"""按配置创建交易所实例。"""

from __future__ import annotations

from ..config import Settings, get_settings
from .protocol import ExchangeMarket

_exchange: ExchangeMarket | None = None


def build_exchange(settings: Settings | None = None) -> ExchangeMarket:
    s = settings or get_settings()
    name = (s.exchange or "okx").strip().lower()
    if name == "okx":
        from .okx.adapter import OkxExchange

        return OkxExchange(s)
    if name in ("binance", "bn"):
        from .binance.adapter import BinanceExchange

        return BinanceExchange(s)
    raise ValueError(f"未知交易所 EXCHANGE={s.exchange!r}，支持 okx / binance")


def get_exchange() -> ExchangeMarket:
    global _exchange
    if _exchange is None:
        _exchange = build_exchange()
    return _exchange


def set_exchange(ex: ExchangeMarket | None) -> None:
    global _exchange
    _exchange = ex