feat: add per-task PDF/DOCX export for service records

Enable generating service-record documents for a single task on /putni-nalozi/racuni while preserving existing full work-order export.

- Backend service-records PDF/DOCX endpoints now accept optional task_id and validate the task belongs to the selected work order.
- Document builders support scoped task lists, and per-task downloads use task-specific filenames.
- Frontend task cards now include per-task PDF/DOCX actions, while top-level buttons are clarified as exporting all service records.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

backend/modules/fleet/views.py

@@ -210,6 +210,32 @@ def _docx_filename(work_order, doc_type):
     return f"{display_code}.work-order.docx"
 
 
+def _service_records_pdf_filename(work_order, task=None):
+    if not task:
+        return _pdf_filename(work_order, 'service_records')
+    display_code = _work_order_display_code(work_order)
+    return f"{display_code}.task-{task.pk}.work-order-service-records.pdf"
+
+
+def _service_records_docx_filename(work_order, task=None):
+    if not task:
+        return _docx_filename(work_order, 'service_records')
+    display_code = _work_order_display_code(work_order)
+    return f"{display_code}.task-{task.pk}.work-order-service-records.docx"
+
+
+def _resolve_service_report_tasks(work_order, task_id):
+    queryset = _work_order_related_tasks_queryset(work_order)
+    if not task_id:
+        return list(queryset), None
+    selected_task = queryset.filter(pk=task_id).first()
+    if not selected_task:
+        raise DRFValidationError({
+            'task_id': 'Odabrani task nije povezan s ovim putnim nalogom.'
+        })
+    return [selected_task], selected_task
+
+
 def _compress_image_for_pdf(image_field, max_width=1280, quality=75):
     """
     Otvori image_field (Django FileField), kompresiraj na max_width JPEG u memoriji,
@@ -884,7 +910,7 @@ def _build_work_order_pdf(work_order):
     return buffer.getvalue()
 
 
-def _build_work_order_service_records_pdf(work_order):
+def _build_work_order_service_records_pdf(work_order, related_tasks=None):
     vehicle = work_order.vehicle
     client_name = getattr(vehicle.client, 'name', None) or '-'
     manufacturer_str = str(vehicle.make or '-')
@@ -900,7 +926,10 @@ def _build_work_order_service_records_pdf(work_order):
     FOOTER_H = 72
     MARGIN = 28
 
-    related_tasks = list(_work_order_related_tasks_queryset(work_order))
+    if related_tasks is None:
+        related_tasks = list(_work_order_related_tasks_queryset(work_order))
+    else:
+        related_tasks = list(related_tasks)
     # Collect service records for all task vehicles (supports cross-crane work orders)
     task_vehicle_ids = list({task.vehicle_id for task in related_tasks if task.vehicle_id})
     service_rows = list(
@@ -1812,7 +1841,7 @@ def _build_work_order_docx_bytes(work_order):
     return buffer.getvalue()
 
 
-def _build_work_order_service_records_docx_bytes(work_order):
+def _build_work_order_service_records_docx_bytes(work_order, related_tasks=None):
     from docx.shared import Cm
 
     doc = _create_docx_document(SERVICE_REPORT_DOCX_TEMPLATE_NAME)
@@ -1821,7 +1850,10 @@ def _build_work_order_service_records_docx_bytes(work_order):
     servicer_name = _user_display_name(work_order.creator) or '-'
     completion_label = "Da ☒    Ne ☐" if work_order.status == 'closed' else "Da ☐    Ne ☒"
 
-    related_tasks = list(_work_order_related_tasks_queryset(work_order).select_related('work_hours_table'))
+    if related_tasks is None:
+        related_tasks = list(_work_order_related_tasks_queryset(work_order).select_related('work_hours_table'))
+    else:
+        related_tasks = list(related_tasks)
     normalized_rows = []
     for task in related_tasks:
         table_data = getattr(getattr(task, 'work_hours_table', None), 'data', None)
@@ -2792,27 +2824,38 @@ class WorkOrderViewSet(viewsets.ModelViewSet):
     @action(detail=True, methods=['get'], url_path='service-records-pdf')
     def service_records_pdf(self, request, pk=None):
         work_order = self.get_object()
-        _cleanup_expired_generated_pdfs()
-        cached = _get_cached_pdf(work_order, 'service_records')
-        if cached:
-            return _cached_pdf_file_response(cached, default_filename=_pdf_filename(work_order, 'service_records'))
+        task_id = request.query_params.get('task_id')
+        related_tasks, selected_task = _resolve_service_report_tasks(work_order, task_id)
 
-        _notify_pdf_request(user=request.user, work_order=work_order, doc_type='service_records', stage='requested')
-        pdf_bytes = _build_work_order_service_records_pdf(work_order)
-        _notify_pdf_request(user=request.user, work_order=work_order, doc_type='service_records', stage='completed')
+        if not selected_task:
+            _cleanup_expired_generated_pdfs()
+            cached = _get_cached_pdf(work_order, 'service_records')
+            if cached:
+                return _cached_pdf_file_response(
+                    cached,
+                    default_filename=_service_records_pdf_filename(work_order),
+                )
+            _notify_pdf_request(user=request.user, work_order=work_order, doc_type='service_records', stage='requested')
+
+        pdf_bytes = _build_work_order_service_records_pdf(work_order, related_tasks=related_tasks)
+
+        if not selected_task:
+            _notify_pdf_request(user=request.user, work_order=work_order, doc_type='service_records', stage='completed')
         response = HttpResponse(pdf_bytes, content_type='application/pdf')
-        response['Content-Disposition'] = f'attachment; filename="{_pdf_filename(work_order, "service_records")}"'
+        response['Content-Disposition'] = f'attachment; filename="{_service_records_pdf_filename(work_order, selected_task)}"'
         return response
 
     @action(detail=True, methods=['get'], url_path='service-records-docx')
     def service_records_docx(self, request, pk=None):
         work_order = self.get_object()
-        docx_bytes = _build_work_order_service_records_docx_bytes(work_order)
+        task_id = request.query_params.get('task_id')
+        related_tasks, selected_task = _resolve_service_report_tasks(work_order, task_id)
+        docx_bytes = _build_work_order_service_records_docx_bytes(work_order, related_tasks=related_tasks)
         response = HttpResponse(
             docx_bytes,
             content_type='application/vnd.openxmlformats-officedocument.wordprocessingml.document',
         )
-        response['Content-Disposition'] = f'attachment; filename="{_docx_filename(work_order, "service_records")}"'
+        response['Content-Disposition'] = f'attachment; filename="{_service_records_docx_filename(work_order, selected_task)}"'
         return response
 
     @action(detail=True, methods=['post'], url_path='service-records-pdf-request')