feat: option

backend/services/option_chain.py

@@ -41,6 +41,32 @@ def _rows_from_df(df) -> List[Dict[str, Any]]:
 
 
 def get_chain_slice(symbol: str, target_days: int = 8, n_expiries: int = 3) -> Dict[str, Any]:
+    """
+    Fetch the real option chain for `symbol` — yfinance by default, with an automatic
+    Saxo fallback for instruments yfinance can't handle (FX/futures options).
+
+    Dispatch: a Saxo-formatted symbol (exchange suffix, e.g. "OG:xcme") goes straight to
+    Saxo; otherwise yfinance is tried first (unchanged, proven path for stocks/ETFs), and
+    only falls back to Saxo if yfinance fails AND a Saxo connection is available.
+    """
+    if ":" in symbol:
+        from services.saxo_client import get_chain_slice_saxo
+        return get_chain_slice_saxo(symbol, target_days, n_expiries)
+
+    try:
+        return _get_chain_slice_yfinance(symbol, target_days, n_expiries)
+    except ValueError:
+        from services import saxo_auth
+        from services.saxo_client import get_chain_slice_saxo
+        if saxo_auth.get_status().get("connected"):
+            try:
+                return get_chain_slice_saxo(symbol, target_days, n_expiries)
+            except Exception as e:
+                logger.debug(f"[OptionChain] Saxo fallback failed for {symbol}: {e}")
+        raise
+
+
+def _get_chain_slice_yfinance(symbol: str, target_days: int = 8, n_expiries: int = 3) -> Dict[str, Any]:
     """
     Fetch the real option chain for `symbol` around a target horizon (days).
     Returns the `n_expiries` expirations closest to target_days, each with