from __future__ import annotations

import pytest

from domain.fuel_rates.fuel import Fuel
from domain.billing.sap_fuel import sap_code_to_fuel
from domain.sap10_calculator.exceptions import UnmappedSapCode


def test_mains_gas_code_maps_to_mains_gas() -> None:
    # Arrange / Act / Assert — Table 32 code 1 is mains gas.
    assert sap_code_to_fuel(1) == Fuel.MAINS_GAS


@pytest.mark.parametrize(
    ("code", "fuel"),
    [
        (1, Fuel.MAINS_GAS),
        (2, Fuel.LPG),
        (4, Fuel.OIL),
        (76, Fuel.OIL),  # bioethanol — a liquid fuel row
        (11, Fuel.COAL),  # house coal
        (15, Fuel.COAL),  # anthracite
        (12, Fuel.SMOKELESS),
        (20, Fuel.WOOD_LOGS),
        (23, Fuel.WOOD_PELLETS),
        (30, Fuel.ELECTRICITY),  # standard tariff
        (32, Fuel.ELECTRICITY_OFF_PEAK),  # 7-hour tariff
        (41, Fuel.HEAT_NETWORK),  # heat from electric heat pump (community)
        (50, Fuel.HEAT_NETWORK),  # electricity for distribution pumping
    ],
)
def test_table_32_codes_map_to_their_billing_fuel(code: int, fuel: Fuel) -> None:
    # Arrange / Act / Assert
    assert sap_code_to_fuel(code) == fuel


@pytest.mark.parametrize(
    ("api_code", "fuel"),
    [
        (26, Fuel.MAINS_GAS),  # gov-API mains-gas enum -> Table 32 code 1
        (0, Fuel.ELECTRICITY),  # API "electricity" -> Table 32 code 30
        (25, Fuel.HEAT_NETWORK),  # API community heat -> Table 32 code 41
        (14, Fuel.COAL),  # API house coal -> Table 32 code 11
    ],
)
def test_raw_api_fuel_codes_normalize_before_mapping(api_code: int, fuel: Fuel) -> None:
    # Arrange — the calculator may carry a raw gov-API fuel code (not yet a Table
    # 32 code); sap_code_to_fuel normalizes via the calculator's own helper first.
    # Act / Assert
    assert sap_code_to_fuel(api_code) == fuel


def test_an_unmapped_code_raises_rather_than_guessing() -> None:
    # Arrange — code 10 (dual fuel) has no single billing fuel.
    # Act / Assert
    with pytest.raises(UnmappedSapCode):
        sap_code_to_fuel(10)