fix(bot): skip deleting absent Telegram webhook

Inspect webhook state before cleanup so long-polling startup does not fail on an empty deleteWebhook response.

Fixes #52

Author: pyed

internal/bot/bot.go

@@ -67,11 +67,8 @@ func New(ctx context.Context, cfg *config.Config, client *transmission.Transmiss
 	}
 	b.API = api
 
-	// Remove any stale webhook so long polling receives updates reliably
-	if _, err := api.DeleteWebhook(ctx, &tgbot.DeleteWebhookParams{
-		DropPendingUpdates: false,
-	}); err != nil {
-		return nil, fmt.Errorf("delete stale Telegram webhook: %w", err)
+	if err := clearWebhook(ctx, api); err != nil {
+		return nil, err
 	}
 
 	me, err := api.GetMe(ctx)
@@ -91,6 +88,21 @@ func New(ctx context.Context, cfg *config.Config, client *transmission.Transmiss
 	return b, nil
 }
 
+func clearWebhook(ctx context.Context, api *tgbot.Bot) error {
+	info, err := api.GetWebhookInfo(ctx)
+	if err != nil {
+		return fmt.Errorf("get Telegram webhook info: %w", err)
+	}
+	if info.URL == "" {
+		return nil
+	}
+
+	if _, err := api.DeleteWebhook(ctx, &tgbot.DeleteWebhookParams{DropPendingUpdates: false}); err != nil {
+		return fmt.Errorf("delete stale Telegram webhook: %w", err)
+	}
+	return nil
+}
+
 // defaultBotCommands returns the list of primary commands to display in Telegram's menu.
 func defaultBotCommands() []models.BotCommand {
 	return []models.BotCommand{

internal/bot/bot_test.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"context"
 	"log/slog"
+	"net/http"
+	"net/http/httptest"
 	"strings"
 	"sync/atomic"
 	"testing"
@@ -162,6 +164,30 @@ func TestDefaultBotCommands(t *testing.T) {
 	}
 }
 
+func TestClearWebhookSkipsDeleteWhenUnset(t *testing.T) {
+	var deleteCalls atomic.Int32
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		if strings.HasSuffix(r.URL.Path, "/getWebhookInfo") {
+			_, _ = w.Write([]byte(`{"ok":true,"result":{"url":"","has_custom_certificate":false,"pending_update_count":0}}`))
+			return
+		}
+		deleteCalls.Add(1)
+	}))
+	defer server.Close()
+
+	api, err := tgbot.New(testBotToken, tgbot.WithServerURL(server.URL), tgbot.WithSkipGetMe())
+	if err != nil {
+		t.Fatalf("create test bot: %v", err)
+	}
+	if err := clearWebhook(context.Background(), api); err != nil {
+		t.Fatalf("clear absent webhook: %v", err)
+	}
+	if got := deleteCalls.Load(); got != 0 {
+		t.Fatalf("deleteWebhook called %d times for an absent webhook", got)
+	}
+}
+
 func TestHelpCoversEveryMenuCommand(t *testing.T) {
 	for _, command := range defaultBotCommands() {
 		if !strings.Contains(config.Help, "/"+command.Command) {