using System;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;

namespace BF
{
    [DisallowMultipleComponent]
    [RequireComponent(typeof(ScrollRect))]
    public abstract class BFScrollRectBase : MonoBehaviour, IBeginDragHandler, IEndDragHandler
    {
        public bool isDrag = false;
        bool unityScrollRectInited = false;
        ScrollRect unityScrollRect;
        protected ScrollRect UnityScrollRect
        {
            get
            {
                if (!unityScrollRectInited)
                {
                    unityScrollRect = GetComponent<ScrollRect>();
                    if (!ReferenceEquals(unityScrollRect, null))
                    {
                        unityScrollRectInited = true;
                    }
                }
                return unityScrollRect;
            }
        }

        bool contentTransInited = false;
        public RectTransform contentTrans;
        public RectTransform ContentTrans
        {
            get
            {
                if (!contentTransInited)
                {
                    contentTrans = UnityScrollRect.content;
                    if (!ReferenceEquals(contentTrans, null))
                    {
                        contentTransInited = true;
                    }
                }
                return contentTrans;
            }
        }

        bool viewportTransInited = false;
        RectTransform viewportTrans;
        protected RectTransform ViewPortTrans
        {
            get
            {
                if (!viewportTransInited)
                {
                    viewportTrans = UnityScrollRect.viewport;
                    if (!ReferenceEquals(viewportTrans, null))
                    {
                        viewportTransInited = true;
                    }
                }
                return viewportTrans;
            }
        }

        protected Action<int, int> RefreshAction;
        protected Action<float, float> OnAnchoredPositionAction;
        protected Action<GameObject> OnInstantiateCell;
        protected Action<bool, int> Selected;
        protected int selectedIndex;

        public void SetRefreshAction(Action<int, int> action)
        {
            RefreshAction = action;
        }

        public void SetOnInstantiateCellAction(Action<GameObject> action)
        {
            OnInstantiateCell = action;
        }

        public void SetSelectedAction(Action<bool, int> action)
        {
            Selected = action;
        }

        public int GetSelectedIndex()
        {
            return selectedIndex;
        }

        public void SetAnchoredPositionChange(Action<float, float> action)
        {
            OnAnchoredPositionAction = action;
        }

        public abstract void RefillCells(int totalCount, int targetIndex);

        public abstract void SetTotalCount(int totalCount);

        public abstract void RefreshAll();

        public abstract void ClearCells();

        public abstract void SetSelected(int index);
        public abstract void AnchoredPositionChange();

        protected abstract void TryFullFill();

        public virtual void MoveToIndex(int index) { }

        public virtual void RemoveCell(int index) { }

        public void OnBeginDrag(PointerEventData eventData)
        {
            isDrag = true;
        }
        public void OnEndDrag(PointerEventData eventData)
        {
            isDrag = false;
        }

        void Update()
        {
            TryFullFill();
        }
    }
}