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

/// <summary>
/// 
/// </summary>
public class UI_Control_ScrollFlow : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler
{
    /// <summary>
    /// 
    /// </summary>
    public RectTransform Rect;
    /// <summary>
    /// 
    /// </summary>
    public List<UI_Control_ScrollFlow_Item> ItemList = new List<UI_Control_ScrollFlow_Item>();

    /// <summary>
    ///  卡牌的像素宽度
    /// </summary>
    public float itemWidth = 500;

    /// <summary>
    /// 最大缩放
    /// </summary>
    public float MaxScale = 1.0f;

    /// <summary>
    /// 开始坐标值
    /// </summary>
    private float startValue = 0.5f;

    /// <summary>
    /// 
    /// </summary>
    private int defaultItemIndex = 0;

    /// <summary>
    /// 卡牌之间的间隔坐标
    /// </summary>
    private float spaceValue = 0.2f;

    /// <summary>
    /// 移动速度曲线
    /// </summary>
    public AnimationCurve SpeedCurve;

    /// <summary>
    /// 坐标曲线
    /// </summary>
    public AnimationCurve PositionCurve;

    /// <summary>
    /// 缩放幅度大小曲线
    /// </summary>
    public AnimationCurve ScaleCurve;

    /// <summary>
    /// 拖拽时候的,托主幅度量
    /// </summary>
    private float dragV = 0;

    /// <summary>
    /// 拖拽时候的,计算值
    /// </summary>
    private Vector2 start_point, add_vect;

    /// <summary>
    ///  移动结束事件
    /// </summary>
    public event CallBack<UI_Control_ScrollFlow_Item> MoveEnd;

    /// <summary>
    /// 更改当前卡牌的状态
    /// </summary>
    public event CallBack<bool, UI_Control_ScrollFlow_Item> EventRefreshCardState;

    /// <summary>
    /// 是否开启动画
    /// </summary>
    public bool _anim = false;

    /// <summary>
    /// 移动的量
    /// </summary>
    private float AddV = 0;

    /// <summary>
    /// 移动方向
    /// </summary>
    private float Vk = 0;

    /// <summary>
    /// 
    /// </summary>
    private float Vtotal = 0;

    /// <summary>
    /// 动画速度 * 单位时间* 移动方向,计算出来的移动值
    /// </summary>
    private float CurrentV = 0;

    /// <summary>
    /// 
    /// </summary>
    private float VT = 0;

    /// <summary>
    /// 
    /// </summary>
    private float _v1 = 0, _v2 = 0;

    /// <summary>
    /// 动画速度
    /// </summary>
    public float _anim_speed = 1f;

    /// <summary>
    /// 
    /// </summary>
    public UI_Control_ScrollFlow_Item Current;
 
    /// <summary>
    ///  初始化组件
    /// </summary>
    public void InitComponments()
    {
        Rect = this.transform.GetComponent<RectTransform>();
        MaxScale = 1.0f;
        itemWidth = 500;
        //PositionCurve = AnimationCurve.EaseInOut(0, 0, 1.0f, 1.0f);         
        float[] tixxx = new float[] {-0.22f, -0.02f, 0.18f, 0.5f, 0.82f, 1.02f, 1.22f, 1.42f, 1.62f, 1.82f, 2.02f, 2.22f, 2.42f, 2.62f, 2.82f, 3.02f, 3.22f, 3.42f, 3.62f, 3.82f, 4.02f, 4.22f, 4.42f, 4.62f, 4.82f };

        Keyframe[] ks = new Keyframe[3];
        ks[0] = new Keyframe(0, 0.95f);
        ks[1] = new Keyframe(0.5f, 1.0f);
        ks[2] = new Keyframe(1.0f, 0.95f);
        ScaleCurve = new AnimationCurve(ks);

        Keyframe[] spks = new Keyframe[5];
        spks[0] = new Keyframe(-1.0f, 2.0f);
        spks[1] = new Keyframe(-0.5f, 1.5f);
        spks[2] = new Keyframe(0, 0.5f);
        spks[3] = new Keyframe(0.5f, 1.5f);
        spks[4] = new Keyframe(1.0f, 2.0f);
        SpeedCurve = new AnimationCurve(spks);

        Keyframe[] posArr = new Keyframe[tixxx.Length];
        int index = 0;
        for (int i = -3; i <= 21; i++)
        {
            posArr[index] = new Keyframe(startValue + i * spaceValue, tixxx[index]);
            index++;
        }

