tender single document download

internal/tender/handler.go

@@ -453,12 +453,14 @@ func (h *TenderHandler) GetDocuments(c echo.Context) error {
 	return response.Success(c, documents, "Tender documents retrieved successfully")
 }
 
-// DownloadDocuments downloads all scraped documents for a tender
+// DownloadDocuments downloads scraped documents for a tender
 // @Summary Download scraped documents for a tender
-// @Description Stream all scraped tender documents from storage as a ZIP archive
+// @Description Stream all scraped tender documents as a ZIP archive, or pass filename to download a single document
 // @Tags Tenders
 // @Produce application/zip
+// @Produce application/octet-stream
 // @Param id path string true "Tender ID"
+// @Param filename query string false "Document filename (from GET /documents); when set, returns that file instead of a ZIP"
 // @Success 200 {file} file
 // @Failure 400 {object} response.APIResponse
 // @Failure 404 {object} response.APIResponse
@@ -470,6 +472,10 @@ func (h *TenderHandler) DownloadDocuments(c echo.Context) error {
 		return response.BadRequest(c, "Tender ID is required", "ID parameter cannot be empty")
 	}
 
+	if filename := strings.TrimSpace(c.QueryParam("filename")); filename != "" {
+		return h.streamDocumentDownload(c, id, filename)
+	}
+
 	download, err := h.service.DownloadDocuments(c.Request().Context(), id)
 	if err != nil {
 		if errors.Is(err, ErrTenderDocumentNotFound) {
@@ -493,6 +499,30 @@ func (h *TenderHandler) DownloadDocuments(c echo.Context) error {
 	return c.Stream(http.StatusOK, download.ContentType, download.Reader)
 }
 
+func (h *TenderHandler) streamDocumentDownload(c echo.Context, tenderID, filename string) error {
+	download, err := h.service.DownloadDocument(c.Request().Context(), tenderID, filename)
+	if err != nil {
+		if errors.Is(err, ErrTenderDocumentNotFound) {
+			return response.NotFound(c, "Tender document not found")
+		}
+		if errors.Is(err, ErrTenderDocumentStorageUnavailable) {
+			return response.InternalServerError(c, "Tender document storage is unavailable")
+		}
+		return response.InternalServerError(c, "Failed to download tender document")
+	}
+	defer download.Reader.Close()
+
+	headers := c.Response().Header()
+	headers.Set(echo.HeaderContentDisposition, mime.FormatMediaType("attachment", map[string]string{
+		"filename": download.Filename,
+	}))
+	if download.Size > 0 {
+		headers.Set(echo.HeaderContentLength, strconv.FormatInt(download.Size, 10))
+	}
+
+	return c.Stream(http.StatusOK, download.ContentType, download.Reader)
+}
+
 // GetAISummary retrieves the AI-generated overall summary for a tender
 // @Summary Get AI-generated tender summary
 // @Description Retrieve the AI-generated overall summary for a tender from the AI pipeline storage