Let us start here, from square one. No, from Zero!

util/flags_helper.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include "external/fmt/include/fmt/format.h"
+
+#define ENUM_VARIANT(value) case (value): return #value
+
+#define FLAGS_START(VAR) \
+    if ((VAR) == 0) { \
+        return "0x0"; \
+    } \
+    \
+    bool first = true; \
+    std::string result
+
+#define FLAG(VAR, value) \
+    do { \
+        if ((VAR) & (value)) { \
+            if (!first) { \
+                result += " | "; \
+            } \
+            first = false; \
+            result += (#value); \
+        } \
+    } while (0)
+
+#define FLAGS_END(VAR) \
+    if (result.empty()) { \
+        result = fmt::format("0x{:08x}", (VAR)); \
+    } \
+    \
+    return result