use std::path::Path;

use color_eyre::Result;
use log::{info, trace, warn};
use tokio::sync::{broadcast, mpsc};

use deckster_shared::handler_communication::{HandlerCommand, HandlerEvent};

use crate::handler_runner;
use crate::model::handler_host_config::Config;

mod mqtt;

pub async fn start(config_directory: &Path, config: Config) -> Result<()> {
    let (commands_sender, commands_receiver) = flume::bounded::<HandlerCommand>(5);
    let (handler_hosts_config_sender, mut handler_hosts_config_receiver) = mpsc::channel(1);
    let events_sender = broadcast::Sender::<HandlerEvent>::new(5);

    info!("Initializing MQTT client…");
    mqtt::start_mqtt_client(&config.mqtt, handler_hosts_config_sender, commands_receiver, events_sender.clone()).await;

    info!("Waiting for initial configuration…");

    let mut is_running = false;

    while let Some(handler_hosts_config) = handler_hosts_config_receiver.recv().await {
        match handler_hosts_config {
            None => {
                if is_running {
                    info!("Stopping handlers…");
                    events_sender.send(HandlerEvent::Stop).ok(); // only fails when all handlers are already stopped.
                }

                is_running = false;
            }
            Some(handler_hosts_config) => {
                if is_running {
                    warn!("A new configuration was received before the old one was cleared.");
                    events_sender.send(HandlerEvent::Stop).ok(); // only fails when all handlers are already stopped.
                }

                is_running = true;

                info!("Received new configuration. Starting handlers…");
                trace!("New configuration: {handler_hosts_config:#?}");

                handler_runner::start(
                    config.host_id.clone(),
                    &config_directory.join("handlers"),
                    handler_hosts_config,
                    commands_sender.clone(),
                    events_sender.subscribe(),
                )
                .await?;
            }
        }
    }

    Ok(())
}