"""行情网关：REST 对齐合约 + WS 推送盘口。"""

from __future__ import annotations

import asyncio
import logging
from typing import Any

from ..config import Settings, get_settings
from .book_cache import BookCache
from .instruments import next_session_expiry_ymd, select_option_pair
from .okx_rest import OkxRestClient
from .okx_ws import OkxPublicWs
from .types import MarketSnapshot, OptionPair

logger = logging.getLogger(__name__)

# 现价偏离当前行权价超过该点数则重选 ATM（ETH 期权常见步进 5）
_ATM_DRIFT_POINTS = 5.0


def _has_open_position() -> bool:
    try:
        from ..models.db import get_db

        row = get_db().fetchone("SELECT status FROM positions WHERE id=1")
        return bool(row and row["status"] == "open")
    except Exception:
        return False


class MarketGateway:
    def __init__(self, settings: Settings | None = None) -> None:
        self.settings = settings or get_settings()
        self.cache = BookCache()
        proxy = self.settings.okx_http_proxy or None
        self.rest = OkxRestClient(self.settings.okx_rest_base, proxy=proxy)
        self.ws = OkxPublicWs(self.settings.okx_ws_public, self.cache, proxy=proxy)
        self._pair: OptionPair | None = None
        self._refresh_task: asyncio.Task[None] | None = None
        self._started = False

    @property
    def pair(self) -> OptionPair | None:
        return self._pair

    async def start(self) -> None:
        if self._started:
            return
        self._started = True
        await asyncio.to_thread(self.align_instruments)
        await self.ws.start()
        self._refresh_task = asyncio.create_task(self._refresh_loop(), name="market-align")

    async def stop(self) -> None:
        self._started = False
        if self._refresh_task:
            self._refresh_task.cancel()
            try:
                await self._refresh_task
            except asyncio.CancelledError:
                pass
            self._refresh_task = None
        await self.ws.stop()
        self.rest.close()

    def align_instruments(self) -> OptionPair | None:
        """同步：拉期权列表，选次日到期 ATM Call/Put，REST 预热盘口，切换 WS 订阅。"""
        s = self.settings
        idx = self.rest.fetch_index_ticker(s.index_inst_id)
        mark = self.rest.fetch_mark_price(s.perp_inst_id) or idx
        if mark is None or mark <= 0:
            raise RuntimeError("无法获取 ETH 标记/指数价格，无法选 ATM")

        instruments = self.rest.fetch_option_instruments(s.option_inst_family)
        ymd = next_session_expiry_ymd()
        pair = select_option_pair(instruments, mark_px=float(mark), expiry_ymd=ymd)
        if pair is None:
            raise RuntimeError(f"未找到到期 {ymd} 的 ATM Call/Put 合约 pair (family={s.option_inst_family})")

        self._pair = pair
        self.cache.set_pair(pair)
        self.cache.set_index_px(idx)

        # REST 预热：永续 + Call + Put
        for inst in (s.perp_inst_id, pair.call_inst_id, pair.put_inst_id):
            bids, asks, ts = self.rest.fetch_books(inst, sz=5)
            self.cache.upsert_book(inst, bids=bids, asks=asks, ts_ms=ts)
            mp = self.rest.fetch_mark_price(inst)
            if mp:
                self.cache.set_mark_px(inst, mp)

        keep = {s.perp_inst_id, pair.call_inst_id, pair.put_inst_id}
        self.cache.drop_except(keep)
        self.ws.set_instruments([s.perp_inst_id, pair.call_inst_id, pair.put_inst_id])
        logger.info(
            "aligned pair expiry=%s strike=%s call=%s put=%s mark=%.2f",
            pair.expiry_ymd,
            pair.strike,
            pair.call_inst_id,
            pair.put_inst_id,
            mark,
        )
        return pair

    async def realign_async(self) -> OptionPair | None:
        old = self._pair
        pair = await asyncio.to_thread(self.align_instruments)
        if old is None or (
            pair
            and (
                pair.call_inst_id != old.call_inst_id
                or pair.put_inst_id != old.put_inst_id
            )
        ):
            await self.ws.resubscribe(
                [
                    self.settings.perp_inst_id,
                    pair.call_inst_id,
                    pair.put_inst_id,
                ]
            )
        return pair

    def _mark_for_atm(self) -> float | None:
        snap = self.snapshot()
        if snap.perp and snap.perp.mark_px:
            return float(snap.perp.mark_px)
        if snap.index_px:
            return float(snap.index_px)
        if snap.perp and snap.perp.bid and snap.perp.ask:
            return (float(snap.perp.bid) + float(snap.perp.ask)) / 2
        return None

    def atm_needs_realign(self, mark_px: float | None = None) -> bool:
        """到期日变了，或现价已偏离当前行权价超过阈值。"""
        if self._pair is None:
            return True
        want = next_session_expiry_ymd()
        if self._pair.expiry_ymd != want:
            return True
        mark = mark_px if mark_px is not None else self._mark_for_atm()
        if mark is None or mark <= 0:
            return False
        return abs(float(self._pair.strike) - float(mark)) >= _ATM_DRIFT_POINTS

    async def ensure_atm_async(self, *, force: bool = False) -> OptionPair | None:
        """空仓时按现价对齐 ATM。有持仓时不切换，避免盯市合约被换掉。"""
        if _has_open_position():
            return self._pair
        if force or self.atm_needs_realign():
            logger.info(
                "ATM realign force=%s old_strike=%s",
                force,
                self._pair.strike if self._pair else None,
            )
            return await self.realign_async()
        return self._pair

    def snapshot(self) -> MarketSnapshot:
        return self.cache.snapshot(self.settings.perp_inst_id)

    def snapshot_dict(self) -> dict[str, Any]:
        return self.snapshot().to_dict()

    async def _refresh_loop(self) -> None:
        """周期性刷新指数价；空仓时按到期/ATM 偏离重对齐。"""
        while True:
            await asyncio.sleep(30)
            try:
                idx = await asyncio.to_thread(
                    self.rest.fetch_index_ticker, self.settings.index_inst_id
                )
                self.cache.set_index_px(idx)
                mark = await asyncio.to_thread(
                    self.rest.fetch_mark_price, self.settings.perp_inst_id
                )
                if mark:
                    self.cache.set_mark_px(self.settings.perp_inst_id, mark)
                await self.ensure_atm_async(force=False)
            except asyncio.CancelledError:
                raise
            except Exception as e:
                logger.warning("market refresh failed: %s", e)


# 进程级单例（FastAPI lifespan 注入）
_gateway: MarketGateway | None = None


def get_gateway() -> MarketGateway:
    global _gateway
    if _gateway is None:
        _gateway = MarketGateway()
    return _gateway


def set_gateway(gw: MarketGateway | None) -> None:
    global _gateway
    _gateway = gw