using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;
namespace Toolset.UI
{
    /// <summary>
    /// 轮播图菜单
    /// </summary>
    public class CarouselMenu : MonoBehaviour/*, IBeginDragHandler, IDragHandler, IEndDragHandler*/, IPointerClickHandler
    {
        public float width = 1000;
        public float maxScale = 1;
        public float startValue = 0.1f;
        public float addValue = 0.4f;
        public float minValue = 0.1f;
        public float maxValue = 0.9f;
        public float rollSpeed = 1;//旋转速度
        public AnimationCurve positionCurve;
        public AnimationCurve scaleCurve;//缩放曲线
        public AnimationCurve alphaCurve;
        public Action<CarouselItem> MoveEndAction;//打印名字的事件

        private RectTransform rect;
        private List<CarouselItem> itemList = new List<CarouselItem>();
        private List<CarouselItem> itemFrontList = new List<CarouselItem>();
        private List<CarouselItem> itemBackList = new List<CarouselItem>();
        private bool isRoll = false;//是否旋转
        public CarouselItem current;//记录子物体V值小于1的
        private Vector2 startPoint;
        private Vector2 addVect;

        private void Start()
        {
            Refresh();
            MoveEndAction += SelectItem;
        }

        private void Update()
        {
            if (isRoll)
            {
                currentV = Time.deltaTime * rollSpeed * vk;//确定转动方向
                vt = vTotal + currentV;
                if (vk > 0 && vt >= addV) { isRoll = false; currentV = addV - vTotal; }
                if (vk < 0 && vt <= addV) { isRoll = false; currentV = addV - vTotal; }

                for (int i = 0; i < itemList.Count; i++)
                {
                    itemList[i].CalculateTrans(currentV);
                    if (itemList[i].v - 0.5f < 0.05f)
                    {
                        current = itemList[i];
                    }
                }
                Check(currentV);
                vTotal = vt;

                if (!isRoll)
                {
                    MoveEndAction?.Invoke(current);
                }
            }
        }

        public void Refresh()
        {
            rect = GetComponent<RectTransform>();//父物体RectTransform
            for (int i = 0; i < rect.childCount; i++)
            {
                Transform trans = rect.GetChild(i);//子物体Transform
                CarouselItem item = trans.GetComponent<CarouselItem>();//子物体CarouselItem脚本
                if (item != null)
                {
                    item.transform.GetChild(0).GetComponent<Text>().text = i.ToString();//命名
                    itemList.Add(item);//记录脚本添加列表
                    item.Init(this);//子物体初始化
                    item.CalculateTrans(startValue + i * addValue);
                    if (item.v - 0.5f < 0.05f)
                    {
                        current = itemList[i];
                    }
                }
            }
            if (rect.childCount < 5)
            {
                maxValue = startValue + 4 * addValue;
            }
            else
            {
                maxValue = startValue + (rect.childCount - 1) * addValue;
            }
        }

        /// <summary>
        /// 获取每个菜单的显隐
        /// </summary>
        /// <param name="v"></param>
        /// <returns></returns>
        public float GetAlpha(float v)
        {
            return alphaCurve.Evaluate(v);
        }

        /// <summary>
        /// 获取每个菜单的位置
        /// </summary>
        /// <param name="v"></param>
        /// <returns></returns>
        public float GetPosition(float v)
        {
            return positionCurve.Evaluate(v) * width;
        }

        /// <summary>
        /// 获取每个菜单的缩放
        /// </summary>
        /// <param name="v"></param>
        /// <returns></returns>
        public float GetScale(float v)
        {
            return scaleCurve.Evaluate(v) * maxScale;
        }

        ///// <summary>
        ///// 开始拖拽触发
        ///// </summary>
        ///// <param name="eventData"></param>
        //public void OnBeginDrag(PointerEventData eventData)
        //{
        //    startPoint = eventData.position;
        //    addVect = Vector2.zero;
        //    isRoll = false;
        //}

