using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.AddressableAssets;
using UnityEngine.ResourceManagement.AsyncOperations;
using UnityEngine.ResourceManagement.ResourceProviders;
using UnityEngine.SceneManagement;

namespace BaseGames.World.Streaming
{
    /// <summary>
    /// 单个房间的流式加载状态包装器。
    /// <para>
    /// 由 <see cref="RoomStreamingManager"/> 创建和管理，封装以下职责：
    /// <list type="bullet">
    ///   <item>Addressables 加载 / 卸载句柄</item>
    ///   <item>Dormantize：批量关闭 Renderer、暂停 IRoomLifecycle（AI、音效等）</item>
    ///   <item>Activate：批量恢复渲染，分帧唤醒 IRoomLifecycle</item>
    ///   <item>Deactivate：玩家离开后关闭本房间内容</item>
    /// </list>
    /// </para>
    /// </summary>
    public class RoomHandle
    {
        // ── 公开属性 ──────────────────────────────────────────────────────────────

        public string    RoomId          { get; }
        public RoomState State           { get; private set; } = RoomState.Unloaded;
        public int       EstimatedMemKB  { get; set; }

        /// <summary>上次处于 Active 状态的时间（Time.time）。用于 LRU 卸载优先级计算。</summary>
        public float     LastActiveTime  { get; private set; }

        /// <summary>加载完成后由 RoomController.Start() 通过 IRoomStreamingManager.RegisterRoomController 注入。</summary>
        public RoomController RoomController { get; set; }

        // ── 私有字段 ──────────────────────────────────────────────────────────────

        private AsyncOperationHandle<SceneInstance> _sceneHandle;

        // 缓存的场景组件集合，Dormantize 后可快速 Activate
        private Renderer[]       _renderers;
        private IRoomLifecycle[] _lifecycles;
        private AudioSource[]    _audioSources;
        private Light[]          _lights;
        private ParticleSystem[] _particleSystems;

        // 分帧激活的协程宿主（由 RoomStreamingManager 提供）
        private MonoBehaviour    _coroutineRunner;
        private int              _lifecycleActivatePerFrame;

        // ── 构造 ──────────────────────────────────────────────────────────────────

        public RoomHandle(string roomId, MonoBehaviour coroutineRunner, int lifecycleActivatePerFrame)
        {
            RoomId                    = roomId;
            _coroutineRunner          = coroutineRunner;
            _lifecycleActivatePerFrame = lifecycleActivatePerFrame;
        }

        // ── 加载 / 卸载 ───────────────────────────────────────────────────────────

        /// <summary>
        /// 开始后台异步加载（Additive）。
        /// 加载完成后自动调用 <see cref="Dormantize"/> 将房间置于休眠状态。
        /// </summary>
        public IEnumerator LoadAsync(string addressableKey)
        {
            if (State != RoomState.Unloaded)
            {
                Debug.LogWarning($"[RoomHandle] {RoomId} 非 Unloaded 状态，忽略重复加载请求。");
                yield break;
            }

            State = RoomState.Loading;

            _sceneHandle = Addressables.LoadSceneAsync(addressableKey, LoadSceneMode.Additive);

            while (!_sceneHandle.IsDone)
                yield return null;

            if (_sceneHandle.Status != AsyncOperationStatus.Succeeded)
            {
                Debug.LogError($"[RoomHandle] {RoomId} 加载失败：{addressableKey}");
                State = RoomState.Unloaded;
                yield break;
            }

            // 收集场景内组件引用，然后置于休眠
            CollectSceneComponents();
            Dormantize();
        }

        /// <summary>异步卸载本房间。完成后 State → Unloaded。</summary>
        public IEnumerator UnloadAsync()
        {
            if (State == RoomState.Unloaded || State == RoomState.Unloading || !_sceneHandle.IsValid()) yield break;

            // Active 状态先走 Deactivate，再设置 Unloading
            bool needsDeactivate = State == RoomState.Active ||
                                   State == RoomState.Activating ||
                                   State == RoomState.Cooling;
            if (needsDeactivate)
                Deactivate();

            State = RoomState.Unloading;

            var op = Addressables.UnloadSceneAsync(_sceneHandle);
            yield return op;

            _renderers       = null;
            _lifecycles      = null;
            _audioSources    = null;
            _lights          = null;
            _particleSystems = null;
            RoomController   = null;
            State            = RoomState.Unloaded;
        }

        // ── Dormantize ────────────────────────────────────────────────────────────

        /// <summary>
        /// 将已加载的房间置于休眠状态。
        /// 关闭所有 Renderer 和 AudioSource，通知所有 IRoomLifecycle 组件进入休眠。
        /// 场景内 GameObject 保持激活（便于快速恢复），但不消耗渲染和 AI 开销。
        /// </summary>
        public void Dormantize()
        {
            // 允许从 Loading（初次加载完成后）、Active、Activating、Cooling 进入
            if (State != RoomState.Loading  &&
                State != RoomState.Active   &&
                State != RoomState.Activating &&
                State != RoomState.Cooling)
            {
                Debug.LogWarning($"[RoomHandle] {RoomId} 在 {State} 状态下调用 Dormantize，忽略。");
                return;
            }

            if (_renderers != null)
                foreach (var r in _renderers) if (r != null) r.enabled = false;

            if (_audioSources != null)
                foreach (var a in _audioSources) if (a != null) { a.Stop(); a.enabled = false; }

            if (_lights != null)
                foreach (var l in _lights) if (l != null) l.enabled = false;

            if (_particleSystems != null)
                foreach (var ps in _particleSystems) if (ps != null) ps.Pause();

            if (_lifecycles != null)
                foreach (var l in _lifecycles) l?.OnRoomDormant();

