#!/usr/bin/env python3
# -*- coding: utf-8 -*-

"""
用于 mindmap-ai v2：从 PDF 中提取分页文本。

注意：
- 本脚本仅做“文本抽取”，不做大纲推断（大纲交给 TS 侧 + LLM/规则）。
- 输出为 JSON，便于 Next.js API 通过 child_process 调用并解析。
"""

from __future__ import annotations

import argparse
import json
import sys
from typing import Any, Dict, List, Optional


def _load_reader(path: str):
    try:
        # pypdf (推荐)
        from pypdf import PdfReader  # type: ignore
        return PdfReader(path)
    except Exception:
        # PyPDF2 兜底
        from PyPDF2 import PdfReader  # type: ignore
        return PdfReader(path)


def _extract_pages(reader, max_pages: Optional[int] = None) -> List[Dict[str, Any]]:
    pages: List[Dict[str, Any]] = []
    total = len(getattr(reader, "pages", []) or [])
    limit = total if max_pages is None else min(total, max_pages)

    for i in range(limit):
        try:
            page = reader.pages[i]
            text = page.extract_text() or ""
        except Exception:
            text = ""
        # 清理一些不可见字符，避免 JSON/解析异常
        text = text.replace("\x00", "").strip()
        pages.append({"page": i + 1, "text": text})
    return pages


def main(argv: List[str]) -> int:
    parser = argparse.ArgumentParser()
    parser.add_argument("--input", required=True, help="PDF 文件路径")
    parser.add_argument("--max-pages", type=int, default=50, help="最多提取页数")
    args = parser.parse_args(argv)

    reader = _load_reader(args.input)
    meta_title = None
    try:
        info = getattr(reader, "metadata", None)
        meta_title = getattr(info, "title", None) if info else None
    except Exception:
        meta_title = None

    pages = _extract_pages(reader, max_pages=args.max_pages)
    payload: Dict[str, Any] = {
        "meta": {"title": meta_title},
        "pages": pages,
        "totalPages": len(getattr(reader, "pages", []) or []),
    }
    # Windows 控制台默认编码可能是 gbk，直接写入会导致 UnicodeEncodeError
    try:
        sys.stdout.reconfigure(encoding="utf-8")  # py3.7+
    except Exception:
        pass
    sys.stdout.write(json.dumps(payload, ensure_ascii=False))
    return 0


if __name__ == "__main__":
    raise SystemExit(main(sys.argv[1:]))