first

backend/internal/modules/telegram/sender.go

@@ -0,0 +1,55 @@
+package telegram
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+// Sender abstracts the actual Telegram Bot API call so the service layer
+// can be unit-tested without making real network requests.
+type Sender interface {
+	Send(ctx context.Context, botToken, chatID, text string) error
+}
+
+type httpSender struct {
+	client *http.Client
+}
+
+func NewHTTPSender() Sender {
+	return &httpSender{client: &http.Client{Timeout: 10 * time.Second}}
+}
+
+func (s *httpSender) Send(ctx context.Context, botToken, chatID, text string) error {
+	if botToken == "" || chatID == "" {
+		return fmt.Errorf("telegram bot token and chat id must be configured")
+	}
+
+	endpoint := fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", botToken)
+	form := url.Values{
+		"chat_id": {chatID},
+		"text":    {text},
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, strings.NewReader(form.Encode()))
+	if err != nil {
+		return fmt.Errorf("build telegram request: %w", err)
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+
+	resp, err := s.client.Do(req)
+	if err != nil {
+		return fmt.Errorf("call telegram api: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode >= 300 {
+		body, _ := io.ReadAll(io.LimitReader(resp.Body, 4096))
+		return fmt.Errorf("telegram api returned status %d: %s", resp.StatusCode, string(body))
+	}
+	return nil
+}