Making the nested proto field drilldowns more generic

They had unique logic specifically for `trigger.` but that means that they wont work for any other nested proto in the future.

xml_converter/generators/code_generator.py

@@ -365,14 +365,7 @@ def generate_cpp_variable_data(
                     xml_fields.append(lowercase(x, delimiter=""))
                 default_xml_field = fieldval['xml_fields'][0]
 
-                # TODO: this should handle more then just `trigger.` variants
-                if fieldval["protobuf_field"].startswith("trigger"):
-                    proto_drilldown_calls = ".trigger()"
-                    # TODO this would not properly catch trigger.something.ourvariable
-                    protobuf_field = fieldval["protobuf_field"].split('.')[1]
-                else:
-                    proto_drilldown_calls = ""
-                    protobuf_field = fieldval["protobuf_field"]
+                proto_drilldown_calls, protobuf_field = split_field_into_drilldown(fieldval["protobuf_field"])
 
                 if fieldval.get("uses_file_path", False):
                     args.append("base_dir")
@@ -471,14 +464,7 @@ def write_attribute(self, output_directory: str) -> None:
             metadata[filepath] = self.data[filepath].metadata
             attribute_name = attribute_name_from_markdown_data(metadata[filepath]['name'])
 
-            # TODO this should handle more then just `trigger.` variants
-            if metadata[filepath]["protobuf_field"].startswith("trigger"):
-                proto_drilldown_calls = ".trigger()"
-                # TODO this would not properly catch trigger.something.ourvariable
-                protobuf_field = metadata[filepath]["protobuf_field"].split('.')[1]
-            else:
-                proto_drilldown_calls = ""
-                protobuf_field = metadata[filepath]["protobuf_field"]
+            proto_drilldown_calls, protobuf_field = split_field_into_drilldown(metadata[filepath]["protobuf_field"])
 
             if metadata[filepath]['type'] == "MultiflagValue":
                 for flag in metadata[filepath]['flags']:
@@ -754,6 +740,22 @@ def generate_auto_docs(self, metadata: Dict[str, SchemaType], content: Dict[str,
         return template.render(field_rows=field_rows), field_rows
 
 
+################################################################################
+# split_field_into_drilldown
+#
+# Splits the field string into a cpp drilldown function call stack and the
+# final proto field name.
+# EG:
+#   field: "trigger.range"
+#   returns: (".trigger()", "range")
+################################################################################
+def split_field_into_drilldown(field: str) -> Tuple[str, str]:
+    components = field.split(".")
+    proto_drilldown_calls = "".join([".{}()".format(x) for x in components[:-1]])
+    protobuf_field = components[-1]
+    return proto_drilldown_calls, protobuf_field
+
+
 ############################################################################
 # attribute_name_from_markdown_data
 #