#if GRAPH_DESIGNER
using Opsive.BehaviorDesigner.Runtime.Tasks;
using Opsive.BehaviorDesigner.Runtime.Tasks.Actions;
using UnityEngine;

namespace BaseGames.Enemies.AI
{
    /// <summary>
    /// BD Action：战斗站位控制。
    /// 在 [m_PreferredMinDist, m_PreferredMaxDist] 范围内保持与玩家的水平距离：
    ///   - 距离过近 → 后退
    ///   - 距离过远 → 靠近
    ///   - 在范围内 → 停止移动，持续朝向玩家
    /// 始终返回 Running，上层 BT 通过 Abort 或条件终止该 Task。
    /// </summary>
    [TaskName("Maintain Combat Distance")]
    [TaskCategory("BaseGames/Enemy/Combat")]
    [TaskDescription("在战斗中维持与目标的理想距离范围")]
    public class BD_MaintainCombatDistance : Action
    {
        [Tooltip("期望最小距离（m）；小于此值开始后退")]
        [SerializeField] private float m_PreferredMinDist = 2f;

        [Tooltip("期望最大距离（m）；大于此值开始靠近")]
        [SerializeField] private float m_PreferredMaxDist = 4f;

        [Tooltip("后退速度（m/s），默认使用 WalkSpeed")]
        [SerializeField] private float m_BackpedaleSpeed = 0f;

        [Tooltip("每帧重新规划路径的阈值（m）；玩家移动超过此距离才重规划，降低频率")]
        [SerializeField] private float m_ReplanThreshold = 0.5f;

        private EnemyBase _enemy;
        private Vector2   _lastPlayerPos;
        private float     _sqrMin;
        private float     _sqrMax;

        public override void OnAwake() => _enemy = GetComponent<EnemyBase>();

        public override void OnStart()
        {
            _sqrMin        = m_PreferredMinDist * m_PreferredMinDist;
            _sqrMax        = m_PreferredMaxDist * m_PreferredMaxDist;
            _lastPlayerPos = Vector2.positiveInfinity;
        }

        public override TaskStatus OnUpdate()
        {
            if (_enemy == null || _enemy.PlayerTransform == null)
                return TaskStatus.Failure;

            if (_enemy.Stats == null)
                return TaskStatus.Failure;

            _enemy.FacePlayer();

            float sqrDist = _enemy.Stats.SqrDistanceToPlayer;

            if (sqrDist < _sqrMin)
            {
                // 距离过近 → 后退（向远离玩家方向移动）
                _enemy.Nav?.StopNavigation();
                Vector2 toPlayer  = ((Vector2)_enemy.PlayerTransform.position - (Vector2)_enemy.transform.position).normalized;
                float   backDir   = -Mathf.Sign(toPlayer.x);
                float   speed     = m_BackpedaleSpeed > 0f ? m_BackpedaleSpeed : _enemy.Stats.WalkSpeed;
                _enemy.Movement?.MoveWithSpeed(backDir, speed);
            }
            else if (sqrDist > _sqrMax)
            {
                // 距离过远 → 靠近
                Vector2 playerPos = _enemy.PlayerTransform.position;
                float   moved     = ((Vector2)playerPos - _lastPlayerPos).sqrMagnitude;
                if (moved > m_ReplanThreshold * m_ReplanThreshold)
                {
                    _lastPlayerPos = playerPos;
                    _enemy.MoveTo(playerPos);
                }
            }
            else
            {
                // 在最优范围内 → 停止导航，原地保持朝向
                _enemy.Nav?.StopNavigation();
                _enemy.Movement?.StopHorizontal();
            }

            return TaskStatus.Running;
        }

        public override void OnEnd()
        {
            _enemy?.Movement?.StopHorizontal();
            _enemy?.Nav?.StopNavigation();
        }
    }
}
#endif