using UnityEngine;
using BaseGames.AI;

namespace BaseGames.Enemies
{
    /// <summary>
    /// 敌人移动执行器：唯一的移动/朝向入口。AI 状态与能力经 IEnemyLocomotion
    /// 声明意图，本组件每帧把当前模式翻译为对 EnemyBase/IPathAgent 的调用。
    /// 取代散落的 MoveTo/StopMovement/FacePlayer/FaceTarget 直调与三个协程能力。
    /// </summary>
    [DisallowMultipleComponent]
    public sealed class EnemyLocomotion : MonoBehaviour, IEnemyLocomotion
    {
        [Header("巡逻策略（P6 实现 Pace/Waypoints；当前仅 Wander）")]
        [SerializeField] private PatrolStrategy _patrolStrategy = PatrolStrategy.Wander;

        private EnemyBase _enemy;
        private LocomotionMode _mode = LocomotionMode.Idle;
        private Transform _approachTarget;
        private Vector2 _facePoint;

        public LocomotionMode CurrentMode => _mode;
        public bool IsMoving => _enemy != null && _enemy.Nav != null && _enemy.Nav.IsMoving;

        private void Awake()
        {
            _enemy = GetComponentInParent<EnemyBase>();
            if (_enemy == null)
                Debug.LogError("[EnemyLocomotion] 找不到 EnemyBase。", this);
        }

        // ── IEnemyLocomotion（声明意图，不立即 actuate 之外的副作用）──
        public void SetMode(LocomotionMode mode)
        {
            if (_mode == mode) return;
            _mode = mode;
            if (mode == LocomotionMode.Idle) _enemy?.StopMovement();
            if (mode == LocomotionMode.Patrol && _enemy?.Stats != null)
                _enemy.Nav?.SetSpeed(_enemy.Stats.WalkSpeed);
        }

        public void Approach(Transform target)
        {
            _mode = LocomotionMode.Approach;
            _approachTarget = target;
            if (_enemy?.Stats != null) _enemy.Nav?.SetSpeed(_enemy.Stats.RunSpeed);
        }

        public void MoveTo(Vector2 point)
        {
            _mode = LocomotionMode.Approach;
            _approachTarget = null;
            _enemy?.MoveTo(point);
        }

        public void Face(Vector2 lookAt)
        {
            _mode = LocomotionMode.Face;
            _facePoint = lookAt;
        }

        public void Stop()
        {
            _mode = LocomotionMode.Idle;
            _enemy?.StopMovement();
        }

        // ── 每帧把模式翻译成执行 ──
        private void Update()
        {
            if (_enemy == null) return;
            switch (_mode)
            {
                case LocomotionMode.Idle:
                    break; // SetMode(Idle) 已停；保持
                case LocomotionMode.Patrol:
                    TickPatrol();
                    break;
                case LocomotionMode.Face:
                    _enemy.StopMovement();
                    _enemy.FaceTarget(_facePoint);
                    break;
                case LocomotionMode.Approach:
                    if (_approachTarget != null) _enemy.MoveTo(_approachTarget.position);
                    break;
            }
        }

        private void TickPatrol()
        {
            var nav = _enemy.Nav;
            if (nav == null) return;
            switch (_patrolStrategy)
            {
                case PatrolStrategy.Wander:
                    if (!nav.IsMoving) nav.WalkToRandom();
                    break;
                // Pace / Waypoints：P6 实现
                default:
                    if (!nav.IsMoving) nav.WalkToRandom();
                    break;
            }
        }
    }
}