using System.Collections;
using System.Collections.Generic;
using System.Threading;
using UnityEngine;
using UnityEngine.UI;

public class ScrollTest2 : MonoBehaviour
{
    // Start is called before the first frame update
    private ScrollRect scroll;
    private Transform content;
    private float contentSize;
    private int count;
    [SerializeField] Button L, R;
    void Start()
    {
        scroll = gameObject.GetComponent<ScrollRect>();
        content = gameObject.transform.Find("Viewport").Find("Content");
        count = content.childCount;
        contentSize = 1f / (content.childCount - 2);
        scroll.horizontalNormalizedPosition = contentSize / 2;
        SetColor();
        if (L != null)
        {
            L.onClick.AddListener(goLeft);
        }
        if (R != null)
        {
            R.onClick.AddListener(goRight);
        }
    }
    void goLeft()
    {
        if (scroll.horizontalNormalizedPosition <= contentSize) return;
        if (!start) startPosition = scroll.horizontalNormalizedPosition;
        start = true;
        scrollValue = -1 * contentSize / 30;
    }
    void goRight()
    {
        if ((scroll.horizontalNormalizedPosition + contentSize) >= 1) return;
        if (!start) startPosition = scroll.horizontalNormalizedPosition;
        start = true;
        scrollValue = contentSize / 30;
    }
    private bool start = false, _lock = false;
    private float scrollValue = 0, totalScrollValue = 0, startPosition = 0;
    void SetColor()
    {
        int index = (int)System.Math.Round(
                    (scroll.horizontalNormalizedPosition + (contentSize / 2)) / contentSize,
                    0);
        for (int i = 1; i < content.childCount-1; i++) 
        {
            string c = "#FFF";
            if (i == index) 
            {
                c = "#FF2742";
            }
            ColorUtility.TryParseHtmlString(c, out Color color);
            content.GetChild(i).Find("Image").GetComponent<Image>().color = color;
        }
    }
    // Update is called once per frame
    void Update()
    {
        if (start)
        {
            totalScrollValue += scrollValue;
            if (System.Math.Abs(totalScrollValue) >= contentSize)
            {
                scrollValue = 0;
                start = false;
                scroll.horizontalNormalizedPosition = startPosition + totalScrollValue;
                //Debug.Log();
                
                SetColor();
                totalScrollValue = 0;
            }
            else 
            {
                scroll.horizontalNormalizedPosition += scrollValue;
            }
        }
    }
}