parse sensor json values

src/config.gleam

@@ -1,9 +1,5 @@
 import envoy
 import glaml
-import gleam/dict
-import gleam/erlang/node
-import gleam/io
-import gleam/list
 import gleam/option.{type Option, None, Some}
 import gleam/result
 import simplifile

src/readings_broadcaster.gleam

@@ -1,5 +1,5 @@
+import gleam/bit_array
 import gleam/erlang/process
-import gleam/io
 import gleam/list
 import gleam/otp/actor
 import sensors
@@ -17,11 +17,13 @@ fn handle_message(
   state: State,
   update: mqtt.Update,
 ) -> actor.Next(State, mqtt.Update) {
+  echo update
   case parse_mqtt_update(update) {
-    Ok(reading) -> {
+    Ok(readings) -> {
       // Publish to all subscribers
+      echo readings
       list.each(state.subscribers, fn(subscriber) {
-        process.send(subscriber, reading)
+        list.each(readings, fn(reading) { process.send(subscriber, reading) })
       })
       actor.continue(state)
     }
@@ -29,12 +31,20 @@ fn handle_message(
   }
 }
 
-fn parse_mqtt_update(update: mqtt.Update) -> Result(sensors.SensorReading, Nil) {
-  io.println("GOT MQTT MESSAGE!")
-  echo update
-  // TODO: Implement parsing logic based on your MQTT topic/payload structure
-  // For now, return an error
-  Error(Nil)
+fn parse_mqtt_update(
+  update: mqtt.Update,
+) -> Result(List(sensors.SensorReading), Nil) {
+  case update {
+    mqtt.ReceivedMessage(topic, payload, _) -> {
+      let assert Ok(payload_str) = bit_array.to_string(payload)
+      case topic {
+        "homeassistant/sensor/bws/node1/state1" ->
+          Ok(sensors.parse_topic_1(payload_str))
+        _ -> Error(Nil)
+      }
+    }
+    _ -> Error(Nil)
+  }
 }
 
 pub fn start(

src/sensors.gleam

@@ -1,5 +1,7 @@
+import gleam/dynamic/decode
 import gleam/float
 import gleam/io
+import gleam/json
 
 pub type Sensor {
   Temperature
@@ -25,7 +27,28 @@ pub fn sensor_name(sensor: Sensor) -> String {
   }
 }
 
-// homeassistant/sensor/bws/node1/state1
+pub const topic_1: String = "homeassistant/sensor/bws/node1/state1"
+
+type Topic1Value {
+  Topic1Value(temp: Float, humidity: Float, pressure: Float)
+}
+
+/// Parses a JSON string into a list of `SensorReading` values.
+/// example input string: {"temp":18.84,"humidity":28.690811,"pressure":944.67}
+pub fn parse_topic_1(json_string: String) -> List(SensorReading) {
+  let decoder = {
+    use temp <- decode.field("temp", decode.float)
+    use humidity <- decode.field("humidity", decode.float)
+    use pressure <- decode.field("pressure", decode.float)
+    decode.success(Topic1Value(temp:, humidity:, pressure:))
+  }
+  let assert Ok(decoded_val) = json.parse(from: json_string, using: decoder)
+  [
+    SensorReading(sensor: Temperature, value: decoded_val.temp),
+    SensorReading(sensor: Humidity, value: decoded_val.humidity),
+    SensorReading(sensor: Pressure, value: decoded_val.pressure),
+  ]
+}
 
 pub fn print_sensor_reading(reading: SensorReading) -> Nil {
   let sensor_name = sensor_name(reading.sensor)