using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class ScalePageScrollView : PageScrollView
{

    #region 字段

    // 所有页的object
    protected GameObject[] items;

    public float currentScale = 1f;
    public float otherScale = 0.6f;

    protected  int lastPage;
    protected  int nextPage;

    #endregion


    #region Unity回调

    protected override void Start()
    {
        base.Start();
        items = new GameObject[pageCount];
        //初始化所有的GameObject
        for (int i = 0; i < pageCount; i++)
        {
            items[i] = transform.Find("Viewport/Content").GetChild(i).gameObject; //获取它的子类
        }
    }

    protected override void Update()
    {
        base.Update();
        ListenerScale();
    }
    #endregion

    //监听scale
    public void ListenerScale()
    {
        //找到上一页和下一页

        for (int i = 0; i < pages.Length; i++)
        {
            if( pages[i] <= rect.horizontalNormalizedPosition )    //若page[i]小于它的位置 则为他的上一页
            {
                lastPage = i;
            }
        }

        for (int i = 0; i < pages.Length; i++)
        {
            if (pages[i] > rect.horizontalNormalizedPosition)    //若page[i]大于它的位置 则为他的下一页
            {
                nextPage = i;
                break;                                           //找到第一个就截止
            }
        }

        if ( nextPage == lastPage )
        {
            return;
        }

        float percent = (rect.horizontalNormalizedPosition - pages[lastPage]) / (pages[nextPage] - pages[lastPage]);               //5个公告的比例percent   当前所处位置的长度 减去 一段的总长
        items[lastPage].transform.localScale = Vector3.Lerp(Vector3.one * currentScale, Vector3.one * otherScale, percent);        //上一页的大小   Vector3.one * currentScale 当前的位置，Vector3.one * otherScale 减去的位置
        items[nextPage].transform.localScale = Vector3.Lerp(Vector3.one * currentScale, Vector3.one * otherScale, 1 - percent);

        for (int i = 0; i < items.Length; i++)
        {
            if ( i != lastPage && i != nextPage )
            {
                items[i].transform.localScale = Vector3.one * otherScale;
            }
        }
    }

}