Introduce group basic federation, event new page and notifications

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

lib/federation/activity_stream/converter/member.ex

@@ -0,0 +1,57 @@
+defmodule Mobilizon.Federation.ActivityStream.Converter.Member do
+  @moduledoc """
+  Member converter.
+
+  This module allows to convert members from ActivityStream format to our own
+  internal one, and back.
+  """
+
+  alias Mobilizon.Actors.Actor
+  alias Mobilizon.Actors.Member, as: MemberModel
+  alias Mobilizon.Federation.ActivityPub
+  alias Mobilizon.Federation.ActivityPub.Utils
+
+  alias Mobilizon.Federation.ActivityStream.Convertible
+
+  defimpl Convertible, for: MemberModel do
+    alias Mobilizon.Federation.ActivityStream.Converter.Member, as: MemberConverter
+
+    defdelegate model_to_as(member), to: MemberConverter
+  end
+
+  @doc """
+  Convert an event struct to an ActivityStream representation.
+  """
+  @spec model_to_as(MemberModel.t()) :: map
+  def model_to_as(%MemberModel{} = member) do
+    %{
+      "type" => "Member",
+      "id" => member.url,
+      "actor" => member.actor.url,
+      "object" => member.parent.url,
+      "role" => member.role
+    }
+  end
+
+  def as_to_model_data(%{
+        "type" => "Member",
+        "actor" => actor,
+        "object" => group,
+        "role" => role,
+        "id" => url
+      }) do
+    with {:ok, %Actor{id: group_id}} <- get_actor(group),
+         {:ok, %Actor{id: actor_id}} <- get_actor(actor) do
+      %{
+        url: url,
+        actor_id: actor_id,
+        parent_id: group_id,
+        role: role
+      }
+    end
+  end
+
+  @spec get_actor(String.t() | map() | nil) :: {:ok, Actor.t()} | {:error, String.t()}
+  defp get_actor(nil), do: {:error, "nil property found for actor data"}
+  defp get_actor(actor), do: actor |> Utils.get_url() |> ActivityPub.get_or_fetch_actor_by_url()
+end