"""SC 13D activist-event study on the PIT US panels.

Event: a new SC 13D filing (originals only; /A amendments excluded; 13G
passive stakes tracked separately) for a company whose CIK maps to a ticker
in the panel universe. EDGAR disseminates same-day, so the conservative
trade date is the next session; CARs run from close(t0) where t0 = first
session at/after the filing date.

Reports market-adjusted forward returns (event minus same-panel member mean,
same window) over 1/5/21/63 sessions, split 13D vs 13G, with yearly means,
plus conditioning on 63d momentum quintile and SVR (short-volume ratio)
tercile to test the squeeze reading.

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

import json
import os
import pickle
import sys

import numpy as np
import pandas as pd
import requests

from research.lab.fetch_us import _proxy_env

EVENTS_CSV = "data/research/edgar_13d.csv"
TICKERS_CACHE = "data/research/company_tickers.json"
UA = {"User-Agent": "quant-research/0.1 gahow@example.com", "Accept-Encoding": "gzip"}
HORIZONS = (1, 5, 21, 63)


def cik_ticker_map() -> dict[int, str]:
    if not os.path.exists(TICKERS_CACHE):
        r = requests.get("https://www.sec.gov/files/company_tickers.json", headers=UA, timeout=60)
        r.raise_for_status()
        json.dump(r.json(), open(TICKERS_CACHE, "w"))
    raw = json.load(open(TICKERS_CACHE))
    out = {}
    for v in raw.values():
        t = str(v["ticker"]).upper().replace(".", "-")
        out.setdefault(int(v["cik_str"]), t)
    return out


def load_svr() -> pd.DataFrame | None:
    path = "data/research/short_volume.pkl"
    if not os.path.exists(path):
        return None
    with open(path, "rb") as fh:
        d = pickle.load(fh)
    return d["short"] / d["total"].replace(0.0, np.nan)


def run(name: str, close: pd.DataFrame, member: pd.DataFrame,
        events: pd.DataFrame, svr: pd.DataFrame | None) -> dict:
    close = close.ffill()
    member = member.reindex_like(close).fillna(False)
    idx = close.index
    rets = close.pct_change(fill_method=None)
    # cross-sectional member mean daily return (market proxy)
    mkt = rets.where(member).mean(axis=1)
    cum = (1 + rets.fillna(0.0)).cumprod()
    cum_mkt = (1 + mkt.fillna(0.0)).cumprod()

    mom = close.pct_change(63)
    svr21 = svr.rolling(21, min_periods=10).mean() if svr is not None else None

