"""Market regime snapshot — computed in code (deterministic, no LLM), injected into every
agent's kickoff so all three personas share the same ground truth about the tape.

Covers: SPY trend (5/20/50d), VIX level, and sector ETF momentum ranking (20d).
"""

from __future__ import annotations

from loguru import logger

_SECTORS = {
    "XLK": "Tech", "XLF": "Financials", "XLE": "Energy", "XLV": "Health",
    "XLY": "Cons.Disc", "XLP": "Staples", "XLI": "Industrials", "XLU": "Utilities",
    "XLB": "Materials", "XLC": "Comms",
}


def _pct(series, days: int) -> float | None:
    try:
        if len(series) <= days:
            return None
        return float((series.iloc[-1] / series.iloc[-1 - days] - 1) * 100)
    except Exception:
        return None


def market_regime() -> str:
    """One compact paragraph describing the current tape. Empty string on failure."""
    try:
        import yfinance as yf

        data = yf.download(
            ["SPY", "^VIX", *_SECTORS], period="4mo", interval="1d",
            progress=False, group_by="ticker", threads=True,
        )
        spy = data["SPY"]["Close"].dropna()
        r5, r20, r50 = _pct(spy, 5), _pct(spy, 20), _pct(spy, 50)
        trend = "uptrend" if (r20 or 0) > 0 and (r50 or 0) > 0 else (
            "downtrend" if (r20 or 0) < 0 and (r50 or 0) < 0 else "mixed/chop")

        try:
            vix = float(data["^VIX"]["Close"].dropna().iloc[-1])
            vol = "low" if vix < 15 else ("elevated" if vix < 25 else "HIGH — risk-off")
            vix_s = f"VIX {vix:.1f} ({vol} volatility)"
        except Exception:
            vix_s = "VIX unavailable"

        sect = []
        for etf, name in _SECTORS.items():
            try:
                r = _pct(data[etf]["Close"].dropna(), 20)
                if r is not None:
                    sect.append((name, r))
            except Exception:
                continue
        sect.sort(key=lambda x: x[1], reverse=True)
        leaders = ", ".join(f"{n} {r:+.1f}%" for n, r in sect[:3])
        laggards = ", ".join(f"{n} {r:+.1f}%" for n, r in sect[-3:])

        return (
            f"MARKET REGIME (computed now): SPY {trend} — 5d {r5:+.1f}%, 20d {r20:+.1f}%, "
            f"50d {r50:+.1f}%. {vix_s}. Sector momentum (20d): leaders {leaders}; "
            f"laggards {laggards}."
        )
    except Exception as e:
        logger.warning("regime snapshot failed: {}", e)
        return ""