"""
抓取微信“小程序话题”下的公众号文章（贴图）并输出为 JSON。

参考实现来源：
- server/src/api/WxAppmsgContent.ts
- server/src/services/content/appmsg/AppMsgService.ts

脚本参数

  --topic：话题名称，例如 #乡源文化挖掘
  --out：输出文件名，默认 data.json

输出

  JSON 数组，每条为 AppMsg：
  * outlinkId: int : 微信官方贴图的 ID，可以拿来去重
  * userId: int : 从小程序传来的用户ID
  * url: str : 实际跳转的 URL
  * title: str : 标题
  * images: List[str] : 封面图
  * content: str : 内容

用法（PowerShell / pwsh）：
  pwsh -NoProfile -Command "python ./collect-app-msg.py --topic '#乡源文化挖掘' --out data.json"

依赖：
  python -m pip install -U requests playwright
  python -m playwright install chromium
"""

from __future__ import annotations

import argparse
import json
import re
import time
from dataclasses import dataclass, asdict
from typing import Any, Dict, Iterable, List, Optional, Tuple, Set

import requests


TOPIC_LIST_ENDPOINT = "https://mp.weixin.qq.com/mp/appmsgtopic"
UA = (
    "Mozilla/5.0 (Windows NT 10.0; Win64; x64) "
    "AppleWebKit/537.36 (KHTML, like Gecko) "
    "Chrome/91.0.4472.124 Safari/537.36"
)


@dataclass
class AppMsg:
    # 结构同 server/src/models/content/appmsg/AppMsgModel.ts
    outlinkId: int = 0
    userId: int = 0
    url: str = ""
    title: str = ""
    images: List[str] = None  # type: ignore[assignment]
    content: str = ""

    def __post_init__(self) -> None:
        if self.images is None:
            self.images = []


def _lazy_import_playwright():
    """
    延迟导入 Playwright，避免未安装时报错（只有用户选择浏览器抓取才需要）。
    """
    try:
        from playwright.sync_api import sync_playwright  # type: ignore

        return sync_playwright
    except Exception as e:
        raise RuntimeError(
            "Playwright 未安装或不可用。请执行：python -m pip install -U playwright && python -m playwright install chromium"
        ) from e

def _load_existing_appmsgs(path: str) -> List[Dict[str, Any]]:
    try:
        # 兼容：历史文件可能是 utf-8 或 utf-8-sig（带 BOM）
        try:
            with open(path, "r", encoding="utf-8-sig") as f:
                data = json.load(f)
        except UnicodeError:
            with open(path, "r", encoding="utf-8") as f:
                data = json.load(f)
        if isinstance(data, list):
            return [x for x in data if isinstance(x, dict)]
    except FileNotFoundError:
        return []
    except json.JSONDecodeError:
        # 文件存在但不是合法 JSON：当作无历史数据
        return []
    return []


def _build_seen_keys(existing: List[Dict[str, Any]]) -> Set[str]:
    """
    用 outlinkId 优先去重；缺失时用 url 兜底。
    """
    seen: Set[str] = set()
    for it in existing:
        outlink_id = it.get("outlinkId")
        if isinstance(outlink_id, int) and outlink_id:
            seen.add(f"id:{outlink_id}")
        url = it.get("url")
        if isinstance(url, str) and url:
            seen.add(f"url:{url}")
    return seen


def _topic_msg_key(topic_msg: Dict[str, Any]) -> Tuple[Optional[str], Optional[int], Optional[str]]:
    outlink_id: Optional[int] = None
    try:
        outlink_id = int(((topic_msg.get("id") or {}).get("msgid")) or 0) or None
    except Exception:
        outlink_id = None
    url = topic_msg.get("jump_url")
    if not isinstance(url, str) or not url:
        url = None
    key = None
    if outlink_id:
        key = f"id:{outlink_id}"
    elif url:
        key = f"url:{url}"
    return key, outlink_id, url


def _requests_session() -> requests.Session:
    s = requests.Session()
    s.headers.update(
        {
            "User-Agent": UA,
            "Accept": "application/json,text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
            "Accept-Language": "zh-CN,zh;q=0.9,en;q=0.8",
        }
    )
    return s


