Introduce instance ICS & Atom feeds (disabled by default)

And refactor the feed modules

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

lib/service/export/common.ex

@@ -0,0 +1,77 @@
+defmodule Mobilizon.Service.Export.Common do
+  @moduledoc """
+  Common tools for exportation
+  """
+
+  alias Mobilizon.{Actors, Events, Posts, Users}
+  alias Mobilizon.Actors.Actor
+  alias Mobilizon.Events.{Event, FeedToken}
+  alias Mobilizon.Storage.Page
+  alias Mobilizon.Users.User
+
+  @spec fetch_actor_event_feed(String.t()) :: String.t()
+  def fetch_actor_event_feed(name) do
+    with %Actor{} = actor <- Actors.get_local_actor_by_name(name),
+         {:visibility, true} <- {:visibility, Actor.is_public_visibility?(actor)},
+         %Page{elements: events} <- Events.list_public_events_for_actor(actor),
+         %Page{elements: posts} <- Posts.get_public_posts_for_group(actor) do
+      {:ok, actor, events, posts}
+    else
+      err ->
+        {:error, err}
+    end
+  end
+
+  # Only events, not posts
+  @spec fetch_events_from_token(String.t()) :: String.t()
+  def fetch_events_from_token(token) do
+    with {:ok, _uuid} <- Ecto.UUID.cast(token),
+         %FeedToken{actor: actor, user: %User{} = user} <- Events.get_feed_token(token) do
+      case actor do
+        %Actor{} = actor ->
+          %{
+            type: :actor,
+            actor: actor,
+            events: fetch_actor_private_events(actor),
+            user: user,
+            token: token
+          }
+
+        nil ->
+          with actors <- Users.get_actors_for_user(user),
+               events <-
+                 actors
+                 |> Enum.map(&fetch_actor_private_events/1)
+                 |> Enum.concat() do
+            %{type: :user, events: events, user: user, token: token, actor: nil}
+          end
+      end
+    end
+  end
+
+  @spec fetch_instance_public_content :: {:ok, list(Event.t()), list(Post.t())}
+  def fetch_instance_public_content do
+    with %Page{elements: events} <- Events.list_public_local_events(),
+         %Page{elements: posts} <- Posts.list_public_local_posts() do
+      {:ok, events, posts}
+    end
+  end
+
+  @spec fetch_actor_private_events(Actor.t()) :: list(Event.t())
+  def fetch_actor_private_events(%Actor{} = actor) do
+    actor |> fetch_identity_participations() |> participations_to_events()
+  end
+
+  @spec fetch_identity_participations(Actor.t()) :: Page.t()
+  defp fetch_identity_participations(%Actor{} = actor) do
+    with %Page{} = page <- Events.list_event_participations_for_actor(actor) do
+      page
+    end
+  end
+
+  defp participations_to_events(%Page{elements: participations}) do
+    participations
+    |> Enum.map(& &1.event_id)
+    |> Enum.map(&Events.get_event_with_preload!/1)
+  end
+end