"""
按 URL 抓取小红书帖子内容。

走 explore 页 HTML 内嵌的 window.__INITIAL_STATE__ JSON，不需要 cookie；
URL 必须带 xsec_token（分享/搜索/explore_feed 链接默认都带）。

输出字段集与 examples/process_pipeline/output/<id>/raw_cases/source.json 的
post 子对象对齐：channel_content_id / title / content_type / body_text /
like_count / publish_timestamp / images / videos / channel / link

用法：
    python xhs_fetch/xhs_fetch.py <url> [<url> ...] [--output <subdir>]
    python xhs_fetch/xhs_fetch.py --urls-file urls.txt
    python xhs_fetch/xhs_fetch.py <url> --stdout            # 不写文件，打 JSON 数组到 stdout

退码：0 全成功 / 1 全失败或参数错 / 2 部分失败 / 130 Ctrl+C

脚本通过探测 .git/pyproject.toml 自动定位项目根，可以放在仓库内任意位置。
"""

import argparse
import json
import re
import sys
from pathlib import Path
from typing import Any, Dict, List, Optional

import httpx

# Windows 控制台 UTF-8（中文输出必备）
for _s in (sys.stdout, sys.stderr):
    try:
        _s.reconfigure(encoding="utf-8")
    except (AttributeError, OSError):
        pass


def _find_project_root(start: Path) -> Path:
    """沿父目录上爬找 .git / pyproject.toml。"""
    p = start.resolve()
    for ancestor in [p, *p.parents]:
        if (ancestor / ".git").exists() or (ancestor / "pyproject.toml").exists():
            return ancestor
    return start.resolve().parent


PROJECT_ROOT = _find_project_root(Path(__file__))
SCRIPT_DIR = Path(__file__).resolve().parent
OUTPUTS_DIR = SCRIPT_DIR / "outputs"

sys.path.insert(0, str(PROJECT_ROOT))

try:
    from dotenv import load_dotenv
    load_dotenv(PROJECT_ROOT / ".env")
except ImportError:
    pass


# ── 抓取 / 解析 ─────────────────────────────────────

HEADERS = {
    "User-Agent": (
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
        "AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0 Safari/537.36"
    ),
    "Accept": "text/html,application/xhtml+xml",
}

# 注意：用 .*? + 后面 </script> 固定锚点。lazy 的 \{.+?\} 在嵌套 JSON 上会断在第一个 }。
INITIAL_STATE_RE = re.compile(
    r"window\.__INITIAL_STATE__\s*=\s*(\{.*?\})\s*</script>", re.S
)


def _parse_initial_state(html: str) -> Dict[str, Any]:
    m = INITIAL_STATE_RE.search(html)
    if not m:
        raise RuntimeError("INITIAL_STATE not found（页面可能未渲染或被风控）")
    # SSR 直接把 JS undefined 当裸字面量塞了进来，json.loads 不接，先替换
    raw = re.sub(r":\s*undefined", ": null", m.group(1))
    return json.loads(raw)


def _coerce_int(v: Any) -> int:
    s = str(v or "").strip()
    if s.isdigit():
        return int(s)
    try:
        return int(float(s))
    except (ValueError, TypeError):
        return 0


def parse_post(html: str) -> Dict[str, Any]:
    """从 explore 页 HTML 解析出一个 post 字典（source.json 兼容格式）。"""
    data = _parse_initial_state(html)
    nd_map = ((data.get("note") or {}).get("noteDetailMap")) or {}
    if not nd_map:
        raise RuntimeError("noteDetailMap empty")
    nid, val = next(iter(nd_map.items()))
    note = (val or {}).get("note") or {}

    images = [
        (img.get("urlDefault") or img.get("url") or "")
        for img in (note.get("imageList") or [])
        if (img.get("urlDefault") or img.get("url"))
    ]
    interact = note.get("interactInfo") or {}

    return {
        "channel_content_id": nid,
        "title": note.get("title") or "",
        "content_type": note.get("type") or "note",
        "body_text": note.get("desc") or "",
        "like_count": _coerce_int(interact.get("likedCount")),
        "publish_timestamp": note.get("time") or "",
        "images": images,
        "videos": [],
        "channel": "xhs",
        "link": f"https://www.xiaohongshu.com/explore/{nid}",
    }


def fetch_one(client: httpx.Client, url: str) -> Dict[str, Any]:
    r = client.get(url, headers=HEADERS, follow_redirects=True, timeout=30.0)
    r.raise_for_status()
    return parse_post(r.text)


