#!/usr/bin/env python3
"""verify_dataset_card.py — check that DATASET_CARD.md describes the bundle truthfully.

The card is the public interface of the dataset: it declares which files load as
which configs and states how many rows each holds. A card that lies is worse than
no card, so every claim it makes in machine-readable form is checked here:

  1. the YAML front matter parses (PyYAML if installed, minimal fallback otherwise);
  2. every `configs[].data_files[].path` exists in this repository;
  3. every declared file is a well-formed comma-separated table with a non-empty
     header, consistent field counts, and one split (train);
  4. every row count stated in the card body equals the count measured here;
  5. the sections the Hugging Face dataset-card evaluation looks for are present;
  6. the license is declared under a key the hub actually reads, and agrees with
     `CITATION.cff` and the root `LICENSE` notice (this repository is dual-licensed
     by path: Creative Commons Attribution 4.0 for text and data, MIT for `scripts/`);
  7. the card carries no internal instruction text — no "paste this file" note, no
     pointer to a file that is deliberately not published (both once shipped, in the
     YAML comment block, where the hub renders nothing but the raw file shows all);
  8. every `python3 <script>` command inside a fenced block names a script that exists
     in whichever repository the card is published into, or the block says the command
     belongs to the other one — an instruction a reader cannot run is a defect in the
     publication, not in the reader.

Exit code 0 = all eight hold. Run it before `hf upload`.

    python3 scripts/verify_dataset_card.py
"""
from __future__ import annotations

import csv
import io
import re
import subprocess
import sys
from pathlib import Path

ROOT = Path(__file__).resolve().parents[1]


def _tracked() -> set[str] | None:
    """The paths git tracks in this checkout, or None when it is not a repository root.

    The root test matters: `git ls-files` lists what is tracked *under the current
    directory*, so asking it from a staging directory inside this repository (which is how
    the data layer is built and then checked) returns nothing at all - and an empty set
    would make every published script look unpublished. Anywhere that is not the top level
    of its own repository falls back to file presence, which is what the published data
    layer (no git at all) gets.
    """
    try:
        prefix = subprocess.run(["git", "-C", str(ROOT), "rev-parse", "--show-prefix"],
                                capture_output=True, text=True, timeout=30)
        if prefix.returncode != 0 or prefix.stdout.strip():
            return None
        run = subprocess.run(["git", "-C", str(ROOT), "ls-files"],
                             capture_output=True, text=True, timeout=30)
    except (OSError, subprocess.SubprocessError):
        return None
    return set(run.stdout.split()) if run.returncode == 0 else None


GIT_TRACKED = _tracked()
# The card is DATASET_CARD.md in the source repository and README.md once it is
# published into the dataset repository; either is accepted.
CARD = next((p for p in (ROOT / "DATASET_CARD.md", ROOT / "README.md") if p.exists()),
             ROOT / "DATASET_CARD.md")

REQUIRED_SECTIONS = ["## Dataset details", "### Composition", "### Collection process",
                     "## Personal and private content", "## Uses", "## Limitations",
                     "## Citation", "## License"]
fails: list[str] = []


def front_matter(text: str) -> str:
    m = re.match(r"^---\n(.*?)\n---\n", text, re.S)
    if not m:
        fails.append("card has no YAML front matter block")
        return ""
    return m.group(1)


def parse_configs(yaml_text: str) -> list[tuple[str, str, str]]:
    """Return [(config_name, split, path)]; PyYAML when available, else regex."""
    out: list[tuple[str, str, str]] = []
    try:
        import yaml  # type: ignore
        doc = yaml.safe_load(yaml_text) or {}
        for cfg in doc.get("configs") or []:
            for df in cfg.get("data_files") or []:
                out.append((cfg["config_name"], df.get("split", "?"), df["path"]))
        return out
    except ImportError:
        cur = "?"
        for line in yaml_text.splitlines():
            if (m := re.match(r"\s*-\s*config_name:\s*(\S+)", line)):
                cur = m.group(1)
            elif (m := re.match(r"\s*path:\s*(\S+)", line)):
                out.append((cur, "train", m.group(1)))
        if not out:
            fails.append("no configs declared in the front matter")
        return out


def declared_licenses(yaml_text: str) -> list[str]:
    """Values of the `license` key, in list or scalar form, comments stripped."""
    block = re.search(r"^license:\n((?:[ \t]+-[^\n]*\n?)+)", yaml_text, re.M)
    if block:
        return [line.strip().lstrip("-").strip().split("#")[0].strip()
                for line in block.group(1).splitlines()]
    scalar = re.search(r"^license:[ \t]+(\S+)", yaml_text, re.M)
    return [scalar.group(1)] if scalar else []


