Put HTTPSignatures, WebFinger and ActivityStream alongside with ActivityPub

lib/federation/activity_stream/converter/flag.ex

@@ -0,0 +1,105 @@
+defmodule Mobilizon.Federation.ActivityStream.Converter.Flag do
+  @moduledoc """
+  Flag converter.
+
+  This module allows to convert reports from ActivityStream format to our own
+  internal one, and back.
+
+  Note: Reports are named Flag in AS.
+  """
+
+  alias Mobilizon.Actors
+  alias Mobilizon.Actors.Actor
+  alias Mobilizon.Events
+  alias Mobilizon.Events.Event
+  alias Mobilizon.Reports.Report
+
+  alias Mobilizon.Federation.ActivityPub.Relay
+  alias Mobilizon.Federation.ActivityStream.{Converter, Convertible}
+
+  @behaviour Converter
+
+  defimpl Convertible, for: Report do
+    alias Mobilizon.Federation.ActivityStream.Converter.Flag, as: FlagConverter
+
+    defdelegate model_to_as(report), to: FlagConverter
+  end
+
+  @doc """
+  Converts an AP object data to our internal data structure.
+  """
+  @impl Converter
+  @spec as_to_model_data(map) :: map
+  def as_to_model_data(object) do
+    with params <- as_to_model(object) do
+      %{
+        "reporter_id" => params["reporter"].id,
+        "uri" => params["uri"],
+        "content" => params["content"],
+        "reported_id" => params["reported"].id,
+        "event_id" => (!is_nil(params["event"]) && params["event"].id) || nil,
+        "comments" => params["comments"]
+      }
+    end
+  end
+
+  @doc """
+  Convert an event struct to an ActivityStream representation
+  """
+  @impl Converter
+  @spec model_to_as(Report.t()) :: map
+  def model_to_as(%Report{} = report) do
+    object = [report.reported.url] ++ Enum.map(report.comments, fn comment -> comment.url end)
+
+    object = if report.event, do: object ++ [report.event.url], else: object
+
+    %{
+      "type" => "Flag",
+      "actor" => Relay.get_actor().url,
+      "id" => report.url,
+      "content" => report.content,
+      "object" => object
+    }
+  end
+
+  @spec as_to_model(map) :: map
+  def as_to_model(%{"object" => objects} = object) do
+    with {:ok, %Actor{} = reporter} <- Actors.get_actor_by_url(object["actor"]),
+         %Actor{} = reported <-
+           Enum.reduce_while(objects, nil, fn url, _ ->
+             case Actors.get_actor_by_url(url) do
+               {:ok, %Actor{} = actor} ->
+                 {:halt, actor}
+
+               _ ->
+                 {:cont, nil}
+             end
+           end),
+         event <-
+           Enum.reduce_while(objects, nil, fn url, _ ->
+             case Events.get_event_by_url(url) do
+               %Event{} = event ->
+                 {:halt, event}
+
+               _ ->
+                 {:cont, nil}
+             end
+           end),
+
+         # Remove the reported actor and the event from the object list.
+         comments <-
+           Enum.filter(objects, fn url ->
+             !(url == reported.url || (!is_nil(event) && event.url == url))
+           end),
+         comments <- Enum.map(comments, &Events.get_comment_from_url/1) do
+      %{
+        "reporter" => reporter,
+        "uri" => object["id"],
+        "content" => object["content"],
+        "reported" => reported,
+        "event" => event,
+        "comments" => comments
+      }
+    end
+  end
+end