Restructured the project structure back to the way it was, there's no reasonable way to split the modules

src/NadekoBot/Db/LevelStats.cs

@@ -0,0 +1,41 @@
+#nullable disable
+
+namespace NadekoBot.Db;
+
+public readonly struct LevelStats
+{
+    public const int XP_REQUIRED_LVL_1 = 36;
+    
+    public long Level { get; }
+    public long LevelXp { get; }
+    public long RequiredXp { get; }
+    public long TotalXp { get; }
+
+    public LevelStats(long xp)
+    {
+        if (xp < 0)
+            xp = 0;
+
+        TotalXp = xp;
+
+        const int baseXp = XP_REQUIRED_LVL_1;
+
+        var required = baseXp;
+        var totalXp = 0;
+        var lvl = 1;
+        while (true)
+        {
+            required = (int)(baseXp + (baseXp / 4.0 * (lvl - 1)));
+
+            if (required + totalXp > xp)
+                break;
+
+            totalXp += required;
+            lvl++;
+        }
+
+        Level = lvl - 1;
+        LevelXp = xp - totalXp;
+        RequiredXp = required;
+    }
+}