# 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.api.geometry
import ifcopenshell.util.element
from typing import Any


def unassign_representation(
    file: ifcopenshell.file, product: ifcopenshell.entity_instance, representation: ifcopenshell.entity_instance
) -> None:
    usecase = Usecase()
    usecase.file = file
    usecase.settings = {"product": product, "representation": representation}
    return usecase.execute()


class Usecase:
    file: ifcopenshell.file
    settings: dict[str, Any]

    def execute(self) -> None:
        product: ifcopenshell.entity_instance = self.settings["product"]
        representation: ifcopenshell.entity_instance = self.settings["representation"]
        if product.is_a("IfcProduct"):
            self.unassign_product_representation(product, representation)
        elif product.is_a("IfcTypeProduct"):
            self.unassign_type_representation()

    def unassign_product_representation(
        self, product: ifcopenshell.entity_instance, representation: ifcopenshell.entity_instance
    ) -> None:
        representations = list(product.Representation.Representations or [])
        if representation not in representations:
            return
        representations.remove(representation)
        if not representations:
            product_def = product.Representation
            # TODO: should somehow find matching shape aspect and remove it
            # even before the last representation is removed.
            self.process_shape_aspects(product_def)
            self.file.remove(product_def)
        else:
            product.Representation.Representations = representations

    def unassign_type_representation(self) -> None:
        matching_representation_map = None

        for representation_map in self.settings["product"].RepresentationMaps or []:
            if representation_map.MappedRepresentation == self.settings["representation"]:
                matching_representation_map = representation_map
                break

        if matching_representation_map:
            self.unassign_products_using_mapped_representation(matching_representation_map)
            self.settings["product"].RepresentationMaps = [
                rm for rm in self.settings["product"].RepresentationMaps if rm != matching_representation_map
            ] or None
            self.process_shape_aspects(matching_representation_map)
            self.remove_representation_map_only(matching_representation_map)

    def process_shape_aspects(self, product_representation: ifcopenshell.entity_instance) -> None:
        # Technically IfcShapeAspect doesn't become invalid when product representation is removed,
        # but shape aspect makes sense only in context of some other representation.
        if self.file.schema == "IFC2X3" and product_representation.is_a("IfcRepresentationMap"):
            shape_aspects = [
                a
                for a in self.file.by_type("IfcShapeAspect")
                if a.PartOfProductDefinitionShape == product_representation
            ]
        else:
            shape_aspects = product_representation.HasShapeAspects
        for shape_aspect in shape_aspects:
            representations = shape_aspect.ShapeRepresentations
            self.file.remove(shape_aspect)
            for rep in representations:
                ifcopenshell.api.geometry.remove_representation(self.file, rep)

    def remove_representation_map_only(self, representation_map: ifcopenshell.entity_instance) -> None:
        representation_map.MappedRepresentation = self.file.createIfcShapeRepresentation()
        ifcopenshell.util.element.remove_deep2(self.file, representation_map)

    def unassign_products_using_mapped_representation(self, representation_map: ifcopenshell.entity_instance) -> None:
        mapped_representations: list[dict[str, ifcopenshell.entity_instance]] = []
        just_representations: list[ifcopenshell.entity_instance] = []
        for map_usage in representation_map.MapUsage or []:
            for inverse in self.file.get_inverse(map_usage):
                if not inverse.is_a("IfcShapeRepresentation"):
                    continue
                for definition in inverse.OfProductRepresentation or []:
                    for product in definition.ShapeOfProduct or []:
                        mapped_representations.append({"product": product, "representation": inverse})
                        just_representations.append(inverse)
        for item in mapped_representations:
            self.unassign_product_representation(item["product"], item["representation"])
        for representation in just_representations:
            ifcopenshell.api.geometry.remove_representation(self.file, representation=representation)