        PositionCurve = new AnimationCurve(posArr);
    }

    /// <summary>
    ///  接手到通知,某个子对象的选中状态发生改变了
    /// </summary>
    public void OnReceiveUpdateState(bool isSelected, UI_Control_ScrollFlow_Item item)
    {
        if (EventRefreshCardState != null)
        {
            EventRefreshCardState(isSelected, item);
        }
    }
   
    /// <summary>
    /// 
    /// </summary>
    public void Refresh(bool resetPosition = false)
    {
        if (Rect.childCount > 0)
        {
            int count = 0;
            for (int i = 0; i < Rect.childCount; i++)
            {
                Transform tran = Rect.GetChild(i);
                if (ItemsOld.Contains(tran))
                {
                    continue;
                }

                if (!tran.gameObject.activeSelf)
                {
                    continue;
                }

                count++;
            }
            //// Debug.LogError("countcountcount:::" + count);
            if (count > 5)
            {
                defaultItemIndex = 5;
            }
            else
            {
                defaultItemIndex = count - 1;
            }
        }
        //// Debug.LogError("defaultItemIndex::::" + defaultItemIndex);
        int rIndex = 0;
        for (int i = 0; i < Rect.childCount; i++)
        {
            Transform tran = Rect.GetChild(i);

            if (ItemsOld.Contains(tran))
            {
                continue;
            }

            if (!tran.gameObject.activeSelf)
            {
                continue;
            }

            UI_Control_ScrollFlow_Item item = tran.GetComponent<UI_Control_ScrollFlow_Item>();
            if (item != null)
            {
                item.Init(this, ItemList.Count);
                ItemList.Add(item);

                //item.Drag(startValue - (ItemList.Count - 1) * spaceValue);
                float dv = startValue + (rIndex - defaultItemIndex) * spaceValue;
                item.Drag(dv);
                //// Debug.LogError("CurrentItem::::" + dv);

                if (Mathf.Abs(dv - startValue) < 0.05f)
                {
                    Current = item;
                    //// Debug.LogError("CurrentItem::::" + item.gameObject.name);
                }

                rIndex++;
            }
        }      

        //if (MoveEnd != null)
        //{       
        //    MoveEnd(Current);
        //}

        for (int i = 0; i < ItemList.Count; i++)
        {
            ItemList[i].Refresh();
        }
        ItemsOld.Clear();
    }

    /// <summary>
    /// 
    /// </summary>
    public List<Transform> ItemsOld;

    /// <summary>
    /// 
    /// </summary>
    public void Clear()
    {
        ItemsOld = new List<Transform>();
        for (int i = 0; i < ItemList.Count; i++)
        {
            ItemsOld.Add(ItemList[i].transform);
            Destroy(ItemList[i].gameObject);
        }

        ItemList.Clear();
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="eventData"></param>
    public void OnBeginDrag(PointerEventData eventData)
    {
        start_point = eventData.position;
        add_vect = Vector3.zero;
        _anim = false;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="eventData"></param>
    public void OnDrag(PointerEventData eventData)
    {
        //判断此时 是不是已经到列表尽头,然后做一个极限设定
        if (ItemList[0].v > startValue)
        {
            float abs = Mathf.Abs(startValue - ItemList[0].v);
            if (abs > spaceValue)
            {
                return;
            }
        }

        if (ItemList[ItemList.Count - 1].v < startValue)
        {
            float abs = Mathf.Abs(startValue - ItemList[ItemList.Count - 1].v);
            if (abs > spaceValue)
            {
                return;
            }
        }

        add_vect = eventData.position - start_point;
        dragV = eventData.delta.x * 1.00f / itemWidth;


        //计算移动量,对应卡牌的比例
        for (int i = 0; i < ItemList.Count; i++)
        {
            ItemList[i].Drag(dragV);
        }
    }

    /// <summary>
    /// 这块需要调整
    /// 要不然不知道拖拽到哪个了......................
    /// </summary>
    /// <param name="eventData"></param>
    public void OnEndDrag(PointerEventData eventData)
    {
        float k = 0, v1;

        for (int i = 0; i < ItemList.Count; i++)
        {
            if (ItemList[i].v >= startValue)
            {
                v1 = (ItemList[i].v - startValue) % spaceValue;

                if (add_vect.x >= 0)
                {
                    k = spaceValue - v1;
                    //确定向右移动 ()
                }
                else
                {
                    k = v1 * -1;
                }
                break;
            }
        }

        add_vect = Vector3.zero;

