ClickerUISystem.cs

using ClickerClass.UI;
using Microsoft.Xna.Framework;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using Terraria;
using Terraria.ModLoader;
using Terraria.UI;

namespace ClickerClass
{
	[Autoload(true, Side = ModSide.Client)]
	public class ClickerUISystem : ModSystem
	{
		private GameTime _lastUpdateUIGameTime;
		private static FieldInfo mouseTextCacheField;
		private static FieldInfo isValidField;
		private static bool reflectionFailed = false;

		public override void UpdateUI(GameTime gameTime)
		{
			_lastUpdateUIGameTime = gameTime;
		}

		public override void ModifyInterfaceLayers(List<GameInterfaceLayer> layers)
		{
			ClickerInterfaceResources.AddInterfaceLayers(layers);

			//Remove Mouse Cursor
			if (Main.cursorOverride == -1 && ClickerConfigClient.Instance.ShowCustomCursors)
			{
				Player player = Main.LocalPlayer;
				if (ClickerCursor.CanDrawCursor(player.HeldItem))
				{
					for (int i = 0; i < layers.Count; i++)
					{
						if (layers[i].Name.Equals("Vanilla: Cursor"))
						{
							//This only removes the default cursor, see DetourSecondCursor for the second one
							layers[i].Active = false;
							//layers.RemoveAt(i); //Do not remove layers, mods with no defensive code cause this to break/delete all UI
							break;
						}
					}
				}
			}
		}

		public override void OnModLoad()
		{
			On_Main.DrawInterface_36_Cursor += DetourSecondCursor;

			try
			{
				/*
					DrawGamepadInstructions();
					if (instance._mouseTextCache.isValid) {
						instance.MouseTextInner(instance._mouseTextCache);
						DrawInterface_36_Cursor(); //Detour only this one
						instance._mouseTextCache.isValid = false;
						instance._mouseTextCache.noOverride = false;
					}
				 */

				Type mainType = typeof(Main);
				mouseTextCacheField = mainType.GetField("_mouseTextCache", BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);

				var nestedTypes = mainType.GetNestedTypes(BindingFlags.Static | BindingFlags.NonPublic | BindingFlags.Public);
				var mouseTextCacheType = nestedTypes.FirstOrDefault(t => t.Name == "MouseTextCache");
				isValidField = mouseTextCacheType.GetField("isValid", BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);
			}
			catch
			{
				reflectionFailed = true;
			}
		}

		public override void OnModUnload()
		{
			mouseTextCacheField = isValidField = null;
			reflectionFailed = false;
		}

		private static void DetourSecondCursor(On_Main.orig_DrawInterface_36_Cursor orig)
		{
			//This is used to detour the second cursor draw which happens on NPC mouseover in DrawInterface_41 after Main.instance._mouseTextCache.valid is true
			if (!reflectionFailed && ClickerCursor.detourSecondCursorDraw)
			{
				ClickerCursor.detourSecondCursorDraw = false;

				var mouseTextCache = mouseTextCacheField.GetValue(Main.instance);
				object isValid = isValidField.GetValue(mouseTextCache);
				if (isValid is bool valid && valid)
				{
					return;
				}
			}

			orig();
		}
	}
}