"""SAP 10.2 (14-03-2025 amendment) Table 12 — fuel prices, CO2 emission
factors, primary energy factors.

Sourced verbatim from BRE, *The Government's Standard Assessment
Procedure for Energy Rating of Dwellings, SAP 10.2* (14-03-2025), page
189 (Table 12). Keys are the SAP 10.2/10.3 fuel code numbers — they
remained stable across the 10.2 → 10.3 jump.

The calculator targets SAP 10.2 per ADR-0010 because no SAP-10.3-lodged
certs exist in the corpus to validate against. SAP 10.3 differs from
SAP 10.2 mainly on CO2 factors (grid electricity 0.136 → 0.086 kg/kWh,
−37%; mains gas 0.210 → 0.214 kg/kWh, +2%); prices and primary energy
factors are largely unchanged. When the corpus migrates to SAP 10.3
this module re-points to those values.

The Energy Cost Deflator stays at 0.36 (used in ECF — see
`domain.sap10_calculator.worksheet.rating`).
"""

from __future__ import annotations

from typing import Final, Optional


# SAP 10.3 Table 12 — unit price in pence per kWh.
UNIT_PRICE_P_PER_KWH: Final[dict[int, float]] = {
    # Gas fuels
    1: 3.64,    # mains gas
    2: 6.74,    # bulk LPG
    3: 9.46,    # bottled LPG (main heating)
    5: 11.20,   # bottled LPG (secondary)
    9: 3.64,    # LPG SC11F
    7: 6.74,    # biogas (including anaerobic digestion)
    # Liquid fuels
    4: 4.94,    # heating oil
    71: 6.79,   # bio-liquid HVO
    73: 6.79,   # bio-liquid FAME
    75: 5.49,   # B30K
    76: 47.0,   # bioethanol
    # Solid fuels
    11: 5.58,   # house coal
    15: 4.19,   # anthracite
    12: 5.91,   # manufactured smokeless fuel
    20: 5.12,   # wood logs
    22: 6.91,   # wood pellets (secondary)
    23: 6.25,   # wood pellets (main)
    21: 3.72,   # wood chips
    10: 4.77,   # dual fuel
    # Electricity
    30: 16.49,  # standard tariff
    32: 19.60,  # 7-hour tariff (high rate)
    31: 9.40,   # 7-hour tariff (low rate / off-peak)
    34: 20.54,  # 10-hour tariff (high rate)
    33: 12.27,  # 10-hour tariff (low rate)
    38: 17.41,  # 18-hour tariff (high rate)
    40: 14.17,  # 18-hour tariff (low rate)
    35: 14.04,  # 24-hour heating tariff
    60: 5.59,   # electricity sold to grid, PV
    36: 5.59,   # electricity sold to grid, other
    # 39 "electricity, any tariff" carries N/A unit price — used only to
    # identify the fuel for a system; cost data comes from a paired
    # standard / off-peak code.
    # Heat networks
    51: 4.44, 52: 4.44, 53: 4.44, 54: 4.44,
    55: 4.44, 56: 4.44, 57: 4.44, 58: 4.44,
    41: 4.44,   # heat from electric heat pump
    42: 4.44,   # heat recovered from waste combustion
    43: 4.44,   # heat from boilers - biomass
    44: 4.44,   # heat from boilers - biogas
    45: 3.11,   # high grade heat recovered from process
    46: 3.11,   # heat recovered from geothermal / natural processes
    48: 3.11,   # heat from CHP
    49: 3.11,   # low grade heat recovered from process
    50: 0.0,    # electricity for pumping in distribution network
    47: 3.11,   # heat recovered from power station
}
_DEFAULT_P_PER_KWH: Final[float] = 3.64  # fall back to mains gas


