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

namespace MinorFunction
{

    public class SlotHandle : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler, IDropHandler
    {
        [HideInInspector]
        public bool isEnter = false;

        [Tooltip("multipleNumber == 0 不做任何限制可以附加无限多个，multipleNumber > 0 任何限制只能附加 multipleNumber个，multipleNumber = -1 不允许附加")]
        public int multipleNumber = 0;


        private DragHandle temporaryDragHandle;
        public List<DragHandle> currentDragHandles = new List<DragHandle>();

        public UnityEvent<DragHandle> onDragEntry; //进入
        public UnityEvent<DragHandle> onDragExit;  //离开
        public UnityEvent<DragHandle> onDragNotExit;  //未离开

        public UnityEvent onPointerEnter;    //鼠标进入
        public UnityEvent onPointerExit;     //鼠标离开

        private void Awake()
        {
            SetMultipleNumber(multipleNumber);
        }

        public void OnPointerEnter(PointerEventData eventData)
        {
            isEnter = true;
            onPointerEnter?.Invoke();
        }

        public void OnPointerExit(PointerEventData eventData)
        {
            isEnter = false;
            onPointerExit?.Invoke();
        }

        public void OnDrop(PointerEventData eventData)
        {

            if (eventData.pointerDrag != null)
            {
                temporaryDragHandle = eventData.pointerDrag.GetComponent<DragHandle>();
                if (temporaryDragHandle.isOverlap)
                {
                    return;
                }
                ModifyDrag(temporaryDragHandle);
            }
        }

        public void ModifyDrag(DragHandle dragHandle)
        {
            temporaryDragHandle = dragHandle;
            if (!currentDragHandles.Contains(temporaryDragHandle))
            {
                if (multipleNumber == 0)  //不做任何限制
                {
                    RemoveDragHandle();
                    ShiftInDragHandle();
                }
                else if (multipleNumber > 0)
                {
                    if (currentDragHandles.Count < multipleNumber)
                    {
                        RemoveDragHandle();
                        ShiftInDragHandle();
                    }
                }
                else if (multipleNumber < 0)
                {
                    return;
                }
            }
            else
            {
                onDragNotExit?.Invoke(temporaryDragHandle);
            }
        }

        public void RemoveDragHandle()
        {
            if (temporaryDragHandle.currentSlotHandle)
            {
                temporaryDragHandle.RemoveSlotHandle();
            }
        }

        public void ShiftInDragHandle()
        {
            Debug.Log("添加");
          //  temporaryDragHandle.currentSlotHandle = this;
           // currentDragHandles.Add(temporaryDragHandle);

            onDragEntry?.Invoke(temporaryDragHandle);
        }

        /// <summary>
        /// 设置多选数量
        /// </summary>
        /// <param name="number">number == 0 不做任何限制可以附加无限多个，number > 0 任何限制只能附加 number 个，number = -1 不允许附加</param>
        public void SetMultipleNumber(int number)
        {
            if (number < 0)
            {
                multipleNumber = -1;
                RemoveAllDragHandles();
            }
            else
            {
                multipleNumber = number;
                if (number < currentDragHandles.Count)
                {
                    for (int i = multipleNumber - 1; i < currentDragHandles.Count; i++)
                    {
                        temporaryDragHandle = currentDragHandles[i];

                        RemoveDragHandle();
                    }
                }
            }
        }

        /// <summary>
        /// 移除全部DragHandle
        /// </summary>
        public void RemoveAllDragHandles()
        {
            for (int i = 0; i < currentDragHandles.Count; i++)
            {
                temporaryDragHandle = currentDragHandles[i];

                RemoveDragHandle();
            }
        }
        /// <summary>
        /// 移除指定DragHandle
        /// </summary>
        /// <param name="index"></param>
        public void RemoveIndexDragHandles(int index)
        {
            temporaryDragHandle = currentDragHandles[index];
            RemoveDragHandle();
        }
        /// <summary>
        /// 移除指定DragHandle
        /// </summary>
        /// <param name="dragHandle"></param>
        public void RemoveIndexDragHandles(DragHandle dragHandle)
        {
            temporaryDragHandle = dragHandle;
            RemoveDragHandle();
        }


    }
}