net10, the refactor finished, and federation that works

The tree had not compiled since its first commit: Group, DmGroup and
IGroupUsersService were referenced and never written, an IDE rename had
turned the user-settings DTO into the ViewAvatarServer enum, and the settings
were saved as an entity they no longer were.

Built now:
- Group (an ActivityPub Group actor with its own keys, members, invitation
  code and optional password) and DmGroup (a conversation), with
  /clientapi/group/{list,insert,update,join,leave,approve}.
- Posts and DMs: /clientapi/post/{list,insert,delete}, /clientapi/dm/{list,insert};
  DM recipients are local usernames or user@host handles resolved by WebFinger.
- Invitation sign-up and login against the group's invitation code, checking
  the password before any account is created.
- Federation: WebFinger, NodeInfo 2.0, actors at /peasants/{name} (Person,
  Group, and an Application instance actor) with SPKI keys, draft-cavage
  RSA-SHA256 HTTP signatures both ways, an inbox handling Follow (+Accept),
  Undo, Create, Delete and Update, an outbox, notes at /posts/{id}, and a
  persisted, retried, signed delivery queue. A post to a group is announced
  by the group to its followers (FEP-1b12).
- The unused, broken typed ActivityPub models are replaced by a renderer;
  NSign's HMAC setup, which could not federate, is gone.

Upgrade: net10.0, MongoDB.Entities 25.1 (instance DB API, Standard GUIDs),
Swashbuckle 10 / OpenApi 2, Serilog.AspNetCore 10, MailKit 4.18,
PasswordGenerator 3. The JWT keys are 64 bytes (IdentityModel 8 refuses
shorter for HS512). Production runs its own mongod on 127.0.0.1:27022, as
Sintopia's apps do, and deploys to privapub.thepra.dev from the build runner.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012CzABvBkbcFqoHdmi8b9WB

PrivaPub/Services/ClientToServer/Private/IPrivateAvatarUsersService.cs

@@ -1,37 +1,37 @@
-using Microsoft.Extensions.Localization;
+using Microsoft.Extensions.Localization;
 
 using MongoDB.Entities;
 
 using PrivaPub.ClientModels;
+using PrivaPub.ClientModels.User;
 using PrivaPub.ClientModels.User.Avatar;
-using PrivaPub.Models;
 using PrivaPub.Models.User;
 using PrivaPub.Resources;
+using PrivaPub.Services.Federation;
 using PrivaPub.StaticServices;
 
-using System.Security.Cryptography;
-
 namespace PrivaPub.Services.ClientToServer.Private
 {
 	public interface IPrivateAvatarUsersService
 	{
 		Task<WebResult> UpdateAvatar(UpdateAvatarForm form);
 		Task<WebResult> InsertAvatar(InsertAvatarForm form);
+		Task<WebResult> GetRootAvatars(string rootUserId, CancellationToken token);
 	}
 
 	public class PrivateAvatarUsersService : IPrivateAvatarUsersService
 	{
-		readonly AppConfigurationService _appConfiguration;
+		readonly ILocalActorService _localActors;
 		readonly DbEntities _dbEntities;
 		readonly IStringLocalizer<GenericRes> _localizer;
 		readonly ILogger<PrivateAvatarUsersService> _logger;
 
-		public PrivateAvatarUsersService(AppConfigurationService appConfiguration,
+		public PrivateAvatarUsersService(ILocalActorService localActors,
 			DbEntities dbEntities,
 			IStringLocalizer<GenericRes> localizer,
 			ILogger<PrivateAvatarUsersService> logger)
 		{
-			_appConfiguration = appConfiguration;
+			_localActors = localActors;
 			_dbEntities = dbEntities;
 			_localizer = localizer;
 			_logger = logger;
@@ -42,54 +42,46 @@ namespace PrivaPub.Services.ClientToServer.Private
 			var result = new WebResult();
 			try
 			{
-				if (await _dbEntities.Avatars.Match(a => a.UserName == form.UserName).ExecuteAnyAsync())
-					return result.Invalidate(_localizer["The username '{0}' is already take.", form.UserName]);
+				var userName = form.UserName?.Trim().ToLowerInvariant();
+				if (string.IsNullOrEmpty(userName) || !userName.All(c => char.IsAsciiLetterOrDigit(c) || c == '_'))
+					return result.Invalidate(_localizer["The username may contain only letters, digits and underscores."]);
+
+				if (await _localActors.IsUserNameTaken(userName, default))
+					return result.Invalidate(_localizer["The username '{0}' is already take.", userName]);
 
 				if (!await IsValidRootUser(form.RootId))
 					return result.Invalidate(_localizer["You can't do this action because of your account status."]);
 
