Model/recommendations/WallRecommendations.py

import itertools
import math

from datatypes.enums import QuantityUnits
from backend.Property import Property
from model_data.BaseUtility import Definitions
from recommendations.recommendation_utils import (
    r_value_per_mm_to_u_value, calculate_u_value_uplift, is_diminishing_returns, update_lowest_selected_u_value,
    get_recommended_part, get_uvalue_estimate
)

external_wall_insulation_parts = [
    {
        # Example product
        # https://insulationgo.co.uk/100mm-rockwool-external-wall-insulation-dual-density-slabs-a1-non-combustible
        # -slab-ewi-render-fire/
        "type": "external_wall_insulation",
        "description": "Mineral Wool External Wall Insulation",
        "depths": [30, 50, 70, 80, 90, 100, 150, 200],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": 0.0278,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": 0.036,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    },
    {
        # Example product
        # https://www.insulationking.co.uk/products/polystyrene-eps70?variant=44156186558759
        "type": "external_wall_insulation",
        "description": "Expanded Polystyrene External Wall Insulation",
        "depths": [25, 50, 100, 125],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": 0.02703,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": 0.037,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    },
    {
        # Example product
        # https://www.insulationshop.co/20mm_kooltherm_k5_external_wall_kingspan.html
        "type": "external_wall_insulation",
        "description": "Phenolic Foam External Wall Insulation",
        "depths": [20, 50, 100],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": 0.043478260869565216,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": 0.023,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"

    },
    {
        "type": "external_wall_insulation",
        "description": "Polyisocyanurate/Polyurethane Foam External Wall Insulation",
        "depths": [],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": None,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": None,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    },
    {
        # Example product
        # https://www.mikewye.co.uk/product/steico-duo-dry/
        "type": "external_wall_insulation",
        "description": "Wood Fiber External Wall Insulation",
        "depths": [40, 60],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": 0.023255813953488375,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": 0.043,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    },
    {
        # Example product
        # https://www.thermablok.co.uk/site/wp-content/uploads/2022/09/Thermablok-Aerogel-Insulation-Blanket-TDS-AIS
        # -and-Steel-Related-Details.pdf
        "type": "external_wall_insulation",
        "description": "Aerogel External Wall Insulation",
        "depths": [10, 20, 30, 40, 50, 60, 70],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": 0.06666666666666667,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": 0.015,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    },
    {
        "type": "external_wall_insulation",
        "description": "Vacuum Insulation Panels External Wall Insulation",
        "depths": [45, 60],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": 0.16666666666666666,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": 0.006,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    }
]

internal_wall_insulation_parts = [
    {
        # Example product
        # https://www.insulationshop.co/25mm_polystyrene_insulation_eps_70jablite.html
        "type": "internal_wall_insulation",
        "description": "Rigid Insulation Boards Internal Wall Insulation",
        "depths": [25, 40, 50, 75, 100],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": 0.026315789473684213,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": 0.038,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    },
    {
        # Example product
        # https://www.rockwool.com/siteassets/rw-uk/downloads/datasheets/flexi.pdf
        "type": "internal_wall_insulation",
        "description": "Mineral Wool Internal Wall Insulation",
        "depths": [140],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": 0.02857142857142857,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": 0.035,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    },
    {
        # Example product
        # https://www.kingspan.com/gb/en/products/insulation-boards/wall-insulation-boards/kooltherm-k118-insulated
        # -plasterboard/
        "type": "internal_wall_insulation",
        "description": "Insulated Plasterboard Internal Wall Insulation",
        "depths": [25, 80],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": 0.02857142857142857,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": 0.019,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    },
    {
        "type": "internal_wall_insulation",
        "description": "Reflective Internal Wall Insulation",
        "depths": [],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": None,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": None,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    },
    {
        # Example product
        # https://www.insulationsuperstore.co.uk/product/vacutherm-vacupor-nt-b2-vacuum-insulated-panel-1m-x-600mm-x
        # -30mm.html
        "type": "internal_wall_insulation",
        "description": "Vacuum Insulation Panels Wall Insulation",
        "depths": [20, 30],
        "depth_unit": "mm",
        "cost": None,
        "cost_unit": None,
        "r_value_per_mm": 0.125,
        "r_value_unit": "square_meter_kelvin_per_watt",
        "thermal_conductivity": 0.008,
        "thermal_conductivity_unit": "watt_per_meter_kelvin"
    },
]

wall_parts = external_wall_insulation_parts + internal_wall_insulation_parts


class WallRecommendations(Definitions):
    YEAR_WALLS_BUILT_WITH_INSULATION = 1990
    # After 1930, Solid brick walls became less populate and instead, cavity walls became a
    # more popular choice
    YEARS_CAVITY_WALLS_BEGAN = 1930
    U_VALUE_UNIT = 'w/m-¦k'

