evershade/Assets/Scripts/Controllers/InventorySlotDisplayController.cs

using System;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.Serialization;

public class InventorySlotDisplayController : MonoBehaviour, IDropHandler
{
    // public Image icon;
    // public Text itemName;
    [FormerlySerializedAs("inventoryItem")]
    public InventoryManager inventoryManager;

    public GameObject inventoryItemPrefab;

    // private Transform inventoryItemContainer;
    private int _slotId;

    public void OnDrop(PointerEventData eventData)
    {
        Debug.Log("Dropped on internal slot: " + _slotId);
        inventoryManager = GameObject.Find("InventoryManager").GetComponent<InventoryManager>();

        var destinationSlot = inventoryManager.GetSlot(_slotId);
        var destinationItem = inventoryManager.GetItemFromSlot(destinationSlot.slotId);
        var draggedSlotController = eventData.pointerDrag.GetComponentInParent<InventorySlotDisplayController>();
        var draggedComponent = eventData.pointerDrag.GetComponent<InventoryItemDisplayController>();
        var draggedItem = draggedComponent.gameItem;

        var draggedSlotId = draggedSlotController._slotId;

        Debug.Log("Dropped item: " + draggedItem.itemName);

        // var sourceSlot = eventData.pointerDrag.GetComponentInParent<InventorySlotDisplayController>();

        if (eventData.pointerDrag != null)
        {
            if (draggedItem == null)
            {
                Debug.Log("inventory item does not exist");
                // Delete visual representation of dragged item
                Destroy(eventData.pointerDrag);
                return;
            }

            // Place the dragged item in this slot
            // draggedComponent.GetComponent<RectTransform>().anchoredPosition =
            // GetComponent<RectTransform>().anchoredPosition;


            if (destinationItem == null)
            {
                Debug.Log("Destination slot is empty");
                inventoryManager.SwapItems(destinationSlot.slotId, draggedSlotId);

                // Re parent to this slot
                draggedComponent.transform.SetParent(transform, false);
                draggedComponent.GetComponent<RectTransform>().anchoredPosition = Vector2.zero;
                draggedComponent.GetComponent<RectTransform>().offsetMin = Vector2.zero;
                draggedComponent.GetComponent<RectTransform>().offsetMax = Vector2.zero;
            }
            else
            {
                Debug.Log("Destination slot is not empty");
                inventoryManager.SwapItems(draggedSlotId, destinationSlot.slotId);

                // Get the parent of the dragged component

                // originalSlot.SetSlotDetails();


                var selfItem = transform.Find("InventoryItem(Clone)").GetComponent<InventoryItemDisplayController>();

                if (selfItem == null) Debug.Log("Self item is null");


                selfItem.transform.SetParent(draggedSlotController.transform, false);
                selfItem.GetComponent<RectTransform>().anchoredPosition = Vector2.zero;
                selfItem.GetComponent<RectTransform>().offsetMin = Vector2.zero;
                selfItem.GetComponent<RectTransform>().offsetMax = Vector2.zero;

                // Re parent to this slot
                draggedComponent.transform.SetParent(transform, false);
                draggedComponent.GetComponent<RectTransform>().anchoredPosition = Vector2.zero;
                draggedComponent.GetComponent<RectTransform>().offsetMin = Vector2.zero;
                draggedComponent.GetComponent<RectTransform>().offsetMax = Vector2.zero;
            }
        }
    }

    public void SetSlotId(int id)
    {
        _slotId = id;
    }

    private void SwapItems(InventoryItemDisplayController draggedItemDisplayController)
    {
        inventoryManager = GameObject.Find("InventoryManager").GetComponent<InventoryManager>();

        Debug.Log("!!!!!Swapping items");
        var destinationSlot = inventoryManager.GetSlot(_slotId);
        var originalSlot = draggedItemDisplayController.GetComponentInParent<InventorySlotDisplayController>();
        var tempItem = destinationSlot.item;

        // assigns to the destination slot the dragged item
        AssignInventoryItem(draggedItemDisplayController.gameItem);


        // If this slot had an item, move it to the dragged item's original slot
        if (destinationSlot.item != null)
        {
            originalSlot.AssignInventoryItem(tempItem);
            UIManager.Instance.InventoryUIController.UpdateUI();
        }
        else
        {
            Destroy(draggedItemDisplayController.gameObject);
        }
    }

    public void AssignInventoryItem(GameItem newItem)
    {
        // Remove any existing InventoryItem(Clone) from this slot
        try
        {
            Destroy(transform.Find("InventoryItem(Clone)")?.gameObject);
        }
        catch (Exception e)
        {
            Debug.Log("No item to destroy");
        }

        if (inventoryItemPrefab == null)
        {
            Debug.LogError("InventoryItemPrefab not set");
            return;
        }

        // Instantiate the new item in this slot
        var newItemInstance = Instantiate(inventoryItemPrefab, transform);
        var itemDisplay = newItemInstance.GetComponent<InventoryItemDisplayController>();
        itemDisplay.SetItem(newItem);
    }

    public void SetInventoryItemPrefab(GameObject prefab)
    {
        inventoryItemPrefab = prefab;
    }

    public void DeleteInventoryItem()
    {
        Destroy(transform.Find("InventoryItem(Clone)")?.gameObject);
    }

    public void SetSlotDetails(InventorySlot slotDetails)
    {
        inventoryManager = GameObject.Find("InventoryManager").GetComponent<InventoryManager>();

        _slotId = slotDetails.slotId;
        if (slotDetails.item != null) AssignInventoryItem(slotDetails.item);
        if (slotDetails.item == null) DeleteInventoryItem();
    }


    public void UpdateUI()
    {
    }
}