def check_licenses(yaml_text: str) -> None:
    for wrong in ("licenses:", "cfg_types:"):
        if re.search(rf"^{wrong}", yaml_text, re.M):
            fails.append(f"front matter key `{wrong[:-1]}` is not read by the hub — the "
                         f"documented key is `license` (it accepts a list)")
    declared = declared_licenses(yaml_text)
    if "cc-by-4.0" not in declared:
        fails.append(f"front matter declares license(s) {declared}; the data is CC-BY-4.0")
    cff = (ROOT / "CITATION.cff").read_text() if (ROOT / "CITATION.cff").exists() else ""
    if "CC-BY-4.0" not in cff or "MIT" not in cff:
        fails.append("CITATION.cff no longer states both halves of the license split")
    root_license = (ROOT / "LICENSE").read_text() if (ROOT / "LICENSE").exists() else ""
    if "dual-licensed by path" not in root_license:
        fails.append("root LICENSE does not state which paths are MIT and which are CC-BY-4.0")


INTERNAL_MARKERS = ("Paste this file", "How to publish", "how to publish",
                    "PUBLICATION.md", "prior-works.md", "methodology_guidance")
# A fenced command is an instruction the reader will try. Every script it names must be
# present in whichever repository this card is published into, or the line has to say who it
# belongs to - which is how the tools/ gate and the paste-in note escaped into the open.
CMD_RE = re.compile(r"^\s*python3\s+([A-Za-z0-9_./-]+\.py)")


def check_no_internal_instructions(text: str) -> list[str]:
    hits = []
    for marker in INTERNAL_MARKERS:
        for n, line in enumerate(text.splitlines(), 1):
            if marker in line:
                hits.append(f"line {n}: internal instruction marker {marker!r} in the published card")
    return hits


def tracked_or_present(rel: str) -> bool:
    """Does this path belong to the *published* set?

    Testing the disk is not enough - `tools/` sits on this workstation and is deliberately
    never published, which is precisely how an unrunnable instruction survived review. At the
    root of a git checkout, ask git what is tracked; elsewhere (a staging directory, or the
    published data layer, which has no git) fall back to file presence.
    """
    if GIT_TRACKED is not None:
        return rel in GIT_TRACKED
    return (ROOT / rel).exists()


def check_commands_run(text: str) -> list[str]:
    blocks, inside, buf = [], False, []
    for line in text.splitlines():
        if line.startswith("```"):
            if inside:
                blocks.append(buf)
            inside, buf = not inside, []
            continue
        if inside:
            buf.append(line)
    problems = []
    for block in blocks:
        for line in block:
            m = CMD_RE.match(line)
            if not m:
                continue
            target = m.group(1)
            if not tracked_or_present(target) and "not published" not in "\n".join(block):
                problems.append(f"command names {m.group(1)!r}, which is not in this repository "
                                f"and is not marked as belonging to the other one")
    return problems


def main() -> int:
    if not CARD.exists():
        print(f"FAIL no {CARD.name} at {CARD}", file=sys.stderr)
        return 1
    text = CARD.read_text()
    body = text.split("\n---\n", 1)[1] if "\n---\n" in text else text
    yaml_text = front_matter(text)
    configs = parse_configs(yaml_text)
    check_licenses(yaml_text)

    measured: dict[str, int] = {}
    for name, split, rel in configs:
        p = ROOT / rel
        if not p.exists():
            fails.append(f"{name}: declared file missing: {rel}")
            continue
        rows = list(csv.reader(io.StringIO(p.read_text(errors="replace"))))
        rows = [r for r in rows if r]
        if len(rows) < 2:
            fails.append(f"{name}: {rel} has no data rows")
            continue
        header, data = rows[0], rows[1:]
        if any(not c.strip() for c in header):
            fails.append(f"{name}: empty column name in header {header}")
        ragged = [i for i, r in enumerate(data, 2) if len(r) != len(header)]
        if ragged:
            fails.append(f"{name}: {len(ragged)} row(s) with the wrong field count, "
                         f"first at line {ragged[0]}")
        if split != "train":
            fails.append(f"{name}: unexpected split {split!r} (the card declares train only)")
        measured[name] = len(data)

    # row counts stated in prose must match the files
    for name, n in re.findall(r"`([a-z0-9_]+)`[^`\n]{0,40}?(\d+)\s+rows", body):
        if name in measured and measured[name] != int(n):
            fails.append(f"{name}: card says {n} rows, file has {measured[name]}")

    for sec in REQUIRED_SECTIONS:
        if sec not in body:
            fails.append(f"missing card section: {sec}")

    fails.extend(check_no_internal_instructions(text))
    fails.extend(check_commands_run(body))

    print(f"verify_dataset_card: {len(configs)} configs declared")
    for name in sorted(measured):
        print(f"  {name:28s} {measured[name]:4d} rows")
    if fails:
        print("\n".join("FAIL " + f for f in fails), file=sys.stderr)
        return 1
    print("dataset card is consistent with the files it declares")
    return 0


if __name__ == "__main__":
    sys.exit(main())