using System.Collections.Generic;
using UnityEngine;

namespace BaseGames.World.Map
{
    /// <summary>
    /// 全局区域注册表 SO。
    ///
    /// 设计原则：<see cref="MapRoomDataSO.RegionId"/> 是房间归属的单一权威来源。
    /// 本 SO 持有所有 <see cref="RegionDefinitionSO"/> 资产引用，运行时从
    /// <see cref="MapDatabaseSO"/> 惰性构建 SceneName → Region 缓存，
    /// 消除了原 RegionDefinitionSO.roomSceneNames 与 MapRoomDataSO.RegionId 的双重冗余。
    ///
    /// 资产路径：Assets/_Game/Data/Map/RegionRegistry.asset
    /// </summary>
    [CreateAssetMenu(menuName = "BaseGames/Map/RegionRegistry", fileName = "RegionRegistry")]
    public class RegionRegistrySO : ScriptableObject
    {
        [Tooltip("项目中所有 RegionDefinitionSO 资产。新增区域 SO 时同步添加到此数组。")]
        [SerializeField] private RegionDefinitionSO[] _regions;

        [Tooltip("地图数据库，用于从 MapRoomDataSO.RegionId 构建 SceneName → Region 缓存（单一权威来源）。")]
        [SerializeField] private MapDatabaseSO _mapDatabase;

        private Dictionary<string, RegionDefinitionSO> _regionById;
        private Dictionary<string, RegionDefinitionSO> _sceneToRegion;

        /// <summary>根据场景名（MapRoomDataSO.RoomId）查找所属区域；未找到返回 null。</summary>
        public RegionDefinitionSO FindBySceneName(string sceneName)
        {
            if (string.IsNullOrEmpty(sceneName)) return null;
            BuildCacheIfNeeded();
            _sceneToRegion.TryGetValue(sceneName, out var region);
            return region;
        }

        /// <summary>根据 regionId 直接查找；未找到返回 null。</summary>
        public RegionDefinitionSO FindById(string regionId)
        {
            if (string.IsNullOrEmpty(regionId)) return null;
            BuildCacheIfNeeded();
            _regionById.TryGetValue(regionId, out var region);
            return region;
        }

        private void BuildCacheIfNeeded()
        {
            if (_sceneToRegion != null) return;

            // Step 1: regionId → RegionDefinitionSO
            _regionById = new Dictionary<string, RegionDefinitionSO>(System.StringComparer.OrdinalIgnoreCase);
            if (_regions != null)
                foreach (var r in _regions)
                    if (r != null && !string.IsNullOrEmpty(r.regionId))
                        _regionById[r.regionId] = r;

            // Step 2: sceneName → RegionDefinitionSO，以 MapRoomDataSO.RegionId 为权威来源
            _sceneToRegion = new Dictionary<string, RegionDefinitionSO>(System.StringComparer.OrdinalIgnoreCase);
            if (_mapDatabase?.AllRooms == null) return;

            foreach (var room in _mapDatabase.AllRooms)
            {
                if (room == null || string.IsNullOrEmpty(room.RoomId) || string.IsNullOrEmpty(room.RegionId))
                    continue;
                if (_regionById.TryGetValue(room.RegionId, out var def))
                    _sceneToRegion[room.RoomId] = def;
            }
        }

        private void OnValidate()
        {
            _sceneToRegion = null;
            _regionById    = null;
        }
    }
}