use preserves_schema::Codec;

use std::convert::TryFrom;
use std::sync::Arc;

use syndicate::actor::*;
use syndicate::enclose;
use syndicate::preserves::rec;
use syndicate::preserves::value::NestedValue;
use syndicate::supervise::{Supervisor, SupervisorConfiguration};
use syndicate::trace;

use tokio::net::TcpListener;

use crate::language::language;
use crate::lifecycle;
use crate::protocol::detect_protocol;
use crate::schemas::internal_services::TcpRelayListener;

use syndicate_macros::during;

pub fn on_demand(t: &mut Activation, ds: Arc<Cap>) {
    t.spawn(Some(AnyValue::symbol("tcp_relay_listener")), move |t| {
        Ok(during!(t, ds, language(), <run-service $spec: TcpRelayListener>, |t| {
            Supervisor::start(
                t,
                Some(rec![AnyValue::symbol("relay"), language().unparse(&spec)]),
                SupervisorConfiguration::default(),
                enclose!((ds, spec) lifecycle::updater(ds, spec)),
                enclose!((ds) move |t| enclose!((ds, spec) run(t, ds, spec))))
        }))
    });
}

fn run(t: &mut Activation, ds: Arc<Cap>, spec: TcpRelayListener) -> ActorResult {
    lifecycle::terminate_on_service_restart(t, &ds, &spec);
    let host = spec.addr.host.clone();
    let port = u16::try_from(&spec.addr.port).map_err(|_| "Invalid TCP port number")?;
    let facet = t.facet.clone();
    let trace_collector = t.trace_collector();
    t.linked_task(Some(AnyValue::symbol("listener")), async move {
        let listen_addr = format!("{}:{}", host, port);
        let listener = TcpListener::bind(listen_addr).await?;

        {
            let cause = trace_collector.as_ref().map(|_| trace::TurnCause::external("readiness"));
            let account = Account::new(Some(AnyValue::symbol("readiness")), trace_collector.clone());
            if !facet.activate(
                &account, cause, |t| {
                    tracing::info!("listening");
                    ds.assert(t, language(), &lifecycle::ready(&spec));
                    Ok(())
                })
            {
                return Ok(LinkedTaskTermination::Normal);
            }
        }

        loop {
            let (stream, addr) = listener.accept().await?;
            let gatekeeper = spec.gatekeeper.clone();
            let name = Some(rec![AnyValue::symbol("tcp"), AnyValue::new(format!("{}", &addr))]);
            let cause = trace_collector.as_ref().map(|_| trace::TurnCause::external("connect"));
            let account = Account::new(name.clone(), trace_collector.clone());
            if !facet.activate(
                &account, cause, enclose!((trace_collector) move |t| {
                    t.spawn(name, move |t| {
                        Ok(t.linked_task(None, {
                            let facet = t.facet.clone();
                            async move {
                                detect_protocol(trace_collector, facet, stream, gatekeeper, addr).await?;
                                Ok(LinkedTaskTermination::KeepFacet)
                            }
                        }))
                    });
                    Ok(())
                }))
            {
                return Ok(LinkedTaskTermination::Normal);
            }
        }
    });
    Ok(())
}