    rows = []
    for _, ev in events.iterrows():
        t = ev["ticker"]
        if t not in close.columns:
            continue
        pos = idx.searchsorted(pd.Timestamp(ev["filed"]), side="left")
        if pos >= len(idx) - max(HORIZONS) - 1:
            continue
        t0 = idx[pos]
        if not bool(member.at[t0, t]):
            continue
        svr_val = np.nan
        if svr21 is not None and t in svr21.columns and t0 in svr21.index:
            v = svr21.at[t0, t]
            if np.isfinite(v):
                svr_val = float(v)
        mom_val = mom.at[t0, t] if t in mom.columns else np.nan
        entry = {"form": ev["form"], "ticker": t, "date": t0, "cik": ev["cik"],
                 "mom": float(mom_val) if np.isfinite(mom_val) else np.nan,
                 "svr": svr_val}
        for h in HORIZONS:
            r = float(cum.iloc[pos + h][t] / cum.iloc[pos][t] - 1.0)
            rm = float(cum_mkt.iloc[pos + h] / cum_mkt.iloc[pos] - 1.0)
            entry[f"car{h}"] = r - rm
        rows.append(entry)
    df = pd.DataFrame(rows)
    print(f"\n=== {name}: {len(df)} events mapped to panel "
          f"({df['date'].min().date() if len(df) else '-'}..{df['date'].max().date() if len(df) else '-'}) ===")
    out = {"universe": name, "n_events": len(df)}
    if len(df) == 0:
        return out
    for form in ("SC 13D", "SC 13G"):
        sub = df[df["form"] == form]
        if len(sub) < 30:
            continue
        line = [f"{form:7s} n={len(sub):5d}"]
        for h in HORIZONS:
            x = sub[f"car{h}"].dropna()
            t = x.mean() / x.std() * np.sqrt(len(x)) if len(x) > 1 else np.nan
            line.append(f"CAR{h}: {x.mean()*100:5.2f}% (t {t:4.1f}, hit {np.mean(x>0)*100:4.0f}%)")
        print("  " + "  ".join(line))
        out[form] = {f"car{h}": {"mean": float(sub[f'car{h}'].mean()),
                                 "t": float(sub[f'car{h}'].mean() / sub[f'car{h}'].std() * np.sqrt(len(sub))),
                                 "hit": float((sub[f'car{h}'] > 0).mean())} for h in HORIZONS}
        yr = sub.groupby(sub["date"].dt.year)["car21"].mean()
        print("    yearly CAR21: " + " ".join(f"{y}:{v*100:+.0f}%" for y, v in yr.items()))
    # conditioning on momentum / svr (13D only)
    d13 = df[df["form"] == "SC 13D"].copy()
    if len(d13) >= 100:
        d13["mom_q"] = d13["mom"].rank(pct=True)
        hi, lo = d13[d13["mom_q"] > 0.66], d13[d13["mom_q"] < 0.34]
        if len(hi) > 20 and len(lo) > 20:
            print(f"    13D x momentum: hi-mom CAR21 {hi['car21'].mean()*100:5.2f}% (n={len(hi)}) "
                  f"| lo-mom CAR21 {lo['car21'].mean()*100:5.2f}% (n={len(lo)})")
            out["13D_mom_hi_car21"] = float(hi["car21"].mean())
            out["13D_mom_lo_car21"] = float(lo["car21"].mean())
        if d13["svr"].notna().sum() > 100:
            d13["svr_t"] = d13["svr"].rank(pct=True)
            hi, lo = d13[d13["svr_t"] > 0.66], d13[d13["svr_t"] < 0.34]
            if len(hi) > 20 and len(lo) > 20:
                print(f"    13D x SVR: hi-fails-short CAR21 {hi['car21'].mean()*100:5.2f}% (n={len(hi)}) "
                      f"| lo CAR21 {lo['car21'].mean()*100:5.2f}% (n={len(lo)})")
                out["13D_svr_hi_car21"] = float(hi["car21"].mean())
                out["13D_svr_lo_car21"] = float(lo["car21"].mean())
    return out


def main() -> None:
    _proxy_env()
    which = sys.argv[1] if len(sys.argv) > 1 else "all"
    targets_csv = os.environ.get("TR9_TARGETS_CSV", "data/research/edgar_13d_targets.csv")
    if not os.path.exists(targets_csv):
        raise SystemExit("run research.lab.fetch_13d_targets first")
    tg = pd.read_csv(targets_csv)
    tg = tg[(tg["target_cik"].fillna(0) > 0)]
    cik2t = cik_ticker_map()
    tg["ticker"] = tg["target_cik"].map(lambda c: cik2t.get(int(c)))
    # fallback: exact name match against the SEC ticker map
    if os.path.exists(TICKERS_CACHE):
        raw = json.load(open(TICKERS_CACHE))
        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)
    ev = tg[tg["ticker"].notna()].copy()
    ev["form"] = "SC 13D"
    # one event per target per day (multiple filers on the same stake day)
    ev = ev.sort_values("filed").drop_duplicates(subset=["ticker", "filed"], keep="first")
    print(f"13D originals mapped to tickers: {len(ev)}")
    svr = load_svr()
    results = []
    if which in ("us", "all"):
        with open("data/research/us.panel.pkl", "rb") as fh:
            p = pickle.load(fh)
        results.append(run("S&P 500", p.close, p.member, ev, svr))
    if which in ("midsmall", "all"):
        with open("data/research/us_midsmall.panel.pkl", "rb") as fh:
            p = pickle.load(fh)
        results.append(run("S&P 400+600", p.close, p.member, ev, svr))
    json.dump(results, open("data/research/results/activists.json", "w"), indent=1, default=str)
    print("saved data/research/results/activists.json")


if __name__ == "__main__":
    main()