package cdns

import (
	"errors"
	"fmt"
	"log"

	"github.com/miekg/dns"
)

func localQuery(mychan chan DNSreply, qname string, qtype uint16) {
	if debug {
		fmt.Printf("DEBUG: start of DNS request \"%s\" / %d\n", qname, qtype)
	}
	var result DNSreply
	result.qname = qname
	result.qtype = qtype
	result.r = nil
	result.err = errors.New("no name server to answer the question")
	localm := new(dns.Msg)
	localm.Id = dns.Id()
	localm.RecursionDesired = true
	localm.Question = make([]dns.Question, 1)
	localm.SetEdns0(bufsize, false) // Even if no EDNS requested, see #9 May be we should retry without it if timeout?
	localm.Question[0] = dns.Question{Name: qname, Qtype: qtype, Qclass: dns.ClassINET}
	for _, server := range conf.Servers {
		result.nameserver = server
		localc := &dns.Client{ReadTimeout: timeout}
		// Brackets are required for IPv6; do not use net.JoinHostPort (see check-soa commit 3e4edb1).
		r, rtt, err := localc.Exchange(localm, "["+server+"]:"+conf.Port)
		if err != nil || r == nil {
			result.r = nil
			result.err = err
			if err != nil {
				log.Println(err)
			}
			continue
		}
		result.rtt = rtt
		if r.Rcode == dns.RcodeSuccess {
			result.r = r
			result.err = nil
			break
		}
		result.r = r
		result.err = errors.New(dns.RcodeToString[r.Rcode])
		break
	}
	if debug {
		fmt.Printf("DEBUG: end of DNS request \"%s\" / %d\n", qname, qtype)
	}
	mychan <- result
}