"""Behaviour of per-measure scoring: the telescoping marginal cascade that
serves both the per-Option optimiser signal (role 1) and the final-package
display attribution (role 3) — ADR-0016. Exercises the real calculator on a
hand-built EPD; no PDF/parser involved.
"""

from typing import Sequence

from datatypes.epc.domain.epc_property_data import (
    BuildingPartIdentifier,
    EpcPropertyData,
)
from domain.modelling.scoring.package_scorer import PackageScorer, Score
from domain.modelling.recommendation import MeasureOption
from domain.modelling.scoring.scoring import (
    MeasureImpact,
    cascade_scores,
    independent_option_impacts,
    marginal_impacts,
    marginals_from_scores,
)
from domain.modelling.simulation import BuildingPartOverlay, EpcSimulation
from domain.sap10_calculator.calculator import Sap10Calculator
from tests.domain.sap10_calculator.worksheet._elmhurst_worksheet_000490 import (
    build_epc,
)

_MAIN_CAVITY = EpcSimulation(
    building_parts={
        BuildingPartIdentifier.MAIN: BuildingPartOverlay(wall_insulation_type=2)
    }
)
_EXT1_CAVITY = EpcSimulation(
    building_parts={
        BuildingPartIdentifier.EXTENSION_1: BuildingPartOverlay(wall_insulation_type=2)
    }
)


class _CountingScorer(PackageScorer):
    """A PackageScorer stand-in that counts score() calls; the score is a
    deterministic function of the overlays so distinct overlays differ."""

    def __init__(self) -> None:
        self.calls = 0

    def score(
        self, baseline: EpcPropertyData, simulations: Sequence[EpcSimulation]
    ) -> Score:
        self.calls += 1
        total = 0.0
        for sim in simulations:
            for overlay in sim.building_parts.values():
                total += overlay.wall_insulation_type or 0
        return Score(
            sap_continuous=total, co2_kg_per_yr=0.0, primary_energy_kwh_per_yr=0.0
        )


def _option(overlay: EpcSimulation) -> MeasureOption:
    return MeasureOption(
        measure_type="cavity_wall_insulation", description="opt", overlay=overlay
    )


def test_independent_option_impacts_score_each_distinct_overlay_once() -> None:
    # Arrange
    baseline: EpcPropertyData = build_epc()
    scorer = _CountingScorer()
    overlay_a = EpcSimulation(
        building_parts={
            BuildingPartIdentifier.MAIN: BuildingPartOverlay(wall_insulation_type=2)
        }
    )
    overlay_a_dup = EpcSimulation(
        building_parts={
            BuildingPartIdentifier.MAIN: BuildingPartOverlay(wall_insulation_type=2)
        }
    )
    overlay_b = EpcSimulation(
        building_parts={
            BuildingPartIdentifier.MAIN: BuildingPartOverlay(wall_insulation_type=3)
        }
    )
    options = [_option(overlay_a), _option(overlay_a_dup), _option(overlay_b)]

    # Act
    impacts: list[MeasureImpact] = independent_option_impacts(
        scorer, baseline, options
    )

    # Assert
    # baseline scored once + one score per DISTINCT overlay (a, b) = 3, not 4
    assert scorer.calls == 3
    assert impacts[0].sap_points == impacts[1].sap_points == 2.0
    assert impacts[2].sap_points == 3.0


def test_single_overlay_marginal_is_its_improvement_over_baseline() -> None:
    # Arrange
    baseline: EpcPropertyData = build_epc()
    scorer = PackageScorer(Sap10Calculator())
    base: Score = scorer.score(baseline, [])
    filled: Score = scorer.score(baseline, [_MAIN_CAVITY])

    # Act
    impacts: list[MeasureImpact] = marginal_impacts(scorer, baseline, [_MAIN_CAVITY])

    # Assert
    assert len(impacts) == 1
    assert impacts[0].sap_points > 0  # cavity fill improves SAP
    assert (
        abs(impacts[0].sap_points - (filled.sap_continuous - base.sap_continuous))
        <= 1e-9
    )


def test_cascade_scores_returns_the_baseline_plus_one_score_per_prefix() -> None:
    # Arrange
    baseline: EpcPropertyData = build_epc()
    scorer = _CountingScorer()
    overlays = [_MAIN_CAVITY, _EXT1_CAVITY]

    # Act
    scores: list[Score] = cascade_scores(scorer, baseline, overlays)

    # Assert
    # baseline (empty prefix) + one score per cumulative prefix
    assert len(scores) == 3
    assert scorer.calls == 3
    assert scores[0].sap_continuous == 0.0  # empty prefix
    assert scores[1].sap_continuous == 2.0  # MAIN cavity (type 2)
    assert scores[2].sap_continuous == 4.0  # + EXTENSION_1 cavity (type 2)


def test_marginals_from_scores_are_the_consecutive_prefix_deltas() -> None:
    # Arrange
    baseline: EpcPropertyData = build_epc()
    scorer = PackageScorer(Sap10Calculator())
    overlays = [_MAIN_CAVITY, _EXT1_CAVITY]
    scores: list[Score] = cascade_scores(scorer, baseline, overlays)

    # Act
    impacts: list[MeasureImpact] = marginals_from_scores(scores)

    # Assert — each marginal is the delta over the previous prefix score
    assert len(impacts) == 2
    assert (
        abs(impacts[0].sap_points - (scores[1].sap_continuous - scores[0].sap_continuous))
        <= 1e-9
    )
    assert (
        abs(impacts[1].sap_points - (scores[2].sap_continuous - scores[1].sap_continuous))
        <= 1e-9
    )


def test_marginals_telescope_to_the_whole_package_total() -> None:
    # Arrange
    baseline: EpcPropertyData = build_epc()
    scorer = PackageScorer(Sap10Calculator())
    overlays = [_MAIN_CAVITY, _EXT1_CAVITY]
    base: Score = scorer.score(baseline, [])
    full: Score = scorer.score(baseline, overlays)

    # Act
    impacts: list[MeasureImpact] = marginal_impacts(scorer, baseline, overlays)

    # Assert
    assert len(impacts) == 2
    assert (
        abs(
            sum(i.sap_points for i in impacts)
            - (full.sap_continuous - base.sap_continuous)
        )
        <= 1e-9
    )
    assert (
        abs(
            sum(i.energy_savings_kwh_per_yr for i in impacts)
            - (base.primary_energy_kwh_per_yr - full.primary_energy_kwh_per_yr)
        )
        <= 1e-6
    )