package main

import (
	"strconv"
	"bytes"
	"log"
	"net"
	"os"
	"time"
	"os/exec"
	"github.com/eclipse/paho.mqtt.golang"
	"github.com/shirou/gopsutil/host"
	"github.com/google/uuid"
	"github.com/urfave/cli"
)

//GetOutboundIP Gets the 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
}

//getMacAddr fetches the first avaible Mac address 
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
}

//SyncPublish Synchronous publish an MQTT topic 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")
		os.Exit(1)
	}
}

//cmdRun Command handler for the run command
func cmdRun(cli *cli.Context) {
	clientid := uuid.New()

	command := "";
	if cli.NArg() > 0 {
		command = cli.Args()[0]
	  } else {
		log.Fatal("You must provide a command to run")
		os.Exit(1)
	  }

	log.Printf("Connection string: %s\n",cli.GlobalString("mqtt"))

	opts := mqtt.NewClientOptions().AddBroker(cli.GlobalString("mqtt")).SetClientID(clientid.String())
	hostname, _ := os.Hostname()
	opts.SetWill("homie/" + hostname + "/$state", "lost", 0, true);
	
	client := mqtt.NewClient(opts)
	log.Println("Connecting...")
	if token := client.Connect(); token.Wait() && token.Error() != nil {
		log.Fatal(token.Error())
		os.Exit(1)
	}
	log.Println("Connected")
	
	SyncPublish(client, "$state", 0, true, "init")
	log.Println("$state -> init")
	SyncPublish(client, "$homie", 0, true, "3.0.1")
	SyncPublish(client, "$name", 0, true, hostname)
	
	SyncPublish(client, "$localip", 0, true, GetOutboundIP().String())
	SyncPublish(client, "$mac", 0, true, getMacAddr())
	SyncPublish(client, "$fw/name", 0, true, "gomie")
	SyncPublish(client, "$fw/version", 0, true, "1.0")
	SyncPublish(client, "$implementation", 0, true, "gomie")
	
	SyncPublish(client, "$stats", 0, true, "uptime")
	uptimeSeconds, _ := host.Uptime()
	SyncPublish(client, "$stats/uptime", 0, true, strconv.FormatUint(uptimeSeconds,10))
	SyncPublish(client, "$stats/interval", 0, true, "0")

	SyncPublish(client, "leax-backup/$name", 0, true, "LEAX Backup")
	SyncPublish(client, "leax-backup/$type", 0, true, "script")
	SyncPublish(client, "leax-backup/$properties", 0, true, "lastrun,stdout,errorcode")

	SyncPublish(client, "$state", 0, true, "ready")
	log.Println("$state -> ready")
	//Done with initialization 

	SyncPublish(client, "leax-backup/started", 0, true, strconv.FormatInt(time.Now().Unix(),10))
	SyncPublish(client, "leax-backup/stdout", 0, true, "") 
	out, err := exec.Command(command).Output()
	if err != nil {
		log.Fatal(err)
	}

	SyncPublish(client, "leax-backup/ended", 0, true, strconv.FormatInt(time.Now().Unix(),10))
	SyncPublish(client, "leax-backup/stdout", 0, true, out) 


	//All done
	SyncPublish(client, "$state", 0, true, "disconnected")
	log.Println("$state -> disconnected")

	client.Disconnect(1000) //Wait one second to disconnect
	log.Println("Disconnected")
}