New assign / unassign declaration usecase, minor code & formatting cleanup

src/ifcopenshell-python/ifcopenshell/api/project/assign_declaration.py

@@ -0,0 +1,51 @@
+import ifcopenshell
+import ifcopenshell.api
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {
+            "definition": None,
+            "relating_context": None,
+        }
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        declares = None
+        if self.settings["relating_context"].Declares:
+            declares = self.settings["relating_context"].Declares[0]
+
+        has_context = None
+        if self.settings["definition"].HasContext:
+            has_context = self.settings["definition"].HasContext[0]
+
+        if has_context and has_context == declares:
+            return
+
+        if has_context:
+            related_definitions = list(has_context.RelatedDefinitions)
+            related_definitions.remove(self.settings["definition"])
+            if related_definitions:
+                has_context.RelatedDefinitions = related_definitions
+                ifcopenshell.api.run("owner.update_owner_history", self.file, **{"element": has_context})
+            else:
+                self.file.remove(has_context)
+
+        if declares:
+            related_definitions = set(declares.RelatedDefinitions)
+            related_definitions.add(self.settings["definition"])
+            declares.RelatedDefinitions = list(related_definitions)
+            ifcopenshell.api.run("owner.update_owner_history", self.file, **{"element": declares})
+        else:
+            declares = self.file.create_entity(
+                "IfcRelDeclares",
+                **{
+                    "GlobalId": ifcopenshell.guid.new(),
+                    "OwnerHistory": ifcopenshell.api.run("owner.create_owner_history", self.file),
+                    "RelatedDefinitions": [self.settings["definition"]],
+                    "RelatingContext": self.settings["relating_context"],
+                }
+            )
+        return declares

src/ifcopenshell-python/ifcopenshell/api/project/unassign_declaration.py

@@ -0,0 +1,25 @@
+import ifcopenshell
+import ifcopenshell.api
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        self.file = file
+        self.settings = {
+            "definition": None,
+            "relating_context": None,
+        }
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        if not self.settings["definition"].HasContext:
+            return
+        rel = self.settings["definition"].HasContext[0]
+        related_definitions = set(rel.RelatedDefinitions) or set()
+        related_definitions.remove(self.settings["definition"])
+        if len(related_definitions):
+            rel.RelatedDefinitions = list(related_definitions)
+            ifcopenshell.api.run("owner.update_owner_history", self.file, **{"element": rel})
+        else:
+            self.file.remove(rel)