package main

import (
        "context"
        "flag"
        "log"
        "time"
        "strings"

        "github.com/grandcat/zeroconf"
)

var (
        service  = flag.String("service", "_workstation._tcp", "Set the service category to look for devices.")
        domain   = flag.String("domain", "local", "Set the search domain. For local networks, default is fine.")
        waitTime = flag.Int("wait", 10, "Duration in [s] to run discovery.")
)

func main() {
        flag.Parse()

        // Discover all services on the network (e.g. _workstation._tcp)
        resolver, err := zeroconf.NewResolver(nil)
        if err != nil {
                log.Fatalln("Failed to initialize resolver:", err.Error())
        }

        entries := make(chan *zeroconf.ServiceEntry)
        go func(results <-chan *zeroconf.ServiceEntry) {
                for entry := range results {
                        log.Println(entry)
                        log.Println("ServiceRecord.Instance:", entry.ServiceRecord.Instance)
                        log.Println("ServiceRecord.Service:", entry.ServiceRecord.Service)
                        log.Println("ServiceRecord.Domain:", entry.ServiceRecord.Domain)
                        log.Println("HostName:", entry.HostName)
                        log.Println("Port:", entry.Port)
                        log.Println("Text:", strings.Join(entry.Text, ","))
                        log.Println("TTL:", entry.TTL)
                        log.Println("AddrIPv4:", entry.AddrIPv4)
                        log.Println("AddrIPv6:", entry.AddrIPv6)
                        for _, s := range entry.Text {
                                log.Println(s)
                        }
                }
                log.Println("No more entries.")
        }(entries)

        ctx, cancel := context.WithTimeout(context.Background(), time.Second*time.Duration(*waitTime))
        defer cancel()
        err = resolver.Browse(ctx, *service, *domain, entries)
        if err != nil {
                log.Fatalln("Failed to browse:", err.Error())
        }

        <-ctx.Done()
        // Wait some additional time to see debug messages on go routine shutdown.
        time.Sleep(1 * time.Second)
}