Shopkeeper/Assets/Scripts/Items/Shelf.cs

using UnityEngine;
using System.Collections.Generic;

public class Shelf : MonoBehaviour
{
    public ShelfData shelfData;
    public ShelfData.ShelfType shelfType => shelfData.shelfType;

    [HideInInspector] public Transform[] stackPoints;
    public List<string> stockedItems = new List<string>();

    public bool useManualLevelHeights = false; // Toggle in Inspector

    void Awake()
    {
        GenerateStaticStackPoints();
    }

    // Generates a static grid of stack points based on rows and columns
    public void GenerateStaticStackPoints()
{
    if (shelfData == null)
    {
        Debug.LogError("ShelfData not assigned!");
        return;
    }

    // --- Preserve stacked items ---
List<Transform> itemsToPreserve = new List<Transform>();
foreach (Transform child in transform)
{
    if (child.name.StartsWith("StackPoint_"))
    {
        // Save and unparent any items parented to this stack point
        List<Transform> toUnparent = new List<Transform>();
        foreach (Transform item in child)
        {
            itemsToPreserve.Add(item);
            toUnparent.Add(item);
        }
        foreach (var item in toUnparent)
            item.parent = this.transform; // Temporarily unparent to shelf root
    }
}

// Remove old stack points
var toRemove = new List<Transform>();
foreach (Transform child in transform)
    if (child.name.StartsWith("StackPoint_"))
        toRemove.Add(child);
foreach (var child in toRemove)
    DestroyImmediate(child.gameObject);

// ...rest of your code...

    int totalPoints = shelfData.rows * shelfData.columns * shelfData.levels;
    stackPoints = new Transform[totalPoints];

    int idx = 0;
    for (int l = 0; l < shelfData.levels; l++)
    {
        float y = useManualLevelHeights && shelfData.manualLevelHeights != null && l < shelfData.manualLevelHeights.Length
            ? shelfData.manualLevelHeights[l]
            : (shelfData.shelfSize.y / shelfData.levels) * (l + 0.5f);

        for (int r = 0; r < shelfData.rows; r++)
        {
            for (int c = 0; c < shelfData.columns; c++)
            {
                float x = (-shelfData.shelfSize.x / 2) + (shelfData.shelfSize.x / shelfData.columns) * (c + 0.5f);
                float z = (shelfData.shelfSize.z / 2) - (shelfData.shelfSize.z / shelfData.rows) * (r + 0.5f);

                Vector3 localOffset = new Vector3(x, y, z) + shelfData.stackOriginOffset;

                GameObject point = new GameObject($"StackPoint_{l}_{r}_{c}");
                point.transform.parent = this.transform;
                point.transform.localPosition = localOffset;
                stackPoints[idx++] = point.transform;
            }
        }
    }

    // --- Re-parent preserved items to the closest new stack point ---
    foreach (var item in itemsToPreserve)
    {
        // Find the nearest stack point to the item's position
        Transform nearest = null;
        float minDist = float.MaxValue;
        foreach (var sp in stackPoints)
        {
            float dist = Vector3.Distance(sp.position, item.position);
            if (dist < minDist)
            {
                minDist = dist;
                nearest = sp;
            }
        }
        if (nearest != null)
            item.parent = nearest;
        else
            item.parent = this.transform; // fallback
    }
}

    public void AddStockedItem(string itemName)
    {
        if (!stockedItems.Contains(itemName))
            stockedItems.Add(itemName);
    }

    public void RemoveStockedItem(string itemName)
    {
        stockedItems.Remove(itemName);
    }

    public Transform GetNextAvailableStackPoint()
    {
        foreach (var point in stackPoints)
        {
            if (point.childCount == 0)
                return point;
        }
        return null;
    }

    public Transform GetNearestStackPoint(Vector3 hitPosition, out bool isOccupied)
    {
        Transform nearest = null;
        float minDist = float.MaxValue;
        isOccupied = false;
        foreach (var point in stackPoints)
        {
            float dist = Vector3.Distance(point.position, hitPosition);
            if (dist < minDist)
            {
                minDist = dist;
                nearest = point;
            }
        }
        if (nearest != null)
            isOccupied = nearest.childCount > 0;
        return nearest;
    }

    // Draws the grid in the editor for configuration
    void OnDrawGizmos()
    {
        if (shelfData == null)
            return;

        Gizmos.color = Color.cyan;
        Gizmos.DrawWireCube(transform.position + Vector3.up * shelfData.shelfSize.y * 0.5f, shelfData.shelfSize);

        for (int l = 0; l < shelfData.levels; l++)
        {
            float y = useManualLevelHeights && shelfData.manualLevelHeights != null && l < shelfData.manualLevelHeights.Length
                ? shelfData.manualLevelHeights[l]
                : (shelfData.shelfSize.y / shelfData.levels) * (l + 0.5f);

            for (int r = 0; r < shelfData.rows; r++)
            {
                for (int c = 0; c < shelfData.columns; c++)
                {
                    float x = (-shelfData.shelfSize.x / 2) + (shelfData.shelfSize.x / shelfData.columns) * (c + 0.5f);
                    // Z: match runtime!
                    float z = (shelfData.shelfSize.z / 2) - (shelfData.shelfSize.z / shelfData.rows) * (r + 0.5f);

                    Vector3 localOffset = new Vector3(x, y, z) + shelfData.stackOriginOffset;
                    Vector3 worldPos = transform.TransformPoint(localOffset);

                    Gizmos.color = Color.yellow;
                    Gizmos.DrawWireCube(worldPos, Vector3.one * 0.04f);
                    Gizmos.color = Color.red;
                    Gizmos.DrawSphere(worldPos, 0.02f);
                }
            }
        }
    }
}