[CHANGE] Added old cipher implementation

Manager.YouTube/Util/Cipher/CipherManager.cs

@@ -0,0 +1,46 @@
+using DotBased.Logging;
+using DotBased.Monads;
+
+namespace Manager.YouTube.Util.Cipher;
+
+public static class CipherManager
+{
+    private static readonly CipherDecoderCollection LoadedCiphers = [];
+    private static readonly ILogger Logger = LogService.RegisterLogger(typeof(CipherManager));
+
+    public static async Task<Result<CipherDecoder>> GetDecoder(YouTubeClient client)
+    {
+        var relativePlayerJsUrl = client.State?.PlayerJsUrl;
+        if (string.IsNullOrEmpty(relativePlayerJsUrl))
+        {
+            return ResultError.Fail("Could not get player js url.");
+        }
+        var version = GetCipherVersion(relativePlayerJsUrl);
+
+        Logger.Debug($"Getting cipher decoder for version: {version}");
+        if (LoadedCiphers.TryGetValue(version, out var cipher))
+        {
+            return cipher;
+        }
+        
+        try
+        {
+            var decoder = await CipherDecoder.CreateAsync(relativePlayerJsUrl, version);
+            LoadedCiphers.Add(decoder);
+        }
+        catch (Exception e)
+        {
+            Logger.Error(e, "Could not create cipher decoder. Version: {DecoderVersion}", version);
+        }
+        
+        return ResultError.Fail($"Could not create cipher decoder for {relativePlayerJsUrl} (v: {version})");
+    }
+
+    private static string GetCipherVersion(string relativePlayerUrl)
+    {
+        var split = relativePlayerUrl.Split('/');
+        var v = split[2];
+        var lang = split[4];
+        return $"{v}_{lang}";
+    }
+}