Add logging interceptor and implement basic user transfer

src/Data/UserDataSeeder.cs

@@ -0,0 +1,52 @@
+using MariesWonderland.Configuration;
+using Microsoft.Extensions.Options;
+using System.Text.Json;
+
+namespace MariesWonderland.Data;
+
+public class UserDataSeeder(IOptions<ServerOptions> options)
+{
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        PropertyNameCaseInsensitive = true
+    };
+
+    private static readonly Type DbType = typeof(DarkUserMemoryDatabase);
+
+    /// <summary>
+    /// Reads all Entity*Table.json files from the configured UserDataPath and populates
+    /// a new DarkUserMemoryDatabase. Returns an empty database if no files are found.
+    /// </summary>
+    public DarkUserMemoryDatabase LoadFromFiles()
+    {
+        DarkUserMemoryDatabase db = new();
+
+        string rawPath = options.Value.Data.UserDataPath;
+        if (string.IsNullOrEmpty(rawPath))
+            return db;
+
+        string dataPath = Path.IsPathRooted(rawPath)
+            ? rawPath
+            : Path.Combine(AppContext.BaseDirectory, rawPath);
+
+        if (!Directory.Exists(dataPath))
+            return db;
+
+        foreach (string file in Directory.EnumerateFiles(dataPath, "Entity*Table.json"))
+        {
+            // "EntityIUserCostumeTable.json" → "EntityIUserCostume"
+            string fileName = Path.GetFileName(file);
+            string propName = fileName[..^"Table.json".Length];
+
+            var prop = DbType.GetProperty(propName);
+            if (prop == null) continue;
+
+            string json = File.ReadAllText(file);
+            var list = JsonSerializer.Deserialize(json, prop.PropertyType, JsonOptions);
+            if (list != null)
+                prop.SetValue(db, list);
+        }
+
+        return db;
+    }
+}

src/Data/UserDataStore.cs

@@ -56,6 +56,22 @@ public class UserDataStore
         return db;
     }
 
+    /// <summary>
+    /// Registers a pre-seeded database under a UUID. If the UUID is already mapped,
+    /// returns the existing userId without overwriting. Otherwise stores the seeded
+    /// database and maps the UUID to the userId found inside it.
+    /// </summary>
+    public long SeedUserFromDatabase(string uuid, DarkUserMemoryDatabase seededDb)
+    {
+        if (_uuidToUserId.TryGetValue(uuid, out var existingId))
+            return existingId;
+
+        long userId = seededDb.EntityIUser.FirstOrDefault()?.UserId ?? GenerateUserId();
+        _uuidToUserId[uuid] = userId;
+        _users[userId] = seededDb;
+        return userId;
+    }
+
     public bool TryGet(long userId, out DarkUserMemoryDatabase db)
         => _users.TryGetValue(userId, out db!);
 

src/Extensions/ServiceExtensions.cs

@@ -21,6 +21,7 @@ public static class ServiceExtensions
         var masterDb = MasterDataLoader.Load(masterDataPath);
         services.AddSingleton(masterDb);
         services.AddSingleton<UserDataStore>();
+        services.AddSingleton<UserDataSeeder>();
 
