"""Backfill main-fuel overrides where an individual wood-logs dwelling was funnelled
into "biomass (community)".

The ``MainFuelType`` taxonomy had no individual wood-logs member (only
``biomass (community)``), so the LLM force-picked the community fuel for
``"Solid Fuel: Wood Logs"`` — inventing a community heat network the dwelling
isn't on. ``MainFuelType.WOOD_LOGS`` (API fuel enum 6 / RdSAP Table 32 code 20)
now exists and ``main_fuel_guard`` resolves the wood-logs token deterministically,
so this fixes the rows written before that change.

Uses the SAME guard as the live path, so the backfill and the classifier cannot
drift. SCOPED TO ONE PORTFOLIO (``--portfolio``, default 796 = Hyde) and only
touches ``property_overrides.override_value`` (TEXT — what the modelling reads);
the global ``landlord_main_fuel_overrides`` classifier cache is left alone (its
``value`` is the Drizzle-owned pgEnum, which needs the FE migration to add the
member first — the Class-A/B deferral Khalim's scripts use).

DRY-RUN BY DEFAULT: prints what it would change and writes nothing. Pass
``--apply`` to execute inside a transaction; it also writes an audit CSV of every
row changed (property_id, uprn, old value, new value) so the change is reversible.
Idempotent — only rows whose stored value differs from the guard's target member
are touched.

    python -m scripts.lisasrequest.reclassify_wood_logs_main_fuel            # dry run
    python -m scripts.lisasrequest.reclassify_wood_logs_main_fuel --apply    # write
"""

from __future__ import annotations

import argparse
import csv
import sys
from collections import Counter
from pathlib import Path

from sqlalchemy import text

_REPO_ROOT = Path(__file__).resolve().parents[2]
sys.path.insert(0, str(_REPO_ROOT))

from domain.epc.property_overrides.main_fuel_guard import main_fuel_guard  # noqa: E402
from scripts.e2e_common import ENV_PATH, build_engine, load_env  # noqa: E402

_SELECT = text(
    """
    SELECT po.property_id, pr.uprn,
           po.original_spreadsheet_description AS description,
           po.override_value AS value
    FROM property_overrides po
    JOIN property pr ON pr.id = po.property_id
    WHERE po.portfolio_id = :portfolio
      AND po.override_component = 'main_fuel'
    """
)
_UPDATE = text(
    """
    UPDATE property_overrides
       SET override_value = :new_value
     WHERE portfolio_id = :portfolio
       AND override_component = 'main_fuel'
       AND property_id = :property_id
       AND override_value <> :new_value
    """
)


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--portfolio", type=int, default=796)
    parser.add_argument(
        "--apply",
        action="store_true",
        help="execute the updates (default: dry-run, writes nothing)",
    )
    args = parser.parse_args()

    load_env(ENV_PATH)
    engine = build_engine()

    audit: list[tuple[int, object, str, str, str]] = []  # pid, uprn, descr, old, new
    tally: Counter[str] = Counter()
    with engine.begin() as conn:
        conn.execute(text("SET statement_timeout = 120000"))
        for property_id, uprn, description, value in conn.execute(
            _SELECT, {"portfolio": args.portfolio}
        ):
            member = main_fuel_guard(description or "")
            if member is None or value == member.value:
                continue
            tally[f"{value!r} -> {member.value!r}"] += 1
            audit.append((property_id, uprn, description, value, member.value))
            if args.apply:
                conn.execute(
                    _UPDATE,
                    {
                        "portfolio": args.portfolio,
                        "property_id": property_id,
                        "new_value": member.value,
                    },
                )
        if not args.apply:
            conn.rollback()

    verb = "re-classified" if args.apply else "would re-classify"
    print(f"portfolio {args.portfolio}: {verb} {len(audit)} main-fuel override row(s)")
    for change, n in tally.most_common():
        print(f"  {n:5d}  {change}")

    if args.apply and audit:
        out = _REPO_ROOT / "scripts" / "lisasrequest" / (
            f"reclassify_wood_logs_main_fuel_{args.portfolio}_audit.csv"
        )
        with out.open("w", newline="") as fh:
            w = csv.writer(fh)
            w.writerow(["property_id", "uprn", "description", "old_value", "new_value"])
            w.writerows(audit)
        print(f"\naudit trail: {out}")
    if not args.apply:
        print("\nDRY-RUN — nothing written. Re-run with --apply to execute.")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())