#if UNITY_EDITOR && UNITY_2021_2_OR_NEWER
using UnityEditor;
using UnityEditor.Overlays;
using UnityEngine;
using UnityEngine.UIElements;

namespace RR.Common.InspectorOverrides
{
    [Overlay(typeof(SceneView), id: "hierarchy-selection-count", displayName: "Hierarchy Selection Count")]
    [Icon("d_UnityEditor.SceneHierarchyWindow")]
    public sealed class HierarchySelectionCountOverlay : Overlay
    {
        private Label _countLabel;

        public override void OnCreated()
        {
            Selection.selectionChanged += UpdateSelectionLabel;
            EditorApplication.hierarchyChanged += UpdateSelectionLabel;
        }

        public override void OnWillBeDestroyed()
        {
            Selection.selectionChanged -= UpdateSelectionLabel;
            EditorApplication.hierarchyChanged -= UpdateSelectionLabel;
        }

        public override VisualElement CreatePanelContent()
        {
            VisualElement root = new() { style = { minWidth = 180 } };

            Label titleLabel = new("Выделение в Hierarchy")
            {
                style =
                {
                    unityFontStyleAndWeight = FontStyle.Bold,
                    marginBottom = 4
                }
            };
            root.Add(titleLabel);

            _countLabel = new Label();
            root.Add(_countLabel);

            UpdateSelectionLabel();
            return root;
        }

        private void UpdateSelectionLabel()
        {
            if (_countLabel == null)
                return;

            int selectedCount = HierarchySelectionCounter.GetSelectedHierarchyObjectCount();
            _countLabel.text = selectedCount == 0
                ? "Сейчас ничего не выделено"
                : $"Выделено объектов: {selectedCount}";
        }
    }
}
#endif