from __future__ import annotations

import argparse
import csv
import re
from pathlib import Path
from typing import Dict, Iterable, List

import sys

try:
    from scripts.defextra_markers import (
        normalize_paper_id,
        normalize_arxiv,
        normalize_doi,
    )
    from scripts.defextra_pdf_aliases import candidate_pdf_aliases
except ModuleNotFoundError as exc:
    if exc.name != "scripts":
        raise
    PROJECT_ROOT = Path(__file__).resolve().parent.parent
    if str(PROJECT_ROOT) not in sys.path:
        sys.path.insert(0, str(PROJECT_ROOT))
    from scripts.defextra_markers import (
        normalize_paper_id,
        normalize_arxiv,
        normalize_doi,
    )
    from scripts.defextra_pdf_aliases import candidate_pdf_aliases


S2_ID_RE = re.compile(r"^[0-9a-f]{40}$", re.IGNORECASE)


def _safe_join(values: Iterable[str]) -> str:
    return ";".join(v for v in values if v)


def _semanticscholar_url(paper_id: str) -> str:
    if S2_ID_RE.match(paper_id):
        return f"https://www.semanticscholar.org/paper/{paper_id}"
    return ""


def _acl_url(paper_id: str) -> str:
    if paper_id.startswith("https://aclanthology.org/"):
        return paper_id
    if re.match(r"^[0-9]{4}\\.[a-z-]+\\.[0-9]+$", paper_id, re.IGNORECASE):
        return f"https://aclanthology.org/{paper_id}"
    return ""


def _doi_url(doi: str, paper_id: str) -> str:
    if doi:
        return f"https://doi.org/{normalize_doi(doi)}"
    if paper_id.startswith("10."):
        return f"https://doi.org/{normalize_doi(paper_id)}"
    if "doi.org/" in paper_id:
        return f"https://doi.org/{normalize_doi(paper_id)}"
    return ""


def _arxiv_url(arxiv: str, paper_id: str) -> str:
    if arxiv:
        return f"https://arxiv.org/abs/{normalize_arxiv(arxiv)}"
    match = re.search(r"arxiv\\.org/(abs|pdf)/([^?#]+)", paper_id)
    if match:
        return f"https://arxiv.org/abs/{match.group(2).replace('.pdf', '')}"
    return ""


def _collect_papers(rows: List[Dict[str, str]]) -> Dict[str, Dict[str, str]]:
    papers: Dict[str, Dict[str, str]] = {}
    for row in rows:
        paper_id = (row.get("paper_id") or "").strip()
        if not paper_id:
            continue
        record = papers.setdefault(
            paper_id,
            {
                "paper_id": paper_id,
                "paper_title": (row.get("paper_title") or "").strip(),
                "paper_doi": (row.get("paper_doi") or "").strip(),
                "paper_arxiv": (row.get("paper_arxiv") or "").strip(),
            },
        )
        if not record["paper_title"] and row.get("paper_title"):
            record["paper_title"] = row.get("paper_title", "").strip()
        if not record["paper_doi"] and row.get("paper_doi"):
            record["paper_doi"] = row.get("paper_doi", "").strip()
        if not record["paper_arxiv"] and row.get("paper_arxiv"):
            record["paper_arxiv"] = row.get("paper_arxiv", "").strip()
    return papers


def main() -> None:
    parser = argparse.ArgumentParser(
        description=(
            "List required PDFs for DefExtra and generate helper links."
        ),
    )
    parser.add_argument(
        "--legal-csv",
        type=Path,
        default=Path("data/defextra_legal.csv"),
        help="Path to DefExtra legal CSV.",
    )
    parser.add_argument(
        "--output-csv",
        type=Path,
        default=None,
        help="Optional output CSV path.",
    )
    parser.add_argument(
        "--output-md",
        type=Path,
        default=None,
        help="Optional output Markdown list path.",
    )
    parser.add_argument(
        "--limit",
        type=int,
        default=10,
        help="How many entries to print to stdout (0 = none).",
    )
    args = parser.parse_args()

    if not args.legal_csv.exists():
        raise SystemExit(f"Legal CSV not found: {args.legal_csv}")

    with args.legal_csv.open("r", encoding="utf-8", newline="") as handle:
        rows = list(csv.DictReader(handle))

    papers = _collect_papers(rows)
    output_rows: List[Dict[str, str]] = []

    for paper_id, record in sorted(papers.items()):
        doi = record.get("paper_doi", "")
        arxiv = record.get("paper_arxiv", "")
        normalized_id = normalize_paper_id(paper_id)
        aliases = candidate_pdf_aliases(paper_id, doi, arxiv)
        output_rows.append(
            {
                "paper_id": paper_id,
                "normalized_id": normalized_id,
                "paper_title": record.get("paper_title", ""),
                "paper_doi": doi,
                "paper_arxiv": arxiv,
                "preferred_pdf_name": f"{normalized_id}.pdf",
                "alias_pdf_names": _safe_join(
                    f"{alias}.pdf" for alias in aliases
                ),
                "url_semanticscholar": _semanticscholar_url(paper_id),
                "url_doi": _doi_url(doi, paper_id),
                "url_arxiv": _arxiv_url(arxiv, paper_id),
                "url_acl": _acl_url(paper_id),
            },
        )

    if args.output_csv:
        args.output_csv.parent.mkdir(parents=True, exist_ok=True)
        with args.output_csv.open("w", encoding="utf-8", newline="") as handle:
            fieldnames = list(output_rows[0].keys()) if output_rows else []
            writer = csv.DictWriter(handle, fieldnames=fieldnames)
            writer.writeheader()
            for row in output_rows:
                writer.writerow(row)
        print(f"Wrote {len(output_rows)} rows to {args.output_csv}")

    if args.output_md:
        lines = ["# DefExtra required PDFs", ""]
        for row in output_rows:
            line = f"- {row['paper_id']} — {row['paper_title']}"
            links = [
                row["url_semanticscholar"],
                row["url_doi"],
                row["url_arxiv"],
                row["url_acl"],
            ]
            links = [link for link in links if link]
            if links:
                line += " (" + ", ".join(links) + ")"
            lines.append(line)
        args.output_md.parent.mkdir(parents=True, exist_ok=True)
        args.output_md.write_text("\n".join(lines) + "\n", encoding="utf-8")
        print(f"Wrote {len(output_rows)} rows to {args.output_md}")

    if args.limit > 0:
        for row in output_rows[: args.limit]:
            print(
                f"{row['paper_id']} | {row['preferred_pdf_name']} | "
                f"{row['url_semanticscholar'] or row['url_doi'] or row['url_arxiv'] or row['url_acl']}",
            )


if __name__ == "__main__":
    main()