package main

/*
   Copyright 2012-2015 Ask Bjørn Hansen

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

import (
	"flag"
	"fmt"
	"log"
	"net"
	"os"
	"os/signal"
	"path/filepath"
	"runtime"
	"runtime/pprof"
	"strings"
	"time"

	"github.com/abh/geodns/applog"
	"github.com/abh/geodns/monitor"
	"github.com/abh/geodns/querylog"
	"github.com/abh/geodns/server"
	"github.com/abh/geodns/zones"
	"github.com/pborman/uuid"
)

// VERSION is the current version of GeoDNS
var VERSION string = "2.7.0"
var buildTime string
var gitVersion string

// Set development with the 'devel' build flag to load
// templates from disk instead of from the binary.
var development bool

var (
	serverInfo *monitor.ServerInfo
)

var (
	flagconfig       = flag.String("config", "./dns/", "directory of zone files")
	flagconfigfile   = flag.String("configfile", "geodns.conf", "filename of config file (in 'config' directory)")
	flagcheckconfig  = flag.Bool("checkconfig", false, "check configuration and exit")
	flagidentifier   = flag.String("identifier", "", "identifier (hostname, pop name or similar)")
	flaginter        = flag.String("interface", "*", "set the listener address")
	flagport         = flag.String("port", "53", "default port number")
	flaghttp         = flag.String("http", ":8053", "http listen address (:8053)")
	flaglog          = flag.Bool("log", false, "be more verbose")
	flagcpus         = flag.Int("cpus", 1, "Set the maximum number of CPUs to use")
	flagLogFile      = flag.String("logfile", "", "log to file")
	flagPrivateDebug = flag.Bool("privatedebug", false, "Make debugging queries accepted only on loopback")

	flagShowVersion = flag.Bool("version", false, "Show dnsconfig version")

	cpuprofile = flag.String("cpuprofile", "", "write cpu profile to file")
	memprofile = flag.String("memprofile", "", "write memory profile to this file")
)

func init() {
	if len(gitVersion) > 0 {
		VERSION = VERSION + "/" + gitVersion
	}

	log.SetPrefix("geodns ")
	log.SetFlags(log.Lmicroseconds | log.Lshortfile)

	serverInfo = &monitor.ServerInfo{}
	serverInfo.UUID = uuid.New()
	serverInfo.Started = time.Now()

}

func main() {
	flag.Parse()

	if *memprofile != "" {
		runtime.MemProfileRate = 1024
	}

	if *flagShowVersion {
		extra := []string{}
		if len(buildTime) > 0 {
			extra = append(extra, buildTime)
		}
		extra = append(extra, runtime.Version())
		fmt.Printf("geodns %s (%s)\n", VERSION, strings.Join(extra, ", "))
		os.Exit(0)
	}

	if *flaglog {
		applog.Enabled = true
	}

	if len(*flagLogFile) > 0 {
		applog.FileOpen(*flagLogFile)
	}

	if len(*flagidentifier) > 0 {
		ids := strings.Split(*flagidentifier, ",")
		serverInfo.ID = ids[0]
		if len(ids) > 1 {
			serverInfo.Groups = ids[1:]
		}
	}

	var configFileName string

	if filepath.IsAbs(*flagconfigfile) {
		configFileName = *flagconfigfile
	} else {
		configFileName = filepath.Clean(filepath.Join(*flagconfig, *flagconfigfile))
	}

	if *flagcheckconfig {
		err := configReader(configFileName)
		if err != nil {
			log.Println("Errors reading config", err)
			os.Exit(2)
		}

		// dirName := *flagconfig
		// Zones := make(zones.Zones)
		// srv.setupPgeodnsZone(Zones)
		// err = srv.zonesReadDir(dirName, Zones)
		if err != nil {
			log.Println("Errors reading zones", err)
			os.Exit(2)
		}
		return
	}

	if *flagcpus == 0 {
		runtime.GOMAXPROCS(runtime.NumCPU())
	} else {
		runtime.GOMAXPROCS(*flagcpus)
	}

	log.Printf("Starting geodns %s (%s)\n", VERSION, runtime.Version())

	if *cpuprofile != "" {
		prof, err := os.Create(*cpuprofile)
		if err != nil {
			panic(err.Error())
		}

		pprof.StartCPUProfile(prof)
		defer func() {
			log.Println("closing file")
			prof.Close()
		}()
		defer func() {
			log.Println("stopping profile")
			pprof.StopCPUProfile()
		}()
	}

	// load geodns.conf config
	configReader(configFileName)

	// load (and re-load) zone data
	go configWatcher(configFileName)

	if *flaginter == "*" {
		addrs, _ := net.InterfaceAddrs()
		ips := make([]string, 0)
		for _, addr := range addrs {
			ip, _, err := net.ParseCIDR(addr.String())
			if err != nil {
				continue
			}
			if !(ip.IsLoopback() || ip.IsGlobalUnicast()) {
				continue
			}
			ips = append(ips, ip.String())
		}
		*flaginter = strings.Join(ips, ",")
	}

	inter := getInterfaces()

	if Config.HasStatHat() {
		log.Println("StatHat integration has been removed in favor of more generic metrics")
	}

	mon := monitor.NewMonitor(serverInfo)
	go mon.Run()

	srv := server.NewServer(serverInfo)

	if qlc := Config.QueryLog; len(qlc.Path) > 0 {
		ql, err := querylog.NewFileLogger(qlc.Path, qlc.MaxSize, qlc.Keep)
		if err != nil {
			log.Fatalf("Could not start file query logger: %s", err)
		}
		srv.SetQueryLogger(ql)
	}

	muxm, err := zones.NewMuxManager(*flagconfig, srv)
	if err != nil {
		log.Printf("error loading zones: %s", err)
	}
	go muxm.Run()

	for _, host := range inter {
		go srv.ListenAndServe(host)
	}

	go func() {
		// setup metrics httpd stuff
	}()

	terminate := make(chan os.Signal)
	signal.Notify(terminate, os.Interrupt)

	<-terminate
	log.Printf("geodns: signal received, stopping")

	if *memprofile != "" {
		f, err := os.Create(*memprofile)
		if err != nil {
			log.Fatal(err)
		}
		pprof.WriteHeapProfile(f)
		f.Close()
	}
	applog.FileClose()
}