1class MaterialType(type):
  2    @property
  3    def name(self):
  4        """Make the class name accessible via "name" for better utility."""
  5        return self.__name__ # self in this case is the _Material class
  6
  7
  8class _Material(metaclass=MaterialType):
  9    """Class that implements all of the materials behaviour."""
 10    density = None # Placeholder
 11    individual_materials = [] # Placeholder
 12
 13    def __init__(self, mass):
 14        self.mass = mass
 15
 16    @property
 17    def name(self):
 18        return self.__class__.__name__
 19
 20    @property
 21    def volume(self):
 22        return self.mass / self.density
 23
 24    @classmethod
 25    def create_composite_material(cls, input_materials):
 26        """Create a new material (type) from multiple existing ones."""
 27        individual_materials = [material
 28                                for input_material in input_materials
 29                                for material in input_material.individual_materials]
 30        new_material_name = "_".join(sorted(material.__name__ for material in individual_materials))
 31        new_material_density = sum(material.density
 32                                   for material in individual_materials) / len(individual_materials)
 33        new_material = cls.create_material(new_material_name, new_material_density)
 34        new_material.individual_materials = individual_materials
 35        return new_material
 36
 37    @classmethod
 38    def create_material(cls, name, density):
 39        """Create a new material (type) based on name and density."""
 40        new_material = MaterialType(name, (cls,), {"density": density})
 41        new_material.individual_materials = [new_material]
 42        return new_material
 43
 44
 45STARTING_MATERIALS = {"Brick": 2000, "Concrete": 2500, "Steel": 7700, "Stone": 1600, "Wood": 600}
 46Brick, Concrete, Steel, Stone, Wood = (_Material.create_material(name, density)
 47                                       for name,density in STARTING_MATERIALS.items())
 48
 49
 50class Factory:
 51    """A factory that produces materials and pieces of a given material."""
 52    existing_materials = {material.name: material for material in (Brick, Concrete, Steel, Stone, Wood)}
 53    expended_material_pieces = set()
 54    factories = []
 55
 56    def __init__(self):
 57        self.produced_material_pieces = set()
 58        self.factories.append(self)
 59
 60    def __call__(self, *args, **kwargs):
 61        """Make an order to the factory."""
 62        if not bool(args) ^ bool(kwargs):
 63            raise ValueError("Ебем ти и вноса.")
 64        if args:
 65            return self.create_new_material(args)
 66        if kwargs:
 67            if any(material not in self.existing_materials for material in kwargs):
 68                raise ValueError("Ебем ти и вноса.")
 69            return self._produce_materials(kwargs)
 70
 71    def create_new_material(self, input_materials):
 72        """Create a new material (type) and register it, return a piece of that material."""
 73        if any(material in self.expended_material_pieces for material in input_materials):
 74            raise AssertionError("Ти кого се опитваш да ментиш?")
 75        self.expended_material_pieces.update(input_materials) # Register the used materials
 76
 77        new_material = _Material.create_composite_material(input_materials)
 78        new_material_mass = sum(material.mass for material in input_materials)
 79        if new_material.name not in self.existing_materials:
 80            self.existing_materials[new_material.name] = new_material # Register the new material
 81        return self._produce_material(new_material.name, new_material_mass)
 82
 83    def _produce_material(self, name, mass):
 84        """Produce a piece of a material and register it's production."""
 85        self.produced_material_pieces.add(production := self.existing_materials[name](mass))
 86        return production
 87
 88    def _produce_materials(self, input_materials):
 89        """Produce pieces of multiple materials."""
 90        return tuple(self._produce_material(name, mass) for name, mass in input_materials.items())
 91
 92    def can_build(self, wall_volume):
 93        """Determine if the factory has produced enough materials to build a wall."""
 94        # A compromise must be made here between getting close to proper line length limits
 95        # and having to define a single "useless" variable
 96        pieces = (piece.volume for piece in self.produced_material_pieces - self.expended_material_pieces)
 97        return sum(pieces) >= wall_volume
 98
 99    @classmethod
100    def can_build_together(cls, wall_volume):
101        """Determine if all factories together have produced enough materials to build a wall."""
102        all_factory_volumes = (piece.volume
103                               for factory in cls.factories
104                               for piece in factory.produced_material_pieces
105                               if piece not in factory.expended_material_pieces)
106        return sum(all_factory_volumes) >= wall_volume