using System;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using BaseGames.Core;
using BaseGames.Core.Events;
using BaseGames.Core.Save;

namespace BaseGames.World.Map
{
    /// <summary>
    /// 运行时地图管理器（架构 15_MapShopModule §1.2）。
    /// 挂在 Persistent 场景 [GameManagers] 下，通过事件驱动记录已探索/已完整地图的房间。
    /// 实现 ISaveable 持久化探索进度。
    /// </summary>
    [DefaultExecutionOrder(-700)]
    public class MapManager : MonoBehaviour, ISaveable, IMapService
    {
        [SerializeField] private MapDatabaseSO _database;

        [Header("Event Channels")]
        [SerializeField] private StringEventChannelSO _onRoomEntered;   // 订阅 EVT_RoomEntered
        [Tooltip("房间被探索/标记时广播（Explored/Mapped）；地图 UI 已改用 C# 事件，此通道保留供地图外部系统订阅（如成就、音效）。")]
        [SerializeField] private StringEventChannelSO _onMapUpdated;    // 发布：房间发现时（地图 UI 内当前无订阅者）
        [SerializeField] private StringEventChannelSO _onRegionChanged; // 发布：玩家首次进入新区域时（EVT_RegionChanged）

        // 三级可见性：
        //   Unknown  → 未进入过（默认）
        //   Explored → 进入过（显示轮廓/格子）
        //   Mapped   → 完整地图信息（购买 MapFragment 或存档点揭示）
        private HashSet<string> _exploredRooms = new();
        private HashSet<string> _mappedRooms   = new();
        private string          _currentRegionId;
        private int             _totalRoomCount = -1;  // -1 = 未缓存；OnLoad 后重置
        private Dictionary<string, MapRoomDataSO[]> _regionCache; // R11-N6 GetRoomsByRegion 结果缓存
        private bool            _isDuplicate;          // Awake 检测到重复实例时置位，OnEnable/OnDisable 提前 return
        private readonly CompositeDisposable _subs = new();

        private void Awake()
        {
            if (ServiceLocator.GetOrDefault<IMapService>() != null) { _isDuplicate = true; Destroy(gameObject); return; }
            ServiceLocator.Register<IMapService>(this);
        }

        private void OnEnable()
        {
            if (_isDuplicate) return;
            _onRoomEntered?.Subscribe(OnRoomEntered).AddTo(_subs);
            ServiceLocator.GetOrDefault<ISaveableRegistry>()?.Register(this);
        }

        private void OnDisable()
        {
            if (_isDuplicate) return;
            _subs.Clear();
            ServiceLocator.GetOrDefault<ISaveableRegistry>()?.Unregister(this);
        }

        // ── ISaveable ─────────────────────────────────────────────────────────

        public void OnSave(SaveData data)
        {
            data.Map.ExploredRooms = new HashSet<string>(_exploredRooms);
            data.Map.MappedRooms   = new HashSet<string>(_mappedRooms);
            data.Map.LastRegionId  = _currentRegionId;
        }

        public void OnLoad(SaveData data)
        {
            _exploredRooms   = data.Map.ExploredRooms != null ? new HashSet<string>(data.Map.ExploredRooms) : new HashSet<string>();
            _mappedRooms     = data.Map.MappedRooms   != null ? new HashSet<string>(data.Map.MappedRooms)   : new HashSet<string>();
            _currentRegionId = data.Map.LastRegionId;  // 恢复区域 ID，避免读档后首次进房误触发 EVT_RegionChanged
            _totalRoomCount  = -1;  // 强制下次调用 GetExplorationProgress 时重新计数

            // 读档后广播：UI 仅需轻量刷新（不重建结构）；订阅 OnExplorationChanged 的 UI 会 RefreshAllCells
            OnExplorationChanged?.Invoke();
        }