        // 判断是否拖拽到极限
        if (ItemList[0].v > startValue)
        {
            //说明向右滑道头了
            k = ItemList[0].v;
            k = startValue - k;

            AnimToEnd(k);
            return;   
        }

        if (ItemList[ItemList.Count - 1].v < startValue)
        {
            k = ItemList[ItemList.Count - 1].v;
            k = startValue - k;

            AnimToEnd(k);
            return;
        }

        AnimToEnd(k);
    }
 
    /// <summary>
    /// 
    /// </summary>
    /// <param name="v"></param>
    /// <returns></returns>
    public float GetPosition(float v, int _index)
    {
        //return v * itemWidth;        
        return PositionCurve.Evaluate(v) * itemWidth;
    }

    /// <summary>
    /// 获取卡牌移动速度
    /// </summary>
    /// <param name="v"></param>    
    /// <returns></returns>
    public float GetMoveSpeed(float v)
    {
        //return v * itemWidth;        
        return SpeedCurve.Evaluate(v) * 1.0f;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="v"></param>
    /// <returns></returns>
    public float GetScale(float v)
    {
        return ScaleCurve.Evaluate(v) * MaxScale;
    }

    /// <summary>
    /// 主要进行排序
    /// 除了中间之外的, 左侧的,从左到右绘制.
    /// 中间右侧,从右到左绘制
    /// </summary>
    public void LateUpdate()
    {
        List<UI_Control_ScrollFlow_Item> left = new List<UI_Control_ScrollFlow_Item>();
        List<UI_Control_ScrollFlow_Item> right = new List<UI_Control_ScrollFlow_Item>();
        List<UI_Control_ScrollFlow_Item> middle = new List<UI_Control_ScrollFlow_Item>();

        int index = 0;

        for (int i = 0; i < ItemList.Count; i++)
        {
            float abs = Mathf.Abs(startValue - ItemList[i].v);
            if (abs < 0.05f)
            {
                middle.Add(ItemList[i]);
            }
            else
            {
                if (ItemList[i].v > startValue)
                {
                    right.Add(ItemList[i]);
                }
                else
                {
                    left.Add(ItemList[i]);
                }
            }
        }

        for (int i = 0; i < left.Count; i++)
        {
            left[i].rect.SetSiblingIndex(index);
            index++;
        }

        for (int i = right.Count - 1; i >= 0; i--)
        {
            right[i].rect.SetSiblingIndex(index);
            index++;
        }
        for (int i = 0; i < middle.Count; i++)
        {
            middle[i].rect.SetSiblingIndex(index);
            index++;
        }
    }

    /// <summary>
    /// 移动结束
    /// </summary>
    /// <param name="k">移动距离</param>
    public void AnimToEnd(float k)
    {
        AddV = k;
        if (AddV > 0)
        {
            Vk = 1;
        }
        else if (AddV < 0)
        {
            Vk = -1;
        }
        else
        {
            return;
        }

        Vtotal = 0;
        _anim_speed = GetMoveSpeed(k);
        _anim = true;  
    }

    /// <summary>
    /// 
    /// </summary>
    private void Update()
    {
        if (_anim)
        {
            //// Debug.LogError("flow:::" + Time.deltaTime + "  VKKK:" + Vk);
            CurrentV = Time.deltaTime * _anim_speed * Vk;
            ////通过update 来累加   CurrentV;
            ////直到移动量,达到要求的结束动画.
            ////主要对点击某个卡牌,移动直到显示某个具体位置卡牌有效.
            VT = Vtotal + CurrentV;

            if (Vk > 0 && VT >= AddV)
            {
                _anim = false;
                CurrentV = AddV - Vtotal;
            }

            if (Vk < 0 && VT <= AddV)
            {
                _anim = false;
                CurrentV = AddV - Vtotal;
            }
            ////=============================================
            for (int i = 0; i < ItemList.Count; i++)
            {
                ItemList[i].Drag(CurrentV);
                if (ItemList[i].v - startValue < 0.05f)
                {
                    Current = ItemList[i];
                }
            }

            Vtotal = VT;  

            if (!_anim)
            {
                //// Debug.LogError("end ened");
                if (MoveEnd != null)
                {
                    MoveEnd(Current);
                }
            }
        }
    }

    /// <summary>
    /// 转到指定子对象显示
    /// </summary>
    /// <param name="script"></param>
    public void ToAppointedItem(UI_Control_ScrollFlow_Item script)
    {
        if (script == null)
            return;
        float k = script.v;
        k = startValue - k;

        AnimToEnd(k);
    } 
}