# ── 输出沙盒 ────────────────────────────────────────

def resolve_output_subdir(rel_path: Optional[str]) -> Path:
    """把 --output 解析到 OUTPUTS_DIR 之下，禁止绝对路径与 '..' 越界。"""
    if not rel_path:
        return OUTPUTS_DIR
    p = Path(rel_path)
    if p.is_absolute():
        raise SystemExit(f"ERROR: --output 必须是相对路径: {rel_path!r}")
    target = (OUTPUTS_DIR / p).resolve()
    try:
        target.relative_to(OUTPUTS_DIR.resolve())
    except ValueError:
        raise SystemExit(f"ERROR: --output 越界到 {target}（不允许 '..'）")
    return target


def safe_filename(post: Dict[str, Any]) -> str:
    title = post.get("title") or post.get("channel_content_id") or "untitled"
    safe = re.sub(r"[^\w一-龥]+", "_", title)[:40].strip("_")
    return f"xhs_{post['channel_content_id'][:12]}_{safe}.json"


# ── 输入收集 ────────────────────────────────────────

def load_urls(args) -> List[str]:
    urls: List[str] = []
    if args.urls_file:
        text = Path(args.urls_file).read_text(encoding="utf-8", errors="replace")
        urls.extend(
            line.strip()
            for line in text.splitlines()
            if line.strip() and not line.strip().startswith("#")
        )
    urls.extend(args.urls or [])
    if not urls:
        raise SystemExit(
            "ERROR: 请通过位置参数或 --urls-file 提供至少一个 URL"
        )
    return urls


# ── CLI ─────────────────────────────────────────────

def build_parser() -> argparse.ArgumentParser:
    p = argparse.ArgumentParser(
        description=__doc__,
        formatter_class=argparse.RawDescriptionHelpFormatter,
    )
    p.add_argument(
        "urls", nargs="*",
        help="小红书 explore URL（一个或多个，需带 xsec_token）",
    )
    p.add_argument(
        "--urls-file",
        help="URL 列表文件路径（每行一个 URL，# 开头为注释）",
    )
    p.add_argument(
        "--output",
        help="相对 outputs/ 的子目录路径，用于本次输出（默认直接写到 outputs/）",
    )
    p.add_argument(
        "--stdout", action="store_true",
        help="不写文件，把抓到的 post 数组打到 stdout（JSON）",
    )
    return p


def run(args) -> int:
    urls = load_urls(args)

    out_dir: Optional[Path] = None
    if not args.stdout:
        out_dir = resolve_output_subdir(args.output)
        out_dir.mkdir(parents=True, exist_ok=True)
        print(f"[info] outputs -> {out_dir}", file=sys.stderr)
    print(f"[info] urls={len(urls)}", file=sys.stderr)

    posts: List[Dict[str, Any]] = []
    failures = 0

    with httpx.Client() as client:
        for i, url in enumerate(urls, 1):
            short = url[:80]
            try:
                post = fetch_one(client, url)
            except Exception as e:
                failures += 1
                print(
                    f"[err  {i}/{len(urls)}] {type(e).__name__}: {e}  url={short}",
                    file=sys.stderr,
                )
                for attr in ("response", "body"):
                    obj = getattr(e, attr, None)
                    if obj is not None:
                        try:
                            text = obj.text if hasattr(obj, "text") else str(obj)
                            print(f"        server body: {text[:400]}", file=sys.stderr)
                        except Exception:
                            pass
                continue

            print(
                f"[info {i}/{len(urls)}] OK id={post['channel_content_id']} "
                f"title={post['title'][:30]!r} body={len(post['body_text'])} "
                f"imgs={len(post['images'])}",
                file=sys.stderr,
            )

            if args.stdout:
                posts.append(post)
            else:
                assert out_dir is not None
                path = out_dir / safe_filename(post)
                path.write_text(
                    json.dumps(post, ensure_ascii=False, indent=2),
                    encoding="utf-8",
                )
                print(f"        -> {path.relative_to(SCRIPT_DIR)}", file=sys.stderr)

    if args.stdout:
        json.dump(posts, sys.stdout, ensure_ascii=False, indent=2)
        sys.stdout.write("\n")

    ok = len(urls) - failures
    print(f"[info] done: ok={ok} fail={failures}", file=sys.stderr)
    if failures == 0:
        return 0
    if failures < len(urls):
        return 2
    return 1


def main():
    try:
        args = build_parser().parse_args()
        sys.exit(run(args))
    except KeyboardInterrupt:
        print("\n[info] interrupted by user (Ctrl+C)", file=sys.stderr)
        sys.exit(130)
    except SystemExit:
        raise
    except BaseException as e:
        import traceback
        print(f"\n!!! UNEXPECTED ERROR: {type(e).__name__}: {e}", file=sys.stderr)
        traceback.print_exc(file=sys.stderr)
        sys.exit(1)


if __name__ == "__main__":
    main()