use crate::{handle_cmd, Command, MonitorCommand, StdError};
use rumqttc::mqttbytes::v4::Packet;
use rumqttc::{Client, Event, MqttOptions, QoS};
use std::env;
use std::sync::mpsc::Sender;
use std::time::Duration;
use tracing::{event, Level};

pub fn run_mqtt(txes: &Vec<Sender<MonitorCommand>>) -> StdError<()> {
    let client_id = env::var("MQTT_CLIENT_ID").unwrap_or("ddcmqtt".into());
    let mqtt_host = env::var("MQTT_HOST").unwrap_or("localhost".into());
    let mqtt_port = env::var("MQTT_PORT")
        .unwrap_or("1883".into())
        .parse::<u16>()?;
    let mqtt_user = env::var("MQTT_USER").ok();
    let mqtt_pass = env::var("MQTT_PASS").ok();
    let mut mqttoptions = MqttOptions::new(client_id, mqtt_host.clone(), mqtt_port);
    // Set credentials if we have user and pass specified.
    // TODO: warn if only one maybe?
    if let (Some(u), Some(p)) = (mqtt_user, mqtt_pass) {
        event!(Level::INFO, user = u, "Using MQTT user/pass from env");
        mqttoptions.set_credentials(u, p);
    }
    mqttoptions.set_keep_alive(Duration::from_secs(5));

    let (mut client, mut connection) = Client::new(mqttoptions, 10);
    client.subscribe("ddcmqtt/#", QoS::AtMostOnce)?;

    event!(Level::INFO, mqtt_host, mqtt_port, "Running MQTT client");

    for notification in connection.iter() {
        event!(Level::INFO, ?notification, "Got notification");
        if let Ok(Event::Incoming(Packet::Publish(p))) = notification {
            let topic: Vec<_> = p.topic.split("/").collect();
            if topic.len() != 3 {
                event!(
                    Level::WARN,
                    ?topic,
                    "Publish topic has wrong format, ignoring."
                );
                continue;
            }
            if topic[0] != "ddcmqtt" {
                event!(
                    Level::ERROR,
                    ?topic,
                    "Got publish that we didn't subscribe to!"
                );
                continue;
            }
            let mon_idx = topic[1].parse::<u8>();
            match (mon_idx, topic[2]) {
                (Ok(idx), "input") => {
                    // TODO: don't crash on these ?s - I'm feeling lazy
                    let input_id = std::str::from_utf8(&p.payload)?.parse::<u8>()?;
                    handle_cmd(
                        Command::Monitor((idx.into(), MonitorCommand::Input(input_id))),
                        &txes,
                    )?;
                }
                _ => {
                    event!(Level::ERROR, ?topic, "Unrecognised or invalid topic");
                    continue;
                }
            }
        }
    }
    Ok(())
}