# wc_period_payload.py – Woo Bridge: Periodenfelder aus Provision/Sync-Payload ableiten
# (ohne /wc/v3/subscriptions REST).
from __future__ import annotations

from typing import Any, Optional, Tuple

from aza_wc_period_sync import _parse_wc_datetime, _subtract_billing_period

# Plausible Unix range: 2000-01-01 … 2100-01-01 UTC
_TS_MIN = 946684800
_TS_MAX = 4102444800


def _normalize_int_ts(v: Optional[int]) -> Optional[int]:
    if v is None:
        return None
    try:
        x = int(v)
    except (TypeError, ValueError):
        return None
    if x > 10**12:  # ms
        x //= 1000
    if _TS_MIN <= x <= _TS_MAX:
        return x
    return None


def coerce_next_payment_unix(value: Any) -> Optional[int]:
    """Unix-Sekunden aus next_payment (int, Ziffernstring oder ISO-Datum)."""
    if value is None:
        return None
    if isinstance(value, bool):
        return None
    if isinstance(value, int):
        return _normalize_int_ts(value)
    if isinstance(value, float):
        return _normalize_int_ts(int(value))
    s = str(value).strip()
    if not s:
        return None
    if s.isdigit():
        return _normalize_int_ts(int(s))
    parsed = _parse_wc_datetime(s)
    return _normalize_int_ts(parsed) if parsed is not None else None


def _normalize_billing_period_word(raw: Optional[str]) -> str:
    """
    WooCommerce REST liefert oft 'month'/'day'/…
    WP Desk Flexible Subscriptions API nutzt Einzelbuchstaben: D, W, M, Y.
    """
    if raw is None or (isinstance(raw, str) and not str(raw).strip()):
        return "month"
    s = str(raw).strip().lower()
    if len(s) == 1:
        return {"d": "day", "w": "week", "m": "month", "y": "year"}.get(s, s)
    return s


def resolve_wc_period_fields(
    *,
    current_period_start: Optional[int] = None,
    current_period_end: Optional[int] = None,
    next_payment_date: Any = None,
    billing_period: Optional[str] = None,
    billing_interval: Optional[int] = None,
) -> Tuple[Optional[int], Optional[int]]:
    """
    Liefert (period_start, period_end) oder (None, None) wenn nicht ableitbar/ungültig.
    Priorität:
      1) Beide current_period_* gesetzt und start < end
      2) next_payment_date + billing_period/billing_interval → Ende = Zahlungszeitpunkt,
         Start = Ende − Abrechnungsintervall (wie Woo-REST-Logik)
    """
    cs = _normalize_int_ts(current_period_start)
    ce = _normalize_int_ts(current_period_end)

    if cs is not None and ce is not None:
        if cs < ce:
            return cs, ce
        return None, None

    # Nur period_end gesetzt: Start aus Abrechnungsintervall rückwärts (Default month/1)
    if ce is not None and cs is None:
        bp = _normalize_billing_period_word(billing_period)
        try:
            bi = int(billing_interval) if billing_interval is not None else 1
        except (TypeError, ValueError):
            bi = 1
        if bi < 1:
            bi = 1
        ps = _subtract_billing_period(ce, bp, bi)
        if ps >= ce:
            ps = ce - 86400
        if ps < ce and _TS_MIN <= ps <= _TS_MAX:
            return ps, ce
        return None, None

    pe = coerce_next_payment_unix(next_payment_date)
    if pe is not None and cs is None and ce is None:
        bp = _normalize_billing_period_word(billing_period)
        try:
            bi = int(billing_interval) if billing_interval is not None else 1
        except (TypeError, ValueError):
            bi = 1
        if bi < 1:
            bi = 1
        ps = _subtract_billing_period(pe, bp, bi)
        if ps >= pe:
            ps = pe - 86400
        if ps < pe and _TS_MIN <= ps <= _TS_MAX:
            return ps, pe
        return None, None

    # Nur eines der Felder – nicht raten
    return None, None