Home Automation with Raspberry Pi

pub enum Output { Select = 6, Down = 13, Stop = 19, Up = 26 }

pub fn trigger_output(output: Output) -> Result<()> {
    let offset = output as u32;
    let req = Request::builder()
        .on_chip("/dev/gpiochip0")
        .with_line(offset)
        .as_output(Value::Active)
        .as_active_low()
        .request()?;
    thread::sleep(Duration::from_millis(60)); // press for 60ms
    req.set_lone_value(Value::Inactive)?;
    Ok(())
}

pub async fn watch_inputs() -> Result<Input> {
    let offsets = [
        Input::L1 as u32,
        Input::L2 as u32,
        Input::L3 as u32,
        Input::L4 as u32,
    ];

    let req = Request::builder()
        .on_chip("/dev/gpiochip0")
        .with_lines(&offsets)
        .as_input()
        .with_edge_detection(EdgeDetection::BothEdges)
        .request()
        .context("Failed to request GPIO lines")?;

    let mut events = AsyncRequest::new(req).edge_events();
    let deadline = Instant::now() + Duration::from_millis(300);
    let mut last_event = None;
    let mut event_count = 0;

    // 16 = 4 inputs × 2 edges × 2 transitions
    const ALL_EVENTS_THRESHOLD: u32 = 16;

    while event_count < ALL_EVENTS_THRESHOLD {
        match timeout_at(deadline, events.next()).await {
            Ok(Some(Ok(event))) => {
                last_event = Some(event.offset);
                event_count += 1;
            }
            Ok(Some(Err(err))) => return Err(err).context("GPIO edge event"),
            _ => break,
        }
    }

    if event_count < ALL_EVENTS_THRESHOLD {
        Input::try_from(last_event.unwrap())
    } else {
        Ok(Input::ALL)
    }
}