玩家侧后 / 上方 / 侧翼，依 <see cref="BlinkPosition"/>）
    /// 2. 隐身（隐藏 SpriteRenderer、关闭碰撞、播放消失 VFX）
    /// 3. 等待 disappearDuration 营造"消失"感
    /// 4. 瞬移到目标点
    /// 5. 现身 + 出现 VFX + 预警闪光（reappearTelegraph）
    /// 6. 调用 followUpAbilityId 指定的能力作为出手（若为空则播放 attackSequence[0]）
    ///
    /// 同时实现 <see cref="INavLinkHandler"/> for <see cref="NavLinkType.Teleport"/>：
    /// 当 PathBerserker2d 路径包含 teleport NavLink 时，本能力接管穿越逻辑，
    /// 播放消失/出现动画后告知 NavAgent 继续路径，而不触发战斗出手。
    /// </summary>
    public sealed class BlinkStrikeAbility : EnemyAbilityBase, INavLinkHandler
    {
        public enum BlinkPosition { BehindTarget, FrontTarget, AboveTarget, FlankTarget }

        [Header("闪烁参数")]
        [SerializeField] private BlinkPosition _blinkPosition  = BlinkPosition.BehindTarget;
        [SerializeField] private float _offsetDistance         = 1.8f;
        [SerializeField] private float _verticalOffsetAbove    = 3.0f;
        [SerializeField] private float _disappearDuration      = 0.25f;
        [SerializeField] private float _reappearTelegraph      = 0.20f;
        [SerializeField] private LayerMask _groundMask;
        [SerializeField] private float _groundSnapMaxDistance  = 3f;

        [Header("视觉")]
        [SerializeField] private SpriteRenderer[] _renderers;
        [SerializeField] private Collider2D[]     _disableDuringBlink;
        [SerializeField] private string _disappearVfxKey       = "";
        [SerializeField] private string _appearVfxKey          = "";

        [Header("出手能力（在现身后触发，若为空则播放第一段攻击动画）")]
        [SerializeField] private string _followUpAbilityId     = "";

        private Rigidbody2D _rb;
        private IObjectPoolService _pool;
        private Coroutine _navLinkCoroutine;

        // ── INavLinkHandler（Teleport 连接段穿越）─────────────────────
        private static readonly NavLinkType[] _handledTypes = new[] { NavLinkType.Teleport };
        public NavLinkType[] HandledLinkTypes => _handledTypes;

        public bool CanHandleLink(NavLinkType type, Vector2 linkStart, Vector2 linkEnd) => true;

        public void BeginLinkTraversal(NavLinkType type, Vector2 linkStart, Vector2 linkEnd, Action onComplete)
        {
            if (_navLinkCoroutine != null) StopCoroutine(_navLinkCoroutine);
            _navLinkCoroutine = StartCoroutine(TeleportNavLinkCoroutine(linkEnd, onComplete));
        }

        public void AbortLinkTraversal()
        {
            if (_navLinkCoroutine != null) { StopCoroutine(_navLinkCoroutine); _navLinkCoroutine = null; }
            SetVisible(true);
        }

        /// <summary>纯导航用传送：消失 → 移动到连接终点 → 出现，不触发战斗出手。</summary>
        private IEnumerator TeleportNavLinkCoroutine(Vector2 destination, Action onComplete)
        {
            _pool ??= ServiceLocator.GetOrDefault<IObjectPoolService>();

            if (!string.IsNullOrEmpty(_disappearVfxKey))
                _pool?.Spawn(_disappearVfxKey, _transform.position, Quaternion.identity);
            SetVisible(false);
            if (_rb != null) _rb.velocity = Vector2.zero;
            yield return EnemyAbilityWaits.Get(_disappearDuration);

            if (_rb != null) _rb.position = destination;
            else _transform.position     = destination;

            SetVisible(true);
            if (!string.IsNullOrEmpty(_appearVfxKey))
                _pool?.Spawn(_appearVfxKey, _transform.position, Quaternion.identity);

