# 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.owner
import ifcopenshell.api.pset
import ifcopenshell.guid
import ifcopenshell.util.element


def unshare_pset(
    file: ifcopenshell.file,
    products: list[ifcopenshell.entity_instance],
    pset: ifcopenshell.entity_instance,
) -> list[ifcopenshell.entity_instance]:
    """Copy a shared pset as linked only to the provided elements.

    Note that method will create a copy of the pset for each element provided.

    :param products: Elements (or element types) to link the pset to.
    :param pset: Shared property set.
    :return: List of copied property sets.

    Example:

    .. code:: python

        element1 = ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcWall")
        element2 = ifcopenshell.api.root.create_entity(self.file, ifc_class="IfcWall")
        ifcopenshell.api.pset.assign_pset(self.file, [element1, element2], pset)

        # Pset is now shared by 2 elements.
        assert ifcopenshell.util.element.get_elements_using_pset(pset) == {element1, element2}

        new_psets = ifcopenshell.api.pset.unshare_pset(self.file, [element2], pset)

        # element2 was unassigned from the original pset.
        assert ifcopenshell.util.element.get_elements_using_pset(pset) == {element1}
        new_pset = new_psets[0]

        # New pset was created and was assigned to element2.
        assert new_pset != pset
        assert ifcopenshell.util.element.get_elements_using_pset(new_pset) == {element2}
    """
    products_occurrences: set[ifcopenshell.entity_instance] = set()
    products_types: set[ifcopenshell.entity_instance] = set()
    for product in products:
        if product.is_a("IfcTypeProduct"):
            products_types.add(product)
        else:
            products_occurrences.add(product)

    ifcopenshell.api.pset.unassign_pset(file, products, pset)

    pset_copies: list[ifcopenshell.entity_instance] = []
    for product in products:
        pset_copy = ifcopenshell.util.element.copy_deep(file, pset)
        pset_copies.append(pset_copy)
        ifcopenshell.api.pset.assign_pset(file, [product], pset_copy)

    return pset_copies