From cad01edab8e52d19739db67f76c1ed86d28956e3 Mon Sep 17 00:00:00 2001
From: Travis Shears <t@travisshears.com>
Date: Wed, 25 Mar 2026 11:21:04 +0100
Subject: [PATCH] parse topic 2

---
 src/readings_broadcaster.gleam |  2 ++
 src/sensors.gleam              | 23 +++++++++++++++++++++--
 test/sensors_test.gleam        | 16 +++++++++++++++-
 3 files changed, 38 insertions(+), 3 deletions(-)

diff --git a/src/readings_broadcaster.gleam b/src/readings_broadcaster.gleam
index 1c115eb..b5cd694 100644
--- a/src/readings_broadcaster.gleam
+++ b/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)
       }
     }
diff --git a/src/sensors.gleam b/src/sensors.gleam
index ba494df..7bbcb3a 100644
--- a/src/sensors.gleam
+++ b/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))
diff --git a/test/sensors_test.gleam b/test/sensors_test.gleam
index 6d02b0c..58d111a 100644
--- a/test/sensors_test.gleam
+++ b/test/sensors_test.gleam
@@ -6,7 +6,7 @@ pub fn main() -> Nil {
   gleeunit.main()
 }
 
-pub fn file_read_test() {
+pub fn sensor_name_and_unit_test() {
   let reading =
     sensors.sensor_name(sensors.Temperature)
     <> " "
@@ -28,3 +28,17 @@ pub fn parse_topic_1_test() {
     sensors.SensorReading(sensor: sensors.Pressure, value: 944.67),
   ])
 }
+
+pub fn parse_topic_2_test() {
+  let json_string = "{\"pm1\":16.83,\"pm2_5\":10.68,\"pm10\":16.619719}"
+  let readings = sensors.parse_topic_2(json_string)
+  readings
+  |> should.equal([
+    sensors.SensorReading(sensor: sensors.ParticalMatterOne, value: 16.83),
+    sensors.SensorReading(
+      sensor: sensors.ParticalMatterTwoPointFive,
+      value: 10.68,
+    ),
+    sensors.SensorReading(sensor: sensors.ParticalMatterTen, value: 16.619719),
+  ])
+}