use std::time::{Duration, Instant};

use mdns_sd::{ServiceDaemon, ServiceEvent};

use crate::{Error, Result, client::Supernote};

const SERVICE: &str = "_http._tcp.local.";

pub fn discover(timeout: Duration) -> Result<Vec<Supernote>> {
    let mdns = ServiceDaemon::new().map_err(Error::from_mdns)?;
    let receiver = mdns.browse(SERVICE).map_err(Error::from_mdns)?;

    let deadline = Instant::now() + timeout;
    let mut found: Vec<Supernote> = Vec::new();

    while let Some(remaining) = deadline.checked_duration_since(Instant::now()) {
        let Ok(evt) = receiver.recv_timeout(remaining) else {
            break;
        };
        let ServiceEvent::ServiceResolved(info) = evt else {
            continue;
        };

        if !looks_like_supernote(info.get_fullname()) {
            continue;
        }
        let Some(addr) = info.get_addresses().iter().next() else {
            continue;
        };
        let host = addr.to_string();
        if found.iter().any(|d| d.host() == host) {
            continue;
        }
        found.push(Supernote::at(host).with_port(info.get_port()));
    }

    let _ = mdns.shutdown();
    Ok(found)
}

fn looks_like_supernote(fullname: &str) -> bool {
    let lower = fullname.to_lowercase();
    lower.contains("supernote") || lower.contains("ratta")
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn matches_supernote_service_names() {
        assert!(looks_like_supernote("Supernote A6X._http._tcp.local."));
        assert!(looks_like_supernote("ratta-nomad._http._tcp.local."));
        assert!(!looks_like_supernote("printer._http._tcp.local."));
    }
}