package main

import (
	"fmt"
	"strings"
	"time"

	"github.com/miekg/dns"
)

func init() {
	dns.HandleFunc(BASE_DOMAIN, serve)
}

func q_String(q dns.Question) string {
	return "" + dns.ClassToString[q.Qclass] + " " + dns.TypeToString[q.Qtype] + " " + q.Name
}

func serve(w dns.ResponseWriter, r *dns.Msg) {
	qStr := ""
	for _, q := range r.Question {
		qStr += "\n" + q_String(q)
	}
	fmt.Printf("got question from %s:%s\n", w.RemoteAddr().String(), qStr)

	m := new(dns.Msg)
	defer w.WriteMsg(m)

	if r.Opcode != dns.OpcodeQuery && len(r.Question) != 1 {
		m.SetRcode(r, dns.RcodeRefused)
		return
	}

	q := r.Question[0]
	qName := strings.ToLower(q.Name)
	qKey := qName[0 : len(q.Name)-len(BASE_DOMAIN)]

	m.SetReply(r)
	m.Authoritative = true
	m.Compress = false
	soa := fmt.Sprintf("%s IN SOA %s hostmaster.%s %d 5 1 1 5", qName, DNS_SERVER, DNS_SERVER, (time.Now().Unix() % 4294967295))
	if soaRR, err := dns.NewRR(soa); err == nil {
		m.Ns = append(m.Answer, soaRR)
	}

	if q.Qtype == dns.TypeTXT {
		for _, rData := range db.Lookup(qKey) {
			if rr, err := dns.NewRR(fmt.Sprintf("$TTL 5\n%s TXT %s", qName, rData)); err == nil {
				m.Answer = append(m.Answer, rr)
			} else {
				fmt.Printf("error building rr: %s\n", err)
			}
		}

		rrStr := ""
		for _, rr := range m.Answer {
			rrStr += "\n" + rr.String()
		}
		fmt.Printf("sending response for %s:%s\n", qName, rrStr)
		return
	} else {
		fmt.Printf("no records for name %s\n", qName)
	}

	m.SetRcode(r, dns.RcodeNameError)
	fmt.Printf("%s\n", m.String())
}