using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;

public class DragDrop : MonoBehaviour, IDragHandler, IPointerDownHandler, IBeginDragHandler, IEndDragHandler
{
  [SerializeField] private Canvas canvas;
  private RectTransform rectTransform;
  private CanvasGroup canvasGroup;
  private Vector2 originalPosition;
  private bool droppedOnValidSlot = false; // Flag

  private void Awake()
  {
    rectTransform = GetComponent<RectTransform>();
    canvasGroup = GetComponent<CanvasGroup>();
    originalPosition = rectTransform.anchoredPosition;
  }

  public void ResetPosition()
  {
    rectTransform.anchoredPosition = originalPosition;
  }

  public void OnBeginDrag(PointerEventData eventData)
  {
    Debug.Log("OnBeginDrag");
    canvasGroup.alpha = .6f;
    canvasGroup.blocksRaycasts = false;
    droppedOnValidSlot = false;
  }

  public void OnEndDrag(PointerEventData eventData)
  {
    Debug.Log("OnEndDrag");
    if (!droppedOnValidSlot)
    {
      ResetPosition();
    }
    canvasGroup.alpha = 1f;
    canvasGroup.blocksRaycasts = true;
  }

  public void OnDrag(PointerEventData eventData)
  {
    Debug.Log("OnDrag");
    rectTransform.anchoredPosition += eventData.delta / canvas.scaleFactor;
  }

  public void OnPointerDown(PointerEventData eventData)
  {
    Debug.Log("OnPointerDown");
  }

  public void SetDroppedSuccessful()
  {
    droppedOnValidSlot = true;
  }
}