from abc import ABC, abstractmethod
from dataclasses import dataclass


@dataclass
class Layer:
    thermal_coefficient: float
    thickness: float

    @property
    def R(self):
        return self.thickness / self.thermal_coefficient


class Surface(ABC):
    def __init__(self, name: str, area: float):
        self.name = name
        self.area = area

    @property
    @abstractmethod
    def U(self) -> float: ...

    @property
    def HT(self) -> float:
        return self.U * self.area


class LayeredSurface(Surface):
    def __init__(
        self,
        name: str,
        area: float,
        layers: list[Layer],
        r_surface_1: float,
        r_surface_2: float,
    ):
        super().__init__(name, area)
        self.layers = layers
        self.r_surface_1 = r_surface_1
        self.r_surface_2 = r_surface_2

    @property
    def U(self) -> float:
        R_layers = sum(layer.R for layer in self.layers)
        R = self.r_surface_1 + R_layers + self.r_surface_2
        return 1 / R


class FixedUSurface(Surface):
    def __init__(self, name: str, area: float, u_value: float):
        super().__init__(name, area)
        self.u_value = u_value

    @property
    def U(self) -> float:
        return self.u_value