package main

import (
	"net"
	"strconv"
	"time"

	"github.com/miekg/dns"
	"os"
)

type Server struct {
	host     string
	port     int
	rTimeout time.Duration
	wTimeout time.Duration
}

func (s *Server) Addr() string {
	if addr := os.Getenv("SERVER_BIND"); addr != "" {
		return addr
	}

	return net.JoinHostPort(s.host, strconv.Itoa(s.port))
}

func (s *Server) Run() {
	handler := NewHandler()

	tcpHandler := dns.NewServeMux()
	tcpHandler.HandleFunc(".", handler.DoTCP)

	udpHandler := dns.NewServeMux()
	udpHandler.HandleFunc(".", handler.DoUDP)

	tcpServer := &dns.Server{
		Addr: s.Addr(),
		Net: "tcp",
		Handler: tcpHandler,
		ReadTimeout: s.rTimeout,
		WriteTimeout: s.wTimeout,
	}

	udpServer := &dns.Server{
		Addr: s.Addr(),
		Net: "udp",
		Handler: udpHandler,
		UDPSize: 65535,
		ReadTimeout: s.rTimeout,
		WriteTimeout: s.wTimeout,
	}

	go s.start(udpServer)
	go s.start(tcpServer)
}

func (s *Server) start(ds *dns.Server) {
	logger.Info("Start %s listener on %s", ds.Net, s.Addr())

	err := ds.ListenAndServe()
	if err != nil {
		logger.Error("Start %s listener on %s failed:%s", ds.Net, s.Addr(), err.Error())
	}
}