"""Behaviour of the ventilation Measure Dependency: the data-declared "fabric
insulation requires adequate ventilation" edge. Production (detection + pricing)
is the ventilation Recommendation Generator's job and is tested in
test_ventilation_recommendation; here we test the forced-edge wrapping and the
trigger set. See CONTEXT.md (Measure Dependency) / ADR-0016.
"""

from typing import Optional

from datatypes.epc.domain.epc_property_data import EpcPropertyData
from domain.modelling.optimisation.measure_dependency import (
    MEASURES_NEEDING_VENTILATION,
    ventilation_dependency,
)
from domain.modelling.optimisation.optimiser import MeasureDependency
from domain.modelling.product import Product
from repositories.product.product_repository import ProductRepository
from tests.domain.sap10_calculator.worksheet._elmhurst_worksheet_000490 import (
    build_epc,
)


class _StubProducts(ProductRepository):
    """In-memory ProductRepository returning a fixed per-unit ventilation cost."""

    def get(self, measure_type: str) -> Product:
        return Product(
            measure_type=measure_type, unit_cost_per_m2=450.0, contingency_rate=0.26
        )


def test_triggers_are_the_fabric_wall_measures() -> None:
    # Arrange / Act / Assert — the data-held trigger set (cf. legacy
    # assumptions.measures_needing_ventilation).
    assert MEASURES_NEEDING_VENTILATION == frozenset(
        {
            "cavity_wall_insulation",
            "internal_wall_insulation",
            "external_wall_insulation",
        }
    )


def test_wraps_the_priced_recommendation_into_a_forced_edge() -> None:
    # Arrange — 000490 needs ventilation, so the generator produces a priced MEV
    # Recommendation that the dependency wraps.
    baseline: EpcPropertyData = build_epc()

    # Act
    dependency: Optional[MeasureDependency] = ventilation_dependency(
        baseline, _StubProducts()
    )

    # Assert — a forced edge triggered by the fabric measures; the required
    # Option carries the generator's price and no role-1 signal (it is never
    # freely scored).
    assert dependency is not None
    assert dependency.triggers == MEASURES_NEEDING_VENTILATION
    assert dependency.required.option.measure_type == "mechanical_ventilation"
    assert dependency.required.sap_gain == 0.0
    cost = dependency.required.option.cost
    assert cost is not None
    assert abs(cost.total - 900.0) <= 1e-9


def test_no_dependency_when_the_dwelling_needs_no_ventilation() -> None:
    # Arrange — already mechanically ventilated, so the generator returns None
    # and there is no edge to force.
    baseline: EpcPropertyData = build_epc()
    assert baseline.sap_ventilation is not None
    baseline.sap_ventilation.mechanical_ventilation_kind = "EXTRACT_OR_PIV_OUTSIDE"

    # Act
    dependency: Optional[MeasureDependency] = ventilation_dependency(
        baseline, _StubProducts()
    )

    # Assert
    assert dependency is None