"""Build the frozen 200-incident hold-out evaluation set.

Run::

    python -m eval.make_holdout --out data/holdout.jsonl

This file is committed to the repo so reviewers can verify reported
numbers byte-for-byte without rerunning the generator.  The seeds used
here are *outside* the SFT and GRPO seed bands declared in
`tasks/registry.py` (seed_offset 1k-4k for training, 90k-94k here) so
there is zero overlap between train and eval.

Each record::

    { "alert": {...}, "events": [...], "ground_truth": "<action>",
      "triggering_log_id": "<id>", "stage": "<stage>", "seed": <int> }

`eval/eval.py` consumes this format directly.
"""

from __future__ import annotations

import argparse
import json
import os
import sys
from collections import Counter

_HERE = os.path.dirname(os.path.abspath(__file__))
sys.path.insert(0, os.path.dirname(_HERE))

from generator import generate_incident, make_alert  # noqa: E402
from verifier import compute_ground_truth  # noqa: E402


# Seed bands — kept distinct from training seed bands.
HOLDOUT_SEED_BAND = {
    "stage1_basic": 90_000,
    "stage2_multi": 91_000,
    "stage3_mixed": 92_000,
    "stage4_adversarial": 93_000,
}


def main() -> None:
    parser = argparse.ArgumentParser()
    parser.add_argument("--n-per-stage", type=int, default=50,
                        help="Number of incidents per stage (default 50 → 200 total).")
    parser.add_argument("--out", default="data/holdout.jsonl")
    args = parser.parse_args()

    out_path = os.path.join(os.path.dirname(_HERE), args.out)
    os.makedirs(os.path.dirname(out_path), exist_ok=True)

    counts: Counter = Counter()
    written = 0
    with open(out_path, "w", encoding="utf-8") as f:
        for stage_id, base in HOLDOUT_SEED_BAND.items():
            for i in range(args.n_per_stage):
                seed = base + i
                params = generate_incident(stage_id, seed)
                alert = make_alert(params, alert_id=f"A-EVAL-{stage_id[-1]}-{seed}")
                gt, sig = compute_ground_truth(params)
                rec = {
                    "alert": alert.model_dump(mode="json"),
                    "events": [e.model_dump(mode="json") for e in params.events],
                    "ground_truth": gt.value,
                    "triggering_log_id": sig.triggering_log_id or params.events[0].log_id,
                    "stage": stage_id,
                    "seed": seed,
                }
                f.write(json.dumps(rec) + "\n")
                counts[gt.value] += 1
                written += 1
    print(f"Wrote {written} hold-out incidents to {out_path}")
    print("Label distribution:")
    for k, v in sorted(counts.items()):
        print(f"  {k:<18} {v:4d} ({100 * v / written:5.1f}%)")


if __name__ == "__main__":
    main()