    # part L building regulations indicate that any rennovations on an existing property's walls should
    # achieve a U-value of no higher than 0.3
    BUILDING_REGULATIONS_PART_L_MAX_U_VALUE = 0.3
    # We don't recommend measures that are too low because it becomes expensive, therefore we aim to avoid
    # diminishing returns. This value should be verified with Osmosis (TODO)
    DIMINISHING_RETURNS_U_VALUE = 0.25

    # Part L regulations indicate that any new build should have walls that achieve a u-value of no higher
    # than 0.18.
    BUILDING_REGULATIONS_PART_L_NEW_BUILD_MAX_U_VALUE = 0.18
    # 0.15 is an often cited diminishing returns value for new builds
    NEW_BUILD_DIMINISHING_RETURNS_U_VALUE = 0.15

    # Add some error so that if, for example, a new part we recommend provides a u-value of 0.19,
    # we still consider it as an option
    U_VALUE_ERROR = 0.01

    # TODO: Review this value against RdSAP
    #       Page 19 of rdsap here:
    #       https://files.bregroup.com/bre-co-uk-file-library-copy/filelibrary/SAP/2012/RdSAP-9.93/RdSAP_2012_9.93.pdf
    #       provides default U-values for solid brick walls depending on age band
    DEFAULT_U_VALUES = {
        "solid_brick": 2,
    }

    def __init__(self, property_instance: Property, uvalue_estimates, total_floor_area_group_decile, materials=None):
        self.property = property_instance
        self.uvalue_estimates = uvalue_estimates
        self.total_floor_area_group_decile = total_floor_area_group_decile
        # For audit purposes, when estimating u values we'll store it
        self.estimated_u_value = None

        # Will contains a list of recommended measures
        self.recommendations = []

        if materials:
            self.materials = materials
        else:
            self.materials = wall_parts

    @property
    def ewi_valid(self):
        """
        This method check available data, to determine if a property is suitable for external wall insulation
        """

        # Current logic: If the property is in a conservation area or a flat, it is not suitable for EWI
        if (self.property.in_conservation_area in ["in_conversation_area"]) or \
            (self.property.data["property-type"].lower() == "flat"):
            return False

        return True

    def recommend(self):
        # if building built after 1990 + we're able to identify U-value +
        # U-value less than 0.18 and if in or close to a conversation area,
        # recommend internal wall insulation as a possible measure

        u_value = self.property.walls["thermal_transmittance"]

        is_cavity_wall = self.property.walls["is_cavity_wall"]
        is_solid_brick = self.property.walls["is_solid_brick"]
        insulation_thickness = self.property.walls["insulation_thickness"]

        # We check if the wall is already insulated and if so, we exit
        if insulation_thickness in ["average", "above average"]:
            return

        if u_value:
            if self.property.walls["thermal_transmittance_unit"] != self.U_VALUE_UNIT:
                raise NotImplementedError("Haven't handled the case of other u value units yet")

            # TODO: It's worth thinking about this logic because depending on when properties were built,
            #       they're likely to be of a certain standard. E.g. properties built within a certain time
            #       period are likely to have cavity walls

            # We can't detect it's a cavity wall, but it was built after 1990 so likely built with insulation already
            # + it already has a U-value WORSE than the building regulations, so we recommend either internal or
            # external wall insulation
            if (not is_cavity_wall) and (self.property.year_built >= self.YEAR_WALLS_BUILT_WITH_INSULATION) and (
                u_value >= self.BUILDING_REGULATIONS_PART_L_MAX_U_VALUE
            ):
                # Recommend insulation
                self.find_insulation(u_value)
                return

