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

namespace Ichni.Editor
{
    public class DynamicUISubcontainer : MonoBehaviour
    {
        Inspector Inspector => EditorManager.instance.uiManager.inspector;
        public DynamicUIContainer parentContainer;
        public RectTransform rect;
        public List<DynamicUIElement> dynamicUIElements;

        /// <summary> 当前行高 </summary>
        [HideInInspector]
        public float rowHeight = 100f;

        /// <summary>
        /// 使用 GridLayoutGroup 实现 N 列自动换行布局。
        /// 当添加的元素数量超过 elementCountPerRow 时，会自动换行到下一行。
        /// </summary>
        public void Initialize(DynamicUIContainer parentContainer, int elementCountPerRow, float height = 100)
        {
            this.parentContainer = parentContainer;
            this.rowHeight = height;

            int columns = Mathf.Max(1, elementCountPerRow);

            // ── 启用 GridLayoutGroup ──
            var grid = GetComponent<GridLayoutGroup>();
            if (grid == null)
                grid = gameObject.AddComponent<GridLayoutGroup>();

            grid.enabled = true;
            grid.constraint = GridLayoutGroup.Constraint.FixedColumnCount;
            grid.constraintCount = columns;
            grid.childAlignment = TextAnchor.UpperLeft;
            grid.startCorner = GridLayoutGroup.Corner.UpperLeft;
            grid.startAxis = GridLayoutGroup.Axis.Horizontal;
            grid.padding = new RectOffset(10, 10, 0, 0);

            float spacing = 10f;
            float totalSpacing = (columns - 1) * spacing;
            float cellWidth = (LayoutPacker.TotalRowWidth - totalSpacing) / columns;
            grid.cellSize = new Vector2(cellWidth, height);
            grid.spacing = new Vector2(spacing, spacing);

            // ── LayoutElement: preferredHeight = -1 让 GridLayoutGroup 的 ILayoutElement 接管高度 ──
            var layoutElement = GetComponent<LayoutElement>();
            if (layoutElement == null)
                layoutElement = gameObject.AddComponent<LayoutElement>();
            layoutElement.preferredHeight = -1;
            layoutElement.flexibleHeight = -1;

            // ── ContentSizeFitter: 让子容器高度随网格行数动态增长 ──
            var fitter = GetComponent<ContentSizeFitter>();
            if (fitter == null)
                fitter = gameObject.AddComponent<ContentSizeFitter>();
            fitter.verticalFit = ContentSizeFitter.FitMode.PreferredSize;
            fitter.horizontalFit = ContentSizeFitter.FitMode.Unconstrained;
            fitter.enabled = true;

            if (dynamicUIElements == null)
                dynamicUIElements = new List<DynamicUIElement>();
            else
                dynamicUIElements.Clear();
        }

        public DynamicUISubcontainer Mark(string mark, IHaveInspection inspection = null)
        {
            inspection ??= Inspector;
            inspection.MarkedSubcontainers.TryAdd(mark, this);
            return this;
        }
    }
}