#if UNITY_6000_3_OR_NEWER
using System.Collections.Generic;
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEditor.Toolbars;
using UnityEditorInternal;
using UnityEngine;
using UnityEngine.Scripting;
using UTools = UnityEditor.Tools;

namespace Module.NavigationTool.Editor.Toolbar
{
    internal static class MainToolbarUIElement
    {
        [Preserve]
        [MainToolbarElement("Toolbar/UI", ussName = "", defaultDockIndex = 0, defaultDockPosition = MainToolbarDockPosition.Middle, menuPriority = 500)]
        public static IEnumerable<MainToolbarElement> Draw()
        {
            var layer = 1 << LayerMask.NameToLayer("UI");
            var toggleValue = (UTools.visibleLayers & layer) != 0;
            
            return new List<MainToolbarElement>(2)
            {
                new MainToolbarToggle(new MainToolbarContent("UI", "Toggles UI visible layer in SceneView"), toggleValue, OnToggleValueChanged),
                new MainToolbarDropdown(new MainToolbarContent("Select"), OnDropdownOpen)
            };
        }

        private static void OnToggleValueChanged(bool result)
        {
            var layer = 1 << LayerMask.NameToLayer("UI");
            
            if (result)
                UTools.visibleLayers |= layer;
            else
                UTools.visibleLayers &= ~layer;

            SceneView.RepaintAll();
        }
        
        private static void OnDropdownOpen(Rect rect)
        {
            var prefabStage = PrefabStageUtility.GetCurrentPrefabStage();
            var canvases = prefabStage != null 
                ? prefabStage.prefabContentsRoot.GetComponentsInParent<Canvas>()
                : Object.FindObjectsByType<Canvas>(FindObjectsInactive.Include, FindObjectsSortMode.InstanceID);

            var list = new List<Canvas>(canvases.Length);
            var menu = new GenericMenu();

            for (var i = 0; i < canvases.Length; i++)
            {
                var root = canvases[i].rootCanvas;
                
                if (list.Contains(root))
                    continue;
                
                list.Add(root);
                menu.AddItem(new GUIContent($"{i}: {root.name}"), false, () => Focus(root.GetInstanceID()));
            }
            
            menu.DropDown(rect);
        }
        
        private static void Focus(int instanceId)
        {
            var obj = EditorUtility.EntityIdToObject(instanceId);
            var canvas = obj as Canvas;
            
            if (canvas == null)
            {
                if (obj != null)
                    Debug.LogWarning("Failed to find Canvas component on object", obj);
                
                return;
            }

            Selection.activeObject = canvas;
            var bounds = InternalEditorUtility.CalculateSelectionBounds(false, true, true);
            var point = bounds.center;
            var direction = canvas.transform.rotation;
            var size = Mathf.Max(bounds.extents.x, bounds.extents.y);
            var ortho = canvas.renderMode == RenderMode.ScreenSpaceOverlay;

            for (var i = 0; i < SceneView.sceneViews.Count; i++)
            {
                var view = (SceneView)SceneView.sceneViews[i];
                view.in2DMode = false;
                view.LookAt(point, direction, size, ortho, false);
            }
        }

        public static void Refresh()
        {
            MainToolbar.Refresh("Toolbar/UI");
        }
    }
}
#endif