            # We can't detect it's a cavity wall, but it was built after 1990 so likely built with insulation already
            # + it already has a U-value better than the building regulations, so we don't need to recommend anything
            if (not is_cavity_wall) and (self.property.year_built >= self.YEAR_WALLS_BUILT_WITH_INSULATION) and (
                u_value <= self.BUILDING_REGULATIONS_PART_L_MAX_U_VALUE
            ):
                # Recommend nothing
                return

            raise NotImplementedError("Not implemented yet")

        if is_solid_brick:

            if insulation_thickness == "none":
                # This is an estimated figure based on industry standards
                u_value = self.DEFAULT_U_VALUES["solid_brick"]
            else:
                u_value = get_uvalue_estimate(
                    uvalue_estimates=self.uvalue_estimates,
                    property=self.property,
                    total_floor_area_group_decile=self.total_floor_area_group_decile
                )
            self.estimated_u_value = u_value

            if u_value >= self.BUILDING_REGULATIONS_PART_L_MAX_U_VALUE:
                self.find_insulation(u_value)
                return

            # If the u-value is within regulations, we don't do anything
            return

        raise NotImplementedError("Not implemented yet")

    def _find_insulation(self, parts, u_value):
        lowest_selected_u_value = None
        recommendations = []
        for part in parts:

            for depth, cost_per_unit in zip(part["depths"], part["cost"]):

                part_u_value = r_value_per_mm_to_u_value(depth, part["r_value_per_mm"])

                _, new_u_value = calculate_u_value_uplift(u_value, part_u_value)
                new_u_value = math.ceil(new_u_value * 100.0) / 100.0

                # If I have a lowest U value and my new u value is higher than that but lower than the
                # diminishing returns threshold, it can be considered

                # If I have a lowest U value and my new u value is lower than the lowest value, it's
                # further into the diminishing returns threshold and can shouldn't be

                if is_diminishing_returns(
                    recommendations, new_u_value, lowest_selected_u_value, self.DIMINISHING_RETURNS_U_VALUE
                ):
                    continue

                # We allow a small tolerance for error so we don't discount the recommendation entirely
                if new_u_value <= self.BUILDING_REGULATIONS_PART_L_MAX_U_VALUE:
                    lowest_selected_u_value = update_lowest_selected_u_value(lowest_selected_u_value, new_u_value)

                    estimated_cost = cost_per_unit * self.property.insulation_wall_area

                    recommendations.append(
                        {
                            "parts": [
                                get_recommended_part(
                                    part=part,
                                    selected_depth=depth,
                                    quantity=self.property.insulation_wall_area,
                                    quantity_unit=QuantityUnits.m2.value,
                                    selected_total_cost=estimated_cost
                                )
                            ],
                            "type": "wall_insulation",
                            "description": "Install " + self._make_description(part, depth),
                            "starting_u_value": u_value,
                            "new_u_value": new_u_value,
                            "sap_points": None,
                            "cost": estimated_cost,
                        }
                    )

        return recommendations

    def find_insulation(self, u_value):
        """
        This function contains the logic for finding potential insulation measures for a property, depending
        on the parts available and whether the property can have external wall insulation installed
        :return:
        """

        ewi_parts = [
            part for part in self.materials if part["type"] == "external_wall_insulation"
        ] if self.ewi_valid else []

        iwi_parts = [part for part in self.materials if part["type"] == "internal_wall_insulation"]

        # Recommend external and internal wall insulation separately
        # Since external and internal wall insulation are sufficiently different,
        # we separate the logic for for recommending them, therefore we don't
        # consider diminishing returns between the two

        ewi_recommendations = self._find_insulation(ewi_parts, u_value)
        iwi_recommendations = self._find_insulation(iwi_parts, u_value)

        self.recommendations += ewi_recommendations + iwi_recommendations

        # We also can recommend both internal and external wall insulation together
        # By looping through ewi first, if there is nothing there, that ensures not combinations are tested
        for ewi_part in ewi_parts:
            for iwi_part in iwi_parts:
                for (ewi_depth, ewi_cost_per_unit), (iwi_depth, iwi_cost_per_unit) in itertools.product(
                    zip(ewi_part["depths"], ewi_part["cost"]),
                    zip(iwi_part["depths"], iwi_part["cost"])
                ):
                    ewi_part_u_value = r_value_per_mm_to_u_value(ewi_depth, ewi_part["r_value_per_mm"])
                    iwi_part_u_value = r_value_per_mm_to_u_value(iwi_depth, iwi_part["r_value_per_mm"])