            _navLinkCoroutine = null;
            onComplete?.Invoke(); // 通知 EnemyNavAgent → CompleteLinkTraversal
        }

        protected override void Awake()
        {
            base.Awake();
            _rb = GetComponentInParent<Rigidbody2D>();
            if (_renderers == null || _renderers.Length == 0)
                _renderers = GetComponentsInChildren<SpriteRenderer>(true);
        }

        protected override IEnumerator ExecuteCoroutine()
        {
            _pool ??= ServiceLocator.GetOrDefault<IObjectPoolService>();
            var target = _enemy != null ? _enemy.PlayerTransform : null;
            if (target == null) yield break;

            // 1. 消失
            if (!string.IsNullOrEmpty(_disappearVfxKey))
                _pool?.Spawn(_disappearVfxKey, _transform.position, Quaternion.identity);
            SetVisible(false);
            if (_rb != null) _rb.velocity = Vector2.zero;
            yield return EnemyAbilityWaits.Get(_disappearDuration);

            // 2. 选目标点 + 瞬移
            Vector2 dest = ComputeBlinkPosition(target);
            if (_rb != null) _rb.position = dest;
            else _transform.position = dest;
            FaceTarget(target);

            // 3. 现身 + 预警
            SetVisible(true);
            if (!string.IsNullOrEmpty(_appearVfxKey))
                _pool?.Spawn(_appearVfxKey, _transform.position, Quaternion.identity);
            Phase = AbilityRunState.Telegraph;
            yield return EnemyAbilityWaits.Get(_reappearTelegraph);

            // 4. 出手
            Phase = AbilityRunState.Active;
            if (!string.IsNullOrEmpty(_followUpAbilityId) && _enemy != null)
            {
                var follow = _enemy.Abilities.Get(_followUpAbilityId);
                if (follow != null)
                {
                    follow.Execute();
                    while (follow.IsRunning) yield return null;
                    yield break;
                }
            }
            // 退化路径：播放第一段动画
            var seq = _config != null ? _config.attackSequence : null;
            if (seq != null && seq.Length > 0)
            {
                var atk = seq[0];
                float dur = atk.fallbackDuration;
                if (atk.clip != null && _animancer != null)
                {
                    var st = _animancer.Play(atk.clip);
                    if (st != null && st.Length > 0f) dur = st.Length;
                }
                yield return EnemyAbilityWaits.Get(dur);
            }
        }

        protected override void OnInterrupted(InterruptReason reason)
        {
            // 中断时同时终止 NavLink 穿越协程（若正在进行），防止 onComplete 回调污染导航状态
            AbortLinkTraversal();
        }

        private Vector2 ComputeBlinkPosition(Transform target)
        {
            Vector2 t = target.position;
            Vector2 selfDir = (t - (Vector2)_transform.position);
            float facing = selfDir.x >= 0f ? 1f : -1f;
            Vector2 raw;
            switch (_blinkPosition)
            {
                case BlinkPosition.FrontTarget: raw = t + new Vector2(facing * _offsetDistance, 0f); break;
                case BlinkPosition.AboveTarget: raw = t + new Vector2(0f, _verticalOffsetAbove);     break;
                case BlinkPosition.FlankTarget:
                    raw = t + new Vector2((UnityEngine.Random.value < 0.5f ? -1f : 1f) * _offsetDistance, 0f);
                    break;
                case BlinkPosition.BehindTarget:
                default:
                    float tFacing = target.localScale.x >= 0f ? 1f : -1f;
                    raw = t - new Vector2(tFacing * _offsetDistance, 0f);
                    break;
            }
            // 贴地（避免悬空）
            var hit = Physics2D.Raycast(raw + Vector2.up * 0.5f, Vector2.down,
                                        _groundSnapMaxDistance + 0.5f, _groundMask);
            if (hit.collider != null) raw.y = hit.point.y + 0.05f;
            return raw;
        }

        private void SetVisible(bool visible)
        {
            if (_renderers != null)
                for (int i = 0; i < _renderers.Length; i++)
                    if (_renderers[i] != null) _renderers[i].enabled = visible;
            if (_disableDuringBlink != null)
                for (int i = 0; i < _disableDuringBlink.Length; i++)
                    if (_disableDuringBlink[i] != null) _disableDuringBlink[i].enabled = visible;
        }
    }
}