Move formspec code from game.cpp to separate file

src/client/game_formspec.h

@@ -0,0 +1,62 @@
+// Luanti
+// SPDX-License-Identifier: LGPL-2.1-or-later
+// Copyright (C) 2024 cx384
+
+#pragma once
+
+#include <string>
+#include "irr_v3d.h"
+
+class Client;
+class RenderingEngine;
+class InputHandler;
+class ISoundManager;
+class GUIFormSpecMenu;
+
+/*
+This object intend to contain the core fromspec functionality.
+It includes:
+  - methods to show specific formspec menus
+  - storing the opened fromspec
+  - handling fromspec related callbacks
+ */
+struct GameFormSpec
+{
+	void init(Client *client, RenderingEngine *rendering_engine, InputHandler *input)
+	{
+		m_client = client;
+		m_rendering_engine = rendering_engine;
+		m_input = input;
+	}
+
+	~GameFormSpec();
+
+	void showFormSpec(const std::string &formspec, const std::string &formname);
+	void showLocalFormSpec(const std::string &formspec, const std::string &formname);
+	void showNodeFormspec(const std::string &formspec, const v3s16 &nodepos);
+	void showPlayerInventory();
+	void showDeathFormspecLegacy();
+	void showPauseMenu();
+
+	void update();
+	void disableDebugView();
+
+	bool handleCallbacks();
+
+#ifdef __ANDROID__
+	// Returns false if no formspec open
+	bool handleAndroidUIInput();
+#endif
+
+private:
+	Client *m_client;
+	RenderingEngine *m_rendering_engine;
+	InputHandler *m_input;
+
+	// Default: "". If other than "": Empty show_formspec packets will only
+	// close the formspec when the formname matches
+	std::string m_formname;
+	GUIFormSpecMenu *m_formspec = nullptr;
+
+	void deleteFormspec();
+};