            State = RoomState.Dormant;
        }

        // ── Activate ──────────────────────────────────────────────────────────────

        /// <summary>
        /// 激活此房间（Dormant → Active）。
        /// 恢复 Renderer、AudioSource，分帧唤醒 IRoomLifecycle，并设置玩家出生点。
        /// 目标房间必须已处于 <see cref="RoomState.Dormant"/> 状态。
        /// </summary>
        public IEnumerator Activate(SpawnContext context)
        {
            if (State != RoomState.Dormant)
            {
                Debug.LogError($"[RoomHandle] {RoomId} 不是 Dormant 状态（当前：{State}），无法激活。");
                yield break;
            }

            State = RoomState.Activating;

            // 先恢复渲染（让玩家立刻能看到新房间）
            if (_renderers != null)
                foreach (var r in _renderers) if (r != null) r.enabled = true;

            if (_audioSources != null)
                foreach (var a in _audioSources) if (a != null) a.enabled = true;

            if (_lights != null)
                foreach (var l in _lights) if (l != null) l.enabled = true;

            if (_particleSystems != null)
                foreach (var ps in _particleSystems) if (ps != null) ps.Play();

            // 相机 + 出生点（由 RoomController 处理）
            RoomController?.OnRoomActivate(context);

            // 分帧激活 IRoomLifecycle（AI、特效等）
            yield return _coroutineRunner.StartCoroutine(ActivateLifecyclesGradually(context));

            State         = RoomState.Active;
            LastActiveTime = Time.time;
        }

        /// <summary>将 IRoomLifecycle 组件分帧激活，避免单帧 CPU 峰值。</summary>
        private IEnumerator ActivateLifecyclesGradually(SpawnContext context)
        {
            if (_lifecycles == null) yield break;

            int activatedThisFrame = 0;
            foreach (var lc in _lifecycles)
            {
                if (lc == null) continue;
                lc.OnRoomActivate(context);
                activatedThisFrame++;
                if (activatedThisFrame >= _lifecycleActivatePerFrame)
                {
                    activatedThisFrame = 0;
                    yield return null;
                }
            }
        }

        // ── Deactivate ────────────────────────────────────────────────────────────

        /// <summary>
        /// 玩家离开后关闭此房间（Active / Activating → Dormant）。
        /// 与 <see cref="Dormantize"/> 相同，但语义上表示从 Active 退出。
        /// </summary>
        public void Deactivate()
        {
            if (State != RoomState.Active && State != RoomState.Activating && State != RoomState.Cooling)
            {
                Debug.LogWarning($"[RoomHandle] {RoomId} 在 {State} 状态下调用 Deactivate，忽略。");
                return;
            }

            Dormantize();
        }

        // ── 冷却 ──────────────────────────────────────────────────────────────────

        /// <summary>
        /// 标记为冷却中，同时休眠渲染和 AI 开销。
        /// 玩家离开后不立即卸载，等待冷却计时结束后再卸载。
        /// </summary>
        public void BeginCooling()
        {
            if (State != RoomState.Active && State != RoomState.Activating) return;
            // 先休眠渲染和 AI（与 Dormantize 相同，但最终 State 设为 Cooling 而非 Dormant）
            Dormantize();
            State = RoomState.Cooling;
        }

        /// <summary>
        /// 冷却期间玩家返回，将状态从 Cooling 重置为 Dormant。
        /// 渲染已在 BeginCooling 时关闭，无需重复操作。
        /// </summary>
        public void ResetToDormant()
        {
            if (State == RoomState.Cooling)
                State = RoomState.Dormant;
        }

        // ── 内部工具 ──────────────────────────────────────────────────────────────

        /// <summary>
        /// 收集加载完成的场景中所有需要被管理的组件引用。
        /// 在 LoadAsync 完成后、Dormantize 之前调用一次。
        /// </summary>
        private void CollectSceneComponents()
        {
            if (!_sceneHandle.IsValid()) return;

            Scene scene = _sceneHandle.Result.Scene;
            GameObject[] roots = scene.GetRootGameObjects();

            var rendererList    = new List<Renderer>();
            var lifecycleList   = new List<IRoomLifecycle>();
            var audioSourceList = new List<AudioSource>();
            var lightList       = new List<Light>();
            var particleList    = new List<ParticleSystem>();

            foreach (var root in roots)
            {
                rendererList.AddRange(root.GetComponentsInChildren<Renderer>(true));
                lifecycleList.AddRange(root.GetComponentsInChildren<IRoomLifecycle>(true));
                audioSourceList.AddRange(root.GetComponentsInChildren<AudioSource>(true));
                lightList.AddRange(root.GetComponentsInChildren<Light>(true));
                particleList.AddRange(root.GetComponentsInChildren<ParticleSystem>(true));
            }

            _renderers       = rendererList.ToArray();
            _lifecycles      = lifecycleList.ToArray();
            _audioSources    = audioSourceList.ToArray();
            _lights          = lightList.ToArray();
            _particleSystems = particleList.ToArray();
        }

        public override string ToString() => $"RoomHandle[{RoomId}, {State}]";
    }
}