"""
Saxo-first pricing for Portfolio positions — options legs are priced off this Cockpit's own
accumulated Saxo option-chain history (services.option_chain, services.vol_surface) whenever
the position's underlying has a saxo_option_symbol link in the Watchlist (Config ->
Instruments Watchlist -> "Option"), the SAME real market data Options Lab and Strategy
Builder already use. Mirrors services.strategy_engine.entry_price()'s own two-tier pattern:
an exact Saxo bid/ask quote for the listed contract if one happens to exist ("saxo_quote"),
else the real Saxo-fitted vol smile (services.vol_surface.Surface) priced through
Black-Scholes ("saxo_surface") — both grounded in real Saxo data, unlike the previous
unconditional fallback to yfinance's historical realized vol as a stand-in for implied vol
("yfinance_bs"), which is what silently produced a materially different premium than Saxo's
real chain (27.2% yfinance-historical vs Saxo's real ~32% chain IV on the ^NDX example that
prompted this).

An exact "saxo_quote" match is rare in practice: positions carry a nominal expiry_date/
expiry_days the AI or user chose freely, not necessarily a real listed Saxo expiry — so
most legs land on "saxo_surface" (real Saxo-implied vol, interpolated to the requested
strike/tenor) rather than a literal listed-contract quote. That's still a real improvement
over yfinance historical vol, and every priced leg carries its `source` so the Portfolio UI
can say plainly which basis was used instead of always labeling everything "Black-Scholes"
regardless of where the inputs actually came from.
"""
from typing import Any, Dict, Optional, Tuple

from services.options_pricer import black_scholes


def resolve_saxo_chain(underlying: str, target_days: int) -> Tuple[Optional[Dict[str, Any]], Optional[Any]]:
    """Returns (chain_slice, Surface) for this underlying's linked Saxo option chain, or
    (None, None) if it isn't linked, or the chain can't be built right now (Saxo down, no
    snapshot yet, entitlement gap, etc.) — callers fall back to yfinance pricing in that case."""
    from services.database import get_saxo_option_symbol_for_ticker
    saxo_symbol = get_saxo_option_symbol_for_ticker(underlying)
    if not saxo_symbol:
        return None, None
    try:
        from services.option_chain import get_chain_slice
        from services.vol_surface import Surface
        chain = get_chain_slice(saxo_symbol, target_days=max(target_days, 1))
        if not chain.get("spot"):
            return None, None
        surface = Surface(chain["spot"], chain["expiries"])
        return chain, surface
    except Exception:
        return None, None


def price_leg(
    strike: float, option_type: str, days_to_expiry: float, r: float,
    chain: Optional[Dict[str, Any]], surface: Optional[Any], expiry_date: Optional[str],
    fallback_spot: float, fallback_sigma: float,
) -> Dict[str, Any]:
    """One leg's {price, spot, sigma, source}."""
    T = max(days_to_expiry, 1) / 365
    if chain is not None and surface is not None:
        quote = None
        if expiry_date:
            from services.option_chain import find_quote
            quote = find_quote(chain, expiry_date, strike, option_type)
        if quote and quote.get("bid", 0) > 0 and quote.get("ask", 0) > 0:
            return {"price": quote["mid"], "spot": chain["spot"], "sigma": quote["iv"], "source": "saxo_quote"}
        sigma = surface.iv_at(strike, max(days_to_expiry, 1))
        price = black_scholes(chain["spot"], strike, T, r, sigma, option_type)["price"]
        return {"price": price, "spot": chain["spot"], "sigma": sigma, "source": "saxo_surface"}
    price = black_scholes(fallback_spot, strike, T, r, fallback_sigma, option_type)["price"]
    return {"price": price, "spot": fallback_spot, "sigma": fallback_sigma, "source": "yfinance_bs"}


