package main

import (
	"fmt"
	"github.com/miekg/dns"
	"strings"
)

func (r *resolver) lookup(qname string) error {
	c := new(dns.Client)
	t := new(dns.Transfer)
	c.Net = "udp"
	if *four {
		c.Net = "udp4"
	}
	if *six {
		c.Net = "udp6"
	}
	if *tcp {
		c.Net = "tcp"
		if *four {
			c.Net = "tcp4"
		}
		if *six {
			c.Net = "tcp6"
		}
	}

	m := &dns.Msg{
		MsgHdr: dns.MsgHdr{
			Authoritative:     false,
			AuthenticatedData: false,
			CheckingDisabled:  false,
			RecursionDesired:  true,
			Opcode:            "query",
		},
		Question: make([]dns.Question, 1),
	}
	if op, ok := dns.StringToOpcode[strings.ToUpper(*opcode)]; ok {
		m.Opcode = op
	}
	m.Rcode = dns.RcodeSuccess
	if rc, ok := dns.StringToRcode[strings.ToUpper(*rcode)]; ok {
		m.Rcode = rc
	}

Query:
	for i, v := range qname {
		if i < len(qtype) {
			qt = qtype[i]
		}
		if i < len(qclass) {
			qc = qclass[i]
		}
		m.Question[0] = dns.Question{Name: dns.Fqdn(v), Qtype: qt, Qclass: qc}
		m.Id = dns.Id()
		if *query {
			fmt.Printf("%s", m.String())
			fmt.Printf("\n;; size: %d bytes\n\n", m.Len())
		}
		r, rtt, err := c.Exchange(m, nameserver)

	Redo:
		switch err {
		case nil:
			//do nothing
		case dns.ErrTruncated:
			if *fallback {
				if !*dnssec {
					fmt.Printf(";; Truncated, trying %d bytes bufsize\n", dns.DefaultMsgSize)
					o := new(dns.OPT)
					o.Hdr.Name = "."
					o.Hdr.Rrtype = dns.TypeOPT
					o.SetUDPSize(dns.DefaultMsgSize)
					m.Extra = append(m.Extra, o)
					r, rtt, err = c.Exchange(m, nameserver)
					*dnssec = true
					goto Redo
				} else {
					// First EDNS, then TCP
					fmt.Printf(";; Truncated, trying TCP\n")
					c.Net = "tcp"
					r, rtt, err = c.Exchange(m, nameserver)
					*fallback = false
					goto Redo
				}
			}
			fmt.Printf(";; Truncated\n")
		default:
			fmt.Printf(";; %s\n", err.Error())
			continue
		}
		if r.Id != m.Id {
			fmt.Fprintf(os.Stderr, "Id mismatch\n")
			return
		}
		if *short {
			// shortenMsg(r)
		}

		fmt.Printf("%v", r)
		fmt.Printf("\n;; query time: %.3d µs, server: %s(%s), size: %d bytes\n", rtt/1e3, nameserver, c.Net, r.Len())
	}
}