"""Map a Landlord-Override enum *value* to the gov-EPC API *code* space.

The `property_overrides` fact layer stores resolved overrides as enum-value
strings ("House", "Detached"); the EPC-API cohort certs carry numeric codes
("0", "2") — `EpcPropertyData.property_type = str(schema.property_type)`. EPC
Prediction filters `comparable.epc.property_type == target.property_type`, so a
target attribute sourced from overrides must be translated into the code space
or no comparable ever matches (ADR-0031, the wiring-handover "every cohort
comes back empty" gotcha).

Codes are the gov RdSAP/SAP table values in `datatypes/epc/domain/epc_codes.csv`.
This module owns "unresolvable": a value that maps to no code returns None.
"""

from __future__ import annotations

from typing import Optional

# property_type codes (epc_codes.csv, `property_type` rows — stable across the
# RdSAP/SAP schemas that carry each member). "Park home" exists only from
# SAP-17.0 / RdSAP-17.0 onward; the code itself is stable where present.
_PROPERTY_TYPE_CODES: dict[str, str] = {
    "House": "0",
    "Bungalow": "1",
    "Flat": "2",
    "Maisonette": "3",
    "Park home": "4",
}

# built_form codes (epc_codes.csv, `built_form` rows). "Not Recorded" lodges as
# the non-numeric "NR", but cohort comparables carry `str(int)` for built_form,
# so an "NR" target could never match — and built_form is the SOFT filter, so a
# non-match only widens the cohort. We therefore treat "Not Recorded" (and the
# classifier "Unknown") as "no usable built-form signal" → None.
_BUILT_FORM_CODES: dict[str, str] = {
    "Detached": "1",
    "Semi-Detached": "2",
    "End-Terrace": "3",
    "Mid-Terrace": "4",
    "Enclosed End-Terrace": "5",
    "Enclosed Mid-Terrace": "6",
}


def property_type_to_code(override_value: str) -> Optional[str]:
    """The gov-EPC `property_type` code for a Landlord-Override value, or None
    when it has no code ("Unknown", or any unmapped value) — which gates the
    Property out of prediction, as `property_type` is the hard cohort filter."""
    return _PROPERTY_TYPE_CODES.get(override_value)


def built_form_to_code(override_value: str) -> Optional[str]:
    """The gov-EPC `built_form` code for a Landlord-Override value, or None when
    it has no usable code ("Unknown", "Not Recorded", or any unmapped value).
    built_form is the soft filter, so None simply leaves it unconditioned."""
    return _BUILT_FORM_CODES.get(override_value)