package dns

import (
	"net"
	"sort"
)

type Domain struct {
	Name string
	NS   []string
}

func CheckDomain(domain string) Domain {
	nameservers, err := net.LookupNS(domain)

	if len(nameservers) > 0 && err == nil {
		return Domain{
			Name: domain,
			NS:   nsToArray(nameservers),
		}
	}
	return Domain{
		Name: domain,
		NS:   []string{},
	}
}

func nsToArray(nameservers []*net.NS) []string {
	var nsArray []string
	for _, nameserver := range nameservers {
		nsArray = append(nsArray, nameserver.Host)
	}

	sort.SliceStable(nsArray, func(i, j int) bool {
		return nsArray[i] < nsArray[j]
	})

	return nsArray
}