using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
    [RequireComponent(typeof(ScrollRect))]
    public class NestingScrollRect : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
    {
        [SerializeField] ScrollRect m_ParentScrollRect;

        ScrollRect m_ScrollRect;
        ScrollRect scrollRect
        {
            get
            {
                if (m_ScrollRect == null)
                {
                    m_ScrollRect = GetComponent<ScrollRect>();
                }
                return m_ScrollRect;
            }
        }

        public void OnBeginDrag(PointerEventData eventData)
        {
            m_ParentScrollRect.OnBeginDrag(eventData);
        }

        public void OnDrag(PointerEventData eventData)
        {
            float angle = Mathf.Abs(Vector2.Angle(eventData.delta, Vector2.up));

            if (angle >= 45 && angle <= 135)
            {
                m_ParentScrollRect.enabled = m_ParentScrollRect.horizontal;
                scrollRect.enabled = scrollRect.horizontal;
            }
            else
            {
                m_ParentScrollRect.enabled = m_ParentScrollRect.vertical;
                scrollRect.enabled = scrollRect.vertical;
            }

            m_ParentScrollRect.OnDrag(eventData);
        }

        public void OnEndDrag(PointerEventData eventData)
        {
            scrollRect.enabled = true;
            m_ParentScrollRect.enabled = true;
            m_ParentScrollRect.OnEndDrag(eventData);
            scrollRect.OnEndDrag(eventData);
        }
    }