"""The Landlord-Override construction-age-band → fabric Simulation Overlay.

An age-band value resolves to the RdSAP letter code the calculator's U-value
cascades read from `SapBuildingPart.construction_age_band`; the overlay targets
the override's building part.
"""

from __future__ import annotations

import pytest

from datatypes.epc.domain.epc_property_data import (
    BuildingPartIdentifier,
    EpcPropertyData,
    SapBuildingPart,
)
from domain.epc.property_overrides.construction_age_band import ConstructionAgeBand
from domain.epc.property_overlays.construction_age_band_overlay import (
    age_band_overlay_for,
)
from domain.modelling.scoring.overlay_applicator import apply_simulations
from tests.domain.sap10_calculator.worksheet._elmhurst_worksheet_000490 import (
    build_epc,
)


def _part(
    epc: EpcPropertyData, identifier: BuildingPartIdentifier
) -> SapBuildingPart:
    return next(p for p in epc.sap_building_parts if p.identifier is identifier)


def test_age_band_overlays_the_main_building_part() -> None:
    # Act — band B (1900-1929) on the main building part.
    simulation = age_band_overlay_for("B", 0)

    # Assert
    assert simulation is not None
    overlay = simulation.building_parts[BuildingPartIdentifier.MAIN]
    assert overlay.construction_age_band == "B"


def test_age_band_overlay_targets_the_extension_building_part() -> None:
    # Act — building_part 1 is the first extension.
    simulation = age_band_overlay_for("L", 1)

    # Assert
    assert simulation is not None
    assert BuildingPartIdentifier.EXTENSION_1 in simulation.building_parts
    assert (
        simulation.building_parts[BuildingPartIdentifier.EXTENSION_1]
        .construction_age_band
        == "L"
    )


def test_lowercase_age_band_is_normalised_to_its_letter_code() -> None:
    # Act
    simulation = age_band_overlay_for("d", 0)

    # Assert — the calculator upper-cases the band; the overlay stores it upper.
    assert simulation is not None
    assert (
        simulation.building_parts[BuildingPartIdentifier.MAIN].construction_age_band
        == "D"
    )


@pytest.mark.parametrize("age_band_value", ["Z", "", "1900-1929", "Unknown"])
def test_unrecognised_age_band_produces_no_overlay(age_band_value: str) -> None:
    # Act
    simulation = age_band_overlay_for(age_band_value, 0)

    # Assert
    assert simulation is None


def test_age_band_override_re_dates_the_main_part_only() -> None:
    # Arrange — baseline main + extension are both band B; the landlord corrects
    # the main building's age band to F (1976-1982).
    baseline = build_epc()
    overlay = age_band_overlay_for("F", 0)
    assert overlay is not None

    # Act
    result = apply_simulations(baseline, [overlay])

    # Assert — the main part is re-dated (its U-value cascade now keys on F); the
    # extension is left untouched.
    assert _part(result, BuildingPartIdentifier.MAIN).construction_age_band == "F"
    assert (
        _part(result, BuildingPartIdentifier.EXTENSION_1).construction_age_band == "B"
    )


@pytest.mark.parametrize(
    "member", [m for m in ConstructionAgeBand if m is not ConstructionAgeBand.UNKNOWN]
)
def test_every_resolvable_age_band_value_decodes_to_an_overlay(
    member: ConstructionAgeBand,
) -> None:
    # A classifier emits a ConstructionAgeBand value; if the overlay can't decode
    # it the override silently no-ops. Every non-UNKNOWN member must resolve.

    # Act
    simulation = age_band_overlay_for(member.value, 0)

    # Assert
    assert simulation is not None