using BeinLab.Util;
using System;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
using XRTool.UI;
using XRTool.Util;

namespace XRTool.WorldUI
{
    /// <summary>
    /// LayoutGroup
    /// </summary>
    public enum LayoutType
    {
        None = -2,
        UnKnow = -1,
        GridLayoutGroup = 0,
        VerticalLayoutGroup = 1,
        HorizontalLayoutGroup = 2,
    }
    /// <summary>
    /// 目标：1实现基本列表功能，生成，销毁，刷新，点击事件的传递等，支持常规的Button，Toggle类型的组件支持
    /// 2，实现滑动循环列表
    /// 3，实现多项内容展示时的优化
    /// 4,指定距离停顿
    /// </summary>
    public class XRScrollRect : ScrollRect
    {
        public bool isLoop;
        public LayoutType layoutType = LayoutType.UnKnow;
        private int allCount;
        private int showCount;
        private Vector2 cellSize;
        private Vector2 cellSpace;
        //private bool isDraging = false;
        private ItemCell superCell;
        private LayoutGroup layoutGroup;
        private List<ItemCell> cellList;
        private Bounds viewBounds;
        //private float dragTime = 0.2f;
        //private float lastDragTime;
        protected override void Start()
        {
            base.Start();
            viewBounds = new Bounds(viewRect.rect.center, viewRect.rect.size);
        }
        public LayoutGroup LayoutGroup
        {
            get
            {
                if (!layoutGroup)
                {
                    layoutGroup = content.GetComponent<LayoutGroup>();
                }
                return layoutGroup;
            }
        }

        public List<ItemCell> CellList { get => cellList; set => cellList = value; }

        protected override void LateUpdate()
        {
            if ( velocity.magnitude > 66 || !IsMoveCalculatePosition())
            {
                base.LateUpdate();
                XRUpdateItemVisibility();
            }
        }
        /// <summary>
        /// 更新显示Scroll
        /// </summary>
        private void XRUpdateItemVisibility()
        {
            ///存在子物体，同时显示数据小于总物体数字时
            if (allCount > 0 && showCount < allCount && content.childCount > 0)
            {
                for (int i = 0; i < content.childCount; i++)
                {
                    RectTransform child = content.GetChild(i) as RectTransform;
                    if (child.anchoredPosition.x < 0)
                    {
                        child.GetChild(0).gameObject.SetActive(false);
                    }
                }
            }
        }

        /// <summary>
        /// 计算最终落点
        /// </summary>
        /// <returns></returns>
        public bool IsMoveCalculatePosition()
        {

            return false;
        }
        /// <summary>
        /// 初始化数据
        /// </summary>
        /// <param name="count"></param>
        /// <param name="showCount"></param>
        /// <param name="cellSize"></param>
        /// <param name="cellSpace"></param>
        /// <param name="prefab"></param>
        public void InitData(int count, int showCount, Vector2 cellSize, Vector3 cellSpace, ItemCell prefab)
        {
            this.allCount = count;
            this.showCount = showCount;
            this.cellSize = cellSize;
            this.cellSpace = cellSpace;
            this.superCell = prefab;
            CreateScrollList();
        }
        public void ClearScrollList()
        {
            if (content)
            {
                for (int i = 0; i < content.childCount; i++)
                {
                    Destroy(content.GetChild(i).gameObject);
                }
            }

            CellList.Clear();
        }
        /// <summary>
        /// 创建列表
        /// </summary>
        private void CreateScrollList(bool isClear = true)
        {
            if (CellList == null)
            {
                CellList = new List<ItemCell>();
            }
            if (isClear)
            {
                ClearScrollList();
            }
            GameObject prefab = superCell.GetInstance();
            ///prefab.GetInstance()获取抽象类的实例，不确定这么做可以正常运行，测试中
            if (prefab)
            {
                if (!isLoop)
                {
                    int instanceCount = showCount;
                    if (showCount >= allCount)
                    {
                        instanceCount = allCount;
                    }
                    for (int i = 0; i < instanceCount; i++)
                    {
                        GameObject obj = Instantiate(prefab);
                        UnityUtil.SetParent(content, obj.transform);
                        CellList.Add(obj.GetComponent<ItemCell>());
                    }
                    RectTransform body = GetComponent<RectTransform>();
                    Vector2 size = body.sizeDelta;
                    if (horizontal && !vertical)
                    {
                        size.y = cellSize.y;
                        //size.x = instanceCount*cellSize.x +
                    }
                    else if (vertical && !horizontal)
                    {
                        size.x = cellSize.x;
                    }
                }
            }

