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

# IfcOpenShell - IFC toolkit and geometry engine
# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
#
# This file is part of IfcOpenShell.
#
# IfcOpenShell is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# IfcOpenShell is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.

import ifcopenshell
import ifcopenshell.api
import ifcopenshell.util.element


class Usecase:
    def __init__(
        self,
        file: ifcopenshell.file,
        definitions: list[ifcopenshell.entity_instance],
        relating_context: ifcopenshell.entity_instance,
    ):
        """Unassigns a list of objects from a project or project library

        Typically used to remove an asset from a project library.

        :param definitions: The list of objects you want to undeclare.
            Typically a list of assets.
        :type definitions: list[ifcopenshell.entity_instance]
        :param relating_context: The IfcProject, or more commonly the
            IfcProjectLibrary that you want the object to no longer be part of.
        :type relating_context: ifcopenshell.entity_instance
        :return: None
        :rtype: None

        Example:

        .. code:: python

            # Programmatically generate a library. You could do this visually too.
            library = ifcopenshell.api.run("project.create_file")
            root = ifcopenshell.api.run("root.create_entity", library, ifc_class="IfcProject", name="Demo Library")
            context = ifcopenshell.api.run("root.create_entity", library,
                ifc_class="IfcProjectLibrary", name="Demo Library")

            # It's necessary to say our library is part of our project.
            ifcopenshell.api.run("project.assign_declaration", library, definitions=[context], relating_context=root)

            # Remove the library from our project
            ifcopenshell.api.run("project.unassign_declaration", library, definitions=[context], relating_context=root)
        """
        self.file = file
        self.settings = {
            "definitions": definitions,
            "relating_context": relating_context,
        }

    def execute(self):
        definitions = set(self.settings["definitions"])
        rels = {rel for obj in definitions if (rel := next(iter(obj.HasContext), None))}

        for rel in rels:
            related_definitions = set(rel.RelatedDefinitions) - definitions
            if related_definitions:
                rel.RelatedDefinitions = list(related_definitions)
                ifcopenshell.api.run("owner.update_owner_history", self.file, **{"element": rel})
            else:
                history = rel.OwnerHistory
                self.file.remove(rel)
                if history:
                    ifcopenshell.util.element.remove_deep2(self.file, history)