+				var (privateKey, publicKey) = Keys.NewKeyPair();
 				var newAvatar = new Avatar
 				{
 					Name = form.Name,
-					UserName = form.UserName,
+					UserName = userName,
 					Biography = form.Biography,
 					Fields = form.Fields,
 					PersonalNote = form.PersonalNote,
+					PrivateKey = privateKey,
+					PublicKey = publicKey,
+					Domain = _localActors.BaseAddress
 				};
-				if (!form.Settings.IsDefault)
-					newAvatar.Settings = new()
-					{
-						IsDefault = false,
-						DarkThemeIndexColour = form.Settings.DarkThemeIndexColour,
-						IconsThemeIndexColour = form.Settings.IconsThemeIndexColour,
-						LanguageCode = form.Settings.LanguageCode,
-						LightThemeIndexColour = form.Settings.LightThemeIndexColour,
-						PreferSystemTheming = form.Settings.PreferSystemTheming,
-						ThemeIsDarkGray = form.Settings.ThemeIsDarkGray,
-						ThemeIsDarkMode = form.Settings.ThemeIsDarkMode,
-						ThemeIsLightGray = form.Settings.ThemeIsLightGray
-					};
+				if (form.Settings is { IsDefault: false })
+					newAvatar.Settings = ToSettings(form.Settings);
 
-				if (_appConfiguration.AppConfiguration == default)
-					await _appConfiguration.Init();
+				var actor = _localActors.FromAvatar(newAvatar);
+				newAvatar.Url = actor.Uri;
+				newAvatar.InboxURL = actor.Inbox;
+				newAvatar.OutboxURL = actor.Outbox;
 
-				newAvatar.Url = _appConfiguration.AppConfiguration.BackendBaseAddress + $"/peasants/{form.UserName}";
-				newAvatar.Domain = _appConfiguration.AppConfiguration.BackendBaseAddress;
-				newAvatar.InboxURL = _appConfiguration.AppConfiguration.BackendBaseAddress + $"/peasants/{form.UserName}/mouth";
-				newAvatar.OutboxURL = _appConfiguration.AppConfiguration.BackendBaseAddress + $"/peasants/{form.UserName}/anus";
-				var rsa = RSA.Create();
-				newAvatar.PrivateKey = rsa.ExportRSAPrivateKeyPem();
-				newAvatar.PublicKey = rsa.ExportRSAPublicKeyPem();
-
-				await newAvatar.SaveAsync();
-				result.Data = newAvatar;
+				await DB.Default.SaveAsync(newAvatar);
+				await DB.Default.SaveAsync(new RootToAvatar { RootId = form.RootId, AvatarId = newAvatar.ID });
 
+				result.Data = ToView(newAvatar);
 				return result;
 			}
 			catch (Exception ex)
 			{
 				_logger.LogError(ex, $"{nameof(PrivateAvatarUsersService)}.{nameof(InsertAvatar)}");
-				return result.Invalidate(_localizer["Error: {0}", ex.ToString()], exception: ex);
+				return result.Invalidate(_localizer["Error: {0}", ex.Message], exception: ex);
 			}
 		}
 
@@ -98,18 +90,106 @@ namespace PrivaPub.Services.ClientToServer.Private
 			var result = new WebResult();
 			try
 			{
+				if (!await IsValidRootUser(form.RootId))
+					return result.Invalidate(_localizer["You can't do this action because of your account status."]);
 
