Simple command line XMPP instant messaging program that opens a conversation with a single contact

im.go

// Adapted from https://github.com/mattn/go-xmpp/blob/master/_example/example.go.

package main

import (
	"crypto/tls"
	"flag"
	"fmt"
	"log"
	"os"
	"strings"

	"golang.org/x/crypto/ssh/terminal"

	"github.com/mattn/go-xmpp"
)

var server = flag.String("server", "", "server")
var username = flag.String("username", "", "username")
var password = flag.String("password", "", "password")
var status = flag.String("status", "xa", "status")
var statusMessage = flag.String("status-msg", "Connected", "status message")
var notls = flag.Bool("notls", false, "No TLS")
var debug = flag.Bool("debug", false, "debug output")
var session = flag.Bool("session", false, "use server session")
var me = flag.String("me", "Me", "name to use for sender")
var recipient = flag.String("recipient", "", "username of contact to message")
var recipientName = flag.String("recipient-name", "", "name to use for recipient")

func serverName(host string) string {
	return strings.Split(host, ":")[0]
}

func main() {
	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, "usage: example [options]\n")
		flag.PrintDefaults()
		os.Exit(2)
	}
	flag.Parse()
	if *username == "" || *password == "" {
		if *debug && *username == "" && *password == "" {
			fmt.Fprintf(os.Stderr, "no username or password were given; attempting ANONYMOUS auth\n")
		} else if *username != "" || *password != "" {
			flag.Usage()
		}
	}

	if !*notls {
		xmpp.DefaultConfig = tls.Config{
			ServerName:         serverName(*server),
			InsecureSkipVerify: false,
		}
	}

	var talk *xmpp.Client
	var err error
	options := xmpp.Options{Host: *server,
		User:          *username,
		Password:      *password,
		NoTLS:         *notls,
		Debug:         *debug,
		Session:       *session,
		Status:        *status,
		StatusMessage: *statusMessage,
	}

	talk, err = options.NewClient()

	if err != nil {
		log.Fatal(err)
	}

	oldState, err := terminal.MakeRaw(0)
	if err != nil {
		panic(err)
	}
	defer func() {
		terminal.Restore(0, oldState)
		fmt.Println()
	}()
	t := terminal.NewTerminal(os.Stdin, "")
	t.SetPrompt(fmt.Sprintf("%s%s%s: ", t.Escape.Red, *me, t.Escape.Reset))

	go func() {
		for {
			chat, err := talk.Recv()
			if err != nil {
				log.Fatal(err)
			}
			switch v := chat.(type) {
			case xmpp.Chat:
				if strings.HasPrefix(v.Remote, *recipient) {
					t.Write([]byte(fmt.Sprintf("%s%s%s: %s\n", t.Escape.Cyan, *recipientName, t.Escape.Reset, v.Text)))
				}
			case xmpp.Presence:
			}
		}
	}()
	for {
		line, err := t.ReadLine()
		if err != nil {
			break
		}
		line = strings.TrimRight(line, "\n")
		if line == "" {
			continue
		}

		talk.Send(xmpp.Chat{Remote: *recipient, Type: "chat", Text: line})
	}
}