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

public class NestedScrollRect : ScrollRect
{
    public override void OnInitializePotentialDrag(PointerEventData eventData)
    {
        m_parentScrollRect?.OnInitializePotentialDrag(eventData);
        base.OnInitializePotentialDrag(eventData);
    }

    public override void OnBeginDrag(PointerEventData eventData)
    {
        m_routeToParent = (!horizontal && Mathf.Abs(eventData.delta.x) > Mathf.Abs(eventData.delta.y)) || (!vertical && Mathf.Abs(eventData.delta.x) < Mathf.Abs(eventData.delta.y));

        if (m_routeToParent)
        {
            m_parentScrollRect?.OnBeginDrag(eventData);
        }
        else
        {
            base.OnBeginDrag(eventData);
        }
    }

    public override void OnDrag(PointerEventData eventData)
    {
        if(m_routeToParent)
        {
            m_parentScrollRect?.OnDrag(eventData);
        }
        else
        {
            base.OnDrag(eventData);
        }
    }

    public override void OnEndDrag(PointerEventData eventData)
    {
        if (m_routeToParent)
        {
            m_parentScrollRect?.OnEndDrag(eventData);
        }
        else
        {
            base.OnEndDrag(eventData);
        }

        m_routeToParent = false;
    }

    [SerializeField] private ScrollRect m_parentScrollRect = null;

    private bool m_routeToParent = false;
}