Extend /api/pleroma/notifications/read to mark multiple notifications

as read and make it respond with Mastoapi entities

lib/pleroma/notification.ex

@@ -102,15 +102,32 @@ defmodule Pleroma.Notification do
         n in Notification,
         where: n.user_id == ^user_id,
         where: n.id <= ^id,
+        where: n.seen == false,
         update: [
           set: [
             seen: true,
             updated_at: ^NaiveDateTime.utc_now()
           ]
-        ]
+        ],
+        # Ideally we would preload object and activities here
+        # but Ecto does not support preloads in update_all
+        select: n.id
       )
 
-    Repo.update_all(query, [])
+    {_, notification_ids} = Repo.update_all(query, [])
+
+    from(n in Notification, where: n.id in ^notification_ids)
+    |> join(:inner, [n], activity in assoc(n, :activity))
+    |> join(:left, [n, a], object in Object,
+      on:
+        fragment(
+          "(?->>'id') = COALESCE((? -> 'object'::text) ->> 'id'::text)",
+          object.data,
+          a.data
+        )
+    )
+    |> preload([n, a, o], activity: {a, object: o})
+    |> Repo.all()
   end
 
   def read_one(%User{} = user, notification_id) do