"""Nav bar BTC/ETH tickers vs Beijing 08:00 open.

OKX:
  sodUtc0 / candle 1Dutc = UTC+0 open = Beijing 08:00  ← use this
  sodUtc8 / candle 1D    = UTC+8 open = Beijing 00:00  (default OKX daily K)
"""

from __future__ import annotations

from datetime import datetime, timedelta
from typing import Any, Callable, Optional
from zoneinfo import ZoneInfo

BJ = ZoneInfo("Asia/Shanghai")

ANCHOR_SOD_FIELD = "sodUtc0"
ANCHOR_CANDLE_BAR = "1Dutc"
ANCHOR_LABEL = "BJ 08:00"

# (base, display, swap instId, spot instId, ccxt swap symbol)
NAV_SPOT_SPECS = (
    ("ETH", "ETHUSDT", "ETH-USDT-SWAP", "ETH-USDT", "ETH/USDT:USDT"),
    ("BTC", "BTCUSDT", "BTC-USDT-SWAP", "BTC-USDT", "BTC/USDT:USDT"),
)


def _safe_float(v: Any) -> Optional[float]:
    try:
        if v is None or v == "":
            return None
        return float(v)
    except (TypeError, ValueError):
        return None


def session_day_key(now: Optional[datetime] = None, reset_hour: int = 8) -> str:
    """Trading day key: before reset_hour BJ belongs to previous calendar day."""
    dt = now or datetime.now(BJ)
    if dt.tzinfo is None:
        dt = dt.replace(tzinfo=BJ)
    else:
        dt = dt.astimezone(BJ)
    if dt.hour < int(reset_hour):
        dt = dt - timedelta(days=1)
    return dt.strftime("%Y-%m-%d")


def _ticker_row(ex: Any, inst_id: str) -> Optional[dict[str, Any]]:
    try:
        rows = ex.public_get_market_ticker({"instId": inst_id}).get("data") or []
        if rows and isinstance(rows[0], dict):
            return rows[0]
    except Exception:
        pass
    return None


def _candle_open(ex: Any, inst_id: str, bar: str) -> Optional[float]:
    """OKX candles: newest first; [ts, o, h, l, c, ...]."""
    try:
        rows = ex.public_get_market_candles(
            {"instId": inst_id, "bar": bar, "limit": "1"}
        ).get("data") or []
        if rows and isinstance(rows[0], (list, tuple)) and len(rows[0]) > 1:
            return _safe_float(rows[0][1])
    except Exception:
        pass
    return None


def _ccxt_last_and_anchor_open(ex: Any, symbol: str) -> tuple[Optional[float], Optional[float]]:
    last = None
    open_px = None
    try:
        t = ex.fetch_ticker(symbol) or {}
        last = _safe_float(t.get("last") or t.get("close"))
        info = t.get("info") if isinstance(t.get("info"), dict) else {}
        open_px = _safe_float(info.get(ANCHOR_SOD_FIELD))
    except Exception:
        pass
    return last, open_px


def _fetch_last_and_open(
    ex: Any, swap_inst: str, spot_inst: str, swap_sym: str
) -> tuple[Optional[float], Optional[float]]:
    """Same instrument last + Beijing 08:00 open. Prefer USDT SWAP."""
    for inst in (swap_inst, spot_inst):
        row = _ticker_row(ex, inst)
        if not row:
            continue
        last = _safe_float(row.get("last"))
        open_px = _safe_float(row.get(ANCHOR_SOD_FIELD))
        if open_px is None:
            open_px = _candle_open(ex, inst, ANCHOR_CANDLE_BAR)
        if last is not None and open_px is not None:
            return last, open_px

    last, open_px = _ccxt_last_and_anchor_open(ex, swap_sym)
    if last is not None and open_px is not None:
        return last, open_px

    last, open_px = _ccxt_last_and_anchor_open(ex, spot_inst.replace("-", "/"))
    if last is not None and open_px is not None:
        return last, open_px

    for inst, sym in ((swap_inst, swap_sym), (spot_inst, spot_inst.replace("-", "/"))):
        row = _ticker_row(ex, inst)
        last = _safe_float(row.get("last")) if row else None
        if last is None:
            last, _ = _ccxt_last_and_anchor_open(ex, sym)
        open_px = _candle_open(ex, inst, ANCHOR_CANDLE_BAR)
        if last is not None and open_px is not None:
            return last, open_px
    return None, None


def build_nav_spot_tickers(
    exchange: Any,
    *,
    reset_hour: int = 8,
    now_fn: Optional[Callable[[], datetime]] = None,
) -> list[dict[str, Any]]:
    """Return ETH then BTC last/change vs Beijing 08:00 open (sodUtc0)."""
    now = now_fn() if now_fn else datetime.now(BJ)
    day_key = session_day_key(now, reset_hour=reset_hour)
    out: list[dict[str, Any]] = []
    for base, display, swap_inst, spot_inst, swap_sym in NAV_SPOT_SPECS:
        last, open_px = _fetch_last_and_open(exchange, swap_inst, spot_inst, swap_sym)
        change = None
        change_pct = None
        if last is not None and open_px is not None and open_px != 0:
            change = last - open_px
            change_pct = (change / open_px) * 100.0
        out.append(
            {
                "base": base,
                "inst_id": swap_inst,
                "symbol": display,
                "last": round(last, 8) if last is not None else None,
                "open": round(open_px, 8) if open_px is not None else None,
                "change": round(change, 8) if change is not None else None,
                "change_pct": round(change_pct, 4) if change_pct is not None else None,
                "session_day": day_key,
                "anchor": ANCHOR_LABEL,
                "anchor_field": ANCHOR_SOD_FIELD,
            }
        )
    return out