"""The dwelling interpretation that feeds `Products.ashp_bundle_cost` — reading
an `EpcPropertyData` into a typed `AshpCostInputs` (ADR-0025). This is the
modelling-layer half of the split: it derives the existing system, property
size band, design heat loss (floor-area proxy), radiator count, and whether a
wet system can be reused — the catalogue math (Products) stays EPC-free.
"""

import copy

from datatypes.epc.domain.epc_property_data import EpcPropertyData
from domain.modelling.generators.heating_recommendation import ashp_cost_inputs
from domain.modelling.products import AshpCostInputs, AshpExistingSystem
from tests.domain.modelling._elmhurst_recommendation import (
    parse_recommendation_summary,
)


def test_mains_gas_dwelling_maps_to_a_reusable_wet_gas_system() -> None:
    # Arrange — a mains-gas regular boiler with radiators (90 m2, 7 habitable
    # rooms): an existing wet system the ASHP can reuse.
    epc = parse_recommendation_summary(
        "ashp_from_system_boiler_with_cylinder_001431_before.pdf"
    )

    # Act
    inputs: AshpCostInputs = ashp_cost_inputs(epc)

    # Assert — gas, large (90 > 75 m2), 4.5 kW (90 x 0.05), 10 radiators
    # (7 habitable + 3), reusable wet system.
    assert inputs.existing_system is AshpExistingSystem.GAS
    assert inputs.is_small_property is False
    assert abs(inputs.design_heat_loss_kw - 4.5) <= 1e-9
    assert inputs.radiator_count == 10
    assert inputs.has_reusable_wet_system is True


def test_electric_dwelling_has_no_reusable_wet_system() -> None:
    # Arrange — an electric storage-heater dwelling (no wet system).
    epc = parse_recommendation_summary(
        "hhr_storage_from_electric_storage_001431_before.pdf"
    )

    # Act
    inputs: AshpCostInputs = ashp_cost_inputs(epc)

    # Assert — electric, so a full new wet distribution is needed.
    assert inputs.existing_system is AshpExistingSystem.ELECTRIC_STORAGE
    assert inputs.has_reusable_wet_system is False


def test_classification_keys_on_fuel_not_the_mains_gas_flag() -> None:
    # Arrange — the 001431 electric fixtures all lodge mains_gas=True (gas is
    # available at the property) while heating electrically (fuel 30). The
    # classifier must key on the fuel, not the flag, or it would misread these
    # as gas and wrongly reuse a non-existent wet system.
    epc = parse_recommendation_summary(
        "hhr_storage_from_electric_storage_001431_before.pdf"
    )

    # Act / Assert
    assert epc.sap_energy_source.mains_gas is True
    inputs: AshpCostInputs = ashp_cost_inputs(epc)
    assert inputs.existing_system is AshpExistingSystem.ELECTRIC_STORAGE
    assert inputs.has_reusable_wet_system is False


def test_oil_and_lpg_dwellings_are_reusable_wet_systems() -> None:
    # Arrange — no oil/LPG fixture exists, so mutate an off-gas dwelling's main
    # fuel to oil (28) and LPG (27); both are wet boiler systems.
    base: EpcPropertyData = parse_recommendation_summary(
        "hhr_storage_from_electric_storage_001431_before.pdf"
    )

    def _with_fuel(code: int) -> EpcPropertyData:
        clone: EpcPropertyData = copy.deepcopy(base)
        clone.sap_energy_source.mains_gas = False
        clone.sap_heating.main_heating_details[0].main_fuel_type = code
        clone.sap_heating.main_heating_details[0].sap_main_heating_code = 199
        return clone

    # Act / Assert
    assert ashp_cost_inputs(_with_fuel(28)).existing_system is AshpExistingSystem.OIL
    assert ashp_cost_inputs(_with_fuel(27)).existing_system is AshpExistingSystem.LPG
    assert ashp_cost_inputs(_with_fuel(28)).has_reusable_wet_system is True