package main
import (
	"strconv"
	"bytes"
	"log"
    "net"
	"os"
	"time"
	"github.com/eclipse/paho.mqtt.golang"
	"github.com/shirou/gopsutil/host"
)


// Get preferred outbound ip of this machine
func GetOutboundIP() net.IP {
    conn, err := net.Dial("udp", "8.8.8.8:80")
    if err != nil {
        log.Fatal(err)
    }
    defer conn.Close()

    localAddr := conn.LocalAddr().(*net.UDPAddr)
	
    return localAddr.IP
}

func getMacAddr() (addr string) {
	interfaces, err := net.Interfaces()
	if err == nil {
		for _, i := range interfaces {
			if i.Flags&net.FlagUp != 0 && bytes.Compare(i.HardwareAddr, nil) != 0 {
				// Don't use random as we have a real address
				addr = i.HardwareAddr.String()
				break
			}
		}
	}
	return
}

//Publish a message and wait for confirmation
func SyncPublish(client mqtt.Client, topic string, qos byte, retained bool, payload interface{}) {

	hostname, _ := os.Hostname()
	prefix := "homie/" + hostname + "/"
	token := client.Publish(prefix + topic, qos, retained, payload)
	if(!token.Wait()) {
		log.Fatal("Timeout on publish")
		log.Fatal(token.Error())
		os.Exit(3)
	}
}

func main() {
	opts := mqtt.NewClientOptions().AddBroker("tcp://mqtt.jcktrue.dk:1883").SetClientID("gotrivial")
	hostname, _ := os.Hostname()
	opts.SetWill("homie/" + hostname + "/$state", "lost", 0, true);
	
	c := mqtt.NewClient(opts)
	if token := c.Connect(); token.Wait() && token.Error() != nil {
		panic(token.Error())
	}

	SyncPublish(c, "$state", 0, true, "init")
	SyncPublish(c, "$homie", 0, true, "3.0.1")
	SyncPublish(c, "$name", 0, true, hostname)
	
	SyncPublish(c, "$localip", 0, true, GetOutboundIP().String())
	SyncPublish(c, "$mac", 0, true, getMacAddr())
	SyncPublish(c, "$fw/name", 0, true, "gomie")
	SyncPublish(c, "$fw/version", 0, true, "1.0")
	SyncPublish(c, "$implementation", 0, true, "gomie")
	
	SyncPublish(c, "$stats", 0, true, "uptime")
	uptimeSeconds, _ := host.Uptime()
	SyncPublish(c, "$stats/uptime", 0, true, strconv.FormatUint(uptimeSeconds,10))
	SyncPublish(c, "$stats/interval", 0, true, "0")

	SyncPublish(c, "leax-backup/$name", 0, true, "LEAX Backup")
	SyncPublish(c, "leax-backup/$type", 0, true, "script")
	SyncPublish(c, "leax-backup/$properties", 0, true, "lastrun,output")

	SyncPublish(c, "trueserver-backup/$name", 0, true, "TRUESERVER Backup")
	SyncPublish(c, "trueserver-backup/$type", 0, true, "script")
	SyncPublish(c, "trueserver-backup/$properties", 0, true, "lastrun,output")

	SyncPublish(c, "$state", 0, true, "ready")
	//Done with initialization 
	
	SyncPublish(c, "leax-backup/lastrun", 0, true, strconv.FormatInt(time.Now().Unix(),10))
	SyncPublish(c, "leax-backup/output", 0, true, "Backup successful") 

	SyncPublish(c, "trueserver-backup/lastrun", 0, true, strconv.FormatInt(time.Now().Unix(),10))
	SyncPublish(c, "trueserver-backup/output", 0, true, "Backup successful") 

	//All done
	SyncPublish(c, "$state", 0, true, "disconnected")

	c.Disconnect(1000) //Wait one second to disconnect
 }