"""
Train the AnemiaLens v8 clinical-robust archive model.

Usage::

    python scripts/train_archive_model_v8.py [--dataset PATH] [--output PATH] [--report PATH]
"""

from __future__ import annotations

import argparse
import json
import sys
import time
from pathlib import Path

import joblib

ROOT = Path(__file__).resolve().parents[2]
BACKEND_ROOT = ROOT / "backend"
sys.path.insert(0, str(BACKEND_ROOT))

from app.config import DEFAULT_TRAINING_REPORT_PATH  # noqa: E402
from app.ml.archive_model_v8 import V8_VERSION, train_archive_model_v8  # noqa: E402

DEFAULT_DATASET = ROOT / "archive" / "dataset anemia"
DEFAULT_OUTPUT = BACKEND_ROOT / "models" / f"{V8_VERSION}.joblib"


def _build_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(
        description="Train the v8 AnemiaLens archive screening model.",
        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
    )
    parser.add_argument("--dataset", type=Path, default=DEFAULT_DATASET)
    parser.add_argument("--output", type=Path, default=DEFAULT_OUTPUT)
    parser.add_argument("--report", type=Path, default=DEFAULT_TRAINING_REPORT_PATH)
    parser.add_argument("--splits", type=int, default=10)
    parser.add_argument("--test-size", type=float, default=0.2)
    return parser


def main(argv: list[str] | None = None) -> int:
    args = _build_parser().parse_args(argv)
    if not args.dataset.exists():
        print(f"ERROR: Dataset directory not found: {args.dataset}", file=sys.stderr)
        return 1

    t0 = time.perf_counter()
    try:
        artifact, report = train_archive_model_v8(
            args.dataset,
            n_splits=args.splits,
            test_size=args.test_size,
        )
    except Exception as exc:
        print(f"ERROR: Training failed — {exc}", file=sys.stderr)
        return 1

    args.output.parent.mkdir(parents=True, exist_ok=True)
    args.report.parent.mkdir(parents=True, exist_ok=True)
    joblib.dump(artifact, args.output)
    args.report.write_text(json.dumps(report, indent=2), encoding="utf-8")

    elapsed = time.perf_counter() - t0
    print(f"Saved artifact to {args.output}")
    print(f"Saved report to   {args.report}")
    print(f"Validation metrics: {json.dumps(report['metrics'], indent=2)}")
    print(f"Completed in {elapsed:.1f}s")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())