                    # First calculate the new U-value after applying external wall insulation
                    _, ewi_new_u_value = calculate_u_value_uplift(u_value, ewi_part_u_value)
                    # Then calculate the new U-value after applying internal wall insulation
                    _, combined_new_u_value = calculate_u_value_uplift(ewi_new_u_value, iwi_part_u_value)
                    combined_new_u_value = round(combined_new_u_value, 2)

                    if combined_new_u_value < self.DIMINISHING_RETURNS_U_VALUE:
                        # We don't recommend an overkill solution
                        continue

                    # Check if the combined new U-value meets the requirement
                    if combined_new_u_value - self.U_VALUE_ERROR <= self.BUILDING_REGULATIONS_PART_L_MAX_U_VALUE:
                        # Here you might want to define a way to add both recommendations together.
                        # For now, I'm adding them as separate items in the list
                        ewi_esimtated_cost = ewi_cost_per_unit * self.property.insulation_wall_area
                        iwi_esimtated_cost = iwi_cost_per_unit * self.property.insulation_wall_area

                        recommendation = {
                            "parts": [
                                get_recommended_part(
                                    part=ewi_part,
                                    selected_depth=ewi_depth,
                                    quantity=self.property.insulation_wall_area,
                                    quantity_unit=QuantityUnits.m2.value,
                                    selected_total_cost=ewi_esimtated_cost
                                ),
                                get_recommended_part(
                                    part=iwi_part,
                                    selected_depth=iwi_depth,
                                    quantity=self.property.insulation_wall_area,
                                    quantity_unit=QuantityUnits.m2.value,
                                    selected_total_cost=iwi_esimtated_cost
                                )
                            ],
                            "type": "wall_insulation",
                            "description": (
                                "Install " + self._make_description(ewi_part, ewi_depth) + " and " +
                                self._make_description(iwi_part, iwi_depth)
                            ),
                            "starting_u_value": u_value,
                            "new_u_value": combined_new_u_value,
                            "sap_points": None,
                            "cost": ewi_esimtated_cost + iwi_esimtated_cost,
                        }
                        self.recommendations.append(recommendation)

        self.prune_diminishing_recommendations()

    @staticmethod
    def _make_description(part, depth):
        return f"{depth}{part['depth_unit']} {part['description']}"

    def prune_diminishing_recommendations(self):
        # For any recommendations, if we have at least 1 reommendation that does not exhibit diminishing returns
        # we trim all others that are beyond the diminishing returns threshold

        # We first check if we have any recommendations that are not diminishing returns
        not_diminishing_return = [
            rec for rec in self.recommendations if rec["new_u_value"] >= self.DIMINISHING_RETURNS_U_VALUE
        ]
        if not_diminishing_return:
            self.recommendations = [
                rec for rec in self.recommendations if rec["new_u_value"] >= self.DIMINISHING_RETURNS_U_VALUE
            ]

    @staticmethod
    def rvalue_per_mm(total_r_value: float, thickness_mm: float) -> float:
        """Return R-value per mm.

        Parameters
        ----------
        total_r_value : float
            Total R-value (in m2K/W).
        thickness_mm : float
            Thickness of the material in mm.

        Returns
        -------
        float
            R-value per mm.
        """
        return total_r_value / thickness_mm

    @staticmethod
    def thermal_conductivity_to_r_value_per_mm(thermal_conductivity: float) -> float:
        """Convert thermal conductivity to R-value per mm.

        Parameters
        ----------
        thermal_conductivity : float
            Thermal conductivity (in W/mK).

        Returns
        -------
        float
            R-value per mm.
        """
        # Calculate R-value in m²K/W for 1 meter of the material
        r_value_per_meter = 1 / thermal_conductivity

        # Convert R-value to R-value per mm
        r_value_per_mm = r_value_per_meter / 1000

        return r_value_per_mm