"""Halacha extraction quality monitor.

Tracks ``avg(confidence)`` of halachot extracted by the LLM pipeline
over time and emits an alert when the recent-window average drops more
than a configurable threshold below the lifetime baseline.

Intended schedule: weekly cron, e.g. ``0 8 * * 1`` (Monday 08:00).

Output: a single-line JSON payload to stdout (suitable for piping
into ``notify.py`` or a webhook), plus a human-readable alert text
on stderr when drift is detected.

Usage
-----

::

    # Default — weekly window, 5% drop threshold (relative)
    python scripts/monitor_halacha_quality.py

    # Custom window/threshold:
    python scripts/monitor_halacha_quality.py --window 14 --threshold 0.03

    # Only emit JSON, no stderr alert:
    python scripts/monitor_halacha_quality.py --silent
"""
from __future__ import annotations

import argparse
import asyncio
import json
import os
import sys
from datetime import datetime, timezone
from pathlib import Path


def _setup_paths():
    """Make ``legal_mcp`` importable when run from anywhere."""
    here = Path(__file__).resolve().parent
    candidates = [
        here.parent / "mcp-server" / "src",  # host
        Path("/app/mcp-server/src"),  # container
    ]
    for c in candidates:
        if c.is_dir() and str(c) not in sys.path:
            sys.path.insert(0, str(c))


_setup_paths()

from legal_mcp.services import db  # noqa: E402


# Statuses considered "trusted" — the baseline is computed only over
# halachot whose extraction the chair has accepted. ``pending_review``
# is the queue waiting for review; their average tends to be lower
# because anything obviously bad gets rejected before approval. So we
# track BOTH series and alert on either one drifting:
#   1. Trusted baseline (approved+published) — drift here means the
#      extractor's "best output" quality is degrading.
#   2. All extracted — drift here means raw extractor accuracy is down.
TRUSTED_STATUSES = ("approved", "published")


async def _collect_metrics(window_days: int) -> dict:
    pool = await db.get_pool()

    # Lifetime baselines
    lifetime_all = await pool.fetchrow(
        "SELECT count(*) AS n, AVG(confidence) AS avg_conf FROM halachot"
    )
    lifetime_trusted = await pool.fetchrow(
        f"""
        SELECT count(*) AS n, AVG(confidence) AS avg_conf
        FROM halachot
        WHERE review_status = ANY($1::text[])
        """,
        list(TRUSTED_STATUSES),
    )

    # Recent window
    recent_all = await pool.fetchrow(
        f"""
        SELECT count(*) AS n, AVG(confidence) AS avg_conf
        FROM halachot
        WHERE created_at > NOW() - INTERVAL '{int(window_days)} days'
        """
    )
    recent_trusted = await pool.fetchrow(
        f"""
        SELECT count(*) AS n, AVG(confidence) AS avg_conf
        FROM halachot
        WHERE created_at > NOW() - INTERVAL '{int(window_days)} days'
          AND review_status = ANY($1::text[])
        """,
        list(TRUSTED_STATUSES),
    )

    # Per-precedent recent (extractor outputs that haven't been reviewed
    # yet) — sometimes the canary that catches drift earliest. We track
    # the most-recent N extractions regardless of review state.
    pending_recent = await pool.fetchrow(
        """
        SELECT count(*) AS n, AVG(confidence) AS avg_conf
        FROM halachot
        WHERE review_status = 'pending_review'
        """
    )

    def _f(rec, key: str) -> float | None:
        v = rec[key]
        if v is None:
            return None
        return float(v)

    def _i(rec, key: str) -> int:
        v = rec[key]
        return int(v) if v is not None else 0

    return {
        "window_days": int(window_days),
        "lifetime_all_count": _i(lifetime_all, "n"),
        "lifetime_all_avg": _f(lifetime_all, "avg_conf"),
        "lifetime_trusted_count": _i(lifetime_trusted, "n"),
        "lifetime_trusted_avg": _f(lifetime_trusted, "avg_conf"),
        "recent_all_count": _i(recent_all, "n"),
        "recent_all_avg": _f(recent_all, "avg_conf"),
        "recent_trusted_count": _i(recent_trusted, "n"),
        "recent_trusted_avg": _f(recent_trusted, "avg_conf"),
        "pending_review_count": _i(pending_recent, "n"),
        "pending_review_avg": _f(pending_recent, "avg_conf"),
    }


def _drift(baseline: float | None, recent: float | None) -> float | None:
    """Return relative drift as a positive number when recent < baseline.