# SAP 10.2 Table 12 — annual-average CO2 emission factor in kg CO2-
# equivalent per kWh of delivered energy. For ELECTRICITY end-uses,
# Table 12d (above) overrides this annual factor with monthly values per
# the spec text on p.194; the value here is the legacy fallback when
# monthly distribution isn't available.
# SAP 10.2 Table 12d (p.194) — monthly variation in CO2 emission factors
# for electricity. The spec text: "Where electricity is the fuel used, the
# relevant set of factors in the table below should be used to calculate
# the monthly CO2 emissions INSTEAD of the annual average factor given in
# Table 12." So for ratings, electricity end-uses use Σ(kWh_m × CO2_m)
# rather than annual_kwh × annual_factor.
CO2_KG_PER_KWH_MONTHLY: Final[dict[int, tuple[float, ...]]] = {
    # Standard tariff (default electricity)
    30: (0.163, 0.160, 0.153, 0.143, 0.132, 0.120, 0.111, 0.112, 0.122, 0.136, 0.151, 0.163),
    # 7-hour tariff
    32: (0.171, 0.168, 0.161, 0.150, 0.138, 0.125, 0.117, 0.118, 0.128, 0.143, 0.158, 0.171),
    31: (0.143, 0.141, 0.135, 0.126, 0.116, 0.105, 0.098, 0.099, 0.107, 0.120, 0.133, 0.144),
    # 10-hour tariff
    34: (0.168, 0.165, 0.159, 0.148, 0.136, 0.124, 0.115, 0.116, 0.126, 0.141, 0.156, 0.168),
    33: (0.155, 0.153, 0.146, 0.137, 0.126, 0.114, 0.106, 0.107, 0.116, 0.130, 0.144, 0.155),
    # 18-hour tariff (matches standard tariff)
    38: (0.163, 0.160, 0.153, 0.143, 0.132, 0.120, 0.111, 0.112, 0.122, 0.136, 0.151, 0.163),
    40: (0.163, 0.160, 0.153, 0.143, 0.132, 0.120, 0.111, 0.112, 0.122, 0.136, 0.151, 0.163),
    # 24-hour heating tariff
    35: (0.163, 0.160, 0.153, 0.143, 0.132, 0.120, 0.111, 0.112, 0.122, 0.136, 0.151, 0.163),
    # Electricity sold to grid (PV)
    60: (0.196, 0.190, 0.175, 0.153, 0.129, 0.106, 0.092, 0.093, 0.110, 0.138, 0.169, 0.197),
    # Electricity sold to grid, other
    36: (0.163, 0.160, 0.153, 0.143, 0.132, 0.120, 0.111, 0.112, 0.122, 0.136, 0.151, 0.163),
    # Electricity, any tariff
    39: (0.163, 0.160, 0.153, 0.143, 0.132, 0.120, 0.111, 0.112, 0.122, 0.136, 0.151, 0.163),
    # Heat from electric heat pump
    41: (0.163, 0.160, 0.153, 0.143, 0.132, 0.120, 0.111, 0.112, 0.122, 0.136, 0.151, 0.163),
    # Low-grade heat recovered from process
    49: (0.163, 0.160, 0.153, 0.143, 0.132, 0.120, 0.111, 0.112, 0.122, 0.136, 0.151, 0.163),
    # Electricity for pumping in distribution network
    50: (0.163, 0.160, 0.153, 0.143, 0.132, 0.120, 0.111, 0.112, 0.122, 0.136, 0.151, 0.163),
}


def co2_monthly_factors_kg_per_kwh(fuel_code: int | None) -> Optional[tuple[float, ...]]:
    """SAP 10.2 Table 12d (p.194) monthly CO2 factors for electricity. Returns
    None for non-electricity fuels (use the annual `co2_factor_kg_per_kwh`)."""
    if fuel_code is None:
        return None
    if fuel_code in CO2_KG_PER_KWH_MONTHLY:
        return CO2_KG_PER_KWH_MONTHLY[fuel_code]
    return None


