WechatOnCloud/bridge/woc_bridge/messaging/friend_watcher.py

"""好友申请监听器：轮询 fmessage 系统消息，解析后触发自动通过。

独立后台协程，不侵入 MessageStreamer 架构。复用其 mtime 感知 +
复合游标 (create_time, local_id) 增量检测模式，但独立游标与频率控制。

auto_accept 关闭时挂起在 asyncio.Event 上，不轮询 DB。
DB_ENCRYPTED 时 _init_cursor 返回 False，每轮重试初始化。
"""

from __future__ import annotations

import asyncio
import logging
from dataclasses import dataclass
from typing import Optional

from woc_bridge.models import AcceptDecision, BridgeError
from woc_bridge.messaging.friend_parser import parse_friend_request

logger = logging.getLogger("woc-bridge")


@dataclass
class FriendRequestInfo:
    """好友申请信息（从 fmessage sysmsg XML 解析）。"""
    stranger_wxid: str          # 申请人 wxid（含 @stranger 后缀）
    nickname: str               # 申请人昵称
    verify_message: str         # 验证消息内容
    scene: str                  # 来源场景（如群聊/搜索/二维码）
    raw_xml: str                # 原始 XML（调试用）
    create_time: int            # 消息时间戳
    msg_local_id: int           # 消息 local_id（游标用）


class FriendRequestWatcher:
    """好友申请监听器：轮询 fmessage 系统消息，解析后触发自动通过。"""

    def __init__(
        self,
        db_reader,          # DbReader（避免类型注解循环 import）
        rule_engine,        # AcceptRuleEngine
        send_queue,         # SendQueue
        idem_cache,         # IdemCache
        xdotool_driver,     # XdotoolDriver
        breaker,            # CircuitBreaker
        poll_interval: float = 3.0,
        cursor_create_time: int = 0,
        cursor_local_id: int = 0,
    ) -> None:
        self._db_reader = db_reader
        self._rule_engine = rule_engine
        self._send_queue = send_queue
        self._idem_cache = idem_cache
        self._xdotool = xdotool_driver
        self._breaker = breaker
        self._poll_interval = poll_interval
        # 复合游标 (create_time, local_id)，与 get_friend_requests_since 返回值对齐
        self._cursor_create_time: int = cursor_create_time
        self._cursor_local_id: int = cursor_local_id
        self._last_db_mtime: float = 0.0
        self._last_wal_mtime: float = 0.0
        self._watcher: Optional[asyncio.Task] = None
        self._enabled_event: asyncio.Event = asyncio.Event()  # auto_accept 开关事件
        self._cursor_inited: bool = False
        # 上轮满载标志：为 True 时跳过 mtime 一级过滤，避免批量积压（>50 条）时
        # 剩余批次因 DB mtime 未变被卡住
        self._has_more_pending: bool = False

        # 状态统计（供 /api/friends/auto_accept/status 查询）
        self._processed_count: int = 0
        self._accepted_count: int = 0
        self._rejected_count: int = 0
        self._last_processed_time: Optional[int] = None

    @property
    def is_running(self) -> bool:
        return self._watcher is not None and not self._watcher.done()

    @property
    def is_enabled(self) -> bool:
        return self._enabled_event.is_set()

    @property
    def processed_count(self) -> int:
        return self._processed_count

    @property
    def accepted_count(self) -> int:
        return self._accepted_count

    @property
    def rejected_count(self) -> int:
        return self._rejected_count

    @property
    def last_processed_time(self) -> Optional[int]:
        return self._last_processed_time

    async def start(self) -> None:
        if self._watcher is None or self._watcher.done():
            self._watcher = asyncio.create_task(self._watch_loop())
            logger.info("FriendRequestWatcher 已启动")

    async def stop(self) -> None:
        if self._watcher is not None and not self._watcher.done():
            self._watcher.cancel()
            try:
                await self._watcher
            except asyncio.CancelledError:
                pass
        self._watcher = None

    def set_enabled(self, enabled: bool) -> None:
        if enabled:
            # 开启时重置游标，避免批量处理积压申请
            self._cursor_inited = False
            self._has_more_pending = False
            self._enabled_event.set()
        else:
            self._enabled_event.clear()
        logger.info("FriendRequestWatcher enabled=%s", enabled)

    async def _init_cursor(self) -> bool:
        """对齐游标到当前 fmessage 表最大 create_time。

        Returns:
            True 表示已对齐（或 DB 不可读但标记为已初始化，避免无限重试）
            False 表示异常，下一轮重试
        """
        try:
            max_ct = await asyncio.to_thread(
                self._db_reader.get_max_create_time_for_talker, "fmessage"
            )
            if max_ct is None:
                # DB 不可读（_ensure_decrypted 抛 BridgeError 已被吞掉返回 None）
                # 不标记 _cursor_inited，下一轮重试
                logger.warning("FriendRequestWatcher 游标初始化: DB 不可读，将在下轮重试")
                return False
            if max_ct and max_ct > 0:
                self._cursor_create_time = max_ct
                self._cursor_local_id = 0
                logger.info(
                    "FriendRequestWatcher 游标对齐到 create_time=%d（跳过历史申请）",
                    self._cursor_create_time,
                )
            # 无论 max_ct 是否为 0（空表），都标记为已初始化，避免空表时无限重试
            self._cursor_inited = True
            return True
        except Exception as e:
            logger.warning("FriendRequestWatcher 游标初始化失败: %s", e)
            return False

    async def _poll_once(self) -> None:
        # 1. mtime 感知（一级过滤，避免空 SQL）
        #    上轮满载时跳过过滤（仍有未读批次），否则会因 DB mtime 未变卡住剩余申请
        mtimes = await asyncio.to_thread(
            self._db_reader.get_db_mtime, "message/message_0.db"
        )
        if mtimes is None:
            return
        db_mtime, wal_mtime = mtimes
        if not self._has_more_pending:
            if db_mtime == self._last_db_mtime and wal_mtime == self._last_wal_mtime:
                return
        self._last_db_mtime = db_mtime
        self._last_wal_mtime = wal_mtime

