using System;
using System.Collections.Generic;
using UnityEngine;
using System.Reflection;
using System.Runtime.Serialization;
using Object = UnityEngine.Object;

#if UNITY_2019_1_OR_NEWER
using UnityEngine.UIElements;
#else
using UnityEngine.Experimental.UIElements;
#endif

namespace Game.NavigationTool.Editor.Toolbar
{
    internal static class ToolbarUtility
    {
        public static void AddGuiListener(Action action)
        {
            Assembly assembly = typeof(UnityEditor.Editor).Assembly;
            Type typeToolbar = assembly.GetType("UnityEditor.Toolbar");
            Object[] toolbars = Resources.FindObjectsOfTypeAll(typeToolbar);
            ScriptableObject so = toolbars.Length > 0 ? (ScriptableObject)toolbars[0] : null;
            
            if (so == null)
                return;
            
            Type typeGuiView = assembly.GetType("UnityEditor.GUIView");

            #if UNITY_2020_1_OR_NEWER
		    Type typeWindowBackend = assembly.GetType("UnityEditor.IWindowBackend");
		    PropertyInfo piWindowBackend = typeGuiView.GetProperty("windowBackend", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
		    PropertyInfo piVisualTree = typeWindowBackend.GetProperty("visualTree", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
            #else
            PropertyInfo piVisualTree = typeGuiView.GetProperty("visualTree", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
            #endif

            if (piVisualTree == null)
                return;
            
            FieldInfo fiImguiContainer = typeof(IMGUIContainer).GetField("m_OnGUIHandler", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);

            if (fiImguiContainer == null)
                return;
            
            #if UNITY_2020_1_OR_NEWER
			var windowBackend = piWindowBackend.GetValue(so);
			var visualTree = (VisualElement)piVisualTree.GetValue(windowBackend, null);
            #else
            var visualTree = (VisualElement)piVisualTree.GetValue(so, null);
            #endif
                
            var container = (IMGUIContainer)visualTree[0];
            var handler = (Action)fiImguiContainer.GetValue(container);
            handler -= action;
            handler += action;
            fiImguiContainer.SetValue(container, handler);
        }

        public static IToolbarDrawer[] GetAllDrawers()
        {
            Assembly[] assemblies = AppDomain.CurrentDomain.GetAssemblies();
            Type iType = typeof(IToolbarDrawer);

            var list = new List<IToolbarDrawer>(8);

            for (var i = 0; i < assemblies.Length; i++)
            {
                Assembly assembly = assemblies[i];
                Type[] types = assembly.GetTypes();

                for (var j = 0; j < types.Length; j++)
                {
                    Type type = types[j];

                    if (!type.IsAbstract && iType.IsAssignableFrom(type))
                        list.Add((IToolbarDrawer)FormatterServices.GetUninitializedObject(type));
                }
            }
            
            return list.ToArray();
        }
    }
}