# SAP 10.2 Table 12e (p.195) — monthly variation in PE (primary energy)
# emission factors for electricity. Spec text: "Where electricity is the
# fuel used, the relevant set of factors in the table below should be
# used to calculate the monthly primary energy instead the annual average
# factor given in Table 12." Same shape as Table 12d (CO2): electricity
# end-uses use Σ(kWh_m × PE_m); gas/non-electricity fuels keep the
# annual Table 12 PE factor.
PE_FACTOR_MONTHLY: Final[dict[int, tuple[float, ...]]] = {
    # Standard tariff
    30: (1.602, 1.593, 1.568, 1.530, 1.487, 1.441, 1.410, 1.413, 1.449, 1.504, 1.558, 1.604),
    # 7-hour tariff
    32: (1.635, 1.626, 1.600, 1.562, 1.518, 1.471, 1.440, 1.443, 1.479, 1.535, 1.591, 1.637),
    31: (1.521, 1.512, 1.488, 1.453, 1.411, 1.368, 1.339, 1.342, 1.376, 1.428, 1.480, 1.522),
    # 10-hour tariff
    34: (1.625, 1.615, 1.590, 1.552, 1.507, 1.462, 1.430, 1.433, 1.470, 1.525, 1.580, 1.626),
    33: (1.571, 1.561, 1.537, 1.500, 1.457, 1.413, 1.382, 1.386, 1.421, 1.474, 1.528, 1.572),
    # 18-hour tariff (matches standard tariff)
    38: (1.602, 1.593, 1.568, 1.530, 1.487, 1.441, 1.410, 1.413, 1.449, 1.504, 1.558, 1.604),
    40: (1.602, 1.593, 1.568, 1.530, 1.487, 1.441, 1.410, 1.413, 1.449, 1.504, 1.558, 1.604),
    # 24-hour heating tariff
    35: (1.602, 1.593, 1.568, 1.530, 1.487, 1.441, 1.410, 1.413, 1.449, 1.504, 1.558, 1.604),
    # Electricity sold to grid (PV) — note (i): deducted, low PE factor
    60: (0.715, 0.697, 0.645, 0.567, 0.478, 0.389, 0.330, 0.336, 0.405, 0.513, 0.623, 0.718),
    # Electricity sold to grid, other
    36: (0.602, 0.593, 0.568, 0.530, 0.487, 0.441, 0.410, 0.413, 0.449, 0.504, 0.558, 0.604),
    # Electricity, any tariff
    39: (1.602, 1.593, 1.568, 1.530, 1.487, 1.441, 1.410, 1.413, 1.449, 1.504, 1.558, 1.604),
    # Heat from electric heat pump
    41: (1.602, 1.593, 1.568, 1.530, 1.487, 1.441, 1.410, 1.413, 1.449, 1.504, 1.558, 1.604),
    # Low-grade heat recovered from process
    49: (1.602, 1.593, 1.568, 1.530, 1.487, 1.441, 1.410, 1.413, 1.449, 1.504, 1.558, 1.604),
    # Electricity for pumping in distribution network
    50: (1.602, 1.593, 1.568, 1.530, 1.487, 1.441, 1.410, 1.413, 1.449, 1.504, 1.558, 1.604),
}


def pe_monthly_factors_kwh_per_kwh(
    fuel_code: int | None,
) -> Optional[tuple[float, ...]]:
    """SAP 10.2 Table 12e (p.195) monthly PE factors for electricity. Returns
    None for non-electricity fuels (use the annual `primary_energy_factor`)."""
    if fuel_code is None:
        return None
    if fuel_code in PE_FACTOR_MONTHLY:
        return PE_FACTOR_MONTHLY[fuel_code]
    return None


CO2_KG_PER_KWH: Final[dict[int, float]] = {
    # Gas fuels
    1: 0.210,
    2: 0.241, 3: 0.241, 5: 0.241, 9: 0.241,
    7: 0.024,
    # Liquid fuels
    4: 0.298,
    71: 0.036, 73: 0.018,
    75: 0.214, 76: 0.105,
    # Solid fuels
    11: 0.395, 15: 0.395, 12: 0.366,
    20: 0.028, 22: 0.053, 23: 0.053, 21: 0.023,
    10: 0.087,
    # Electricity — all grid tariffs use the same annual-average CO2 factor.
    30: 0.136, 31: 0.136, 32: 0.136, 33: 0.136, 34: 0.136, 35: 0.136,
    38: 0.136, 40: 0.136, 39: 0.136, 60: 0.136, 36: 0.136,
    # Heat networks
    51: 0.210, 52: 0.241, 53: 0.298, 54: 0.375, 55: 0.269,
    56: 0.298, 57: 0.036, 58: 0.018,
    41: 0.136, 42: 0.015, 43: 0.029, 44: 0.024,
    45: 0.015, 46: 0.011, 47: 0.011, 48: 0.136, 49: 0.136,
    50: 0.0,
}
_DEFAULT_CO2_KG_PER_KWH: Final[float] = 0.210  # mains gas baseline


