"""R-C — re-ingest arXiv papers from LaTeX source (section-aware, higher fidelity).

For each arXiv paper, download its source via :func:`codex.sources.arxiv.fetch_source`
(multi-file ``\\input``/``\\include`` flattened), write it to a temp ``.tex``, and
re-ingest through :func:`codex.ingest.ingest_paper`. The ``.tex`` ingest path is
section-aware (:func:`codex.parsing.tex.chunk_sections`), so the stored ``section``
column is labelled from real ``\\section`` headings instead of mostly ``body`` —
serving DQ-3 (fidelity vs the OCR'd ``.txt``) and audit R-12 (weak ``section`` column).

Only arXiv papers have downloadable source; DOI/journal papers and books are skipped.
Re-ingest REPLACES the paper's chunks (DELETE + re-INSERT) — that is the intended R-C
improvement (flattened ``.txt`` → clean ``.tex`` chunks). It is idempotent and
**dry-run by default**; pass ``--write`` to mutate the live corpus.

Usage
-----
    # dry-run: list arXiv papers + source availability (no writes)
    PYTHONPATH=. python scripts/rc_tex_reingest.py

    # re-ingest every arXiv paper from .tex
    PYTHONPATH=. python scripts/rc_tex_reingest.py --write

    # one paper
    PYTHONPATH=. python scripts/rc_tex_reingest.py --only 2305.10988 --write

Needs ``DATABASE_URL`` (Jetson tunnel) as documented in
``docs/audit/DATA-QUALITY-2026-06-15.md``.
"""

from __future__ import annotations

import argparse
import logging
import tempfile

import psycopg
import psycopg.rows

from codex.db import get_conn
from codex.ingest import ingest_paper
from codex.sources import arxiv

logger = logging.getLogger(__name__)


def is_arxiv_id(paper_id: str) -> bool:
    """Return True for arXiv ids (the only papers with downloadable LaTeX source).

    arXiv ids are modern (``2305.10988``) or legacy (``math/0603097``). DOIs start
    with ``10.``; OpenAlex W-ids start with ``W`` or an ``https://openalex.org/`` URL.
    """
    p = (paper_id or "").strip()
    return bool(p) and not p.startswith("10.") and not p.startswith(("W", "https://"))


def _section_dist(conn: psycopg.Connection[psycopg.rows.DictRow], paper_id: str) -> dict[str, int]:
    """Return the section-label distribution for a paper's stored chunks."""
    rows = conn.execute(
        "SELECT coalesce(section, '(null)') AS s, count(*) AS n "
        "FROM chunks WHERE paper_id = %s GROUP BY 1 ORDER BY 2 DESC",
        (paper_id,),
    ).fetchall()
    return {r["s"]: int(r["n"]) for r in rows}


def main(argv: list[str] | None = None) -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--only", default=None, help="restrict to a single arXiv id")
    parser.add_argument("--limit", type=int, default=None, help="cap number of papers")
    parser.add_argument(
        "--write", action="store_true", help="re-ingest into the live DB (default: dry-run)"
    )
    args = parser.parse_args(argv)
    logging.basicConfig(level=logging.INFO, format="%(levelname)s %(message)s")

    with get_conn() as conn:
        rows = conn.execute("SELECT id FROM papers ORDER BY id").fetchall()
    targets = [
        r["id"]
        for r in rows
        if is_arxiv_id(r["id"]) and (args.only is None or r["id"] == args.only)
    ]
    if args.limit is not None:
        targets = targets[: args.limit]

    logger.info(
        "arXiv papers to process=%d | mode=%s",
        len(targets),
        "WRITE" if args.write else "DRY-RUN",
    )

    for pid in targets:
        try:
            src = arxiv.fetch_source(pid)
        except Exception as exc:
            logger.warning("%s: source fetch failed: %s", pid, exc)
            continue
        if not src:
            logger.warning("%s: no LaTeX source available — skipping", pid)
            continue
        if not args.write:
            logger.info("%s: source OK (%d chars)", pid, len(src))
            continue

        with get_conn() as conn:
            before = _section_dist(conn, pid)
        with tempfile.NamedTemporaryFile("w", suffix=".tex", delete=True) as tf:
            tf.write(src)
            tf.flush()
            res = ingest_paper(pid, source_path=tf.name)
        with get_conn() as conn:
            after = _section_dist(conn, pid)
        logger.info(
            "%s: chunks %d->%d | section before=%s after=%s",
            pid,
            sum(before.values()),
            res.chunks_upserted,
            before,
            after,
        )
    return 0


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