# 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/>.


class Usecase:
    def __init__(self, file, material=None, style=None, context=None, should_use_presentation_style_assignment=False):
        """Assigns a style to a material

        A style may either be assigned directly to an object's representation,
        or to a material which is then associated with the object. If both
        exist, then the style assigned directly to the object's representation
        takes precedence. It is recommended to use materials and assign styles
        to materials. This API function provides that capability.

        :param material: The IfcMaterial which you want to assign the style to.
        :type material: ifcopenshell.entity_instance.entity_instance
        :param style: The IfcPresentationStyle (typically IfcSurfaceStyle) that
            you want to assign to the material. This will then be applied to all
            objects that have that material.
        :type style: ifcopenshell.entity_instance.entity_instance
        :param context: The IfcGeometricRepresentationSubContext at which this
            style should be used. Typically this is the Model BODY context.
        :type context: ifcopenshell.entity_instance.entity_instance
        :param should_use_presentation_style_assignment: This is a technical
            detail to accommodate a bug in Revit. This should always be left as
            the default of False, unless you are finding that colours aren't
            showing up in Revit. In that case, set it to True, but keep in mind
            that this is no longer a valid IFC. Blame Autodesk.
        :type should_use_presentation_style_assignment: bool
        :return: None
        :rtype: None

        Example:

        .. code:: python

            # A model context is needed to store 3D geometry
            model3d = ifcopenshell.api.run("context.add_context", model, context_type="Model")

            # Specifically, we want to store body geometry
            body = ifcopenshell.api.run("context.add_context", model,
                context_type="Model", context_identifier="Body", target_view="MODEL_VIEW", parent=model3d)

            # Let's create a new wall. The wall does not have any geometry yet.
            wall = ifcopenshell.api.run("root.create_entity", model, ifc_class="IfcWall")

            # Let's use the "3D Body" representation we created earlier to add a
            # new wall-like body geometry, 5 meters long, 3 meters high, and
            # 200mm thick
            representation = ifcopenshell.api.run("geometry.add_wall_representation", model,
                context=body, length=5, height=3, thickness=0.2)

            # Assign our new body geometry back to our wall
            ifcopenshell.api.run("geometry.assign_representation", model,
                product=wall, representation=representation)

            # Place our wall at the origin
            ifcopenshell.api.run("geometry.edit_object_placement", model, product=wall)

            # Let's prepare a concrete material. Note that our concrete material
            # does not have any colours (styles) at this point.
            concrete = ifcopenshell.api.run("material.add_material", model, name="CON01", category="concrete")

            # Assign our concrete material to our wall
            ifcopenshell.api.run("material.assign_material", model,
                product=wall, type="IfcMaterial", material=concrete)

            # Create a new surface style
            style = ifcopenshell.api.run("style.add_style", model)

            # Create a simple grey shading colour and transparency.
            ifcopenshell.api.run("style.add_surface_style", model,
                style=style, ifc_class="IfcSurfaceStyleShading", attributes={
                    "SurfaceColour": { "Name": None, "Red": 0.5, "Green": 0.5, "Blue": 0.5 },
                    "Transparency": 0., # 0 is opaque, 1 is transparent
                })

            # Now any element (like our wall) with a concrete material will have
            # a grey colour applied.
            ifcopenshell.api.run("style.assign_material_style", model, material=concrete, style=style, context=body)
        """
        self.file = file
        self.settings = {
            "material": material,
            "style": style,
            "context": context,
            "should_use_presentation_style_assignment": should_use_presentation_style_assignment,
        }

    def execute(self):
        self.style = self.settings["style"]
        if self.file.schema == "IFC2X3" or self.settings["should_use_presentation_style_assignment"]:
            self.style = self.file.createIfcPresentationStyleAssignment([self.settings["style"]])

        if self.settings["material"].HasRepresentation:
            self.modify_existing_definition_representation()
        else:
            self.create_new_definition_representation()

    def modify_existing_definition_representation(self):
        definition_representation = self.settings["material"].HasRepresentation[0]
        representation = self.get_styled_representation(definition_representation)
        if representation:
            potential_orphans = []
            items = list(representation.Items)
            new_items = []
            removed_items = []
            for item in items:
                if not item.is_a("IfcStyledItem"):
                    continue
                if self.has_proposed_style(item):
                    return
                if self.has_same_style_type(item):
                    removed_items.append(item)
                else:
                    new_items.append(item)
            new_items.append(self.create_styled_item())
            representation.Items = new_items
            for item in removed_items:
                if len(self.file.get_inverse(item)) == 0:
                    self.file.remove(item)
        else:
            representations = list(definition_representation.Representations)
            representations.append(self.create_styled_representation())
            definition_representation.Representations = representations

    def has_proposed_style(self, styled_item):
        return bool([s for s in styled_item.Styles if s == self.settings["style"]])

    def has_same_style_type(self, styled_item):
        return bool([s for s in styled_item.Styles if s.is_a() == self.settings["style"].is_a()])

    def create_new_definition_representation(self):
        representation = self.create_styled_representation()
        definition_representation = self.file.create_entity(
            "IfcMaterialDefinitionRepresentation",
            **{"Representations": [representation], "RepresentedMaterial": self.settings["material"]}
        )

    def get_styled_representation(self, definition_representation):
        representations = [
            r
            for r in definition_representation.Representations
            if r.is_a("IfcStyledRepresentation") and r.ContextOfItems == self.settings["context"]
        ]
        if representations:
            return representations[0]

    def create_styled_representation(self):
        return self.file.create_entity(
            "IfcStyledRepresentation",
            **{
                "ContextOfItems": self.settings["context"],
                "RepresentationIdentifier": self.settings["context"].ContextIdentifier,
                "Items": [self.create_styled_item()],
            }
        )

    def create_styled_item(self):
        return self.file.create_entity("IfcStyledItem", **{"Styles": [self.style], "Name": self.settings["style"].Name})
