"""期权标的白名单:OKX_OPTIONS_UNDERLYINGS + DEFAULT_UNDERLY."""
from __future__ import annotations

import os
from typing import Any

_ALLOWED = ("ETH", "BTC")


def parse_options_underlyings() -> list[str]:
    """env 白名单;空或缺省为 ETH,BTC.仅认 ETH/BTC."""
    raw = (os.getenv("OKX_OPTIONS_UNDERLYINGS") or "").strip()
    if not raw:
        return ["ETH", "BTC"]
    out: list[str] = []
    for part in raw.replace(";", ",").split(","):
        u = part.strip().upper()
        if u in _ALLOWED and u not in out:
            out.append(u)
    return out or ["ETH", "BTC"]


def resolve_default_underly(allowed: list[str] | None = None) -> str:
    """DEFAULT 落在白名单内;否则取白名单第一项."""
    allow = list(allowed) if allowed is not None else parse_options_underlyings()
    if not allow:
        allow = ["ETH", "BTC"]
    d = (os.getenv("OKX_OPTIONS_DEFAULT_UNDERLY") or "ETH").strip().upper() or "ETH"
    if d in allow:
        return d
    return allow[0]


def underly_from_inst_id(inst_id: str) -> str:
    return (str(inst_id or "").split("-")[0] or "").strip().upper()


def underly_not_allowed_msg(underlying: str, allowed: list[str] | None = None) -> str | None:
    """白名单外返回拒因;允许则 None."""
    allow = list(allowed) if allowed is not None else parse_options_underlyings()
    u = (underlying or "").strip().upper()
    if u in allow:
        return None
    return f"标的 {u or '—'} 不在本机白名单({','.join(allow) or '—'})"


def inst_underly_not_allowed_msg(inst_id: str, allowed: list[str] | None = None) -> str | None:
    return underly_not_allowed_msg(underly_from_inst_id(inst_id), allowed)


def underly_cfg_snapshot() -> dict[str, Any]:
    allow = parse_options_underlyings()
    return {
        "allowed_underlys": allow,
        "default_underly": resolve_default_underly(allow),
    }