using UnityEngine;
using Animancer;
using BaseGames.Combat;

namespace BaseGames.Enemies
{
    /// <summary>
    /// 敌人基类（架构 07_EnemyModule §1）。
    /// 实现 IDamageable，为 Behavior Designer 任务提供统一虚方法接口。
    /// Phase 1 实现：完整骨架，BD 接口、受击、死亡流程。
    /// ⚠️ _nav 字段类型为 IPathAgent（在 BaseGames.Enemies.Navigation 中实现具体类）。
    /// </summary>
    public class EnemyBase : MonoBehaviour, IDamageable
    {
        [Header("配置 SO")]
        [SerializeField] protected EnemyStatsSO           _statsSO;
        [SerializeField] protected EnemyAnimationConfigSO _animConfig;

        [Header("子组件（Prefab Inspector 绑定）")]
        [SerializeField] protected EnemyStats       _stats;
        [SerializeField] protected EnemyMovement    _movement;
        [SerializeField] protected EnemyCombat      _combat;
        [SerializeField] protected AnimancerComponent _animancer;
        [SerializeField] protected EnemyFeedback    _feedback;
        [SerializeField] protected HurtBox          _hurtBox;

        [Header("事件频道")]
        [SerializeField] private BaseGames.Core.Events.TransformEventChannelSO _onEnemyDied;

        // ── 导航代理（IPathAgent；由 EnemyNavAgent 实现）───────────────────
        // Phase 1：通过接口引用，避免对 Navigation 程序集的直接依赖。
        // 由子类 / Inspector 注入，或者运行时 GetComponent<IPathAgent>() 获取。
        protected IPathAgent _nav;

        // ── 状态 ──────────────────────────────────────────────────────────
        private EnemyStateType _currentState;
        public EnemyStateType CurrentState => _currentState;

        // ── IDamageable ───────────────────────────────────────────────────
        public bool IsInvincible => _currentState == EnemyStateType.Dead;
        public int  Defense      => _stats != null ? _stats.Defense : 0;

        public void TakeDamage(DamageInfo info)
        {
            if (_currentState == EnemyStateType.Dead) return;

            _stats?.TakeDamage(info.FinalDamage);
            _feedback?.OnHit(info);

            if (_stats != null && _stats.CurrentHP <= 0)
            {
                Die();
                return;
            }

            // Phase 2：根据霸体结果选 Stagger / Hurt
            ForceState(EnemyStateType.Hurt);
        }

        // ── BD 行为树接口（虚方法）────────────────────────────────────────

        public virtual void MoveTo(Vector2 target)
            => _nav?.RequestMoveTo(target);

        public virtual void MoveInDirection(float dir)
            => _movement?.MoveHorizontal(dir);

        public virtual void StopMovement()
        {
            _nav?.StopNavigation();
            _movement?.StopHorizontal();
        }

        public virtual void BeginAttack(AttackType type)
        {
            _combat?.StartAttack(type);
            _stats?.ResetAttackCooldown();
        }

        public virtual bool CanAttack()
            => _stats != null && _stats.AttackCooldownTimer <= 0f;

        public virtual bool IsPlayerInRange(float range)
            => _stats != null && _stats.DistanceToPlayer <= range;

        public virtual void FacePlayer()
        {
            if (_playerTransform != null)
                _movement?.FaceTarget(_playerTransform.position);
        }

        public virtual void Knockback(DamageInfo info)
        {
            if (info.Flags.HasFlag(DamageFlags.NoKnockback)) return;
            _movement?.ApplyKnockback(info.KnockbackDirection, info.KnockbackForce);
        }

        // ── 状态控制 ──────────────────────────────────────────────────────
        public void ForceState(EnemyStateType newState)
        {
            _currentState = newState;
            // Phase 2：根据状态播放对应动画 / 触发硬直计时
        }

        // ── Unity 生命周期 ────────────────────────────────────────────────
        protected virtual void Awake()
        {
            _nav = GetComponent<IPathAgent>() ?? new NullPathAgent();

            if (_stats != null && _statsSO != null)
                _stats.Initialize(_statsSO);

            // Phase 1：简单查找玩家；Phase 2 改为事件频道订阅
            var playerGO = GameObject.FindWithTag("Player");
            if (playerGO != null) _playerTransform = playerGO.transform;
        }

        protected virtual void Update()
        {
            _stats?.TickAttackCooldown(Time.deltaTime);

            if (_playerTransform != null && _stats != null)
                _stats.DistanceToPlayer = Vector2.Distance(transform.position, _playerTransform.position);
        }

        protected virtual void Start()
        {
            // 播放 Idle 动画（若 Animancer 和配置都就绪）
            if (_animancer != null && _animConfig != null && _animConfig.Idle != null)
                _animancer.Play(_animConfig.Idle);
        }

        // ── 内部 ──────────────────────────────────────────────────────────
        private Transform _playerTransform;

        protected virtual void Die()
        {
            if (_currentState == EnemyStateType.Dead) return;
            ForceState(EnemyStateType.Dead);

            // 禁用所有碰撞体
            foreach (var col in GetComponentsInChildren<Collider2D>())
                col.enabled = false;

            // 播放死亡动画
            if (_animancer != null && _animConfig != null && _animConfig.Dead != null)
            {
                var state = _animancer.Play(_animConfig.Dead);
                state.Events(this).OnEnd = () => Destroy(gameObject);
            }
            else
            {
                Destroy(gameObject, 1.5f);
            }

            _feedback?.OnDeath();
            _onEnemyDied?.Raise(transform);
        }
    }

    // ── 枚举（架构 07 §1）────────────────────────────────────────────────
    public enum EnemyStateType { Controlled, Hurt, Stagger, Dead }
    public enum AttackType     { Melee, Ranged, Special }
}