    >>> _drift(0.85, 0.80)  # -> 0.0588 (5.88% drop)
    """
    if baseline is None or recent is None or baseline <= 0:
        return None
    return (baseline - recent) / baseline


def _evaluate(metrics: dict, threshold: float, min_sample: int) -> dict:
    """Decide whether any series is drifting below threshold."""
    alerts: list[dict] = []
    series = [
        (
            "trusted",
            metrics["lifetime_trusted_avg"],
            metrics["recent_trusted_avg"],
            metrics["recent_trusted_count"],
        ),
        (
            "all_extracted",
            metrics["lifetime_all_avg"],
            metrics["recent_all_avg"],
            metrics["recent_all_count"],
        ),
    ]
    for name, baseline, recent, recent_n in series:
        d = _drift(baseline, recent)
        entry = {
            "series": name,
            "baseline": baseline,
            "recent": recent,
            "recent_n": recent_n,
            "drift": d,
            "alert": False,
            "reason": None,
        }
        if recent_n < min_sample:
            entry["reason"] = f"recent_n={recent_n} below min_sample={min_sample}"
        elif d is None:
            entry["reason"] = "missing baseline or recent average"
        elif d >= threshold:
            entry["alert"] = True
            entry["reason"] = (
                f"drift {d:.1%} >= threshold {threshold:.1%} "
                f"(baseline={baseline:.3f}, recent={recent:.3f}, n={recent_n})"
            )
        else:
            entry["reason"] = (
                f"drift {d:.1%} < threshold {threshold:.1%} — within tolerance"
            )
        alerts.append(entry)

    any_alert = any(a["alert"] for a in alerts)
    return {"alert": any_alert, "series": alerts}


def _format_alert_text(metrics: dict, decision: dict) -> str:
    lines = [
        f"Halacha quality alert — window={metrics['window_days']}d",
        "",
    ]
    for s in decision["series"]:
        sym = "ALERT" if s["alert"] else "ok"
        baseline = f"{s['baseline']:.3f}" if s["baseline"] is not None else "—"
        recent = f"{s['recent']:.3f}" if s["recent"] is not None else "—"
        drift = f"{s['drift']:.1%}" if s["drift"] is not None else "—"
        lines.append(
            f"  [{sym}] {s['series']}: baseline={baseline} recent={recent} "
            f"drift={drift} n={s['recent_n']}"
        )
        if s["reason"]:
            lines.append(f"          {s['reason']}")
    return "\n".join(lines)


async def run(
    *,
    window_days: int,
    threshold: float,
    min_sample: int,
) -> dict:
    metrics = await _collect_metrics(window_days)
    decision = _evaluate(metrics, threshold, min_sample)
    return {
        "generated_at": datetime.now(timezone.utc).isoformat(),
        "window_days": window_days,
        "threshold_rel": threshold,
        "min_sample": min_sample,
        "metrics": metrics,
        "decision": decision,
    }


def main():
    parser = argparse.ArgumentParser(
        description="Monitor halacha extraction quality (confidence drift)."
    )
    parser.add_argument(
        "--window", type=int, default=7,
        help="Recent window in days (default: 7).",
    )
    parser.add_argument(
        "--threshold", type=float, default=0.05,
        help="Relative drop alert threshold (default: 0.05 = 5%%).",
    )
    parser.add_argument(
        "--min-sample", type=int, default=5,
        help="Minimum halachot in window to evaluate (default: 5). "
             "Below this, the series is reported but not alerted on.",
    )
    parser.add_argument(
        "--silent", action="store_true",
        help="Suppress stderr alert text; only print JSON.",
    )
    parser.add_argument(
        "--exit-on-alert", action="store_true",
        help="Exit with status 1 when an alert fires (default: always exit 0).",
    )
    args = parser.parse_args()

    report = asyncio.run(
        run(
            window_days=args.window,
            threshold=args.threshold,
            min_sample=args.min_sample,
        )
    )

    # JSON to stdout
    print(json.dumps(report, ensure_ascii=False, indent=2))

    if report["decision"]["alert"] and not args.silent:
        print("", file=sys.stderr)
        print(_format_alert_text(report["metrics"], report["decision"]), file=sys.stderr)

    if args.exit_on_alert and report["decision"]["alert"]:
        sys.exit(1)


if __name__ == "__main__":
    main()