Forbid creating usernames with uppercase characters

We don't actually enforce anything on the ActivityPub level, only
user-facing interfaces

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/graphql/resolvers/group.ex

@@ -123,6 +123,7 @@ defmodule Mobilizon.GraphQL.Resolvers.Group do
       ) do
     with creator_actor_id <- Map.get(args, :creator_actor_id),
          {:is_owned, %Actor{} = creator_actor} <- User.owns_actor(user, creator_actor_id),
+         args <- Map.update(args, :preferred_username, "", &String.downcase/1),
          args <- Map.put(args, :creator_actor, creator_actor),
          args <- save_attached_pictures(args),
          {:ok, _activity, %Actor{type: :Group} = group} <-

lib/graphql/resolvers/person.ex

@@ -120,7 +120,8 @@ defmodule Mobilizon.GraphQL.Resolvers.Person do
       ) do
     args = Map.put(args, :user_id, user.id)
 
-    with args <- save_attached_pictures(args),
+    with args <- Map.update(args, :preferred_username, "", &String.downcase/1),
+         args <- save_attached_pictures(args),
          {:ok, %Actor{} = new_person} <- Actors.new_person(args) do
       {:ok, new_person}
     end
@@ -220,6 +221,7 @@ defmodule Mobilizon.GraphQL.Resolvers.Person do
          user_actor <- Users.get_actor_for_user(user),
          no_actor <- is_nil(user_actor),
          {:no_actor, true} <- {:no_actor, no_actor},
+         args <- Map.update(args, :preferred_username, "", &String.downcase/1),
          args <- Map.put(args, :user_id, user.id),
          args <- save_attached_pictures(args),
          {:ok, %Actor{} = new_person} <- Actors.new_person(args, true) do

lib/mobilizon/actors/actor.ex

@@ -18,6 +18,7 @@ defmodule Mobilizon.Actors.Actor do
 
   alias Mobilizon.Web.Endpoint
   alias Mobilizon.Web.Router.Helpers, as: Routes
+  import Mobilizon.Web.Gettext, only: [dgettext: 2]
 
   require Logger
 
@@ -337,7 +338,11 @@ defmodule Mobilizon.Actors.Actor do
        ) do
     with nil <- Map.get(changes, :domain, nil),
          %__MODULE__{preferred_username: _} <- Actors.get_local_actor_by_name(username) do
-      add_error(changeset, :preferred_username, "Username is already taken")
+      add_error(
+        changeset,
+        :preferred_username,
+        dgettext("errors", "This username is already taken.")
+      )
     else
       _ -> changeset
     end