Implement support for removing styles. See #1557.

src/ifcopenshell-python/ifcopenshell/api/style/remove_style.py

@@ -0,0 +1,30 @@
+import ifcopenshell.util.element
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {"style": None}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        self.purge_styled_items(self.settings["style"])
+        ifcopenshell.util.element.remove_deep(self.file, self.settings["style"])
+
+    def purge_styled_items(self, style):
+        for inverse in self.file.get_inverse(style):
+            if inverse.is_a("IfcStyledItem") and len(inverse.Styles) == 1:
+                self.purge_styled_representations(inverse)
+                self.file.remove(inverse)
+
+    def purge_styled_representations(self, styled_item):
+        for inverse in self.file.get_inverse(styled_item):
+            if inverse.is_a("IfcStyledRepresentation") and len(inverse.Items) == 1:
+                self.purge_material_definition_representations(inverse)
+                self.file.remove(inverse)
+
+    def purge_material_definition_representations(self, styled_representation):
+        for inverse in self.file.get_inverse(styled_representation):
+            if inverse.is_a("IfcMaterialDefinitionRepresentation") and len(inverse.Representations) == 1:
+                self.file.remove(inverse)