fix: actually include sensor firmware version string in repo, /version response

lib/localiser/domain/sensors.ex

@@ -59,9 +59,29 @@ defmodule Localiser.Domain.Sensors do
     {:ok, sensor}
   end
 
+  @version_timeout_ms 5_000
+
   def get_version(%Sensor{} = sensor) do
-    Localiser.MQTT.Connection.publish(cmd_topic(sensor), Jason.encode!(%{action: "version"}))
-    {:ok, sensor}
+    :ok = Phoenix.PubSub.subscribe(Localiser.PubSub, "sensors")
+
+    case Localiser.MQTT.Connection.publish(cmd_topic(sensor), Jason.encode!(%{action: "version"})) do
+      :ok ->
+        result =
+          receive do
+            {:sensor_announced, %Sensor{sensor_id: sid, firmware_version: v}}
+            when sid == sensor.sensor_id and not is_nil(v) ->
+              {:ok, v}
+          after
+            @version_timeout_ms -> {:error, :timeout}
+          end
+
+        Phoenix.PubSub.unsubscribe(Localiser.PubSub, "sensors")
+        result
+
+      error ->
+        Phoenix.PubSub.unsubscribe(Localiser.PubSub, "sensors")
+        error
+    end
   end
 
   def send_ota_update(%Sensor{} = sensor, url, version) do
@@ -169,12 +189,22 @@ defmodule Localiser.Domain.Sensors do
 
   # Called when an ESP board self-announces on MQTT. Inserts a new unplaced sensor
   # record, or marks it confirmed if the sensor_id already exists.
-  def upsert_announced(sensor_id) do
+  def upsert_announced(sensor_id, firmware_version \\ nil) do
+    attrs = %{sensor_id: sensor_id, confirmed: true}
+    attrs = if firmware_version, do: Map.put(attrs, :firmware_version, firmware_version), else: attrs
+
+    on_conflict =
+      if firmware_version do
+        [set: [confirmed: true, firmware_version: firmware_version, updated_at: DateTime.utc_now()]]
+      else
+        [set: [confirmed: true, updated_at: DateTime.utc_now()]]
+      end
+
     result =
       %Sensor{}
-      |> Sensor.changeset(%{sensor_id: sensor_id, confirmed: true})
+      |> Sensor.changeset(attrs)
       |> Repo.insert(
-        on_conflict: [set: [confirmed: true, updated_at: DateTime.utc_now()]],
+        on_conflict: on_conflict,
         conflict_target: :sensor_id,
         returning: true
       )