More restructuring

src/Nadeko.Bot.Db/Extensions/UserXpExtensions.cs

@@ -1,5 +1,6 @@
 #nullable disable
 using LinqToDB;
+using LinqToDB.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore;
 using NadekoBot.Services.Database;
 using NadekoBot.Services.Database.Models;
@@ -60,4 +61,12 @@ public static class UserXpExtensions
 
     public static void ResetGuildXp(this DbSet<UserXpStats> xps, ulong guildId)
         => xps.Delete(x => x.GuildId == guildId);
+    
+    public static async Task<LevelStats> GetLevelDataFor(this ITable<UserXpStats> userXp, ulong guildId, ulong userId)
+            => await userXp
+                     .Where(x => x.GuildId == guildId && x.UserId == userId)
+                     .FirstOrDefaultAsyncLinqToDB() is UserXpStats uxs
+                ? new(uxs.Xp + uxs.AwardedXp)
+                : new(0);
+    
 }

src/Nadeko.Bot.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;
+    }
+}