feat(examples): add echo bot

examples/echo-bot/main.go

@@ -0,0 +1,153 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"regexp"
+	"strings"
+	"syscall"
+	"time"
+
+	_ "embed"
+
+	"github.com/mr-linch/go-tg"
+	"github.com/mr-linch/go-tg/tgb"
+)
+
+var (
+	flagToken         string
+	flagServer        string
+	flagWebhookURL    string
+	flagWebhookListen string
+	flagDebug         bool
+)
+
+var (
+	//go:embed resources/gopher.png
+	gopherPNG []byte
+)
+
+func main() {
+	flag.StringVar(&flagToken, "token", "", "Telegram Bot API token")
+	flag.StringVar(&flagServer, "server", "https://api.telegram.org", "Telegram Bot API server")
+	flag.StringVar(&flagWebhookURL, "webhook-url", "", "Telegram Bot API webhook URL, if not provdide run in longpoll mode")
+	flag.StringVar(&flagWebhookListen, "webhook-listen", ":8000", "Telegram Bot API webhook URL")
+	flag.BoolVar(&flagDebug, "debug", false, "Debug mode")
+	flag.Parse()
+
+	ctx := context.Background()
+
+	ctx, cancel := signal.NotifyContext(ctx, os.Interrupt, os.Kill, syscall.SIGTERM)
+	defer cancel()
+
+	if err := run(ctx); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func run(ctx context.Context) error {
+	if flagToken == "" {
+		return fmt.Errorf("token is required")
+	}
+
+	client := tg.New(flagToken,
+		tg.WithServer(flagServer),
+	)
+
+	me, err := client.Me(ctx)
+	if err != nil {
+		return fmt.Errorf("get me: %w", err)
+	}
+	log.Printf("auth as https://t.me/%s", me.Username)
+
+	bot := newBot()
+
+	if flagWebhookURL != "" {
+		return runWebhook(ctx, client, bot, flagWebhookURL, flagWebhookListen)
+	} else {
+		return fmt.Errorf("long poll is not implimented")
+	}
+}
+
+func newBot() *tgb.Bot {
+
+	return tgb.New().
+		// handles /start and /help
+		Message(tgb.HandlerFunc(func(ctx context.Context, update *tg.Update) error {
+			return update.Respond(ctx, tg.NewSendMessageCall(
+				update.Message.Chat,
+				strings.Join([]string{
+					`👋 Hi, I'm echo bot!`,
+					``,
+					`<i>🚀Powered by <a href="github.com/mr-linch/go-tg">go-tg</a></i>`,
+				}, "\n"),
+			).ParseMode("HTML"))
+		}), tgb.Command("start", tgb.WithCommandAlias("help"))).
+		// handles gopher image
+		Message(tgb.HandlerFunc(func(ctx context.Context, update *tg.Update) error {
+			// if update is from webhook we will answer to it here
+			if err := update.Respond(ctx, tg.NewSendChatActionCall(
+				update.Message.Chat,
+				"upload_photo",
+			)); err != nil {
+				return fmt.Errorf("send chat action: %w", err)
+			}
+
+			// second call was send as call to api
+			return update.Respond(ctx, tg.NewSendPhotoCall(update.Message.Chat, tg.FileArg{
+				Upload: tg.NewInputFileBytes("gopher.png", gopherPNG),
+			}))
+
+		}), tgb.Regexp(regexp.MustCompile(`(go|golang|gopher)[$\s+]?`))).
+		// handle other messages
+		Message(tgb.HandlerFunc(func(ctx context.Context, update *tg.Update) error {
+			return update.Respond(ctx, tg.NewCopyMessageCall(
+				update.Message.Chat,
+				update.Message.Chat,
+				update.Message.ID,
+			))
+		}))
+
+}
+
+func runWebhook(ctx context.Context, client *tg.Client, bot *tgb.Bot, url, listen string) error {
+	webhook := tgb.NewWebhook(
+		url,
+		bot,
+		client,
+	)
+
+	if err := webhook.Setup(ctx, true); err != nil {
+		return fmt.Errorf("webhook: %w", err)
+	}
+
+	server := http.Server{
+		Handler: webhook,
+		Addr:    listen,
+	}
+
+	go func() {
+		<-ctx.Done()
+
+		log.Printf("shutdown webhook server")
+
+		closeCtx, close := context.WithTimeout(context.Background(), 10*time.Second)
+		defer close()
+
+		if err := server.Shutdown(closeCtx); err != nil {
+			log.Printf("server shutdown error: %v", err)
+		}
+	}()
+
+	log.Printf("start webhook server on %s", listen)
+	if err := server.ListenAndServe(); err != http.ErrServerClosed {
+		return fmt.Errorf("listen and serve: %w", err)
+	}
+
+	return nil
+}