Model/tests/domain/modelling/test_heating_recommendation.py

"""Behaviour of the heating Recommendation Generator: detecting a dwelling
whose heating system should be replaced and emitting one "Heating & Hot Water"
Recommendation of competing whole-system bundles (ADR-0024). This slice covers
the high-heat-retention storage (HHRSH) bundle; ASHP and boiler bundles land in
later slices. Detection + pricing only; impact is produced by scoring (ADR-0016).
"""

from datatypes.epc.domain.epc_property_data import EpcPropertyData
from domain.geospatial.planning_restrictions import PlanningRestrictions
from domain.modelling.generators.heating_recommendation import recommend_heating
from domain.modelling.product import Product
from domain.modelling.recommendation import Recommendation
from domain.modelling.simulation import HeatingOverlay
from repositories.product.product_repository import ProductRepository
from tests.domain.modelling._elmhurst_recommendation import (
    parse_recommendation_summary,
)
from tests.domain.sap10_calculator.worksheet._elmhurst_worksheet_000490 import (
    build_epc,
)

# Electricity main-fuel code (Elmhurst → SAP10) and the Table 4a SAP code an
# existing (non-HHR) electric storage system lodges.
_ELECTRICITY = 30
_OLD_STORAGE_SAP_CODE = 402


def _electric_storage_baseline() -> EpcPropertyData:
    """A 000490 dwelling re-cast as an existing (non-HHR) electric storage
    system: electric main fuel, Table 4a code 402."""
    epc: EpcPropertyData = build_epc()
    main = epc.sap_heating.main_heating_details[0]
    main.main_fuel_type = _ELECTRICITY
    main.sap_main_heating_code = _OLD_STORAGE_SAP_CODE
    return epc


class _StubProducts(ProductRepository):
    """In-memory ProductRepository returning a fixed HHRSH product cost."""

    def get(self, measure_type: str) -> Product:
        return Product(
            measure_type=measure_type, unit_cost_per_m2=3500.0, contingency_rate=0.26
        )


def test_electric_storage_dwelling_yields_an_hhr_storage_bundle() -> None:
    # Arrange — an existing electric storage system (not HHR).
    baseline: EpcPropertyData = _electric_storage_baseline()

    # Act
    recommendation: Recommendation | None = recommend_heating(baseline, _StubProducts())

    # Assert — one "Heating & Hot Water" Recommendation carrying the HHRSH
    # bundle, whose overlay is the absolute HHR end-state.
    assert recommendation is not None
    assert recommendation.surface == "Heating & Hot Water"
    options = {o.measure_type: o for o in recommendation.options}
    assert "high_heat_retention_storage_heaters" in options
    assert options["high_heat_retention_storage_heaters"].overlay.heating == HeatingOverlay(
        main_fuel_type=30,
        sap_main_heating_code=409,
        main_heating_control=2404,
        water_heating_code=903,
        water_heating_fuel=30,
        cylinder_size=2,
        cylinder_insulation_type=1,
        cylinder_insulation_thickness_mm=120,
        cylinder_thermostat="Y",
        has_hot_water_cylinder=True,
        meter_type="Dual",
    )


def test_on_gas_boiler_dwelling_yields_no_hhr_storage_bundle() -> None:
    # Arrange — 000490 is a mains-gas combi (fuel 26, mains_gas True). HHR
    # storage suits off-gas / electric dwellings, not an on-gas gas boiler.
    baseline: EpcPropertyData = build_epc()

    # Act
    recommendation: Recommendation | None = recommend_heating(baseline, _StubProducts())

    # Assert — no HHRSH bundle (no other bundle is built in this slice → None).
    if recommendation is not None:
        assert "high_heat_retention_storage_heaters" not in {
            o.measure_type for o in recommendation.options
        }


def test_already_hhr_storage_dwelling_yields_no_hhr_bundle() -> None:
    # Arrange — an electric dwelling already on HHR storage (Table 4a code 409)
    # must not be told to install HHR storage again (ASHP may still be offered as
    # a better end-state — it is a house here).
    baseline: EpcPropertyData = _electric_storage_baseline()
    baseline.sap_heating.main_heating_details[0].sap_main_heating_code = 409

    # Act
    recommendation: Recommendation | None = recommend_heating(baseline, _StubProducts())

    # Assert — no HHRSH bundle.
    if recommendation is not None:
        assert "high_heat_retention_storage_heaters" not in {
            o.measure_type for o in recommendation.options
        }


def test_existing_heat_pump_dwelling_yields_no_hhr_storage_bundle() -> None:
    # Arrange — an electric dwelling already on a heat pump (category 4) is never
    # downgraded to storage heaters.
    baseline: EpcPropertyData = _electric_storage_baseline()
    baseline.sap_heating.main_heating_details[0].main_heating_category = 4

    # Act / Assert
    assert recommend_heating(baseline, _StubProducts()) is None


def test_hhr_storage_bundle_carries_the_product_cost_and_contingency() -> None:
    # Arrange
    baseline: EpcPropertyData = _electric_storage_baseline()

