from __future__ import annotations

from typing import TYPE_CHECKING

import pytest

from datatypes.epc.domain.epc import Epc
from datatypes.epc.domain.epc_property_data import (
    EpcPropertyData,
    RenewableHeatIncentive,
)
from domain.fuel_rates.fuel import Fuel
from domain.billing.bill import BillSection
from domain.property_baseline.property_baseline_performance import PropertyBaselinePerformance
from domain.property_baseline.performance import Performance
from domain.property_baseline.rebaseliner import (
    RebaselineNotImplemented,
    RebaselineResult,
    Rebaseliner,
    StubRebaseliner,
)
from domain.property.property import Property, PropertyIdentity
from domain.sap10_calculator.calculator import SapResult
from orchestration.property_baseline_orchestrator import PropertyBaselineOrchestrator
from repositories.fuel_rates.fuel_rates_static_file_repository import (
    FuelRatesStaticFileRepository,
)
from tests.orchestration.fakes import (
    FakePropertyBaselineRepo,
    FakePropertyRepo,
    FakeUnitOfWork,
)

if TYPE_CHECKING:
    from datatypes.epc.domain.epc_property_data import EpcPropertyData


def _property(*, sap_version: float) -> Property:
    epc = object.__new__(EpcPropertyData)
    epc.energy_rating_current = 72
    epc.current_energy_efficiency_band = Epc.C
    epc.co2_emissions_current = 1.8
    epc.energy_consumption_current = 180
    epc.sap_version = sap_version
    epc.renewable_heat_incentive = RenewableHeatIncentive(
        space_heating_kwh=5000.0, water_heating_kwh=2000.0
    )
    return Property(
        identity=PropertyIdentity(
            portfolio_id=1, postcode="A0 0AA", address="1 Some Street", uprn=123
        ),
        epc=epc,
    )


def test_run_establishes_persists_and_commits_the_batch_once() -> None:
    # Arrange
    property_baseline_repo = FakePropertyBaselineRepo()
    uow = FakeUnitOfWork(
        property=FakePropertyRepo({10: _property(sap_version=10.2)}),
        property_baseline=property_baseline_repo,
    )
    orchestrator = PropertyBaselineOrchestrator(
        unit_of_work=lambda: uow,
        rebaseliner=StubRebaseliner(),
        fuel_rates=FuelRatesStaticFileRepository(),
    )

    # Act
    orchestrator.run([10])

    # Assert — one Baseline Performance persisted (both halves equal, kWh off the
    # RHI, no bill because the stub ran no calculator), and the batch committed
    # exactly once.
    lodged = Performance(
        sap_score=72, epc_band=Epc.C, co2_emissions=1.8, primary_energy_intensity=180
    )
    assert property_baseline_repo.saved == [
        (
            PropertyBaselinePerformance(
                lodged=lodged,
                effective=lodged,
                rebaseline_reason="none",
                space_heating_kwh=5000.0,
                water_heating_kwh=2000.0,
                bill=None,
            ),
            10,
        )
    ]
    assert uow.commits == 1


def test_run_raises_on_a_pre_sap10_property_and_does_not_commit() -> None:
    # Arrange — a pre-SAP10 cert needs ML rebaselining, which is not wired yet.
    property_baseline_repo = FakePropertyBaselineRepo()
    uow = FakeUnitOfWork(
        property=FakePropertyRepo({10: _property(sap_version=9.94)}),
        property_baseline=property_baseline_repo,
    )
    orchestrator = PropertyBaselineOrchestrator(
        unit_of_work=lambda: uow,
        rebaseliner=StubRebaseliner(),
        fuel_rates=FuelRatesStaticFileRepository(),
    )

    # Act / Assert — the raise propagates; the batch is neither persisted nor
    # committed (all-or-nothing).
    with pytest.raises(RebaselineNotImplemented):
        orchestrator.run([10])
    assert property_baseline_repo.saved == []
    assert uow.commits == 0


_LIGHTING_KWH = 400.0


def _sap_result_with_lighting() -> SapResult:
    """A minimal scored picture carrying only lighting energy — enough for Bill
    Derivation to produce one electric section. Mirrors the constructor shape in
    tests/domain/property_baseline/test_energy_breakdown.py::_sap_result."""
    return SapResult(
        sap_score=72,
        sap_score_continuous=72.0,
        ecf=0.0,
        total_fuel_cost_gbp=0.0,
        co2_kg_per_yr=0.0,
        space_heating_kwh_per_yr=0.0,
        space_cooling_kwh_per_yr=0.0,
        fabric_energy_efficiency_kwh_per_m2_yr=0.0,
        main_heating_fuel_kwh_per_yr=0.0,
        main_2_heating_fuel_kwh_per_yr=0.0,
        secondary_heating_fuel_kwh_per_yr=0.0,
        space_cooling_fuel_kwh_per_yr=0.0,
        hot_water_kwh_per_yr=0.0,
        pumps_fans_kwh_per_yr=0.0,
        lighting_kwh_per_yr=_LIGHTING_KWH,
        appliances_kwh_per_yr=0.0,
        cooking_kwh_per_yr=0.0,
        main_heating_fuel_code=None,
        main_2_heating_fuel_code=None,
        secondary_heating_fuel_code=None,
        hot_water_fuel_code=None,
        pv_exported_kwh_per_yr=0.0,
        primary_energy_kwh_per_yr=0.0,
        primary_energy_kwh_per_m2=0.0,
        monthly=(),
        intermediate={},
    )


class _ScoringRebaseliner(Rebaseliner):
    """A rebaseliner that returns a fixed scored picture (a SapResult) so the
    orchestrator's Bill Derivation wiring exercises (StubRebaseliner returns
    sap_result=None, which never bills)."""

