from typing import Optional

import pytest

from scripts.audit.anomalies import (
    PropertyAudit,
    _effective_lodged_divergence,
    _implausible_lodged_score,
    _plan_stops_short_of_goal,
)


def _make_audit(
    *,
    lodged_sap: Optional[float] = None,
    effective_sap: Optional[float] = None,
    rebaseline_reason: str = "both",
    scenario_goal_band: Optional[str] = None,
    scenario_budget: Optional[float] = None,
    post_band: Optional[str] = None,
    post_sap: Optional[float] = None,
    cost_of_works: Optional[float] = None,
) -> PropertyAudit:
    return PropertyAudit(
        property_id=1,
        uprn=None,
        portfolio_id=796,
        scenario_id=None,
        scenario_goal_band=scenario_goal_band,
        scenario_budget=scenario_budget,
        lodged_sap=lodged_sap,
        lodged_band=None,
        effective_sap=effective_sap,
        effective_band=None,
        rebaseline_reason=rebaseline_reason,
        post_sap=post_sap,
        post_band=post_band,
        cost_of_works=cost_of_works,
        energy_bill_savings=None,
        energy_consumption_savings=None,
        solar_sap_points=None,
        solar_bill_savings=None,
        n_measures=0,
    )


class TestEffectiveLodgedDivergence:
    def test_silent_when_lodged_sap_below_floor(self) -> None:
        # Arrange — Class C exemplar: lodged=1, effective=76 (gap +75, but lodged is implausible upstream data)
        audit = _make_audit(lodged_sap=1.0, effective_sap=76.0)

        # Act
        result = _effective_lodged_divergence(audit)

        # Assert
        assert result is None

    def test_fires_when_lodged_sap_at_or_above_floor_with_large_gap(self) -> None:
        # Arrange — lodged=20 (band G, plausible), effective=65 (band D), gap +45
        audit = _make_audit(lodged_sap=20.0, effective_sap=65.0)

        # Act
        result = _effective_lodged_divergence(audit)

        # Assert
        assert result is not None
        assert "65" in result
        assert "20" in result


class TestImplausibleLodgedScore:
    def test_fires_when_lodged_sap_below_floor_and_gap_large(self) -> None:
        # Arrange — Class C exemplar: lodged=1, effective=76 (gap +75)
        audit = _make_audit(lodged_sap=1.0, effective_sap=76.0)

        # Act
        result = _implausible_lodged_score(audit)

        # Assert
        assert result is not None
        assert "1" in result

    def test_silent_when_gap_below_threshold(self) -> None:
        # Arrange — lodged=9, effective=5 (gap -4, below ±15): both low, not a divergence anomaly
        audit = _make_audit(lodged_sap=9.0, effective_sap=5.0)

        # Act
        result = _implausible_lodged_score(audit)

        # Assert
        assert result is None

    def test_silent_when_lodged_sap_at_or_above_floor(self) -> None:
        # Arrange — lodged=13 is on the floor boundary; effective=70 gives large gap
        audit = _make_audit(lodged_sap=13.0, effective_sap=70.0)

        # Act
        result = _implausible_lodged_score(audit)

        # Assert
        assert result is None


class TestPlanStopsShortOfGoal:
    def test_fires_when_short_of_goal_on_unlimited_budget(self) -> None:
        # Arrange — goal C, plan lands at D, budget unlimited (None): a shortfall
        # the engine should be able to explain (Khalim's 742121 class).
        audit = _make_audit(
            scenario_goal_band="C",
            scenario_budget=None,
            post_band="D",
            post_sap=63.0,
            cost_of_works=8000.0,
        )

        # Act
        result = _plan_stops_short_of_goal(audit)

        # Assert
        assert result is not None
        assert "D" in result
        assert "C" in result

    def test_silent_when_plan_meets_goal(self) -> None:
        # Arrange — goal C, plan reaches C: nothing to explain.
        audit = _make_audit(
            scenario_goal_band="C", scenario_budget=None, post_band="C", post_sap=70.0
        )

        # Act
        result = _plan_stops_short_of_goal(audit)

        # Assert
        assert result is None

    def test_silent_when_budget_capped(self) -> None:
        # Arrange — goal C, plan short at D, but the scenario is budget-capped:
        # falling short is expected once the money runs out, not an anomaly.
        audit = _make_audit(
            scenario_goal_band="C",
            scenario_budget=5000.0,
            post_band="D",
            post_sap=63.0,
            cost_of_works=5000.0,
        )

        # Act
        result = _plan_stops_short_of_goal(audit)

        # Assert
        assert result is None