wip: utility function to get stop by ID

lib/arrow/shuttles.ex

@@ -9,10 +9,12 @@ defmodule Arrow.Shuttles do
   alias ArrowWeb.ErrorHelpers
 
   alias Arrow.Gtfs.Route, as: GtfsRoute
+  alias Arrow.Gtfs.Stop, as: GtfsStop
   alias Arrow.Shuttles.KML
   alias Arrow.Shuttles.Shape
   alias Arrow.Shuttles.ShapesUpload
   alias Arrow.Shuttles.ShapeUpload
+  alias Arrow.Shuttles.Stop
 
   @doc """
   Returns the list of shapes.
@@ -331,4 +333,17 @@ defmodule Arrow.Shuttles do
     query = from(r in GtfsRoute, where: r.type in [:light_rail, :heavy_rail])
     Repo.all(query)
   end
+
+  @doc """
+  Given a stop ID, returns either an Arrow-created stop, or a
+  stop from GTFS. Prefers the Arrow-created stop if both are
+  present.
+  """
+  @spec stop_or_gtfs_stop_for_stop_id(String.t()) :: Stop.t() | GtfsStop.t() | nil
+  def stop_or_gtfs_stop_for_stop_id(id) do
+    case Repo.get(Stop, id) do
+      nil -> Repo.get(GtfsStop, id)
+      stop -> stop
+    end
+  end
 end

test/arrow/shuttles_test.exs

@@ -4,6 +4,7 @@ defmodule Arrow.ShuttlesTest do
   alias Arrow.Shuttles
   alias Arrow.Shuttles.Shape
   import Arrow.ShuttlesFixtures
+  import Arrow.StopsFixtures
   import Test.Support.Helpers
 
   describe "shapes with s3 functionality enabled (mocked)" do
@@ -214,4 +215,11 @@ defmodule Arrow.ShuttlesTest do
       assert %Ecto.Changeset{} = Shuttles.change_shuttle(shuttle)
     end
   end
+
+  describe "stop_or_gtfs_stop_for_stop_id/1" do
+    test "fetches Arrow stop" do
+      stop = stop_fixture()
+      assert ^stop = Shuttles.stop_or_gtfs_stop_for_stop_id(stop.id)
+    end
+  end
 end