Model/tests/domain/modelling/test_solar_recommendation.py

"""Behaviour of the Solar PV Recommendation Generator (ADR-0026): one "Solar
PV" Recommendation of competing whole-array Options — up to five
conservatively-sized configs × {no battery, battery} — built from a typed
`SolarPotential`. Detection + pricing only; impact is produced by scoring.
"""

import json
from dataclasses import replace
from pathlib import Path
from typing import Any, Optional

from datatypes.epc.domain.epc_property_data import EpcPropertyData, PhotovoltaicArray
from domain.geospatial.planning_restrictions import PlanningRestrictions
from domain.modelling.generators.solar_recommendation import recommend_solar
from domain.modelling.product import Product
from domain.modelling.recommendation import Recommendation
from domain.modelling.solar_potential import SolarPotential
from repositories.product.product_repository import ProductRepository
from tests.domain.modelling._elmhurst_recommendation import (
    parse_recommendation_summary,
)

_FIXTURE: Path = (
    Path(__file__).resolve().parent
    / "fixtures"
    / "google_building_insights_001431.json"
)
_SOLAR_MEASURE_TYPE = "solar_pv"
_BATTERY_CAPACITY_KWH = 5.0


class _StubProducts(ProductRepository):
    """In-memory ProductRepository returning a fixed solar_pv catalogue row."""

    def get(self, measure_type: str) -> Product:
        return Product(
            measure_type=measure_type,
            unit_cost_per_m2=0.0,
            contingency_rate=0.15,
            id=909,
        )


def _solar_potential() -> SolarPotential:
    with _FIXTURE.open(encoding="utf-8") as handle:
        data: dict[str, Any] = json.load(handle)
    potential = SolarPotential.from_building_insights(data)
    assert potential is not None
    return potential


def _eligible_house() -> EpcPropertyData:
    """The solar 001431 before cert: a House with a hot-water cylinder, no
    existing PV — solar-eligible."""
    return parse_recommendation_summary("solar_pv_001431_before.pdf")


def test_eligible_house_yields_a_solar_pv_recommendation_of_competing_options() -> None:
    # Arrange — a house with feasible Google solar potential (5 conservative
    # configs) and a cylinder.
    baseline = _eligible_house()

    # Act
    recommendation: Optional[Recommendation] = recommend_solar(
        baseline, _StubProducts(), _solar_potential()
    )

    # Assert — one "Solar PV" Recommendation, 5 configs × {no battery, battery}
    # = 10 competing Options, all measure_type solar_pv.
    assert recommendation is not None
    assert recommendation.surface == "Solar PV"
    assert len(recommendation.options) == 10
    assert {o.measure_type for o in recommendation.options} == {_SOLAR_MEASURE_TYPE}
    assert all(o.material_id == 909 for o in recommendation.options)


def test_each_option_overlay_installs_per_segment_arrays_and_ensures_export() -> None:
    # Arrange
    baseline = _eligible_house()

    # Act
    recommendation = recommend_solar(baseline, _StubProducts(), _solar_potential())

    # Assert — every option folds a SolarOverlay: one PhotovoltaicArray per
    # config segment, export ensured, diverter set (the dwelling has a cylinder).
    assert recommendation is not None
    for option in recommendation.options:
        overlay = option.overlay.solar
        assert overlay is not None
        assert overlay.is_dwelling_export_capable is True
        assert overlay.pv_diverter_present is True
        # A newly-installed recommended array is connected to the dwelling's own
        # meter, so it must be tagged pv_connection=2 ("connected") — the value
        # the SAP cascade credits. (1 = present-but-not-connected → zero credit.)
        assert overlay.pv_connection == 2
        arrays = overlay.photovoltaic_arrays
        assert arrays is not None and len(arrays) >= 1
        assert all(isinstance(a, PhotovoltaicArray) for a in arrays)
        assert all(1 <= a.orientation <= 8 for a in arrays)
        assert all(1 <= a.pitch <= 5 for a in arrays)
        assert all(1 <= a.overshading <= 4 for a in arrays)


def test_smallest_config_array_peak_power_matches_panels_times_capacity() -> None:
    # Arrange — the smallest conservative config is 4 panels × 400 W = 1.6 kWp
    # on one SE plane (≈32° → pitch code 2), back-solved to a heavy-ish bucket.
    baseline = _eligible_house()