def get_topic_list(
    sess: requests.Session, *, topic: str, paging: str = ""
) -> Dict[str, Any]:
    """
    等价于 WxAppmsgContentApi.getTopicList：
    GET /mp/appmsgtopic?action=topic_list&topic=...&paging=...&f=json...
    """
    params = {
        "action": "topic_list",
        "topic": topic,
        "paging": paging or "",
        "sort_type": 1,
        "from": 1,
        # 下面这些字段在 TS 侧是固定值/空值，保持一致以提高兼容性
        "from_biz": 3636524509,
        "from_msgid": 2247483692,
        "from_itemidx": 1,
        "appid": "",
        "silent": 1,
        "uin": 0,
        "key": "",
        "pass_ticket": "",
        "wxtoken": "",
        "devicetype": "",
        "clientversion": "false",
        "version": "false",
        "appmsg_token": "",
        "x5": 0,
        "f": "json",
        "user_article_role": 0,
    }
    r = sess.get(TOPIC_LIST_ENDPOINT, params=params, timeout=30)
    r.raise_for_status()
    data = r.json()
    # 微信侧常见返回：{ code, message, ... } 或直接业务字段
    if isinstance(data, dict) and "code" in data and data.get("code") not in (None, 0):
        raise RuntimeError(f"topic_list failed: code={data.get('code')} message={data.get('message')}")
    return data


def parse_cgi_data_new_from_html(html: str) -> Dict[str, Any]:
    raise RuntimeError("已移除基于 HTML 的解析方式，请使用 Playwright 读取 window.cgiDataNew")


def get_appmsg_detail_via_playwright(url: str, *, timeout_ms: int = 30000) -> Dict[str, Any]:
    """
    使用浏览器直接读取 window.cgiDataNew（最接近“页面真实运行态”）。
    优点：避免 HTML 文本解析/对象字面量兼容问题。
    """
    sync_playwright = _lazy_import_playwright()
    with sync_playwright() as p:
        browser = p.chromium.launch(headless=True)
        context = browser.new_context(
            user_agent=UA,
            locale="zh-CN",
            extra_http_headers={
                "Accept-Language": "zh-CN,zh;q=0.9,en;q=0.8",
            },
        )
        page = context.new_page()
        try:
            page.goto(url, wait_until="domcontentloaded", timeout=timeout_ms)
            data = page.evaluate(
                """() => {
                  const d = (globalThis && globalThis.cgiDataNew) ? globalThis.cgiDataNew : (window && window.cgiDataNew);
                  if (!d) return null;
                  return JSON.parse(JSON.stringify(d));
                }"""
            )
            # python side validation
            if not isinstance(data, dict):
                raise RuntimeError("window.cgiDataNew not found or not an object")
            return data
        finally:
            try:
                context.close()
            finally:
                browser.close()


def get_appmsg_detail(sess: requests.Session, url: str) -> Dict[str, Any]:
    # 已移除 json5 / node 的 HTML 解析逻辑，统一走浏览器读取 window.cgiDataNew
    return get_appmsg_detail_via_playwright(url)


def _extract_user_id_from_detail(detail: Dict[str, Any]) -> int:
    """
    复刻 AppMsgService.collectAppMsgContent 中的 userId 推导逻辑。
    """
    try:
        eps = detail.get("ext_publish_source") or {}
        weapp = eps.get("weapp_info") or {}
        desc = weapp.get("desc") or ""
        if isinstance(desc, str) and desc.startswith("亮乡源话题"):
            m = re.search(r"亮乡源话题(\d+)", desc)
            if m:
                return int(m.group(1))
    except Exception:
        pass
    return 0


def _extract_images_from_detail(detail: Dict[str, Any]) -> List[str]:
    pics = detail.get("picture_page_info_list") or []
    images: List[str] = []
    if isinstance(pics, list):
        for it in pics:
            if isinstance(it, dict):
                url = it.get("cdn_url")
                if isinstance(url, str) and url:
                    images.append(url)
    return images


def build_appmsg(topic_msg: Dict[str, Any], detail: Dict[str, Any]) -> AppMsg:
    outlink_id = 0
    try:
        outlink_id = int(((topic_msg.get("id") or {}).get("msgid")) or 0)
    except Exception:
        outlink_id = 0