# Gov EPC API main_fuel_type → SAP 10.3 Table 12 fuel code. Lifted from
# the SAP 10.2 mapper (`domain.sap10_ml.sap_efficiencies._API_TO_TABLE32`) —
# the API enum and Table 32/12 codes are unchanged across spec versions.
API_FUEL_TO_TABLE_12: Final[dict[int, int]] = {
    0: 30, 1: 1, 2: 2, 3: 3, 4: 4, 5: 15, 6: 20, 7: 23, 8: 21, 9: 10,
    10: 30, 11: 42, 12: 43, 13: 44, 14: 11, 15: 12, 16: 22, 17: 9,
    18: 75, 19: 76, 20: 51, 21: 52, 22: 53, 23: 55, 24: 54, 25: 41,
    26: 1, 27: 2, 28: 4, 29: 30,
}


def unit_price_p_per_kwh(fuel_code: int | None) -> float:
    """Unit price (p/kWh) for the given fuel code. Accepts either a
    Table 12 code or a gov API main_fuel_type / water_heating_fuel
    enum; translates the latter via `API_FUEL_TO_TABLE_12`. Unknown →
    mains gas (3.64 p/kWh)."""
    if fuel_code is None:
        return _DEFAULT_P_PER_KWH
    if fuel_code in UNIT_PRICE_P_PER_KWH:
        return UNIT_PRICE_P_PER_KWH[fuel_code]
    translated = API_FUEL_TO_TABLE_12.get(fuel_code)
    if translated is not None and translated in UNIT_PRICE_P_PER_KWH:
        return UNIT_PRICE_P_PER_KWH[translated]
    return _DEFAULT_P_PER_KWH


# SAP 10.2 Table 12 "Primary energy factor" column. The cert's
# `energy_consumption_current` field (PEUI) is delivered energy times
# this factor per fuel, summed across end-uses, divided by TFA.
PRIMARY_ENERGY_FACTOR: Final[dict[int, float]] = {
    # Gas
    1: 1.130,
    2: 1.141, 3: 1.141, 5: 1.133, 9: 1.163,
    7: 1.286,
    # Liquid
    4: 1.180,
    71: 1.180, 73: 1.180, 75: 1.136, 76: 1.472,
    # Solid
    11: 1.064, 15: 1.064, 12: 1.261, 20: 1.046,
    22: 1.325, 23: 1.325, 21: 1.046, 10: 1.049,
    # Electricity — all grid tariffs same PEF.
    30: 1.501, 31: 1.501, 32: 1.501, 33: 1.501, 34: 1.501, 35: 1.501,
    38: 1.501, 40: 1.501, 39: 1.501, 60: 0.501, 36: 0.501,
    # Heat networks (sample — main values; less common)
    51: 1.130, 52: 1.141, 53: 1.180, 54: 1.064, 55: 1.180,
    56: 1.180, 57: 1.180, 58: 1.180,
    41: 1.501, 42: 0.063, 43: 1.037, 44: 1.286,
    45: 0.051, 46: 0.051, 47: 0.063, 48: 1.501, 49: 1.501,
    50: 0.0,
}
_DEFAULT_PEF: Final[float] = 1.130  # mains gas baseline


def primary_energy_factor(fuel_code: int | None) -> float:
    """Primary energy factor for the given fuel code, accepting either
    Table 12 code or gov API enum (translated). Unknown → mains gas
    (1.13)."""
    if fuel_code is None:
        return _DEFAULT_PEF
    if fuel_code in PRIMARY_ENERGY_FACTOR:
        return PRIMARY_ENERGY_FACTOR[fuel_code]
    translated = API_FUEL_TO_TABLE_12.get(fuel_code)
    if translated is not None and translated in PRIMARY_ENERGY_FACTOR:
        return PRIMARY_ENERGY_FACTOR[translated]
    return _DEFAULT_PEF


def co2_factor_kg_per_kwh(fuel_code: int | None) -> float:
    """CO2 emission factor (kg CO2e/kWh) for the given fuel code, with
    the same accept-either-API-or-Table-12-code translation as
    `unit_price_p_per_kwh`. Unknown → mains gas (0.214)."""
    if fuel_code is None:
        return _DEFAULT_CO2_KG_PER_KWH
    if fuel_code in CO2_KG_PER_KWH:
        return CO2_KG_PER_KWH[fuel_code]
    translated = API_FUEL_TO_TABLE_12.get(fuel_code)
    if translated is not None and translated in CO2_KG_PER_KWH:
        return CO2_KG_PER_KWH[translated]
    return _DEFAULT_CO2_KG_PER_KWH