parse topic 2

src/readings_broadcaster.gleam

@@ -40,6 +40,8 @@ fn parse_mqtt_update(
       case topic {
         "homeassistant/sensor/bws/node1/state1" ->
           Ok(sensors.parse_topic_1(payload_str))
+        "homeassistant/sensor/bws/node1/state2" ->
+          Ok(sensors.parse_topic_2(payload_str))
         _ -> Error(Nil)
       }
     }

src/sensors.gleam

@@ -27,8 +27,6 @@ pub fn sensor_name(sensor: Sensor) -> String {
   }
 }
 
-pub const topic_1: String = "homeassistant/sensor/bws/node1/state1"
-
 type Topic1Value {
   Topic1Value(temp: Float, humidity: Float, pressure: Float)
 }
@@ -50,6 +48,27 @@ pub fn parse_topic_1(json_string: String) -> List(SensorReading) {
   ]
 }
 
+type Topic2Value {
+  Topic2Value(pm1: Float, pm2: Float, pm10: Float)
+}
+
+/// Parses a JSON string into a list of `SensorReading` values from topic 2.
+/// example input string: {"pm1":16.83,"pm2_5":10.68,"pm10":16.619719}
+pub fn parse_topic_2(json_string: String) -> List(SensorReading) {
+  let decoder = {
+    use pm1 <- decode.field("pm1", decode.float)
+    use pm2 <- decode.field("pm2_5", decode.float)
+    use pm10 <- decode.field("pm10", decode.float)
+    decode.success(Topic2Value(pm1:, pm2:, pm10:))
+  }
+  let assert Ok(decoded_val) = json.parse(from: json_string, using: decoder)
+  [
+    SensorReading(sensor: ParticalMatterOne, value: decoded_val.pm1),
+    SensorReading(sensor: ParticalMatterTwoPointFive, value: decoded_val.pm2),
+    SensorReading(sensor: ParticalMatterTen, value: decoded_val.pm10),
+  ]
+}
+
 pub fn print_sensor_reading(reading: SensorReading) -> Nil {
   let sensor_name = sensor_name(reading.sensor)
   io.println(sensor_name <> ": " <> float.to_string(reading.value))