fix(Store.Predictions): Only remove trips if there are no other predi…

…ctions (#217)

* chore: cleanup prediction store trip logs

* fix(Store.Predictions): Only remove trips if there are no other predictions for that trip

lib/mbta_v3_api/store/predictions.ex

@@ -95,7 +95,7 @@ defmodule MBTAV3API.Store.Predictions.Impl do
           Store.timed_fetch(
             @trips_table_name,
             trip_match_specs,
-            "fetch_keys=#{inspect(trip_fetch_keys_list)}"
+            "trip_count=#{inspect(length(trip_fetch_keys_list))}"
           )
 
     vehicles =
@@ -189,12 +189,25 @@ defmodule MBTAV3API.Store.Predictions.Impl do
   @impl true
   def process_remove(references) do
     for reference <- references do
-      Logger.info("#{__MODULE__} process_remove #{inspect(reference)}")
-
       case reference do
-        %{type: "prediction", id: id} -> :ets.delete(@predictions_table_name, id)
-        %{type: "trip", id: id} -> :ets.delete(@trips_table_name, id)
-        _ -> :ok
+        %{type: "prediction", id: id} ->
+          Logger.info("#{__MODULE__} process_remove type=prediction id=#{id}")
+          :ets.delete(@predictions_table_name, id)
+
+        %{type: "trip", id: id} ->
+          exsiting_predictions_for_trip = fetch(trip_id: id)
+
+          if Enum.empty?(exsiting_predictions_for_trip) do
+            Logger.info("#{__MODULE__} process_remove type=trip id=#{id}")
+            :ets.delete(@trips_table_name, id)
+          else
+            Logger.info(
+              "#{__MODULE__} process_remove skipping removal type=trip id=#{id} remaining_prediction_count=#{length(exsiting_predictions_for_trip)}"
+            )
+          end
+
+        _ ->
+          :ok
       end
     end
 

test/mbta_v3_api/store/predictions_test.exs

@@ -83,13 +83,58 @@ defmodule MBTAV3API.Store.PredictionsTest do
           ])
         end)
 
-      assert msg =~ "process_remove %MBTAV3API.JsonApi.Reference{type: \"prediction\", id: \"1\"}"
-      assert msg =~ "process_remove %MBTAV3API.JsonApi.Reference{type: \"trip\", id: \"trip_1\"}"
+      assert msg =~ "process_remove type=prediction id=1"
+      assert msg =~ "process_remove type=trip id=trip_1"
 
       assert JsonApi.Object.to_full_map([prediction_2, trip_2]) ==
                Store.Predictions.fetch_with_associations(stop_id: "12345")
     end
 
+    @tag :capture_log
+    test "process_remove when trip still has predictions on another route, trip not deleted", %{
+      prediction_1: prediction_1,
+      prediction_2: prediction_2,
+      trip_1: trip_1,
+      trip_2: trip_2
+    } do
+      set_log_level(:info)
+
+      trip_1_prediction_other_route = %{
+        prediction_1
+        | id: "other_prediction_trip_1",
+          route_id: "OTHER_ROUTE"
+      }
+
+      Store.Predictions.process_upsert(:add, [
+        prediction_1,
+        prediction_2,
+        trip_1_prediction_other_route,
+        trip_1,
+        trip_2
+      ])
+
+      msg =
+        capture_log([level: :info], fn ->
+          Store.Predictions.process_remove([
+            %Reference{type: "prediction", id: prediction_1.id},
+            %Reference{type: "trip", id: trip_1.id}
+          ])
+        end)
+
+      assert msg =~ "process_remove type=prediction id=1"
+
+      assert msg =~
+               "process_remove skipping removal type=trip id=trip_1 remaining_prediction_count=1"
+
+      assert JsonApi.Object.to_full_map([
+               prediction_2,
+               trip_1_prediction_other_route,
+               trip_1,
+               trip_2
+             ]) ==
+               Store.Predictions.fetch_with_associations(stop_id: "12345")
+    end
+
     test "process_reset" do
       prediction_66 =
         build(:prediction, id: "1", stop_id: "12345", route_id: "66", trip_id: "trip_1")