# 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.element


def disconnect_port(file: ifcopenshell.file, port: ifcopenshell.entity_instance) -> None:
    """Disconnects a port from any other port

    A port may only be connected to one other port, so the other port is not
    needed to be specified.

    :param port: The IfcDistributionPort to disconnect.
    :return: None

    Example:

    .. code:: python

        # A completely empty distribution system
        system = ifcopenshell.api.system.add_system(model)

        # Create a duct and a 90 degree bend fitting
        duct = ifcopenshell.api.root.create_entity(model,
            ifc_class="IfcDuctSegment", predefined_type="RIGIDSEGMENT")
        fitting = ifcopenshell.api.root.create_entity(model,
            ifc_class="IfcDuctFitting", predefined_type="BEND")

        # The duct and fitting is part of the system
        ifcopenshell.api.system.assign_system(model, products=[duct], system=system)
        ifcopenshell.api.system.assign_system(model, products=[fitting], system=system)

        # Create 2 ports, one for either end of both the duct and fitting.
        duct_port1 = ifcopenshell.api.system.add_port(model, element=duct)
        duct_port2 = ifcopenshell.api.system.add_port(model, element=duct)
        fitting_port1 = ifcopenshell.api.system.add_port(model, element=fitting)
        fitting_port2 = ifcopenshell.api.system.add_port(model, element=fitting)

        # Connect the duct and fitting together. At this point, we have not
        # yet determined the direction of the flow, so we leave direction as
        # NOTDEFINED.
        ifcopenshell.api.system.connect_port(model, port1=duct_port2, port2=fitting_port1)

        # Disconnect the port. note we could've equally disconnected
        # fitting_port1 instead of duct_port2
        ifcopenshell.api.system.disconnect_port(model, port=duct_port2)
    """
    rels = port.ConnectedTo or ()
    rels += port.ConnectedFrom or ()

    for rel in rels:
        rel.RelatingPort.FlowDirection = None
        rel.RelatedPort.FlowDirection = None
        history = rel.OwnerHistory
        file.remove(rel)
        if history:
            ifcopenshell.util.element.remove_deep2(file, history)
