#!/usr/bin/env python3
"""Extract answer markers from text and populate the `answer` field."""

from __future__ import annotations

import argparse
import json
import re
from pathlib import Path


ANSWER_PATTERN = re.compile(
    r"\*\*\s*answer\s*:\s*(.+?)\s*\*\*",
    flags=re.IGNORECASE | re.DOTALL,
)


def build_parser() -> argparse.ArgumentParser:
    parser = argparse.ArgumentParser(
        description=(
            "Extract `**Answer:x**` from each item's `text` and fill `answer`."
        )
    )
    parser.add_argument(
        "--input",
        default="video_dataset.json",
        help="Input JSON path (default: video_dataset.json).",
    )
    parser.add_argument(
        "--output",
        default="",
        help="Output JSON path (default: overwrite --input in place).",
    )
    parser.add_argument(
        "--overwrite",
        action="store_true",
        help="Overwrite non-empty existing `answer` values.",
    )
    parser.add_argument(
        "--dry-run",
        action="store_true",
        help="Only report stats; do not write output.",
    )
    parser.add_argument(
        "--ensure-ascii",
        action="store_true",
        help="Write escaped unicode (default keeps unicode characters).",
    )
    return parser


def extract_answer(text: str) -> str:
    match = ANSWER_PATTERN.search(text or "")
    if not match:
        return ""
    raw = match.group(1).strip()
    return re.sub(r"\s+", " ", raw)


def main() -> None:
    args = build_parser().parse_args()
    input_path = Path(args.input)
    output_path = Path(args.output) if args.output else input_path

    with input_path.open("r", encoding="utf-8") as f:
        data = json.load(f)

    if not isinstance(data, list):
        raise ValueError("Input JSON must be a list of objects.")

    total = 0
    with_marker = 0
    updated = 0
    skipped_existing = 0
    no_marker = 0

    for item in data:
        if not isinstance(item, dict):
            continue
        total += 1
        text = "" if item.get("text") is None else str(item.get("text"))
        extracted = extract_answer(text)
        if not extracted:
            no_marker += 1
            continue

        with_marker += 1
        current = "" if item.get("answer") is None else str(item.get("answer")).strip()
        if current and not args.overwrite:
            skipped_existing += 1
            continue

        if current != extracted:
            item["answer"] = extracted
            updated += 1

    if not args.dry_run:
        with output_path.open("w", encoding="utf-8") as f:
            json.dump(data, f, ensure_ascii=args.ensure_ascii, indent=2)
            f.write("\n")

    print(
        "Processed "
        f"{total} items | markers: {with_marker} | updated: {updated} | "
        f"skipped_existing: {skipped_existing} | no_marker: {no_marker} | "
        f"output: {output_path if not args.dry_run else '(dry-run)'}"
    )


if __name__ == "__main__":
    main()