using UnityEngine;

namespace BaseGames.World.Map
{
    /// <summary>
    /// 将玩家世界坐标转换为地图格子坐标，供 MapPanel 显示玩家位置图标（架构 15_MapShopModule §1.4）。
    /// 挂在 Player GameObject 上（LateUpdate 每帧计算）。
    /// </summary>
    public class MapPlayerTracker : MonoBehaviour
    {
        [SerializeField] private Transform     _playerTransform;
        [SerializeField] private MapDatabaseSO _database;

        [Header("世界坐标 → 格子坐标换算参数")]
        [SerializeField] private float _worldUnitsPerCell = 18f;    // 1 格 = N 世界单位

        /// <summary>玩家当前所在房间 ID（用于地图高亮当前房间）。</summary>
        public string  CurrentRoomId              { get; private set; }

        /// <summary>玩家在当前格子房间内的归一化坐标（0~1）。</summary>
        public Vector2 NormalizedPositionInRoom   { get; private set; }

        private void LateUpdate()
        {
            if (_playerTransform == null || _database?.AllRooms == null) return;

            Vector2    worldPos = _playerTransform.position;
            Vector2Int cellPos  = WorldToCell(worldPos);

            foreach (var room in _database.AllRooms)
            {
                if (room == null) continue;
                var rect = new RectInt(room.GridPosition, room.GridSize);
                if (rect.Contains(cellPos))
                {
                    CurrentRoomId = room.RoomId;
                    Vector2 inRoom = (Vector2)(cellPos - room.GridPosition);
                    NormalizedPositionInRoom = new Vector2(
                        inRoom.x / Mathf.Max(1, room.GridSize.x),
                        inRoom.y / Mathf.Max(1, room.GridSize.y));
                    return;
                }
            }
        }

        private Vector2Int WorldToCell(Vector2 worldPos)
            => new(
                Mathf.FloorToInt(worldPos.x / _worldUnitsPerCell),
                Mathf.FloorToInt(worldPos.y / _worldUnitsPerCell));
    }
}