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

namespace QuestAppLauncher
{
    public class ScrollRectOverride : ScrollRect, IMoveHandler, IPointerClickHandler, IScrollHandler
    {
        private const float speedMultiplier = 15f;
        private float cellHeight = 0f;

        void Start()
        {
            this.cellHeight = this.transform.GetComponentInChildren<GridLayoutGroup>().cellSize.y;
        }

        void Update()
        {
            // Get vector from either left or right thumbstick
            var moveVector = OVRInput.Get(OVRInput.Axis2D.PrimaryThumbstick);
            if (moveVector.x == 0 && moveVector.y == 0)
            {
                moveVector = OVRInput.Get(OVRInput.Axis2D.SecondaryThumbstick);
            }

            // Scroll by a fixed amount proportional to thumbstick position on each frame
            // and map this to a fraction of the total viewport size:
            //   moveVector.y: The thumbstick vertical position normalized to [-1,1].
            //   Time.deltaTime: The time delta since last frame
            //   speedMultiplier: Just a multiplier to get a good scrolling speed.
            // So, moveVector.y * Time.deltaTime * speedMultiplier = the amount to scroll in "units"
            //   proportional to thumbstick position since last frame.
            // this.cellHeight / this.content.sizeDelta.y = cell height / total content height.
            float verticalIncrement = moveVector.y * Time.deltaTime * speedMultiplier * this.cellHeight / this.content.sizeDelta.y;
            this.verticalNormalizedPosition = Mathf.Clamp01(this.verticalNormalizedPosition + verticalIncrement);
        }

        public void OnPointerClick(PointerEventData e)
        {
        }

        public override void OnBeginDrag(PointerEventData eventData)
        {
        }

        void IMoveHandler.OnMove(AxisEventData e)
        {
        }

        void IScrollHandler.OnScroll(PointerEventData eventData)
        {
        }

        void OnMouseDrag()
        {
        }

        void OnMouseUp()
        {
        }

        void OnMouseDown()
        {
        }
    }
}