        ///// <summary>
        ///// 拖动中触发
        ///// </summary>
        ///// <param name="eventData"></param>
        //public void OnDrag(PointerEventData eventData)
        //{
        //    addVect = eventData.position - startPoint;
        //    float v = eventData.delta.x * 1.0f / width;
        //    for (int i = 0; i < itemList.Count; i++)
        //    {
        //        itemList[i].CalculateTrans(v);
        //    }
        //    Check(v);
        //}

        ///// <summary>
        ///// 停止拖动触发
        ///// </summary>
        ///// <param name="eventData"></param>
        //public void OnEndDrag(PointerEventData eventData)
        //{
        //    float k = 0, vTemp;
        //    for (int i = 0; i < itemList.Count; i++)
        //    {
        //        if (itemList[i].v >= minValue)
        //        {
        //            vTemp = (itemList[i].v - minValue) % addValue;
        //            if (addVect.x > 0)
        //            {
        //                k = addValue - vTemp;
        //            }
        //            else
        //            {
        //                k = vTemp * -1;
        //            }
        //            break;
        //        }
        //    }
        //    addVect = Vector2.zero;
        //    AnimToEnd(k);
        //}

        /// <summary>
        /// 点击UI接口
        /// </summary>
        /// <param name="eventData"></param>
        public void OnPointerClick(PointerEventData eventData)
        {
            if (addVect.sqrMagnitude <= 1)
            {
                CarouselItem item = eventData.pointerPressRaycast.gameObject.GetComponent<CarouselItem>();//记录子物体CarouselItem脚本
                if (item != null)
                {
                    float k = item.v;
                    k = 0.5f - k;
                    AnimToEnd(k);
                }
            }
        }

        private float addV = 0, vk = 0, currentV = 0, vTotal = 0, vt = 0;

        /// <summary>
        /// 大于0左，小于0右
        /// </summary>
        /// <param name="k"></param>
        private void AnimToEnd(float k)
        {
            addV = k;
            if (k > 0) vk = 1;
            else if (k < 0) vk = -1;
            else return;
            vTotal = 0;
            isRoll = true;
        }


        private void Check(float _v)
        {
            if (_v < 0)//向左滑动
            {
                for (int i = 0; i < itemList.Count; i++)
                {
                    if (itemList[i].v < (minValue - addValue / 2))
                    {
                        itemBackList.Add(itemList[i]);
                    }
                }
                if (itemBackList.Count > 0)
                {
                    for (int i = 0; i < itemBackList.Count; i++)
                    {
                        itemBackList[i].v = itemList[itemList.Count - 1].v + addValue;
                        itemList.Remove(itemBackList[i]);
                        itemList.Add(itemBackList[i]);
                    }
                    itemBackList.Clear();
                }
            }
            else if (_v > 0)//向右滑动
            {
                for (int i = itemList.Count - 1; i > 0; i--)
                {
                    if (itemList[i].v > maxValue)
                    {
                        itemFrontList.Add(itemList[i]);
                    }
                }
                if (itemFrontList.Count > 0)
                {
                    for (int i = 0; i < itemFrontList.Count; i++)
                    {
                        itemFrontList[i].v = itemList[0].v - addValue;
                        itemList.Remove(itemFrontList[i]);
                        itemList.Insert(0, itemFrontList[i]);
                    }
                    itemFrontList.Clear();
                }
            }
        }


        public void SelectItem(CarouselItem item)
        {
            print(item.name);
        }


        void OnDestroy()
        {
            MoveEndAction -= SelectItem;
        }


        public void Btn_Left(Button button)
        {
            StartCoroutine(delayed_Left(button));
        }

        IEnumerator delayed_Left(Button button)
        {
            button.interactable = false;
            AnimToEnd(+0.2f);
            yield return new WaitForSeconds(0.2f);
            button.interactable = true;

        }

        public void Btn_Right(Button button)
        {
            StartCoroutine(delayed_Right(button));
        }

        IEnumerator delayed_Right(Button button)
        {
            button.interactable = false;
            AnimToEnd(-0.2f);
            yield return new WaitForSeconds(0.2f);
            button.interactable = true;

        }
    }
}