            if (LayoutGroup)
            {
                if (LayoutGroup is GridLayoutGroup)
                {
                    var lay = (LayoutGroup as GridLayoutGroup);
                    lay.cellSize = this.cellSize;
                    lay.spacing = this.cellSpace;
                }
                else if (LayoutGroup is VerticalLayoutGroup)
                {
                    var lay = (LayoutGroup as VerticalLayoutGroup);
                    lay.spacing = this.cellSpace.y;
                }
                else if (LayoutGroup is HorizontalLayoutGroup)
                {
                    var lay = (LayoutGroup as HorizontalLayoutGroup);
                    lay.spacing = this.cellSpace.x;
                }
            }
        }

        //private void XRUpdateScrollbarVisibility()
        //{
        //    if (horizontalScrollbar && !isShowHorizontal && horizontalScrollbar.isActiveAndEnabled)
        //    {
        //        horizontalScrollbar.gameObject.SetActive(false);
        //    }
        //    if (verticalScrollbar && !isShowVertical && verticalScrollbar.isActiveAndEnabled)
        //    {
        //        verticalScrollbar.gameObject.SetActive(false);
        //    }
        //}

        public override void OnDrag(PointerEventData eventData)
        {
            base.OnDrag(eventData);
        }

        protected override void SetContentAnchoredPosition(Vector2 position)
        {
            base.SetContentAnchoredPosition(position);
        }
        //public override void OnBeginDrag(PointerEventData eventData)
        //{
        //    base.OnBeginDrag(eventData);
        //    //isDraging = true;
        //    //lastDragTime = Time.time;
        //}
        //public override void OnEndDrag(PointerEventData eventData)
        //{
        //    base.OnEndDrag(eventData);
        //    //isDraging = false;
        //    //if (Time.time - lastDragTime < dragTime)
        //    //{
        //    //    if (eventData.pointerEnter)
        //    //    {
        //    //        var tmpbutton = eventData.pointerEnter.GetComponentInParent<IPointerClickHandler>();
        //    //        if (tmpbutton != null)
        //    //        {
        //    //            tmpbutton.OnPointerClick(eventData);
        //    //        }
        //    //    }
        //    //}
        //}
        protected override void OnRectTransformDimensionsChange()
        {
            base.OnRectTransformDimensionsChange();
            viewBounds = new Bounds(viewRect.rect.center, viewRect.rect.size);
        }
        private static float XRRubberDelta(float overStretching, float viewSize)
        {
            return (1 - (1 / ((Mathf.Abs(overStretching) * 0.55f / viewSize) + 1))) * viewSize * Mathf.Sign(overStretching);
        }
        private Vector2 XRCalculateOffset(Vector2 delta)
        {
            return XRInternalCalculateOffset(ref viewBounds, ref m_ContentBounds, horizontal, vertical, movementType, ref delta);
        }
        internal static Vector2 XRInternalCalculateOffset(ref Bounds viewBounds, ref Bounds contentBounds, bool horizontal, bool vertical, MovementType movementType, ref Vector2 delta)
        {
            Vector2 offset = Vector2.zero;
            if (movementType == MovementType.Unrestricted)
                return offset;

            Vector2 min = contentBounds.min;
            Vector2 max = contentBounds.max;

            // min/max offset extracted to check if approximately 0 and avoid recalculating layout every frame (case 1010178)

            if (horizontal)
            {
                min.x += delta.x;
                max.x += delta.x;

                float maxOffset = viewBounds.max.x - max.x;
                float minOffset = viewBounds.min.x - min.x;

                if (minOffset < -0.001f)
                    offset.x = minOffset;
                else if (maxOffset > 0.001f)
                    offset.x = maxOffset;
            }

            if (vertical)
            {
                min.y += delta.y;
                max.y += delta.y;

                float maxOffset = viewBounds.max.y - max.y;
                float minOffset = viewBounds.min.y - min.y;

                if (maxOffset > 0.001f)
                    offset.y = maxOffset;
                else if (minOffset < -0.001f)
                    offset.y = minOffset;
            }

            return offset;
        }
    }
}