MCP error logging

telegram_helpers.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+
+	tgbot "github.com/go-telegram/bot"
+	"github.com/go-telegram/bot/models"
+)
+
+// largestPhotoSize returns the highest-resolution PhotoSize from the slice
+// Telegram returns for a single photo. Telegram pre-renders each upload at
+// several resolutions; we want the largest for vision quality. Falls back to
+// the zero value when the slice is empty (caller should guard upstream).
+func largestPhotoSize(photos []models.PhotoSize) models.PhotoSize {
+	if len(photos) == 0 {
+		return models.PhotoSize{}
+	}
+	largest := photos[0]
+	largestArea := largest.Width * largest.Height
+	for i := 1; i < len(photos); i++ {
+		area := photos[i].Width * photos[i].Height
+		if area > largestArea {
+			largest = photos[i]
+			largestArea = area
+		}
+	}
+	return largest
+}
+
+// downloadTelegramFile resolves a Telegram file_id via the bot API, fetches the
+// download URL, and reads the bytes into memory. The two-step dance (GetFile +
+// fetch via FileDownloadLink) is required by Telegram's protocol — direct
+// downloads aren't possible from file_id alone. Buffered into []byte because
+// downstream callers (multipart uploads to ElevenLabs and Anthropic) re-read
+// the body; streaming would require either tee-ing or a temp file.
+func (b *Bot) downloadTelegramFile(ctx context.Context, fileID string) ([]byte, error) {
+	fileInfo, err := b.tgBot.GetFile(ctx, &tgbot.GetFileParams{FileID: fileID})
+	if err != nil {
+		return nil, fmt.Errorf("telegram GetFile %s: %w", fileID, err)
+	}
+	downloadURL := b.tgBot.FileDownloadLink(fileInfo)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, downloadURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("telegram download request %s: %w", fileID, err)
+	}
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("telegram download %s: %w", fileID, err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("telegram download %s: status %d", fileID, resp.StatusCode)
+	}
+	data, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("telegram download read %s: %w", fileID, err)
+	}
+	return data, nil
+}