using Opsive.BehaviorDesigner.AddOns.MovementPack.Runtime.Tasks;
using Opsive.BehaviorDesigner.AddOns.Shared.Runtime.Pathfinding;
using Opsive.BehaviorDesigner.Runtime.Tasks;
using Opsive.BehaviorDesigner.Runtime.Utility;
using Opsive.GraphDesigner.Runtime;
using Opsive.GraphDesigner.Runtime.Variables;
using Opsive.Shared.Utility;
using Unity.Entities;
using UnityEngine;
using UnityEngine.AI;

namespace Cielonos.MainGame.Characters.AI
{
    [Description("在初始出生点附近的指定半径内随机选取一个 NavMesh 上的点并移动过去。到达后等待一段时间（可选），然后返回 Success。")]
    [NodeIcon("Assets/Sprites/Icon/Play.png")]
    [Category("Cielonos/Movement")]
    public class WanderInRange : MovementBase
    {
        [Tooltip("初始移动速度。")]
        [SerializeField] protected SharedVariable<float> m_StartSpeed = 10f;
        
        [Tooltip("以初始出生点为圆心的游走半径（单位：米）。")]
        [SerializeField] protected SharedVariable<float> m_WanderRadius = 10f;

        [Tooltip("到达目标点后等待的时间范围（秒）。Min 与 Max 均为 0 时不等待，直接返回 Success。")]
        [SerializeField] protected SharedVariable<RangeFloat> m_WaitAtDestinationDuration = new RangeFloat(0f, 0f);

        [Tooltip("判定到达目的地所需的剩余距离阈值（单位：米）。")]
        [SerializeField] protected SharedVariable<float> m_ArrivalDistance = 0.5f;

        [Tooltip("每次寻路 tick 中，选取随机目标点的最大重试次数。")]
        [SerializeField] protected SharedVariable<int> m_DestinationRetries = 5;

#if UNITY_EDITOR
        [Tooltip("是否在无效目标点处绘制调试射线？")]
        [SerializeField] protected bool m_DrawInvalidDestinationRay;
#endif

        // 记录行为树初始化时的出生点位置
        private Vector3 m_SpawnPosition;
        private NavMeshAgentPathfinder _navPathfinder;
        private NavMeshAgent _agent;

        // 到达后等待状态
        private float m_WaitDuration = -1f;
        private float m_DestinationReachedTime = -1f;

        // 本次 OnStart 是否已成功派发了目标点
        private bool m_HasDestination;

        /// <summary>
        /// 记录出生点，仅在行为树初始化时调用一次。
        /// </summary>
        public override void OnAwake()
        {
            base.OnAwake();
            _navPathfinder = m_Pathfinder as NavMeshAgentPathfinder;
            if (_navPathfinder == null)
            {
                Debug.LogError("[PrecisePursue] Requires NavMeshAgentPathfinder.");
                return;
            }
            _agent = _navPathfinder.m_NavMeshAgent;
            m_SpawnPosition = transform.position;
        }

        /// <summary>
        /// 每次节点开始执行时，重置状态并选取新目标。
        /// </summary>
        public override void OnStart()
        {
            base.OnStart();

            m_WaitDuration = -1f;
            m_DestinationReachedTime = -1f;
            m_HasDestination = TrySetDestination();
        }

        /// <summary>
        /// 每帧检查是否到达目标点，并处理到达后的等待逻辑。
        /// </summary>
        public override TaskStatus OnUpdate()
        {
            // 若初始选点失败，再尝试一次；仍然失败则返回 Failure
            if (!m_HasDestination)
            {
                m_HasDestination = TrySetDestination();
                if (!m_HasDestination)
                    return TaskStatus.Failure;
            }

            _agent.speed = m_StartSpeed.Value;
            
            // 到达判定：HasArrived() 或剩余距离小于阈值
            if (HasArrived() || RemainingDistance < m_ArrivalDistance.Value)
            {
                // 首次到达：决定是否等待
                if (m_WaitDuration < 0f)
                {
                    m_WaitDuration = m_WaitAtDestinationDuration.Value.RandomValue;

                    if (m_WaitDuration > 0f)
                    {
                        m_DestinationReachedTime = Time.time;
                        return TaskStatus.Running;
                    }

                    return TaskStatus.Success;
                }

                // 等待中：检查是否已等待足够时间
                if (Time.time >= m_DestinationReachedTime + m_WaitDuration)
                {
                    return TaskStatus.Success;
                }
            }

            return TaskStatus.Running;
        }

        /// <summary>
        /// 在出生点半径内随机采样 NavMesh 上的有效点，并设定为寻路目标。
        /// </summary>
        /// <returns>成功设定目标点返回 true，所有重试均失败返回 false。</returns>
        private bool TrySetDestination()
        {
            for (int i = 0; i < m_DestinationRetries.Value; i++)
            {
                // 在 XZ 平面的圆形范围内随机选点
                var randomOffset = Random.insideUnitCircle * m_WanderRadius.Value;
                var candidate = m_SpawnPosition + new Vector3(randomOffset.x, 0f, randomOffset.y);

                if (SamplePosition(ref candidate))
                {
                    // 防止 NavMesh 采样将点吸附到半径外
                    if (Vector3.Distance(candidate, m_SpawnPosition) <= m_WanderRadius.Value)
                    {
                        SetDestination(candidate);
                        return true;
                    }
                }

#if UNITY_EDITOR
                if (m_DrawInvalidDestinationRay)
                    Debug.DrawRay(candidate, Vector3.up * 2f, Color.red, 1f);
#endif
            }

            return false;
        }

        /// <summary>
        /// 节点结束时重置等待状态。
        /// </summary>
        public override void OnEnd()
        {
            base.OnEnd();

            m_WaitDuration = -1f;
            m_DestinationReachedTime = -1f;
            m_HasDestination = false;
        }

        /// <summary>
        /// 保存当前节点运行状态（等待剩余时间）。
        /// </summary>
        public override object Save(World world, Entity entity)
        {
            var saveData = new object[3];
            saveData[0] = base.Save(world, entity);
            saveData[1] = m_WaitDuration;
            // 存储已等待时长而非绝对时间戳，以兼容时间暂停/恢复
            saveData[2] = m_DestinationReachedTime >= 0f ? Time.time - m_DestinationReachedTime : -1f;
            return saveData;
        }

        /// <summary>
        /// 恢复节点运行状态。
        /// </summary>
        public override void Load(object saveData, World world, Entity entity)
        {
            var arr = (object[])saveData;
            base.Load(arr[0], world, entity);
            m_WaitDuration = (float)arr[1];
            var elapsed = (float)arr[2];
            m_DestinationReachedTime = elapsed >= 0f ? Time.time - elapsed : -1f;
        }

        /// <summary>
        /// 编辑器重置，恢复字段默认值。
        /// </summary>
        public override void Reset()
        {
            base.Reset();

            m_WanderRadius = 8f;
            m_WaitAtDestinationDuration = new RangeFloat(0f, 0f);
            m_ArrivalDistance = 0.5f;
            m_DestinationRetries = 5;
#if UNITY_EDITOR
            m_DrawInvalidDestinationRay = false;
#endif
        }
    }
}