using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;

public class InventoryItemUI : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler, IPointerClickHandler
{
    private Item item;
    private int quantity;
    private InventoryUI inventoryUI;
    private Image itemImage;
    private Text quantityText;
    private Canvas canvas;
    private GraphicRaycaster raycaster;
    private CanvasGroup canvasGroup;

    public void Initialize(Item newItem, int qty, InventoryUI ui)
    {
        item = newItem;
        quantity = qty;
        inventoryUI = ui;

        itemImage = GetComponent<Image>();
        quantityText = GetComponentInChildren<Text>();
        canvas = GetComponentInParent<Canvas>();
        canvasGroup = GetComponent<CanvasGroup>();

        if (itemImage != null && item.itemIcon != null)
            itemImage.sprite = item.itemIcon;

        if (quantityText != null)
            quantityText.text = quantity > 1 ? quantity.ToString() : "";

        // Make draggable
        if (canvasGroup == null)
            canvasGroup = gameObject.AddComponent<CanvasGroup>();

        GetComponent<RectTransform>().sizeDelta = new Vector2(64, 64);
    }

    public void OnBeginDrag(PointerEventData eventData)
    {
        canvasGroup.alpha = 0.6f;
        canvasGroup.blocksRaycasts = false;
    }

    public void OnDrag(PointerEventData eventData)
    {
        GetComponent<RectTransform>().anchoredPosition += eventData.delta / canvas.scaleFactor;
    }

    public void OnEndDrag(PointerEventData eventData)
    {
        canvasGroup.alpha = 1f;
        canvasGroup.blocksRaycasts = true;

        // Reset position on drop (TODO: check if dropped on equip slot)
        GetComponent<RectTransform>().anchoredPosition = Vector2.zero;
    }

    public void OnPointerClick(PointerEventData eventData)
    {
        if (eventData.button == PointerEventData.InputButton.Right)
        {
            inventoryUI.ShowContextMenu(this, item);
        }
    }
}