# 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


class Usecase:
    def __init__(self, file, **settings):
        self.file = file
        self.settings = {
            "product": None,
            "constraint": None,
        }
        for key, value in settings.items():
            self.settings[key] = value

    def execute(self):
        rel = self.get_constraint_rel()
        related_objects = set(rel.RelatedObjects) if rel.RelatedObjects else set()
        related_objects.add(self.settings["product"])
        rel.RelatedObjects = list(related_objects)
        return rel

    def get_constraint_rel(self):
        for rel in self.file.by_type("IfcRelAssociatesConstraint"):
            if rel.RelatingConstraint == self.settings["constraint"]:
                return rel
        return self.file.create_entity(
            "IfcRelAssociatesConstraint",
            **{
                "GlobalId": ifcopenshell.guid.new(),
                # TODO: owner history
                "RelatingConstraint": self.settings["constraint"],
            }
        )