marks notifications as read after mute

lib/pleroma/notification.ex

@@ -648,4 +648,16 @@ defmodule Pleroma.Notification do
     )
     |> Repo.one()
   end
+
+  @spec mark_as_read(User.t(), Activity.t()) :: {integer(), nil | [term()]}
+  def mark_as_read(%User{id: id}, %Activity{data: %{"context" => context}}) do
+    from(
+      n in Notification,
+      join: a in assoc(n, :activity),
+      where: n.user_id == ^id,
+      where: n.seen == false,
+      where: fragment("?->>'context'", a.data) == ^context
+    )
+    |> Repo.update_all(set: [seen: true])
+  end
 end

lib/pleroma/web/common_api/common_api.ex

@@ -452,7 +452,8 @@ defmodule Pleroma.Web.CommonAPI do
   end
 
   def add_mute(user, activity) do
-    with {:ok, _} <- ThreadMute.add_mute(user.id, activity.data["context"]) do
+    with {:ok, _} <- ThreadMute.add_mute(user.id, activity.data["context"]),
+         _ <- Pleroma.Notification.mark_as_read(user, activity) do
       {:ok, activity}
     else
       {:error, _} -> {:error, dgettext("errors", "conversation is already muted")}