"""Activist event sleeve: hold fresh SC 13D targets, lab-engine evaluation.

Event study first (research/lab/activists.py): +1.2% CAR1 excess in S&P
400/600 (t 4.2), +2.2% CAR21 in the S&P 500 (t 2.2); low-SVR events beat
high-SVR events (+3.6% vs +0.8% CAR21).

Strategy: on each session, equal-weight all panel members whose SC 13D was
filed in the last H sessions (most recent K at most; daily rebalance to the
target basket, 20bp costs are built into the mid/small panels). PIT: the
weights row for day D includes filings with `filed <= D` and is executed at
the next open by the engine, i.e. after the filing is public.

    PYTHONPATH=. uv run python -m research.lab.activist_strategy [mid|small|midsmall|us]
"""
from __future__ import annotations

import json
import os
import pickle
import sys

import numpy as np
import pandas as pd

from research.lab.activists import cik_ticker_map
from research.lab.engine import simulate
from research.lab.factor_scan import stats

TARGETS = "data/research/edgar_13d_targets.csv"
SVR_PATH = "data/research/short_volume.pkl"


def load_events() -> pd.DataFrame:
    tg = pd.read_csv(TARGETS)
    tg = tg[tg["target_cik"].fillna(0) > 0].copy()
    cik2t = cik_ticker_map()
    tg["ticker"] = tg["target_cik"].map(lambda c: cik2t.get(int(c)))
    tg = tg[tg["ticker"].notna()]
    # fallback by exact name
    if os.path.exists("data/research/company_tickers.json"):
        raw = json.load(open("data/research/company_tickers.json"))
        by_name = {str(v["title"]).strip().upper(): str(v["ticker"]).upper().replace(".", "-")
                   for v in raw.values()}
        miss = tg["ticker"].isna()
        tg.loc[miss, "ticker"] = tg.loc[miss, "target_name"].str.strip().str.upper().map(by_name)
    tg = tg.sort_values("filed").drop_duplicates(subset=["ticker", "filed"], keep="first")
    return tg[["ticker", "filed"]].dropna()


def svr21() -> pd.DataFrame | None:
    if not os.path.exists(SVR_PATH):
        return None
    with open(SVR_PATH, "rb") as fh:
        d = pickle.load(fh)
    return (d["short"] / d["total"].replace(0.0, np.nan)).rolling(21, min_periods=10).mean()


def build_weights(p, events: pd.DataFrame, hold: int, k_max: int,
                  svr_filter: str | None = None, svr_lag: int = 2) -> pd.DataFrame:
    dates = p.dates
    cols = list(p.close.columns)
    pos = {c: i for i, c in enumerate(cols)}
    W = np.zeros((len(dates), len(cols)))
    svr = svr21()
    if svr is not None:
        svr = svr.reindex(columns=cols).shift(svr_lag)
        med = svr.where(p.member).median(axis=1)

    acts: list[tuple[int, int]] = []  # (start_idx, end_idx, col_idx)
    for _, ev in events.iterrows():
        i = pos.get(ev["ticker"])
        if i is None:
            continue
        t0 = dates.searchsorted(pd.Timestamp(ev["filed"]), side="left")
        if t0 >= len(dates) - 2:
            continue
        start, end = t0 + 1, min(t0 + 1 + hold, len(dates) - 1)
        if svr_filter and svr is not None and dates[t0] in svr.index:
            v = svr.at[dates[t0], ev["ticker"]] if ev["ticker"] in svr.columns else np.nan
            m = med.get(dates[t0], np.nan)
            if np.isfinite(v) and np.isfinite(m):
                if svr_filter == "low" and v >= m:
                    continue
                if svr_filter == "high" and v < m:
                    continue
        acts.append((start, end, i))
    if not acts:
        return pd.DataFrame(0.0, index=dates, columns=cols)
    starts = np.array([a[0] for a in acts])
    ends = np.array([a[1] for a in acts])
    idx = np.array([a[2] for a in acts])
    for d in range(len(dates)):
        active = np.where((starts <= d) & (d <= ends))[0]
        if len(active) == 0:
            continue
        if k_max and len(active) > k_max:
            active = active[np.argsort(-starts[active])][:k_max]  # most recent filings
        W[d, idx[active]] = 1.0 / len(active)
    return pd.DataFrame(W, index=dates, columns=cols)


def run(mkt: str, events: pd.DataFrame, hold: int, k_max: int,
        svr_filter: str | None = None) -> dict:
    if mkt == "us":
        with open("data/research/us.panel.pkl", "rb") as fh:
            p = pickle.load(fh)
    else:
        from research.lab.panel_mid import load_us_mid
        p = load_us_mid(mkt)
    W = build_weights(p, events, hold, k_max, svr_filter)
    r = simulate(p, target_weights=W, exec_at="open", min_trade=0.002)
    blocks = {}
    for a, b in (("2016-09-27", "2021-09-26"), ("2021-09-27", "2026-09-24")):
        st = stats(r.equity.loc[a:b], r.turnover.loc[a:b])
        blocks[f"{a[:4]}-{b[:4]}"] = st
    return {"mkt": mkt, "hold": hold, "k": k_max, "svr": svr_filter or "none",
            "blocks": blocks}


def main() -> None:
    mkts = sys.argv[1:] or ["midsmall"]
    events = load_events()
    print(f"events loaded: {len(events)}")
    results = []
    for mkt in mkts:
        for hold, k_max, svr_filter in ((21, 20, None), (21, 20, "low"), (63, 20, None),
                                        (63, 20, "low"), (21, 10, None), (21, 10, "low")):
            res = run(mkt, events, hold, k_max, svr_filter)
            results.append(res)
            line = f"{mkt:8s} H{hold:<3d} K{k_max:<3d} svr={res['svr']:4s}"
            for blk, st in res["blocks"].items():
                line += f" | {blk} cagr {st['cagr']*100:5.1f}% sh {st['sharpe']:5.2f} mdd {st['mdd']*100:5.1f}%"
            print(line)
    json.dump(results, open("data/research/results/activist_sleeve.json", "w"), indent=1)
    print("saved data/research/results/activist_sleeve.json")


if __name__ == "__main__":
    main()