"""
tiingo_provider.py — Tiingo top-of-book bid/ask quotes
======================================================

Supplementary LIVE-QUOTE provider, NOT an OHLCV source: Twelve Data
remains the signal/backtest data provider. Tiingo's forex endpoint
(GET /tiingo/fx/top) returns real bid/ask, which mid-price OHLCV
cannot provide. Two uses:

1. Spread visibility on alerts — signal messages show the live
   bid/ask and warn when the spread is ≥ WIDE_SPREAD_MULTIPLE × the
   assumed round-trip cost (PAIR_INFO ``default_spread``, $0.30 on
   XAU) that every backtest charges.

   Warn-only BY DESIGN: no historical bid/ask exists to replay, so a
   suppressing gate could never be validated (live == backtest rule).
   This sits in the same safety category as the staleness check.

2. Spread logging (logs/spread_log.csv, 5-min sampler in the bot) —
   builds the dataset to validate or refute the $0.30 round-trip
   assumption against reality.

Signals NEVER consume bid/ask — indicators stay on mid OHLCV. Every
failure path returns None (alerts go out without the spread block
rather than being delayed or dropped).

Key resolution: env TIINGO_API_KEY (or TIINGO, e.g. from .env) →
config.json data_providers.tiingo.api_key → "" (feature disabled).
See app_config.tiingo_api_key.
"""

import logging
import os
import threading
import time
from dataclasses import dataclass
from datetime import datetime, timezone
from typing import Dict, Optional

import requests

logger = logging.getLogger(__name__)

_TIINGO_FX_TOP_URL = "https://api.tiingo.com/tiingo/fx/top"

# Spread ≥ this multiple of the pair's assumed round-trip cost is
# flagged as "wide" on alerts (2× the $0.30 XAU assumption = $0.60).
WIDE_SPREAD_MULTIPLE = 2.0

# A quote younger than this is served from cache — dedupes bursts
# (alert refresh right after a sampler tick) without hiding real moves.
QUOTE_TTL_SECONDS = 10.0

SPREAD_LOG_PATH = os.path.join(
    os.path.dirname(os.path.abspath(__file__)), "logs", "spread_log.csv")
_CSV_HEADER = "ts_utc,symbol,bid,ask,mid,spread\n"


def tiingo_ticker(symbol: str) -> str:
    """Canonical '"XAU/USD"' form → Tiingo's 'xauusd'."""
    return symbol.replace("/", "").lower()


@dataclass
class Quote:
    """One top-of-book snapshot. ``spread`` (ask − bid) IS the
    round-trip cost a market order pays."""
    symbol: str                     # canonical form, e.g. "XAU/USD"
    bid: float
    ask: float
    mid: float
    spread: float
    quote_time: Optional[datetime]  # venue timestamp (UTC) if provided
    fetched_at: float               # time.time() at fetch

    def age_seconds(self) -> float:
        return time.time() - self.fetched_at


class TiingoQuoteProvider:
    """Minimal /tiingo/fx/top client with a short TTL cache.

    Lock held across the fetch (news_engine convention) so concurrent
    scan threads share one request instead of racing the API.
    """

    def __init__(self, api_key: str, quote_ttl: float = QUOTE_TTL_SECONDS):
        self.api_key = api_key
        self.quote_ttl = quote_ttl
        self._cache: Dict[str, Quote] = {}
        self._lock = threading.Lock()

    def get_quote(self, symbol: str) -> Optional[Quote]:
        with self._lock:
            cached = self._cache.get(symbol)
            if cached is not None and cached.age_seconds() < self.quote_ttl:
                return cached
            quote = self._fetch(symbol)
            if quote is not None:
                self._cache[symbol] = quote
            return quote

    def _fetch(self, symbol: str) -> Optional[Quote]:
        try:
            resp = requests.get(
                _TIINGO_FX_TOP_URL,
                params={"tickers": tiingo_ticker(symbol),
                        "token": self.api_key},
                timeout=10,
            )
            resp.raise_for_status()
            payload = resp.json()
            if not isinstance(payload, list) or not payload:
                logger.warning(
                    f"Tiingo: unexpected payload for {symbol}: {payload!r:.200}")
                return None
            row = payload[0]
            bid, ask = row.get("bidPrice"), row.get("askPrice")
            if not isinstance(bid, (int, float)) or not isinstance(ask, (int, float)):
                logger.warning(f"Tiingo: no bid/ask for {symbol}: {row!r:.200}")
                return None
            mid = row.get("midPrice")
            if not isinstance(mid, (int, float)):
                mid = (bid + ask) / 2
            quote_time: Optional[datetime] = None
            raw_ts = row.get("quoteTimestamp")
            if isinstance(raw_ts, str):
                try:
                    quote_time = datetime.fromisoformat(
                        raw_ts.replace("Z", "+00:00"))
                except ValueError:
                    pass
            return Quote(
                symbol=symbol, bid=float(bid), ask=float(ask),
                mid=float(mid), spread=float(ask) - float(bid),
                quote_time=quote_time, fetched_at=time.time(),
            )
        except Exception as exc:
            logger.warning(f"Tiingo quote fetch failed for {symbol}: {exc}")
            return None


def log_quote(quote: Quote, path: str = SPREAD_LOG_PATH) -> None:
    """Append one row to the spread log (creates dir + header on first
    write). ~15 KB/day at 5-min sampling — no rotation needed."""
    try:
        os.makedirs(os.path.dirname(path), exist_ok=True)
        is_new = not os.path.exists(path)
        with open(path, "a", encoding="utf-8") as fh:
            if is_new:
                fh.write(_CSV_HEADER)
            ts = datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ")
            fh.write(
                f"{ts},{quote.symbol},{quote.bid:.5f},{quote.ask:.5f},"
                f"{quote.mid:.5f},{quote.spread:.5f}\n")
    except OSError as exc:
        logger.warning(f"Spread log write failed: {exc}")