    # Act
    recommendation: Recommendation | None = recommend_heating(baseline, _StubProducts())

    # Assert — the bundle's fully-loaded cost + contingency come from the product.
    assert recommendation is not None
    option = next(
        o
        for o in recommendation.options
        if o.measure_type == "high_heat_retention_storage_heaters"
    )
    assert option.cost is not None
    assert abs(option.cost.total - 3500.0) <= 1e-9
    assert abs(option.cost.contingency_rate - 0.26) <= 1e-9


def _gas_boiler_house() -> EpcPropertyData:
    """A 000490 mains-gas combi dwelling, explicitly a House — ASHP-eligible."""
    epc: EpcPropertyData = build_epc()
    epc.property_type = "House"
    return epc


def test_gas_boiler_house_yields_an_ashp_bundle() -> None:
    # Arrange — a mains-gas house; ASHP is offered for any non-flat house/
    # bungalow regardless of current system or efficiency (ADR-0024).
    baseline: EpcPropertyData = _gas_boiler_house()

    # Act
    recommendation: Recommendation | None = recommend_heating(baseline, _StubProducts())

    # Assert — the ASHP bundle carries the absolute heat-pump end-state.
    assert recommendation is not None
    options = {o.measure_type: o for o in recommendation.options}
    assert "air_source_heat_pump" in options
    assert options["air_source_heat_pump"].overlay.heating == HeatingOverlay(
        main_fuel_type=30,
        main_heating_control=2210,
        main_heating_index_number=110257,
        main_heating_category=4,
        water_heating_code=901,
        water_heating_fuel=30,
        cylinder_size=4,
        cylinder_insulation_type=1,
        cylinder_insulation_thickness_mm=50,
        cylinder_thermostat="Y",
        has_hot_water_cylinder=True,
        meter_type="Single",
        mains_gas=False,
    )


def test_ashp_bundle_carries_the_composite_per_dwelling_cost() -> None:
    # Arrange — a mains-gas regular boiler with a cylinder (90 m2, 7 habitable
    # rooms): the ASHP reuses the existing wet system (ADR-0025).
    epc: EpcPropertyData = parse_recommendation_summary(
        "ashp_from_system_boiler_with_cylinder_001431_before.pdf"
    )

    # Act
    recommendation: Recommendation | None = recommend_heating(epc, _StubProducts())
    assert recommendation is not None
    option = next(
        o for o in recommendation.options if o.measure_type == "air_source_heat_pump"
    )

    # Assert — composite: decommission (gas) 720 + pump (4.5 kW band) 9720 +
    # cylinder 2382.60 + reuse distribution (flush 168 + 0.5 x dist(10) 5220 =
    # 2778) = 15600.60, with the separate 25% ASHP contingency.
    assert option.cost is not None
    assert abs(option.cost.total - 15600.60) <= 1e-9
    assert abs(option.cost.contingency_rate - 0.25) <= 1e-9


def test_listed_building_yields_no_ashp_bundle() -> None:
    # Arrange — a listed building protects the fabric; an external ASHP unit is
    # not auto-offered (ADR-0024). The dwelling is on gas, so HHRSH is also out.
    baseline: EpcPropertyData = _gas_boiler_house()

    # Act
    recommendation: Recommendation | None = recommend_heating(
        baseline, _StubProducts(), PlanningRestrictions(is_listed=True)
    )

    # Assert
    assert recommendation is None


def test_conservation_area_still_yields_an_ashp_bundle() -> None:
    # Arrange — unlike glazing, a conservation area does NOT exclude ASHP; it is
    # offered with a planning caveat (ADR-0024, research-grounded).
    baseline: EpcPropertyData = _gas_boiler_house()

    # Act
    recommendation: Recommendation | None = recommend_heating(
        baseline, _StubProducts(), PlanningRestrictions(in_conservation_area=True)
    )

    # Assert
    assert recommendation is not None
    assert "air_source_heat_pump" in {o.measure_type for o in recommendation.options}


def test_flat_yields_no_ashp_bundle() -> None:
    # Arrange — flats are not auto-offered an individual ASHP (siting/lease/
    # MCS-020 need a survey — ADR-0024).
    baseline: EpcPropertyData = _gas_boiler_house()
    baseline.property_type = "Flat"

    # Act
    recommendation: Recommendation | None = recommend_heating(baseline, _StubProducts())

    # Assert — no ASHP (and the gas flat is not HHRSH-eligible either → None).
    if recommendation is not None:
        assert "air_source_heat_pump" not in {
            o.measure_type for o in recommendation.options
        }


def test_existing_heat_pump_yields_no_ashp_bundle() -> None:
    # Arrange — a dwelling already on a heat pump (category 4) is not re-offered
    # an ASHP.
    baseline: EpcPropertyData = _gas_boiler_house()
    baseline.sap_heating.main_heating_details[0].main_heating_category = 4

    # Act
    recommendation: Recommendation | None = recommend_heating(baseline, _StubProducts())

    # Assert
    if recommendation is not None:
        assert "air_source_heat_pump" not in {
            o.measure_type for o in recommendation.options
        }