/*
 * FancyScrollView (https://github.com/setchi/FancyScrollView)
 * Copyright (c) 2020 setchi
 * Licensed under MIT (https://github.com/setchi/FancyScrollView/blob/master/LICENSE)
 */

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

namespace FancyScrollView.FocusOn
{
    class ScrollView : FancyScrollView<ItemData, Context>
    {
        [SerializeField] Scroller scroller = default;
        [SerializeField] GameObject cellPrefab = default;

        Action<int,bool> onSelectionChanged;


        protected override GameObject CellPrefab => cellPrefab;

        protected override void Initialize()
        {
            base.Initialize();

            Context.OnCellClicked = onClick;

            scroller.OnValueChanged(UpdatePosition);
            scroller.OnSelectionChanged((index) => {
                Context.ScrollSelectedIndex = index;
                Debug.Log("Context.ScrollSelectedIndex:"+ Context.ScrollSelectedIndex);
                UpdateSelection(index);
            });
        }

        void UpdateSelection(int index)
        {
            if (Context.SelectedIndex == index)
            {
                return;
            }

            Context.SelectedIndex = index;
            Refresh();

            onSelectionChanged?.Invoke(index,false);
        }

        public void UpdateData(IList<ItemData> items)
        {
            UpdateContents(items);
            scroller.SetTotalCount(items.Count);
        }

        public void OnClickEvent(Action<int> OnCellClicked) { 

        }

        public void OnSelectionChanged(Action<int,bool> callback)
        {
            onSelectionChanged = callback;
        }

        //public void SelectNextCell()
        //{
        //    int nextIndex = Context.SelectedIndex + 4;
        //    int index = nextIndex < ItemsSource.Count ? nextIndex : nextIndex - ItemsSource.Count;
        //     Debug.LogWarning("Context.SelectedIndex:"+ Context.SelectedIndex + ",nextIndex:" + nextIndex+ ",index："+ index + ",ItemsSource.Count:"+ ItemsSource.Count);
        //    //翻页（4个一组）
        //    SelectCell(index);
        //}

        public void SelectNextCell()
        {
            int itemsPerPage = 4;
            int totalItems = ItemsSource.Count;

            // 计算目标索引
            int targetIndex = Context.ScrollSelectedIndex + itemsPerPage;

            // 确保 targetPageStartIndex 在总项范围内
            if (targetIndex >= totalItems)
            {
                targetIndex -= totalItems;
            }

            //Debug.LogWarning(
            //                 "Context.ScrollSelectedIndex:" + Context.ScrollSelectedIndex +
            //                 "Context.SelectedIndex:" + Context.SelectedIndex +
            //                 ", targetIndex:" + targetIndex +
            //                 ", totalItems:" + totalItems);

            // 翻页（4个一组）
            SelectCell(targetIndex);
        }



        //public void SelectPrevCell()
        //{
        //    int nextIndex = Context.SelectedIndex - 4;
        //    int index = nextIndex >= 0 ? nextIndex : ItemsSource.Count + nextIndex;
        //    // Debug.LogWarning("nextIndex:" + nextIndex + ",index：" + index + ",ItemsSource.Count:" + ItemsSource.Count);
        //    SelectCell(index);
        //}
        public void SelectPrevCell()
        {
            int itemsPerPage = 4;
            int totalItems = ItemsSource.Count;

            // 计算目标索引
            int prevIndex = Context.ScrollSelectedIndex - itemsPerPage;

            // 确保 prevIndex 在总项范围内
            if (prevIndex < 0)
            {
                prevIndex += totalItems;
            }

            //Debug.LogWarning(
            //    "Context.ScrollSelectedIndex:" + Context.ScrollSelectedIndex +
            //    ", Context.SelectedIndex:" + Context.SelectedIndex +
            //    ", prevIndex:" + prevIndex +
            //    ", totalItems:" + totalItems);

            // 翻页（4个一组）
            SelectCell(prevIndex);
        }


        public void SelectCell(int index,bool bScrollTo = true)
        {
            if (index < 0 || index >= ItemsSource.Count || index == Context.SelectedIndex)
            {
                //if (index == Context.SelectedIndex) {
                //    onSelectionChanged?.Invoke(index,true);
                //}
                return;
            }

            UpdateSelection(index);
            if(bScrollTo)
                scroller.ScrollTo(index, 0.35f, Ease.OutCubic);
        }

        public void onClick(int index, bool bSelectedAndNav = true) {
            Context.SelectedIndex = index;
            Refresh();
            //点击按钮算触发
            onSelectionChanged?.Invoke(index, bSelectedAndNav);
        }
    }
}