feat: include self-reported tx_power in measurement calls

lib/localiser/localisation/sensor/server.ex

@@ -21,9 +21,10 @@ defmodule Localiser.Localisation.Sensor.Server do
     {:via, Registry, {Localiser.Registry, {:sensor, sensor_id}}}
   end
 
-  # Returns %{sensor_id, floor_x, floor_y, distance} for a raw RSSI reading.
+  # Returns %{sensor_id, floor_x, floor_y, distance, rssi, tx_power} for a raw RSSI reading.
-  def measure(sensor_id, rssi) do
+  # tx_power is the beacon-advertised expected RSSI at 1 m (nil if not available).
-    GenServer.call(via(sensor_id), {:measure, rssi})
+  def measure(sensor_id, rssi, tx_power \\ nil) do
+    GenServer.call(via(sensor_id), {:measure, rssi, tx_power})
   end
 
   # Returns true if the sensor is currently collecting calibration samples.
@@ -66,14 +67,16 @@ defmodule Localiser.Localisation.Sensor.Server do
   end
 
   @impl true
-  def handle_call({:measure, rssi}, _from, state) do
+  def handle_call({:measure, rssi, tx_power}, _from, state) do
     distance = rssi_to_distance(rssi, state.rssi_ref, state.path_loss_exp)
 
     measurement = %{
       sensor_id: state.sensor_id,
       floor_x: state.floor_x,
       floor_y: state.floor_y,
-      distance: distance
+      distance: distance,
+      rssi: rssi,
+      tx_power: tx_power
     }
 
     {:reply, measurement, state}

lib/localiser/mqtt/router.ex

@@ -51,20 +51,29 @@ defmodule Localiser.MQTT.Router do
   end
 
   defp handle_rssi(sensor_id, payload) do
-    with {:ok, %{"tag_id" => tag_id, "rssi" => rssi}} <-
+    case Jason.decode(payload) do
-           Jason.decode(payload) do
+      {:ok, %{"id" => tag_id, "rssi" => rssi} = decoded} ->
+        reading = %{
+          sensor_id: sensor_id,
+          tag_id: tag_id,
+          rssi: rssi,
+          tx_power: Map.get(decoded, "tx_power"),
+          timestamp: DateTime.utc_now()
+        }
+        Localiser.MQTT.Telemetry.count_reading()
+        Localiser.RSSI.Buffer.push(reading)
 
-      reading = %{
+      {:ok, %{"tag_id" => tag_id, "rssi" => rssi}} ->
-        sensor_id: sensor_id,
+        reading = %{
-        tag_id: tag_id,
+          sensor_id: sensor_id,
-        rssi: rssi,
+          tag_id: tag_id,
-        timestamp: DateTime.utc_now()
+          rssi: rssi,
-      }
+          tx_power: nil,
+          timestamp: DateTime.utc_now()
+        }
+        Localiser.MQTT.Telemetry.count_reading()
+        Localiser.RSSI.Buffer.push(reading)
 
-      Localiser.MQTT.Telemetry.count_reading()
-      Localiser.RSSI.Buffer.push(reading)
-
-    else
       {:error, reason} ->
         Logger.error("[MQTT.Router] Bad payload from #{sensor_id}: #{inspect(reason)}")
         Localiser.MQTT.Telemetry.count_error()

lib/localiser/rssi_buffer.ex

@@ -6,7 +6,7 @@ defmodule Localiser.RSSI.Buffer do
 
   @flush_interval_ms 500
 
-  # reading :: %{sensor_id: String.t(), tag_id: String.t(), rssi: integer()}
+  # reading :: %{sensor_id: String.t(), tag_id: String.t(), rssi: integer(), tx_power: integer() | nil}
   def push(reading) do
     GenServer.cast(__MODULE__, {:push, reading})
   end
@@ -50,14 +50,14 @@ defmodule Localiser.RSSI.Buffer do
   # If the sensor is in calibration mode, feeds the reading to Sensor.Server instead
   # and returns [] so the sample is excluded from Tag.Filter measurements.
   # If the sensor server isn't running, returns [].
-  defp resolve_measurement(%{sensor_id: sensor_id, rssi: rssi}) do
+  defp resolve_measurement(%{sensor_id: sensor_id, rssi: rssi, tx_power: tx_power}) do
     case Registry.lookup(Localiser.Registry, {:sensor, sensor_id}) do
       [{_pid, _}] ->
         if SensorServer.calibrating?(sensor_id) do
           SensorServer.calibration_reading(sensor_id, rssi)
           []
         else
-          [SensorServer.measure(sensor_id, rssi)]
+          [SensorServer.measure(sensor_id, rssi, tx_power)]
         end
 
       [] ->