"""Backfill the per-fund alpha REFERENCE into search_all.json.

The alpha search verdict (fundlab/search.py) computes alpha as the OLS
intercept of the fund's daily total returns against the sleeves BIC
forward-selection picked from the 21 broad sleeve axes (the same set for
every fund). The picked sleeves ARE the fund's reference - a fitted
sleeve mix, not a single index - but the screen never stored them, so
the app couldn't show them.

This script recomputes the forward selection (full + last-5y) for every
screened fund and stores a compact, human-readable reference string on
each row:

  ref_5y   "ivv +0.62, tlt +0.31"   (sleeves picked for the 5y model)
  ref_full "ivv +0.38, efa +0.15, ..."
  "pure alpha (no sleeve selected)" when the model has no components

Resumable: rows that already carry ref_5y are skipped.

Run: .venv/bin/python -m fundlab.refback   (logs to fundlab/refback.log)
"""
from __future__ import annotations

import json
import time

from fundlab import decompose
from fundlab.searchlist import BROAD_SLEEVES

HERE = __import__("pathlib").Path(__file__).parent
SRC = HERE / "search_all.json"
LOG = HERE / "refback.log"


def log(msg: str) -> None:
    line = f"[{time.strftime('%Y-%m-%d %H:%M:%S')}] {msg}"
    print(line, flush=True)
    with LOG.open("a") as f:
        f.write(line + "\n")


def _fmt(m: dict) -> str:
    comps = m.get("components") or []
    if not comps:
        return "pure alpha (no sleeve selected)"
    return ", ".join(f"{c['sym']} {c['beta']:+.2f}" for c in comps)


def run() -> None:
    d = json.loads(SRC.read_text())
    todo = [k for k, v in d.items()
            if isinstance(v, dict)
            and isinstance(v.get("r2_5y"), (int, float))
            and "ref_5y" not in v]
    log(f"rows={len(d)} todo={len(todo)}")
    for i, k in enumerate(todo, 1):
        sym = d[k]["sym"]
        try:
            rec = decompose.decompose(sym, start=decompose.RECENT_WINDOW,
                                      candidates={sym: BROAD_SLEEVES})
            full = decompose.decompose(sym, candidates={sym: BROAD_SLEEVES})
            d[k]["ref_5y"] = _fmt(rec)
            d[k]["ref_full"] = _fmt(full)
        except Exception as e:  # noqa: BLE001 - batch must not die
            d[k]["ref_5y"] = f"(backfill failed: {e})"
        if i % 25 == 0 or i == len(todo):
            SRC.write_text(json.dumps(d, indent=1))
            log(f"{i}/{len(todo)} done (saved)")
    SRC.write_text(json.dumps(d, indent=1))
    n = sum(1 for v in d.values()
            if isinstance(v, dict) and v.get("ref_5y"))
    log(f"done: {n} rows carry a reference")


if __name__ == "__main__":
    run()