Reload nodes based on object index

Refactored the code in order to extract the index of the node inside
the file and then use that index to reload the correct object from the
file.

CURA-7333

cura/CuraApplication.py

@@ -2,6 +2,7 @@
 # Cura is released under the terms of the LGPLv3 or higher.
 
 import os
+import re
 import sys
 import time
 from typing import cast, TYPE_CHECKING, Optional, Callable, List, Any
@@ -1382,23 +1383,63 @@ class CuraApplication(QtApplication):
         if not nodes:
             return
 
-        for obj, node in enumerate(nodes):
+        objects_in_filename = {}
+        for node in nodes:
             mesh_data = node.getMeshData()
-
             if mesh_data:
                 file_name = mesh_data.getFileName()
                 if file_name:
-                    job = ReadMeshJob(file_name)
-                    job.object_to_be_reloaded = obj  # The object index to be loaded by this specific ReadMeshJob
-                    job._node = node  # type: ignore
-                    job.finished.connect(self._reloadMeshFinished)
-                    if has_merged_nodes:
-                        job.finished.connect(self.updateOriginOfMergedMeshes)
-
-                    job.start()
+                    if file_name not in objects_in_filename:
+                        objects_in_filename[file_name] = []
+                    if file_name in objects_in_filename:
+                        objects_in_filename[file_name].append(node)
                 else:
                     Logger.log("w", "Unable to reload data because we don't have a filename.")
 
+        for file_name, nodes in objects_in_filename.items():
+            for object_index, node in enumerate(nodes):
+                job = ReadMeshJob(file_name)
+                job.object_to_be_reloaded = self._getObjectIndexInFile(file_name, node.getName())  # The object index in file to be loaded by this specific job
+                job._node = node  # type: ignore
+                job.finished.connect(self._reloadMeshFinished)
+                if has_merged_nodes:
+                    job.finished.connect(self.updateOriginOfMergedMeshes)
+
+                job.start()
+
+    @staticmethod
+    def _getObjectIndexInFile(file_name: str, node_name: str) -> int:
+        """
+        This function extracts the index of the object inside a file. This is achieved by looking into the name
+        of the node. There are two possibilities:
+         * The node is named as filename.ext, filename.ext(1), filename.ext(2), etc, which maps to indices 0, 1, 2, ...
+         * The node is named as Object 1, Object 2, Object 3 etc, which maps to indices 0, 1, 2 ...
+
+        :param file_name: The name of the file where the node has been retrieved from
+        :param node_name: The name of the node as presented in the Scene
+        :return: The index of the node inside the file_name
+        """
+        file_name = file_name.split("/")[-1]  # Keep only the filename, without the path
+        node_int_index = 0
+        if file_name in node_name:
+            # if the file_name exists inside the node_name, remove it along with all parenthesis and spaces
+            node_str_index = re.sub(r'[() ]', '', node_name.replace(file_name, ""))
+            try:
+                node_int_index = int(node_str_index)
+            except ValueError:
+                Logger.warning("Object '{}' has an incorrect index '{}'.".format(node_name, node_str_index))
+                return 0
+        elif "Object " in node_name:
+            # if the nodes are named as Object 1, Object 2, etc, remove 'Object ' and keep only the number
+            node_str_index = node_name.replace("Object ", "")
+            try:
+                node_int_index = int(node_str_index) - 1
+            except ValueError:
+                Logger.warning("Object '{}' has an incorrect index '{}'.".format(node_name, node_str_index))
+                return 0
+        return node_int_index
+
+
     @pyqtSlot("QStringList")
     def setExpandedCategories(self, categories: List[str]) -> None:
         categories = list(set(categories))