import gleam/bit_array
import gleam/erlang/process
import gleam/list
import gleam/otp/actor
import sensors
import spoke/mqtt

// pub type Message {
//   MqttUpdate(update: mqtt.Update)
// }

type State {
  State(subscribers: List(process.Subject(sensors.SensorReading)))
}

fn handle_message(
  state: State,
  update: mqtt.Update,
) -> actor.Next(State, mqtt.Update) {
  echo update
  case parse_mqtt_update(update) {
    Ok(readings) -> {
      // Publish to all subscribers
      echo readings
      list.each(state.subscribers, fn(subscriber) {
        list.each(readings, fn(reading) { process.send(subscriber, reading) })
      })
      actor.continue(state)
    }
    Error(_) -> actor.continue(state)
  }
}

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(
  subscribers: List(process.Subject(sensors.SensorReading)),
) -> Result(process.Subject(mqtt.Update), actor.StartError) {
  let initial_state = State(subscribers: subscribers)
  let assert Ok(started) =
    actor.new(initial_state)
    |> actor.on_message(handle_message)
    |> actor.start
  Ok(started.data)
}
// pub fn subscribe(
//   reader: process.Subject(Message),
// ) -> process.Subject(sensors.SensorReading) {
//   let mailbox = process.new_subject()
//   process.send(reader, Subscribe(mailbox))
//   mailbox
// }