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

public class Shirt : MonoBehaviour, IDropHandler
{
    public const string DRAGGABLE_TAG = "UIDraggable";

    private bool dragging = false;

    private Vector2 originalPosition;

    private Transform objectToDrag;
    private Object objectToDragImage;

    List<RaycastResult> hitObjects = new List<RaycastResult>();

    private void Update()
    {
        if (Input.GetMouseButton(0))
        {

            objectToDrag = GetDraggableTransformUnderMouse();

            if (objectToDrag != null)
            {
                dragging = true;

                objectToDrag.SetAsLastSibling();

                originalPosition = objectToDrag.position;
                
                objectToDrag.GetComponent<BoxCollider2D>().enabled = false;
            }

            if (dragging)
            {
                objectToDrag.position = Input.mousePosition;
            }

            if (Input.GetMouseButtonUp(0))
            {
                if (objectToDrag != null)
                {
                    Transform objectToReplace = GetDraggableTransformUnderMouse();

                    if (objectToReplace != null)
                    {
                        objectToDrag.position = objectToReplace.position;
                        objectToReplace.position = originalPosition;
                    }
                    else
                    {
                        objectToDrag.position = originalPosition;
                    }

                    objectToDrag.GetComponent<BoxCollider2D>().enabled = true;
                    objectToDrag = null;
                }

                dragging = false;
            }
        }
    }


    private GameObject GetObjectUnderMouse()
    {
        var pointer = new PointerEventData(EventSystem.current);

        pointer.position = Input.mousePosition;

        EventSystem.current.RaycastAll(pointer, hitObjects);

        if (hitObjects.Count <= 0)
        {
            return null;
        }

        return hitObjects.First().gameObject;
    }

    private Transform GetDraggableTransformUnderMouse()
    {

        GameObject clickedObject = GetObjectUnderMouse();

        if (clickedObject != null && clickedObject.tag == DRAGGABLE_TAG)
        {
            return clickedObject.transform;
        }

        return null;
    }

    
}