    url = topic_msg.get("jump_url") or ""
    if not isinstance(url, str):
        url = ""

    title = detail.get("title") or ""
    if not isinstance(title, str):
        title = ""

    content = detail.get("content_noencode") or ""
    if not isinstance(content, str):
        content = ""

    return AppMsg(
        id=0,
        outlinkId=outlink_id,
        userId=_extract_user_id_from_detail(detail),
        url=url,
        title=title,
        images=_extract_images_from_detail(detail),
        content=content,
    )


def collect_topic_appmsgs(
    *,
    topic: str,
    max_pages: int = 10,
    sleep_sec: float = 0.3,
    seen_keys: Optional[Set[str]] = None,
) -> List[AppMsg]:
    sess = _requests_session()
    paging = ""
    page = 0
    results: List[AppMsg] = []
    local_seen: Set[str] = set(seen_keys or set())

    while True:
        page += 1
        if max_pages > 0 and page > max_pages:
            break

        data = get_topic_list(sess, topic=topic, paging=paging)
        topic_msgs = data.get("topic_msgs") or []
        if not isinstance(topic_msgs, list):
            break

        page_has_new = False
        for item in topic_msgs:
            if not isinstance(item, dict):
                continue

            key, outlink_id, jump_url = _topic_msg_key(item)
            if key and key in local_seen:
                continue
            if not jump_url:
                continue

            # 只有未抓取过的条目才请求详情页
            detail = get_appmsg_detail(sess, jump_url)
            appmsg = build_appmsg(item, detail)

            # 标记为已抓取
            if appmsg.outlinkId:
                local_seen.add(f"id:{appmsg.outlinkId}")
            if appmsg.url:
                local_seen.add(f"url:{appmsg.url}")
            results.append(appmsg)
            page_has_new = True

            if sleep_sec > 0:
                time.sleep(sleep_sec)

        # 如果这一页全部在已有 JSON 中（没有任何新条目），终止后续翻页
        if not page_has_new:
            break

        paging = data.get("topic_paging") or ""
        if not isinstance(paging, str) or not paging:
            break

        # 如果本页没抓到任何内容，就停止继续翻页
        if len(topic_msgs) == 0:
            break

    return results


def main(argv: Optional[List[str]] = None) -> int:
    parser = argparse.ArgumentParser(description="抓取微信话题下的公众号文章（贴图）并输出 JSON")
    parser.add_argument("--topic", required=True, help="话题名称，例如：#乡源文化挖掘")
    parser.add_argument("--out", default="data.json", help="输出文件名，默认 data.json")
    parser.add_argument("--max-pages", type=int, default=10, help="最多抓取页数，默认 10（<=0 表示不限制）")
    parser.add_argument("--sleep", type=float, default=0.3, help="每条之间的延迟秒数，默认 0.3")
    args = parser.parse_args(argv)

    existing = _load_existing_appmsgs(args.out)
    seen = _build_seen_keys(existing)

    new_appmsgs = collect_topic_appmsgs(
        topic=args.topic,
        max_pages=args.max_pages,
        sleep_sec=args.sleep,
        seen_keys=seen,
    )
    new_payload = [asdict(x) for x in new_appmsgs]

    # 保存时：最新抓到的放在最上面；并按 outlinkId/url 去重（新覆盖旧）
    merged: List[Dict[str, Any]] = []
    merged_seen: Set[str] = set()
    for it in new_payload + existing:
        if not isinstance(it, dict):
            continue
        key: Optional[str] = None
        outlink_id = it.get("outlinkId")
        url = it.get("url")
        if isinstance(outlink_id, int) and outlink_id:
            key = f"id:{outlink_id}"
        elif isinstance(url, str) and url:
            key = f"url:{url}"
        if key and key in merged_seen:
            continue
        if key:
            merged_seen.add(key)
        merged.append(it)

    # 写出 utf-8-sig（带 BOM），避免部分 Windows 工具按 ANSI/GBK 误判导致“中文乱码”
    with open(args.out, "w", encoding="utf-8-sig") as f:
        json.dump(merged, f, ensure_ascii=False, indent=2)

    print(
        f"OK: topic={args.topic} new={len(new_payload)} total={len(merged)} out={args.out}"
    )
    return 0


if __name__ == "__main__":
    raise SystemExit(main())