DinQuant/backend_api_python/app/services/symbol_name.py

"""
Symbol/company name resolver for local-only mode.

Goal:
- When a symbol is not present in our seed list, try to resolve a human-readable name
  from public data sources, then persist it into watchlist records.

Notes:
- For US stocks we use Finnhub (if configured) or yfinance.
- For Crypto/Forex/Futures we provide best-effort fallbacks.
"""

from __future__ import annotations

import os
from typing import Optional

import requests

from app.data.market_symbols_seed import get_symbol_name as seed_get_symbol_name
from app.utils.logger import get_logger

logger = get_logger(__name__)


def _normalize_symbol_for_market(market: str, symbol: str) -> str:
    s = (symbol or "").strip().upper()
    return s


def _resolve_name_from_yfinance(symbol: str) -> Optional[str]:
    """
    Best-effort company name via yfinance.
    """

    def _try_one(sym: str) -> Optional[str]:
        import yfinance as yf

        t = yf.Ticker(sym)
        info = getattr(t, "info", None)
        if not isinstance(info, dict) or not info:
            return None
        name = (info.get("longName") or info.get("shortName") or "").strip()
        return name if name else None

    try:
        # yfinance uses '-' for some tickers (e.g. BRK-B) while users may input 'BRK.B'
        out = _try_one(symbol)
        if out:
            return out
        if "." in symbol:
            out = _try_one(symbol.replace(".", "-"))
            if out:
                return out
        return None
    except Exception as e:
        logger.debug(f"yfinance name resolve failed: {symbol}: {e}")
        return None


def _resolve_name_from_finnhub(symbol: str) -> Optional[str]:
    """
    Finnhub company profile (requires FINNHUB_API_KEY).
    https://finnhub.io/docs/api/company-profile2
    """
    try:
        api_key = (os.getenv("FINNHUB_API_KEY") or "").strip()
        if not api_key:
            return None
        url = "https://finnhub.io/api/v1/stock/profile2"
        resp = requests.get(url, params={"symbol": symbol, "token": api_key}, timeout=8)
        if resp.status_code != 200:
            return None
        data = resp.json() if resp.text else {}
        if not isinstance(data, dict) or not data:
            return None
        name = (data.get("name") or data.get("ticker") or "").strip()
        return name if name else None
    except Exception as e:
        logger.debug(f"Finnhub name resolve failed: {symbol}: {e}")
        return None


def resolve_symbol_name(market: str, symbol: str) -> Optional[str]:
    """
    Resolve a display name for a symbol.
    Priority:
    1) Seed mapping (fast, offline)
    2) Market-specific public sources
    3) Reasonable fallback (None)
    """
    m = (market or "").strip()
    s = _normalize_symbol_for_market(m, symbol)
    if not m or not s:
        return None

    # 1) Seed
    seed = seed_get_symbol_name(m, s)
    if seed:
        return seed

    # 2) Market-specific
    if m == "USStock":
        # Prefer Finnhub if configured (more stable for company name),
        # otherwise fall back to yfinance.
        return _resolve_name_from_finnhub(s) or _resolve_name_from_yfinance(s)

    # Crypto: at least return base ticker-like display (not a "company", but better than empty)
    if m == "Crypto":
        if "/" in s:
            base = s.split("/")[0].strip()
            return base if base else None
        return s

    # Forex: keep as-is (e.g. EURUSD) – you can later replace with a nicer mapping if needed.
    if m == "Forex":
        return s

    # Futures: keep as-is
    if m == "Futures":
        return s

    return None