cmd

var ScanCmd = &cobra.Command{
	Use:   "scan [IP address]",
	Short: "Port scanner to probe for all open ports on a target IP.",
	Long:  `Port scanner to probe for all open ports on a target IP.`,

	PreRunE: func(cmd *cobra.Command, args []string) error {
		if len(args) < 1 {
			return fmt.Errorf("requires argument IP address to scan")
		}
		if _, err := checkIPAddress(args[0]); err != nil {
			return err
		}
		ipAddress = args[0]
		rangeData := strings.Split(portRange, "-")

		if len(rangeData) == 2 {
			var err error
			startPort, err = strconv.Atoi(rangeData[0])
			if err != nil {
				return fmt.Errorf("enter range in the format 15-2000")
			}
			endPort, err = strconv.Atoi(rangeData[1])
			if err != nil {
				return fmt.Errorf("enter range in the format 15-2000")
			}
			if !(startPort >= 1 && startPort <= 65535) {
				return fmt.Errorf("%d port is not valid. It should be between 1-65535", startPort)
			}
			if !(endPort >= 1 && endPort <= 65535) {
				return fmt.Errorf("%d port is not valid. It should be between 1-65535", endPort)
			}
		} else {
			if strings.ToLower(portRange) == "all" {
				startPort = 1
				endPort = 65535
			} else {

				return fmt.Errorf("enter range in the format 15-2000")
			}
		}
		proto := [2]string{"tcp", "udp"}

		if !contains(proto, strings.ToLower(scanProtocol)) {
			return fmt.Errorf("protocol: select either tcp or udp")
		}

		if len(proxyURL) == 0 {
			proxyURL = ""
		} else {
			s := strings.Split(proxyURL, ":")
			if len(s) == 2 {
				ps, err := strconv.Atoi(s[1])
				if err != nil {
					return fmt.Errorf("port should be an integer between 1-65535")
				}
				if !(ps >= 1 && ps <= 65535) {
					return fmt.Errorf("%d port is not valid. It should be between 1-65535", startPort)
				}

				_, err = checkIPAddress(s[0])
				if err != nil {
					return err
				}
			} else {
				return fmt.Errorf("proxy should in the format as 127.0.0.1:9050")
			}

		}

		return nil
	},
	Run: func(cmd *cobra.Command, args []string) {

		fmt.Printf("Scanning %s for open ports between %d-%d\n", ipAddress, startPort, endPort)

		ports := make(chan int, threadCount)
		results := make(chan int)

		var openPorts []int
		for i := 0; i <= cap(ports); i++ {
			go worker(ports, results)
		}

		go func() {
			for i := startPort; i <= endPort; i++ {
				ports <- i
			}
		}()

		for i := startPort; i <= endPort; i++ {

			port := <-results
			if port != 0 {
				fmt.Printf("%d port is open\n", port)
				openPorts = append(openPorts, port)
			}

		}

		close(ports)
		close(results)
		sort.Ints(openPorts)
		op := strings.Join(strings.Fields(fmt.Sprint(openPorts)), ",")
		opData := op[1 : len(op)-1]
		fmt.Printf("List of open ports : %s", opData)
		if outFile != "" {
			outFilefile, err := os.OpenFile(outFile, os.O_RDWR|os.O_CREATE, 0666)
			printFatalError(err)
			defer outFilefile.Close()
			outFilefile.WriteString("Scan IP address: " + ipAddress + "\n")
			outFilefile.WriteString("List of open ports : " + opData + "\n")

		}
	},
}