Put HTTPSignatures, WebFinger and ActivityStream alongside with ActivityPub

lib/federation/activity_stream/converter/participant.ex

@@ -0,0 +1,31 @@
+defmodule Mobilizon.Federation.ActivityStream.Converter.Participant do
+  @moduledoc """
+  Participant converter.
+
+  This module allows to convert reports from ActivityStream format to our own
+  internal one, and back.
+  """
+
+  alias Mobilizon.Events.Participant, as: ParticipantModel
+
+  alias Mobilizon.Federation.ActivityStream.Convertible
+
+  defimpl Convertible, for: ParticipantModel do
+    alias Mobilizon.Federation.ActivityStream.Converter.Participant, as: ParticipantConverter
+
+    defdelegate model_to_as(participant), to: ParticipantConverter
+  end
+
+  @doc """
+  Convert an event struct to an ActivityStream representation.
+  """
+  @spec model_to_as(ParticipantModel.t()) :: map
+  def model_to_as(%ParticipantModel{} = participant) do
+    %{
+      "type" => "Join",
+      "id" => participant.url,
+      "actor" => participant.actor.url,
+      "object" => participant.event.url
+    }
+  end
+end