Initial codex telegram bot source

internal/telegram/download.go

@@ -0,0 +1,26 @@
+package telegram
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+)
+
+func (c *Client) DownloadFilePath(ctx context.Context, filePath string) ([]byte, error) {
+	u := c.fileBaseURL + "/" + strings.TrimLeft(filePath, "/")
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
+	if err != nil {
+		return nil, err
+	}
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		return nil, fmt.Errorf("download file: telegram returned %s", resp.Status)
+	}
+	return io.ReadAll(resp.Body)
+}