weather-portal/src/mqtt_dummy.gleam

52 lines
1.1 KiB
Gleam

import gleam/erlang/process
import gleam/list
import gleam/otp/actor
import sensors
pub type Subscriber =
process.Subject(sensors.SensorReading)
pub type Message {
Subscribe(subscriber: Subscriber)
Proc
}
pub type Subscribers =
List(Subscriber)
fn handle_message(
subscribers: Subscribers,
message: Message,
) -> actor.Next(Subscribers, Message) {
case message {
Subscribe(subscriber) -> {
let new_subscribers = [subscriber, ..subscribers]
actor.continue(new_subscribers)
}
Proc -> {
list.each(subscribers, fn(subscriber) {
process.send(
subscriber,
sensors.SensorReading(sensors.Temperature, 26.6),
)
})
actor.continue(subscribers)
}
}
}
// Subscribe to receive ticks from the dummy actor
pub fn subscribe(actor_ref: process.Subject(Message)) -> Subscriber {
let mailbox = process.new_subject()
process.send(actor_ref, Subscribe(mailbox))
mailbox
}
// Start the actor
pub fn start() -> Result(process.Subject(Message), actor.StartError) {
let assert Ok(started) =
actor.new([])
|> actor.on_message(handle_message)
|> actor.start
Ok(started.data)
}