use std::{net::IpAddr, io};
use tokio::runtime::Handle;
use libmdns::{Responder, Service};
use multicast_dns::discovery::{DiscoveryManager, DiscoveryListeners, ResolveListeners};
use crate::{constants, print_error};

const SERVICE_TYPE: &str = "_aira._tcp";

pub async fn advertise_me() -> io::Result<Service> {
    Ok(Responder::spawn(&Handle::current())?.register(
        SERVICE_TYPE.to_string(),
        "AIRA Node".to_string(),
        constants::PORT,
        &[]
    ))
}

pub fn discover_peers<F: Fn(&DiscoveryManager, IpAddr)>(on_service_discovered: F) {
    let discovery_manager = DiscoveryManager::new();
    match discovery_manager.discover_services(SERVICE_TYPE, DiscoveryListeners{
        on_service_discovered: Some(&|service| {
            discovery_manager.resolve_service(service, ResolveListeners{
                on_service_resolved: Some(&|service| {
                    match service.address {
                        Some(service_ip) => on_service_discovered(&discovery_manager, service_ip.parse().unwrap()),
                        None => print_error!("Service discovered without IP address: {:?}", service)
                    };
                })
            });
        }),
        on_all_discovered: Some(&|| {
            discovery_manager.stop_service_discovery();
        })
    }) {
        Ok(_) => {},
        Err(e) => print_error!(e)
    }
}