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

namespace UIExt
{
    [AddComponentMenu("UI Extensions/LayoutGroup/GridLayoutGroupExt")]
    [DisallowMultipleComponent]
    [CanEditMultipleObjects]
    public class GridLayoutGroupExt
        : UIBehaviour
        , ILayoutElement
        , ILayoutGroup
    {
        public enum ScrollMode
        {
            Vertical = 1,
            Horizontal = 2,
            Auto = 3 // both horizontal and vertical
        }

        public enum MovementType
        {
            Unrestricted, // Unrestricted movement -- can scroll forever
            Elastic, // Restricted but flexible -- can go past the edges, but springs back in place
            Clamped, // Restricted movement where it's not possible to go past the edges
        }

        [System.NonSerialized] private RectTransform m_Rect;
        protected RectTransform rectTransform
        {
            get
            {
                if (m_Rect == null)
                    m_Rect = GetComponent<RectTransform>();
                return m_Rect;
            }
        }

        [SerializeField] private ScrollRect m_Scrollrect;
        public ScrollRect scrollRect { get { return m_Scrollrect; } set { m_Scrollrect = value; } }

        [SerializeField] private RectTransform m_Content;
        public RectTransform content { get { return m_Content; } set { m_Content = value; } }

        [SerializeField] private LayoutItem m_ItemTemplate;
        public LayoutItem itemTemplate { get { return m_ItemTemplate; } set { m_ItemTemplate = value; } }

        [SerializeField] private int m_RowCount;
        public int rowCount { get { return m_RowCount; } set { m_RowCount = value; } }
        [SerializeField] private int m_ColumCount;
        public int columCount { get { return m_ColumCount; } set { m_ColumCount = value; } }

        [SerializeField] protected RectOffset m_Padding = new RectOffset();
        public RectOffset padding { get { return m_Padding; } set { SetProperty(ref m_Padding, value); } }

        [SerializeField] private Vector2Int m_CellSize;
        public Vector2Int cellSize { get { return m_CellSize; } set { m_CellSize = value; } }

        [SerializeField] private Vector2Int m_Spacing;
        public Vector2Int spacing { get { return m_Spacing; } set { m_Spacing = value; } }

        [SerializeField] private ScrollMode m_ScrollMode = ScrollMode.Vertical;

        [SerializeField] private MovementType m_MovementType = MovementType.Elastic;

        private List<object> m_DataList;
        public List<object> dataList { get { return m_DataList; } }

        public float minWidth
        {
            get
            {
                throw new System.NotImplementedException();
            }
        }

        public float preferredWidth { get { return 0; } }

        public float flexibleWidth { get { return 0; } }

        public float minHeight { get { return 0; } }

        public float preferredHeight { get { return 0; } }

        public float flexibleHeight { get { return 0; } }

        public int layoutPriority { get { return 0; } }

        public void SetList(List<object> datalist)
        {
            m_DataList = datalist;
        }

        public void MoveTo(int indexOfData)
        {

        }

        public void MoveTo(object data)
        {

        }

        public void CalculateLayoutInputHorizontal()
        {

        }

        public void CalculateLayoutInputVertical()
        {

        }

        public void SetLayoutHorizontal()
        {
        }

        public void SetLayoutVertical()
        {
        }

        protected void SetProperty<T>(ref T currentValue, T newValue)
        {
            if ((currentValue == null && newValue == null) || (currentValue != null && currentValue.Equals(newValue)))
                return;
            currentValue = newValue;
            SetDirty();
        }

        protected void SetDirty()
        {
            if (!IsActive())
                return;

            if (!CanvasUpdateRegistry.IsRebuildingLayout())
                LayoutRebuilder.MarkLayoutForRebuild(rectTransform);
            else
                StartCoroutine(DelayedSetDirty(rectTransform));
        }

        IEnumerator DelayedSetDirty(RectTransform rectTransform)
        {
            yield return null;
            LayoutRebuilder.MarkLayoutForRebuild(rectTransform);
        }

    }

}