    def __init__(self, result: SapResult) -> None:
        self._result = result

    def rebaseline(
        self,
        property_id: int,
        effective_epc: EpcPropertyData,
        lodged: Performance,
        *,
        physical_state_changed: bool = False,
    ) -> RebaselineResult:
        return RebaselineResult(
            effective=lodged, reason="none", sap_result=self._result
        )


def _property_without_rhi(*, sap_version: float = 10.2) -> Property:
    """A predicted-style property whose EPC carries no lodged RHI block (ADR-0031
    predicted EPCs deep-copy a template that may lack RHI)."""
    epc = object.__new__(EpcPropertyData)
    epc.energy_rating_current = 72
    epc.current_energy_efficiency_band = Epc.C
    epc.co2_emissions_current = 1.8
    epc.energy_consumption_current = 180
    epc.sap_version = sap_version
    epc.renewable_heat_incentive = None
    return Property(
        identity=PropertyIdentity(
            portfolio_id=1, postcode="A0 0AA", address="1 Some Street", uprn=123
        ),
        epc=epc,
    )


def _sap_result_with_heating(*, space_kwh: float, water_kwh: float) -> SapResult:
    result = _sap_result_with_lighting()
    object.__setattr__(result, "space_heating_kwh_per_yr", space_kwh)
    object.__setattr__(result, "hot_water_kwh_per_yr", water_kwh)
    # hot-water kWh must carry a fuel code for Bill Derivation (1 = mains gas).
    object.__setattr__(result, "hot_water_fuel_code", 1)
    return result


def test_run_falls_back_to_computed_kwh_when_epc_has_no_rhi() -> None:
    # Arrange — a predicted property with no lodged RHI, scored by a rebaseliner
    # that returns a SapResult carrying the property's own computed energy.
    property_baseline_repo = FakePropertyBaselineRepo()
    uow = FakeUnitOfWork(
        property=FakePropertyRepo({10: _property_without_rhi()}),
        property_baseline=property_baseline_repo,
    )
    orchestrator = PropertyBaselineOrchestrator(
        unit_of_work=lambda: uow,
        rebaseliner=_ScoringRebaseliner(
            _sap_result_with_heating(space_kwh=4200.0, water_kwh=1600.0)
        ),
        fuel_rates=FuelRatesStaticFileRepository(),
    )

    # Act
    orchestrator.run([10])

    # Assert — baseline kWh come from the computed SapResult, not a (missing) RHI.
    (baseline, _) = property_baseline_repo.saved[0]
    assert baseline.space_heating_kwh == 4200.0
    assert baseline.water_heating_kwh == 1600.0
    assert uow.commits == 1


def test_run_raises_when_no_rhi_and_no_scored_result() -> None:
    # Arrange — no lodged RHI AND the stub rebaseliner scores nothing: there is
    # genuinely no source for baseline kWh, so the batch must fail noisily.
    property_baseline_repo = FakePropertyBaselineRepo()
    uow = FakeUnitOfWork(
        property=FakePropertyRepo({10: _property_without_rhi()}),
        property_baseline=property_baseline_repo,
    )
    orchestrator = PropertyBaselineOrchestrator(
        unit_of_work=lambda: uow,
        rebaseliner=StubRebaseliner(),
        fuel_rates=FuelRatesStaticFileRepository(),
    )

    # Act / Assert
    with pytest.raises(ValueError, match="renewable_heat_incentive"):
        orchestrator.run([10])
    assert property_baseline_repo.saved == []
    assert uow.commits == 0


def test_run_derives_and_persists_a_bill_when_the_rebaseliner_scores() -> None:
    # Arrange — a rebaseliner that hands back a SapResult with lighting energy,
    # so the orchestrator prices it into a Bill at the committed snapshot.
    property_baseline_repo = FakePropertyBaselineRepo()
    uow = FakeUnitOfWork(
        property=FakePropertyRepo({10: _property(sap_version=10.2)}),
        property_baseline=property_baseline_repo,
    )
    orchestrator = PropertyBaselineOrchestrator(
        unit_of_work=lambda: uow,
        rebaseliner=_ScoringRebaseliner(_sap_result_with_lighting()),
        fuel_rates=FuelRatesStaticFileRepository(),
    )

    # Act
    orchestrator.run([10])

    # Assert — the persisted baseline carries a populated bill; the LIGHTING
    # section is the lighting kWh priced at the snapshot's electricity rate
    # (read from the snapshot, not hard-coded).
    rates = FuelRatesStaticFileRepository().get_current()
    expected_cost = _LIGHTING_KWH * rates.unit_rate_p_per_kwh(Fuel.ELECTRICITY) / 100.0
    (baseline, _) = property_baseline_repo.saved[0]
    assert baseline.bill is not None
    lighting = baseline.bill.sections[BillSection.LIGHTING]
    assert lighting.kwh == _LIGHTING_KWH
    assert abs(lighting.cost_gbp - expected_cost) <= 1e-9