fixup: fix lat and lon inputs

lib/arrow_web/live/stop_live/stop_live.ex

@@ -126,19 +126,27 @@ defmodule ArrowWeb.StopViewLive do
     {:ok, socket}
   end
 
+  defp valid_float(str) do
+    case Float.parse(str) do 
+      {float, _} -> float
+      _ -> nil
+    end
+  end
+
   def handle_event("validate", %{"stop" => stop_params}, socket) do
     form = Stops.change_stop(socket.assigns.stop, stop_params) |> to_form(action: :validate)
 
     {existing_stops, existing_gtfs_stops} =
       case stop_params do
-        %{"stop_lat" => lat, "stop_lon" => lon, "stop_id" => stop_id}
-        when not is_nil(lat) and not is_nil(lon) and lat != "" and lon != "" ->
-          lat_float = String.to_float(lat)
-          lon_float = String.to_float(lon)
-
-          {Stops.get_stops_within_mile(stop_id, {lat_float, lon_float}),
-           GtfsStop.get_stops_within_mile(stop_id, {lat_float, lon_float})}
-
+        %{"stop_lat" => lat, "stop_lon" => lon, "stop_id" => stop_id} ->
+          float_lat = valid_float(lat)
+          float_lon = valid_float(lon)
+          if is_float(float_lat) and is_float(float_lon) do
+            {Stops.get_stops_within_mile(stop_id, {float_lat, float_lon}),
+             GtfsStop.get_stops_within_mile(stop_id, {float_lat, float_lon})}
+          else
+            {nil, nil}
+          end
         _ ->
           {nil, nil}
       end