using System;
using System.Collections.Generic;
using SC.XR.Unity.Module_InputSystem;
using UnityEngine;
using UnityEngine.EventSystems;
using UnityEngine.UI;

namespace GHZLangChao
{
    public class CustomVerticleScrollView : MonoBehaviour, IPointerDownHandler
    {
        public List<string> data = new List<string>();

        public RectTransform content;
        public List<RoomName_Item> itemList = new List<RoomName_Item>();
        private Vector3 lastPosition;
        private float offset;

        public int startIndex = 0;
        public int endIndex = 0;

        private float size;
        private float index0Y;

        private bool isMoveItem; // 标记当前的Item是否需要挪动
        private bool sliderUp;
        private bool isDrag;

        public float moveSpeed = 2000;

        private void Awake()
        {
            for (int i = 0; i < 20; i++) // 添加10个数据
            {
                data.Add("4A-"+i.ToString()+"机房");
            }
            //data = MachineRoomManager.Instance.listRoomName;

            size = itemList[0].GetComponent<RectTransform>().rect.size.y;
            index0Y = itemList[0].transform.localPosition.y;

            for (int i = 0; i < itemList.Count; i++) // 显示几个数据（这里为5个）
            {
                itemList[i].GetComponentInChildren<Text>().text = data[i];
            }

            startIndex = 0;
            endIndex = itemList.Count - 2;
            DispatcherBase.KeyDownDelegateRegister(downEvent);
        }

        private void downEvent(InputKeyCode keyCode, InputDevicePartBase part)
        {
            if (part.inputDataBase.SCPointEventData.pointerCurrentRaycast.gameObject != null)
            {
                checkMoveDown(part.inputDataBase.SCPointEventData.pointerCurrentRaycast.gameObject, part);
            }
        }

        public void checkMoveDown(GameObject obj, InputDevicePartBase part)
        {
            if (obj)
            {
                if (obj.name==this.gameObject.name)
                {
                    Debug.Log("OnPointerDown");
                    isDrag = true;
                    lastPosition = part.inputDataBase.SCPointEventData.position;
                }
                else
                {
                    if (obj.transform.parent != null)
                        checkMoveDown(obj.transform.parent.gameObject, part);
                }
            }
        }

        private void UpdateList(Vector2 position)
        {
            offset = position.y - lastPosition.y;
            offset = Mathf.Clamp(offset, -75, 75); // Item高/2
            lastPosition = position;
            for (int i = 0; i < itemList.Count; i++)
            {
                itemList[i].transform.localPosition += Vector3.up * offset;
            }

            if (offset > 0) // 往上滑动
            {
                if (!sliderUp && isMoveItem)
                {
                    startIndex++;
                    if (startIndex > data.Count - 1)
                        startIndex = 0;
                    isMoveItem = false;
                }
                sliderUp = true;

                if (itemList[0].transform.localPosition.y >= index0Y && !isMoveItem)
                {
                    isMoveItem = true;
                    Debug.Log("添加一个Item到末尾");
                    itemList[itemList.Count - 1].transform.localPosition = itemList[itemList.Count - 2].transform.localPosition - Vector3.up * size;
                    endIndex++;
                    if (endIndex > data.Count - 1)
                        endIndex = 0;

                    itemList[itemList.Count - 1].GetComponentInChildren<Text>().text = data[endIndex];
                }
                else
                {
                    if (itemList[0].transform.localPosition.y >= index0Y + size)
                    {
                        isMoveItem = false;
                        Debug.Log("将第一个Item放到末尾");
                        RoomName_Item temp = itemList[0];
                        temp.transform.localPosition = itemList[itemList.Count - 1].transform.localPosition - Vector3.up * size;
                        for (int i = 1; i < itemList.Count; i++)
                        {
                            itemList[i - 1] = itemList[i];
                        }
                        itemList[itemList.Count - 1] = temp;

                        startIndex++;
                        if (startIndex > data.Count - 1)
                            startIndex = 0;
                    }
                }

            }
            else if (offset < 0)// 往下滑动
            {
                if (sliderUp && isMoveItem)
                {
                    endIndex--;
                    if (endIndex < 0)
                        endIndex = data.Count - 1;
                    isMoveItem = false;
                }
                sliderUp = false;

                if (itemList[0].transform.localPosition.y <= index0Y && !isMoveItem)
                {
                    isMoveItem = true;
                    Debug.Log("添加一个Item到顶部");
                    itemList[itemList.Count - 1].transform.localPosition = itemList[0].transform.localPosition + Vector3.up * size;
                    startIndex--;
                    if (startIndex < 0)
                        startIndex = data.Count - 1;

                    itemList[itemList.Count - 1].GetComponentInChildren<Text>().text = data[startIndex];
                }
                else
                {
                    if (itemList[0].transform.localPosition.y <= index0Y - size)
                    {
                        Debug.Log("将最后一个Item放到顶部");
                        RoomName_Item temp = itemList[itemList.Count - 1];
                        temp.transform.localPosition = itemList[0].transform.localPosition + Vector3.up * size;
                        isMoveItem = false;
                        for (int i = itemList.Count - 1; i >= 1; i--)
                        {
                            itemList[i] = itemList[i - 1];
                        }
                        itemList[0] = temp;

                        endIndex--;
                        if (endIndex < 0)
                            endIndex = data.Count - 1;
                    }
                }

            }
        }

        private Vector3 targetPos;
        private Vector3 currentPos;
        private void Update()
        {
            if (isDrag)
            {
                if (Input.GetMouseButtonUp(0))
                {
                    isDrag = false;
                    targetPos = Input.mousePosition + Vector3.Project(Input.mousePosition - currentPos, Vector3.up) * moveSpeed;
                }
                else
                {
                    currentPos = Input.mousePosition;
                    UpdateList(currentPos);
                }
            }
            else
            {
                currentPos = Vector3.Lerp(currentPos, targetPos, Time.deltaTime);
                UpdateList(currentPos);
            }
        }

        public void OnPointerDown(PointerEventData eventData)
        {
            isDrag = true;
            lastPosition = eventData.position;
        }
    }
}