        // ── 事件驱动房间发现 ──────────────────────────────────────────────────

        private void OnRoomEntered(string roomId)
        {
            if (string.IsNullOrEmpty(roomId)) return;
            bool changed = _exploredRooms.Add(roomId);
            if (changed)
            {
                _onMapUpdated?.Raise(roomId);
                OnExplorationChanged?.Invoke();
            }

            // 区域变化检测：RegionId 非空且与上一次不同时广播 EVT_RegionChanged
            var regionId = _database?.GetRoom(roomId)?.RegionId;
            if (!string.IsNullOrEmpty(regionId) && regionId != _currentRegionId)
            {
                _currentRegionId = regionId;
                _onRegionChanged?.Raise(regionId);
            }
        }

        /// <summary>
        /// 标记为已获取地图碎片信息（购买 MapFragment SO 触发）。
        /// 仅写入 _mappedRooms；若玩家尚未亲自踏入该房间则显示为灰色轮廓（Mapped），
        /// 亲自踏入后（Explored）优先级更高，显示为白色。
        /// </summary>
        public void SetMapped(string roomId)
        {
            if (string.IsNullOrEmpty(roomId)) return;
            if (_mappedRooms.Add(roomId))
            {
                _onMapUpdated?.Raise(roomId);
                OnRoomMapped?.Invoke(roomId);
                OnExplorationChanged?.Invoke();
            }
        }

        /// <inheritdoc/>
        public void SetMappedBatch(IEnumerable<string> roomIds)
        {
            if (roomIds == null) return;
            bool anyAdded = false;
            foreach (var roomId in roomIds)
            {
                if (string.IsNullOrEmpty(roomId)) continue;
                if (_mappedRooms.Add(roomId))
                {
                    _onMapUpdated?.Raise(roomId);
                    OnRoomMapped?.Invoke(roomId);
                    anyAdded = true;
                }
            }
            if (anyAdded) OnExplorationChanged?.Invoke();
        }

        // ── 查询 API ──────────────────────────────────────────────────────────

        public bool IsExplored(string roomId)   => _exploredRooms.Contains(roomId);
        public bool IsMapped(string roomId)     => _mappedRooms.Contains(roomId);
        public string CurrentRegionId           => _currentRegionId;
        public MapDatabaseSO Database           => _database;
        public int ExploredRoomCount            => _exploredRooms.Count;

        public float GetExplorationProgress()
        {
            if (_database?.AllRooms == null || _database.AllRooms.Length == 0) return 0f;
            if (_totalRoomCount < 0)
                _totalRoomCount = _database.AllRooms.Count(r => r != null);
            return _totalRoomCount > 0 ? Mathf.Clamp01((float)_exploredRooms.Count / _totalRoomCount) : 0f;
        }

        public MapRoomDataSO[] GetRoomsByRegion(string regionId)
        {
            if (string.IsNullOrEmpty(regionId) || _database?.AllRooms == null)
                return System.Array.Empty<MapRoomDataSO>();

            // R11-N6 懒加载缓存，避免每帧 LINQ 扫描全量房间数组
            _regionCache ??= new Dictionary<string, MapRoomDataSO[]>();
            if (!_regionCache.TryGetValue(regionId, out var cached))
            {
                cached = _database.AllRooms.Where(r => r != null && r.RegionId == regionId).ToArray();
                _regionCache[regionId] = cached;
            }
            return cached;
        }

        // ── 数据库热更事件 ────────────────────────────────────────────────────

        /// <inheritdoc/>
        public event Action OnDatabaseChanged;

        /// <inheritdoc/>
        public event Action OnExplorationChanged;

        /// <inheritdoc/>
        public event Action<string> OnRoomMapped;

        /// <inheritdoc/>
        public void NotifyDatabaseChanged()
        {
            _database?.InvalidateIndex();
            _totalRoomCount = -1;
            _regionCache    = null; // R11-N6 数据库变更时清空区域缓存
            OnDatabaseChanged?.Invoke();
        }

        private void OnDestroy()
        {
            if (_isDuplicate) return;
            ServiceLocator.Unregister<IMapService>(this);
        }
    }
}