Fix adhesion checkbox in recommended mode

CURA-6182

Move complex logic to Python.

cura/UI/RecommendedMode.py

@@ -0,0 +1,50 @@
+# Copyright (c) 2019 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from PyQt5.QtCore import QObject, pyqtSlot
+
+
+#
+# This object contains helper/convenience functions for Recommended mode.
+#
+class RecommendedMode(QObject):
+
+    # Sets to use the adhesion or not for the "Adhesion" CheckBox in Recommended mode.
+    @pyqtSlot(bool)
+    def setAdhesion(self, checked: bool) -> None:
+        from cura.CuraApplication import CuraApplication
+
+        application = CuraApplication.getInstance()
+        global_stack = application.getMachineManager().activeMachine
+        if global_stack is None:
+            return
+
+        # Remove the adhesion type value set by the user.
+        adhesion_type_key = "adhesion_type"
+        user_changes_container = global_stack.userChanges
+        if adhesion_type_key in user_changes_container.getAllKeys():
+            user_changes_container.removeInstance(adhesion_type_key)
+
+        # Get the default value of adhesion type after user's value has been removed.
+        # skirt and none are counted as "no adhesion", the others are considered as "with adhesion". The conditions are
+        # as the following:
+        #  - if the user checks the adhesion checkbox, get the default value (including the custom quality) for adhesion
+        #    type.
+        #     (1) If the default value is "skirt" or "none" (no adhesion), set adhesion_type to "brim".
+        #     (2) If the default value is "with adhesion", do nothing.
+        #  - if the user unchecks the adhesion checkbox, get the default value (including the custom quality) for
+        #    adhesion type.
+        #     (1) If the default value is "skirt" or "none" (no adhesion), do nothing.
+        #     (2) Otherwise, set adhesion_type to "skirt".
+        value = global_stack.getProperty(adhesion_type_key, "value")
+        if checked:
+            if value in ("skirt", "none"):
+                value = "brim"
+        else:
+            if value not in ("skirt", "none"):
+                value = "skirt"
+
+        user_changes_container.setProperty(adhesion_type_key, "value", value)
+
+
+__all__ = ["RecommendedMode"]