SOURCE_LABELS = {
    "saxo_quote": "Cotation Saxo réelle",
    "saxo_surface": "Surface de vol Saxo (réelle)",
    "yfinance_bs": "Black-Scholes (vol historique yfinance)",
}


def _intrinsic(S: float, K: float, option_type: str) -> float:
    return max(0.0, S - K) if option_type == "call" else max(0.0, K - S)


def compute_payoff(pos: Dict[str, Any], n_points: int = 61, range_pct: float = 0.25) -> Dict[str, Any]:
    """P&L vs. underlying price across a ±range_pct band around the current spot — two
    curves: "at_expiry" (pure intrinsic value, no vol at all — the textbook payoff diagram)
    and "today" (Black-Scholes reprice at each hypothetical spot, holding each leg's
    CURRENT implied vol fixed — from the real Saxo surface when linked, so the time-value
    bulge/skew asymmetry actually reflects Saxo's real market vol instead of a flat
    textbook number). Both curves net out entry cost and entry fees, so y=0 is genuine
    breakeven, matching what the Position card's PnL already shows at the current spot."""
    from datetime import date, datetime
    from services.data_fetcher import get_quote

    underlying = pos["underlying"]
    legs = pos.get("legs", [])
    if not legs:
        return {"spot_range": [], "at_expiry": [], "today": [], "current_spot": None,
                "entry_spot": pos.get("entry_underlying_price"), "strikes": [], "pricing_source": None}

    expiry_date = pos.get("expiry_date") or ""
    if expiry_date:
        try:
            exp = datetime.strptime(expiry_date[:10], "%Y-%m-%d").date()
            days_remaining = max(0, (exp - date.today()).days)
        except ValueError:
            days_remaining = 0
    else:
        entry = datetime.strptime(pos["entry_date"][:10], "%Y-%m-%d").date()
        days_remaining = max(0, pos.get("expiry_days", 90) - (date.today() - entry).days)

    r = 0.05
    chain, surface = resolve_saxo_chain(underlying, target_days=max(days_remaining, 1))
    fallback_spot = pos.get("entry_underlying_price") or 100.0
    fallback_sigma = 0.20
    if chain is None:
        q = get_quote(underlying)
        fallback_spot = (q.get("price") if q else None) or fallback_spot
        from services.data_fetcher import compute_historical_iv
        fallback_sigma = compute_historical_iv(underlying)
    S = chain["spot"] if chain else fallback_spot

    resolved_legs = []
    for leg in legs:
        K = leg.get("strike") or S
        opt_type = leg.get("option_type", "call")
        entry_premium = leg.get("premium_paid")
        if entry_premium is None:
            entry_premium = price_leg(K, opt_type, pos.get("expiry_days", 90), r, chain, surface,
                                       expiry_date, fallback_spot, fallback_sigma)["price"]
        priced_now = price_leg(K, opt_type, days_remaining, r, chain, surface, expiry_date, fallback_spot, fallback_sigma)
        resolved_legs.append({
            "strike": K, "option_type": opt_type, "qty": leg.get("quantity", 1),
            "sign": 1 if leg.get("position", "long") == "long" else -1,
            "entry_premium": entry_premium, "sigma": priced_now["sigma"],
        })

    ib_entry = pos.get("ib_fees_entry", 0)
    lo, hi = S * (1 - range_pct), S * (1 + range_pct)
    spot_range = [lo + (hi - lo) * i / (n_points - 1) for i in range(n_points)]
    T_remaining = days_remaining / 365

    at_expiry, today = [], []
    for Sx in spot_range:
        pnl_exp = -ib_entry
        pnl_today = -ib_entry
        for leg in resolved_legs:
            pnl_exp += leg["sign"] * leg["qty"] * 100 * (_intrinsic(Sx, leg["strike"], leg["option_type"]) - leg["entry_premium"])
            bs_price = (black_scholes(Sx, leg["strike"], T_remaining, r, leg["sigma"], leg["option_type"])["price"]
                        if T_remaining > 0 else _intrinsic(Sx, leg["strike"], leg["option_type"]))
            pnl_today += leg["sign"] * leg["qty"] * 100 * (bs_price - leg["entry_premium"])
        at_expiry.append(round(pnl_exp, 2))
        today.append(round(pnl_today, 2))

    return {
        "spot_range": [round(s, 4) for s in spot_range],
        "at_expiry": at_expiry,
        "today": today,
        "current_spot": round(S, 4),
        "entry_spot": pos.get("entry_underlying_price"),
        "strikes": sorted({leg["strike"] for leg in resolved_legs}),
        "pricing_source": "saxo" if chain else "yfinance_bs",
    }