    # Act
    recommendation = recommend_solar(baseline, _StubProducts(), _solar_potential())

    # Assert — find the no-battery option whose single array totals 1.6 kWp.
    assert recommendation is not None
    no_battery_arrays: list[list[PhotovoltaicArray]] = []
    for option in recommendation.options:
        overlay = option.overlay.solar
        assert overlay is not None
        if overlay.pv_batteries is None and overlay.photovoltaic_arrays is not None:
            no_battery_arrays.append(overlay.photovoltaic_arrays)
    smallest = min(
        no_battery_arrays, key=lambda arrays: sum(a.peak_power for a in arrays)
    )
    assert len(smallest) == 1
    assert abs(smallest[0].peak_power - 1.6) <= 1e-9
    assert smallest[0].orientation == 4  # SE
    assert smallest[0].pitch == 2  # ~32° → 30°


def test_battery_variant_adds_a_five_kwh_battery_and_costs_more() -> None:
    # Arrange
    baseline = _eligible_house()

    # Act
    recommendation = recommend_solar(baseline, _StubProducts(), _solar_potential())

    # Assert — for the same array size, the battery variant carries a 5 kWh
    # battery and a higher cost than its no-battery twin.
    assert recommendation is not None
    by_size: dict[float, dict[bool, float]] = {}
    for option in recommendation.options:
        overlay = option.overlay.solar
        assert overlay is not None and option.cost is not None
        size = round(sum(a.peak_power for a in (overlay.photovoltaic_arrays or [])), 6)
        has_battery = overlay.pv_batteries is not None
        by_size.setdefault(size, {})[has_battery] = option.cost.total
        if has_battery:
            assert overlay.pv_batteries is not None
            assert (
                abs(
                    overlay.pv_batteries.pv_battery.battery_capacity
                    - _BATTERY_CAPACITY_KWH
                )
                <= 1e-9
            )
    for size, costs in by_size.items():
        assert costs[True] > costs[False], size


def test_combi_dwelling_gets_no_diverter() -> None:
    # Arrange — the same house without a cylinder (a combi has nothing to divert
    # surplus PV to), so the diverter field is left unset.
    baseline = _eligible_house()
    baseline.has_hot_water_cylinder = False

    # Act
    recommendation = recommend_solar(baseline, _StubProducts(), _solar_potential())

    # Assert
    assert recommendation is not None
    for option in recommendation.options:
        assert option.overlay.solar is not None
        assert option.overlay.solar.pv_diverter_present is None


def test_flat_is_not_eligible() -> None:
    # Arrange — a flat needs building-level shared-roof coordination (deferred).
    baseline = _eligible_house()
    baseline.property_type = "Flat"

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


def test_listed_building_blocks_solar() -> None:
    # Arrange — a listed building protects the fabric (blocks_internal).
    baseline = _eligible_house()

    # Act / Assert
    assert (
        recommend_solar(
            baseline,
            _StubProducts(),
            _solar_potential(),
            PlanningRestrictions(is_listed=True),
        )
        is None
    )


def test_conservation_area_does_not_block_solar() -> None:
    # Arrange — a conservation area blocks external work generally, but PV is
    # offered (installed sympathetically) — same gate as ASHP, not blocks_external.
    baseline = _eligible_house()

    # Act
    recommendation = recommend_solar(
        baseline,
        _StubProducts(),
        _solar_potential(),
        PlanningRestrictions(in_conservation_area=True),
    )

    # Assert
    assert recommendation is not None
    assert len(recommendation.options) == 10


def test_existing_pv_dwelling_is_not_eligible() -> None:
    # Arrange — a dwelling that already has PV (existing-PV top-up is deferred).
    baseline = _eligible_house()
    baseline.sap_energy_source.photovoltaic_arrays = [
        PhotovoltaicArray(peak_power=2.0, pitch=2, orientation=5, overshading=1)
    ]

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


def test_no_solar_potential_yields_no_recommendation() -> None:
    # Arrange — no Google solar data (or no feasible config) → no recommendation.
    baseline = _eligible_house()

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


def test_infeasible_potential_yields_no_recommendation() -> None:
    # Arrange — a potential whose only config faces due north (dropped → empty).
    baseline = _eligible_house()
    potential = _solar_potential()
    north_only = replace(potential, configurations=())

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