         return services;
     }

src/Interceptors/LoggingInterceptor.cs

@@ -0,0 +1,97 @@
+using Google.Protobuf;
+using Grpc.Core;
+using Grpc.Core.Interceptors;
+using MariesWonderland.Proto.Data;
+using MariesWonderland.Proto.User;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+namespace MariesWonderland.Interceptors;
+
+public class LoggingInterceptor(ILogger<LoggingInterceptor> logger) : Interceptor
+{
+    private static readonly List<string> ExcludedPropertyNames = [
+        nameof(AuthUserResponse.DiffUserData),
+        nameof(TableNameList.TableName),
+        nameof(UserDataGetResponse.UserDataJson)
+        ];
+
+    public override async Task<TResponse> UnaryServerHandler<TRequest, TResponse>(
+        TRequest request,
+        ServerCallContext context,
+        UnaryServerMethod<TRequest, TResponse> continuation)
+    {
+        string methodName = context.Method;
+
+        if (logger.IsEnabled(LogLevel.Debug))
+        {
+            logger.LogDebug("[GRPC] >> {Method}  (request)", methodName);
+            logger.LogDebug("{Json}", Serialize(request));
+        }
+
+        TResponse response = await continuation(request, context);
+
+        if (logger.IsEnabled(LogLevel.Debug))
+        {
+            logger.LogDebug("[GRPC] << {Method}  (response)", methodName);
+            logger.LogDebug("{Json}", Serialize(response));
+        }
+
+        return response;
+    }
+
+    private static string Serialize(object obj)
+    {
+        string json = obj is IMessage message
+            ? JsonFormatter.Default.Format(message)
+            : JsonSerializer.Serialize(obj);
+
+        return RemovePropertiesFromJson(json);
+    }
+
+    private static string RemovePropertiesFromJson(string json)
+    {
+        try
+        {
+            JsonNode? node = JsonNode.Parse(json);
+            if (node is null) return json;
+
+            RemoveProperties(node);
+
+            // Use compact JSON (no indentation) to match prior logging style.
+            return node.ToJsonString(new JsonSerializerOptions { WriteIndented = false });
+        }
+        catch
+        {
+            // If parsing fails for any reason, return the original JSON so logging still occurs.
+            return json;
+        }
+    }
+
+    private static void RemoveProperties(JsonNode? node)
+    {
+        if (node is JsonObject obj)
+        {
+            // Iterate over a snapshot of the keys because we'll be mutating the object.
+            foreach (var key in obj.Select(kvp => kvp.Key).ToList())
+            {
+                if (ExcludedPropertyNames.Contains(key, StringComparer.OrdinalIgnoreCase))
+                {
+                    obj.Remove(key);
+                }
+                else
+                {
+                    RemoveProperties(obj[key]);
+                }
+            }
+        }
+        else if (node is JsonArray arr)
+        {
+            foreach (var item in arr)
+            {
+                RemoveProperties(item);
+            }
+        }
+        // Primitives (JsonValue) do not contain nested properties; nothing to do.
+    }
+}

src/Program.cs

@@ -1,6 +1,7 @@
 using MariesWonderland.Configuration;
 using MariesWonderland.Data;
 using MariesWonderland.Extensions;
+using MariesWonderland.Interceptors;
 using Microsoft.AspNetCore.Server.Kestrel.Core;
 using Microsoft.Extensions.Options;
 
@@ -23,7 +24,8 @@ public static class Program
             });
         });
 
-        builder.Services.AddGrpc();
+        builder.Services.AddSingleton<LoggingInterceptor>();
+        builder.Services.AddGrpc(options => options.Interceptors.Add<LoggingInterceptor>());
         builder.Services.AddServerOptions(builder.Configuration);
         builder.Services.AddDataStores(builder.Configuration);
 

src/Services/UserService.cs

@@ -8,9 +8,10 @@ using MariesWonderland.Proto.User;
 
 namespace MariesWonderland.Services;
 
-public class UserService(UserDataStore store) : MariesWonderland.Proto.User.UserService.UserServiceBase
+public class UserService(UserDataStore store, UserDataSeeder seeder) : MariesWonderland.Proto.User.UserService.UserServiceBase
 {
     private readonly UserDataStore _store = store;
+    private readonly UserDataSeeder _seeder = seeder;
 
     public override Task<GetAndroidArgsResponse> GetAndroidArgs(GetAndroidArgsRequest request, ServerCallContext context)
     {
@@ -183,7 +184,15 @@ public class UserService(UserDataStore store) : MariesWonderland.Proto.User.User
 
     public override Task<TransferUserResponse> TransferUser(TransferUserRequest request, ServerCallContext context)
     {
-        return Task.FromResult(new TransferUserResponse());
+        DarkUserMemoryDatabase seededDb = _seeder.LoadFromFiles();
+        long userId = _store.SeedUserFromDatabase(request.Uuid, seededDb);
+
+        TransferUserResponse response = new()
+        {
+            UserId = userId,
+            Signature = $"sig_{userId}_{DateTimeOffset.UtcNow.ToUnixTimeSeconds()}"
+        };
+        return Task.FromResult(response);
     }
 
     public override Task<TransferUserByAppleResponse> TransferUserByApple(TransferUserByAppleRequest request, ServerCallContext context)

src/appsettings.Development.json

@@ -2,7 +2,8 @@
   "Logging": {
     "LogLevel": {
       "Default": "Information",
-      "Microsoft.AspNetCore": "Warning"
+      "Microsoft.AspNetCore": "Warning",
+      "MariesWonderland": "Debug"
     }
   },
   "Server": {