package nats

import (
	"fmt"
	"os"
	"time"

	"github.com/nats-io/nats-server/v2/server"
	"gitlab.com/tozd/go/errors"
	"go.alanpearce.eu/x/log"
)

const flyPrivateHostname = "fly-local-6pn"

var srv *server.Server

func Start(log *log.Logger) error {
	var err error

	appName := os.Getenv("FLY_APP_NAME")
	if appName == "" {
		log.Warn("no FLY_APP_NAME")

		return nil
	}
	privateIP := os.Getenv("FLY_PRIVATE_IP")
	if privateIP == "" {
		log.Warn("no FLY_PRIVATE_IP")

		return nil
	}

	hostname := fmt.Sprintf("%s.internal", appName)

	opts := &server.Options{
		ServerName: os.Getenv("FLY_MACHINE_ID"),
		Host:       flyPrivateHostname,
		Port:       4222,
		Cluster: server.ClusterOpts{
			Name:           appName,
			Host:           flyPrivateHostname,
			Port:           7221,
			ConnectRetries: 60,
		},
		RoutesStr: "nats-route://" + hostname + ":7221",
	}

	srv, err = server.NewServer(opts)
	if err != nil {
		return errors.WithMessage(err, "could not start NATS server")
	}

	srv.SetLoggerV2(adaptLogger(log), false, false, false)
	srv.Start()

	if !srv.ReadyForConnections(4 * time.Second) {
		log.Warn("server not ready")
	}

	return nil
}

func Stop() {
	go srv.Shutdown()
	srv.WaitForShutdown()
}