feat(wip): implementing edit history and un-re-do

modules/terrain_editor/edit_history.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include "core/object/class_db.h"
+#include "core/object/object.h"
+#include "core/variant/callable.h"
+#include "terrain_editor/register_types.h"
+
+class EditHistory : public Object {
+	GDCLASS(EditHistory, Object);
+	static void _bind_methods();
+	static EditHistory *singleton_instance;
+	friend void initialize_terrain_editor_module(ModuleInitializationLevel p_level);
+	struct EditAction {
+		Callable do_action;
+		Callable undo_action;
+	};
+
+public:
+	static EditHistory *get_singleton() { return singleton_instance; }
+	void push_action(Callable do_action, Callable undo_action);
+	void undo();
+	void redo();
+
+private:
+	size_t undo_count{ 0 };
+	Vector<EditAction> history{};
+};