# IfcOpenShell - IFC toolkit and geometry engine
# Copyright (C) 2022 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.placement


class Usecase:
    def __init__(self, file, element=None, port=None):
        """Assigns a port to an element

        If you have an orphaned port, you may assign it to a distribution
        element using this function. Ports should typically not be orphaned, but
        it may be useful when patching up models.

        :param element: The IfcDistributionElement to assign the port to.
        :type element: ifcopenshell.entity_instance.entity_instance
        :param port: The IfcDistributionPort you want to assign.
        :type port: ifcopenshell.entity_instance.entity_instance
        :return: The IfcRelNests relationship, or the
            IfcRelConnectsPortToElement for IFC2X3.
        :rtype: ifcopenshell.entity_instance.entity_instance

        Example:

        .. code:: python

            # Create a duct
            duct = ifcopenshell.api.run("root.create_entity", model,
                ifc_class="IfcDuctSegment", predefined_type="RIGIDSEGMENT")

            # Create 2 ports, one for either end.
            port1 = ifcopenshell.api.run("system.add_port", model, element=duct)
            port2 = ifcopenshell.api.run("system.add_port", model, element=duct)

            # Unassign one port for some weird reason.
            ifcopenshell.api.run("system.unassign_port", model, element=duct, port=port1)

            # Reassign it back
            ifcopenshell.api.run("system.assign_port", model, element=duct, port=port1)
        """
        self.file = file
        self.settings = {
            "element": element,
            "port": port,
        }

    def execute(self):
        if self.file.schema == "IFC2X3":
            return self.execute_ifc2x3()

        rels = self.settings["element"].IsNestedBy or []

        for rel in rels:
            if self.settings["port"] in rel.RelatedObjects:
                return

        if rels:
            rel = rels[0]
            related_objects = set(rel.RelatedObjects) or set()
            related_objects.add(self.settings["port"])
            rel.RelatedObjects = list(related_objects)
            ifcopenshell.api.run("owner.update_owner_history", self.file, **{"element": rel})
        else:
            rel = self.file.create_entity(
                "IfcRelNests",
                GlobalId=ifcopenshell.guid.new(),
                OwnerHistory=ifcopenshell.api.run("owner.create_owner_history", self.file),
                RelatedObjects=[self.settings["port"]],
                RelatingObject=self.settings["element"],
            )

        self.update_port_placement()

        return rel

    def execute_ifc2x3(self):
        for rel in self.settings["element"].HasPorts or []:
            if rel.RelatingPort == self.settings["port"]:
                return
        rel = self.file.create_entity(
            "IfcRelConnectsPortToElement",
            GlobalId=ifcopenshell.guid.new(),
            OwnerHistory=ifcopenshell.api.run("owner.create_owner_history", self.file),
            RelatingPort=self.settings["port"],
            RelatedElement=self.settings["element"],
        )
        self.update_port_placement()
        return rel

    def update_port_placement(self):
        placement = getattr(self.settings["port"], "ObjectPlacement", None)
        if placement and placement.is_a("IfcLocalPlacement"):
            ifcopenshell.api.run(
                "geometry.edit_object_placement",
                self.file,
                product=self.settings["port"],
                matrix=ifcopenshell.util.placement.get_local_placement(self.settings["port"].ObjectPlacement),
                is_si=False,
            )