+				var owns = await _dbEntities.RootToAvatars
+					.Match(ra => ra.RootId == form.RootId && ra.AvatarId == form.AvatarId)
+					.ExecuteAnyAsync();
+				if (!owns)
+					return result.Invalidate(_localizer["Avatar not found."], StatusCodes.Status404NotFound);
+
+				var avatar = await _dbEntities.Avatars.MatchID(form.AvatarId).ExecuteFirstAsync();
+				if (avatar == default || avatar.DeletionAt.HasValue)
+					return result.Invalidate(_localizer["Avatar not found."], StatusCodes.Status404NotFound);
+
+				avatar.Name = form.Name;
+				avatar.Biography = form.Biography;
+				avatar.Fields = form.Fields ?? new();
+				avatar.PersonalNote = form.PersonalNote;
+				if (form.Settings != default)
+					avatar.Settings = ToSettings(form.Settings);
+				avatar.UpdatedAt = DateTime.UtcNow;
+				await DB.Default.SaveAsync(avatar);
+
+				result.Data = ToView(avatar);
+				return result;
 			}
 			catch (Exception ex)
 			{
 				_logger.LogError(ex, $"{nameof(PrivateAvatarUsersService)}.{nameof(UpdateAvatar)}");
-				return result.Invalidate(_localizer["Error: {0}", ex.ToString()], exception: ex);
+				return result.Invalidate(_localizer["Error: {0}", ex.Message], exception: ex);
+			}
+		}
+
+		public async Task<WebResult> GetRootAvatars(string rootUserId, CancellationToken token)
+		{
+			var result = new WebResult();
+			try
+			{
+				var avatarIds = (await _dbEntities.RootToAvatars.Match(ra => ra.RootId == rootUserId).ExecuteAsync(token))
+					.Select(ra => ra.AvatarId)
+					.ToList();
+				var avatars = avatarIds.Count == 0
+					? new List<Avatar>()
+					: await _dbEntities.Avatars.Match(a => avatarIds.Contains(a.ID) && !a.DeletionAt.HasValue).ExecuteAsync(token);
+				result.Data = avatars.Select(ToView).ToList();
+				return result;
+			}
+			catch (Exception ex)
+			{
+				_logger.LogError(ex, $"{nameof(PrivateAvatarUsersService)}.{nameof(GetRootAvatars)}");
+				return result.Invalidate(_localizer["Error: {0}", ex.Message], exception: ex);
 			}
 		}
 
 		async ValueTask<bool> IsValidRootUser(string rootUserId) =>
-			await _dbEntities.RootUsers.MatchID(rootUserId)
-			.Match(ru => !ru.DeletedAt.HasValue)
-			.ExecuteAnyAsync();
+			!string.IsNullOrEmpty(rootUserId)
+			&& await _dbEntities.RootUsers.MatchID(rootUserId)
+				.Match(ru => !ru.DeletedAt.HasValue && !ru.IsBanned)
+				.ExecuteAnyAsync();
+
+		static AvatarSettings ToSettings(ViewAvatarSettings settings) => new()
+		{
+			IsDefault = settings.IsDefault,
+			DarkThemeIndexColour = settings.DarkThemeIndexColour,
+			IconsThemeIndexColour = settings.IconsThemeIndexColour,
+			LanguageCode = settings.LanguageCode,
+			LightThemeIndexColour = settings.LightThemeIndexColour,
+			PreferSystemTheming = settings.PreferSystemTheming,
+			ThemeIsDarkGray = settings.ThemeIsDarkGray,
+			ThemeIsDarkMode = settings.ThemeIsDarkMode,
+			ThemeIsLightGray = settings.ThemeIsLightGray
+		};
+
+		ViewAvatar ToView(Avatar avatar) => new()
+		{
+			Id = avatar.ID,
+			Url = avatar.Url,
+			Handle = _localActors.FromAvatar(avatar).Handle,
+			Name = avatar.Name,
+			UserName = avatar.UserName,
+			Biography = avatar.Biography,
+			Fields = avatar.Fields,
+			PictureURL = avatar.PictureURL,
+			ThumbnailURL = avatar.ThumbnailURL,
+			SharedPersonalContacts = avatar.SharedPersonalContacts,
+			AccountState = (ViewAvatarState)(int)avatar.AccountState,
+			ServerType = ViewAvatarServer.PrivaPub,
+			Settings = new()
+			{
+				IsDefault = avatar.Settings.IsDefault,
+				LanguageCode = avatar.Settings.LanguageCode,
+				IconsThemeIndexColour = avatar.Settings.IconsThemeIndexColour,
+				LightThemeIndexColour = avatar.Settings.LightThemeIndexColour,
+				DarkThemeIndexColour = avatar.Settings.DarkThemeIndexColour,
+				PreferSystemTheming = avatar.Settings.PreferSystemTheming,
+				ThemeIsDarkMode = avatar.Settings.ThemeIsDarkMode,
+				ThemeIsDarkGray = avatar.Settings.ThemeIsDarkGray,
+				ThemeIsLightGray = avatar.Settings.ThemeIsLightGray
+			},
+			UpdatedAt = avatar.UpdatedAt,
+			CreatedAt = avatar.CreatedAt
+		};
 	}
 }