"""SIMULAZIONE — PREVDAY come overlay di tail-hedge sul portafoglio attivo (NON deploy).

PREVDAY (src/strategies/prevday_breakout) resta in FORWARD-MONITOR. Qui misuriamo SOLO, in
simulazione, cosa farebbe al portafoglio live (TP01 55% + XS01 25% + VRP01 20%) aggiungerlo come
overlay a peso W, riscalando i tre sleeve esistenti a (1-W) e tenendo le loro proporzioni. La
trilogia (fill-haircut/turnover/bootstrap) ha stabilito che PREVDAY e' un HEDGE di regime-down
(tutto il valore = gamba short) eseguibile a taglia reale: l'overlay si giudica sul TAGLIO DEL
DRAWDOWN del portafoglio, non sul ritorno.

NB outer-join: PREVDAY parte dal 2018, XS01 dal 2024, VRP01 dal 2021. I pesi sono rinormalizzati
ogni giorno fra i soli sleeve con dato -> nel 2019-20 (solo TP01+PREVDAY) PREVDAY pesa di piu' del
target W; nell'hold-out 2025+ (tutti e 4 attivi) pesa esattamente ~W. Per questo l'HOLD-OUT e' il
confronto piu' pulito a "peso 10%".

    uv run python scripts/portfolio/prevday_overlay.py
"""
from __future__ import annotations
import sys
from pathlib import Path

PROJECT_ROOT = Path(__file__).resolve().parents[2]
sys.path.insert(0, str(PROJECT_ROOT))
import numpy as np
import pandas as pd

from src.backtest.harness import load
from src.strategies import prevday_breakout as pb
from src.portfolio.portfolio import StrategyPortfolio, Sleeve, metrics, HOLDOUT
from src.portfolio.sleeves import _tp01_returns, _xsec_returns, _vrp_combo_returns

ASSETS = ("BTC", "ETH")
FEE_SIDE = 0.0005
BASE_W = dict(TP01=0.55, XS01=0.25, VRP01=0.20)   # proporzioni dei tre sleeve attivi
HEADLINE = 0.10


def _prevday_returns() -> pd.Series:
    """Rendimenti netti per-barra (1h) del libro PREVDAY 50/50 BTC+ETH (parametri congelati)."""
    series = {}
    for a in ASSETS:
        df = load(a, "1h").reset_index(drop=True)
        c = df["close"].values.astype(float)
        r = np.zeros(len(c)); r[1:] = c[1:] / c[:-1] - 1.0
        tgt = np.nan_to_num(pb.target(df), nan=0.0)
        held = np.zeros(len(tgt)); held[1:] = tgt[:-1]
        net = held * r - FEE_SIDE * np.abs(np.diff(tgt, prepend=tgt[0]))
        series[a] = pd.Series(net, index=pd.to_datetime(df["datetime"], utc=True))
    J = pd.concat(series, axis=1, join="inner").fillna(0.0)
    return pd.Series(0.5 * J.iloc[:, 0].values + 0.5 * J.iloc[:, 1].values, index=J.index)


def build_portfolio(series_cache: dict, w_prev: float) -> StrategyPortfolio:
    """Portafoglio coi 3 sleeve riscalati a (1-w_prev) + PREVDAY a w_prev (0 = baseline)."""
    sl = [
        Sleeve("TP01_trend_1d", BASE_W["TP01"] * (1 - w_prev), lambda s=series_cache["TP01"]: s),
        Sleeve("XS01_xsec_hl", BASE_W["XS01"] * (1 - w_prev), lambda s=series_cache["XS01"]: s),
        Sleeve("VRP01_shortvol", BASE_W["VRP01"] * (1 - w_prev), lambda s=series_cache["VRP01"]: s),
    ]
    if w_prev > 0:
        sl.append(Sleeve("PREVDAY_hedge", w_prev, lambda s=series_cache["PREVDAY"]: s))
    return StrategyPortfolio(sl)


def line(label, m):
    return (f"  {label:<22s} Sh {m['sharpe']:>5.2f} | ret {m['ret']*100:>+8.1f}% "
            f"CAGR {m['cagr']*100:>+6.1f}% | DD {m['maxdd']*100:>5.1f}% | n {m['n']}")


def main():
    print("=" * 92)
    print("  PREVDAY OVERLAY (simulazione, NON deploy) — tail-hedge sul portafoglio TP01+XS01+VRP01")
    print("=" * 92)
    print("  Precalcolo sleeve...", flush=True)
    cache = dict(TP01=_tp01_returns(), XS01=_xsec_returns(),
                 VRP01=_vrp_combo_returns(), PREVDAY=_prevday_returns())

    print(f"\n  PREVDAY standalone (per riferimento):")
    from src.portfolio.portfolio import to_daily
    pvd = to_daily(cache["PREVDAY"])
    print(line("PREVDAY full", metrics(pvd)))
    print(line("PREVDAY hold-out", metrics(pvd[pvd.index >= HOLDOUT])))

    print(f"\n  SWEEP PESO OVERLAY (FULL | HOLD-OUT) — headline {HEADLINE*100:.0f}%:")
    print(f"  {'peso PREVDAY':<14s} {'FULL Sharpe':>11s} {'FULL DD':>9s} | {'HOLD Sharpe':>11s} {'HOLD DD':>9s} {'HOLD ret':>9s}")
    rows = {}
    for w in (0.0, 0.05, 0.10, 0.15, 0.20):
        bt = build_portfolio(cache, w).backtest()
        rows[w] = bt
        tag = "BASELINE" if w == 0 else f"{w*100:.0f}%"
        star = "  <-- headline" if abs(w - HEADLINE) < 1e-9 else ""
        print(f"  {tag:<14s} {bt['full']['sharpe']:>11.2f} {bt['full']['maxdd']*100:>8.1f}% | "
              f"{bt['holdout']['sharpe']:>11.2f} {bt['holdout']['maxdd']*100:>8.1f}% "
              f"{bt['holdout']['ret']*100:>+8.1f}%{star}")

    base, ov = rows[0.0], rows[HEADLINE]
    print(f"\n  DETTAGLIO a {HEADLINE*100:.0f}% vs BASELINE:")
    print(line("BASELINE   FULL", base['full']));   print(line(f"OVERLAY{HEADLINE*100:.0f}% FULL", ov['full']))
    print(line("BASELINE   HOLD", base['holdout'])); print(line(f"OVERLAY{HEADLINE*100:.0f}% HOLD", ov['holdout']))
    dSh = ov['holdout']['sharpe'] - base['holdout']['sharpe']
    dDD = (ov['holdout']['maxdd'] - base['holdout']['maxdd']) * 100
    print(f"\n  >> HOLD-OUT: ΔSharpe {dSh:+.2f}  |  ΔmaxDD {dDD:+.1f}pp  "
          f"(tail-hedge = ci aspettiamo DD piu' basso)")

    print(f"\n  PER ANNO (baseline -> overlay {HEADLINE*100:.0f}%): ret%  /  DD%")
    yb, yo = base['yearly'], ov['yearly']
    for y in sorted(set(yb) | set(yo)):
        b = yb.get(y, {}); o = yo.get(y, {})
        print(f"    {y}: ret {b.get('ret',0)*100:>+7.1f}% -> {o.get('ret',0)*100:>+7.1f}%   "
              f"DD {b.get('dd',0)*100:>5.1f}% -> {o.get('dd',0)*100:>5.1f}%")
    print("=" * 92)
    print("  Nota: PREVDAY resta FORWARD-MONITOR. Questa e' una simulazione di impatto, non un deploy.")


if __name__ == "__main__":
    main()