        # 2. 查询 fmessage 分片表增量消息（复合游标）
        result = await asyncio.to_thread(
            self._db_reader.get_friend_requests_since,
            self._cursor_create_time,
            self._cursor_local_id,
            50,  # limit
        )
        if result is None:
            # DB 不可读（_ensure_decrypted 抛 BridgeError）
            return

        raw_items: list[dict] = result["requests"]

        # 3. 解析 XML + 逐条处理
        for item in raw_items:
            info = parse_friend_request(
                item["content"], item["create_time"], item["local_id"]
            )
            if info is None:
                # 非 verifyUser 类型或解析失败，跳过
                continue
            await self._handle_request(info)

        # 4. 推进复合游标（与 get_friend_requests_since 返回字段对齐）
        self._cursor_create_time = result["next_create_time"]
        self._cursor_local_id = result["next_local_id"]

        # 5. 满载标志：本批达 limit 则置 True，下轮跳过 mtime 过滤继续读剩余批次
        self._has_more_pending = len(raw_items) >= 50

    async def _watch_loop(self) -> None:
        while True:
            try:
                # auto_accept 关闭时挂起，避免空轮询
                await self._enabled_event.wait()

                # 游标未初始化时先对齐（DB 恢复可读后自动补齐）
                # DB_ENCRYPTED 时 _init_cursor 返回 False，下一轮仍会重试
                if not self._cursor_inited:
                    await self._init_cursor()
                    if not self._cursor_inited:
                        # DB 仍不可读，本轮跳过 _poll_once
                        await asyncio.sleep(self._poll_interval)
                        continue

                await asyncio.sleep(self._poll_interval)
                await self._poll_once()
            except asyncio.CancelledError:
                raise
            except Exception as e:
                logger.exception("FriendRequestWatcher 异常: %s", e)
                await asyncio.sleep(5.0)

    async def _handle_request(self, req: FriendRequestInfo) -> None:
        self._processed_count += 1
        self._last_processed_time = req.create_time

        # 1. 规则匹配
        decision = await self._rule_engine.evaluate(req)
        if decision == AcceptDecision.REJECT:
            self._rejected_count += 1
            logger.info(
                "friend_request: wxid=%s nickname=%s → decision=%s（拒绝）",
                req.stranger_wxid, req.nickname, decision.value,
            )
            return
        if decision != AcceptDecision.ACCEPT:
            logger.info(
                "friend_request: wxid=%s nickname=%s → decision=%s（跳过）",
                req.stranger_wxid, req.nickname, decision.value,
            )
            return

        # 2. 幂等去重（TTL=300s，5 分钟内不重复处理同一申请人）
        #    content 参数传空串（去重 key 是 stranger_wxid，无内容维度）
        cached = self._idem_cache.get(
            "friend_accept", req.stranger_wxid, "", ""
        )
        if cached is not None:
            logger.info(
                "friend_request: wxid=%s → 幂等命中，跳过",
                req.stranger_wxid,
            )
            return

        # 3. 熔断检查
        if not self._breaker.allow():
            logger.warning(
                "friend_request: wxid=%s → 熔断器 OPEN，跳过",
                req.stranger_wxid,
            )
            return

        # 4. 入队执行（lambda 用默认参数捕获 req，避免延迟执行时变量被覆盖）
        try:
            result = await self._send_queue.enqueue(
                lambda req=req: self._xdotool.accept_friend_request(
                    stranger_wxid=req.stranger_wxid,
                    nickname=req.nickname,
                ),
                delay_ms=None,  # 使用 send_queue 默认间隔
            )

            # 5. 等待微信 DB WAL 刷盘后校验（微信 DB 写入有 1-3s 延迟）
            await asyncio.sleep(2.0)
            verified = await asyncio.to_thread(
                self._db_reader.verify_friend_accepted, req.stranger_wxid
            )

            if verified:
                # set 签名: (flow_name, to_wxid, content, value, client_request_id)
                self._idem_cache.set(
                    "friend_accept", req.stranger_wxid, "",
                    {"success": True, "verified": True}, "",
                )
                self._breaker.record_success()
                self._accepted_count += 1
                logger.info(
                    "friend_request: wxid=%s nickname=%s → 通过并验证成功",
                    req.stranger_wxid, req.nickname,
                )
            else:
                # UI 操作完成但 DB 校验未通过（可能有延迟）
                self._idem_cache.set(
                    "friend_accept", req.stranger_wxid, "",
                    {"success": True, "verified": False}, "",
                )
                self._breaker.record_failure()
                logger.warning(
                    "friend_request: wxid=%s → UI 操作完成但 DB 校验未通过",
                    req.stranger_wxid,
                )
        except BridgeError as e:
            # 透传 BridgeError 错误码（RATE_LIMITED / SEND_FAILED / WINDOW_NOT_FOUND 等）
            self._breaker.record_failure()
            logger.error(
                "friend_request: wxid=%s → BridgeError code=%s: %s",
                req.stranger_wxid, getattr(e, "code", "UNKNOWN"), e,
            )
        except Exception as e:
            self._breaker.record_failure()
            logger.error(
                "friend_request: wxid=%s → 失败: %s",
                req.stranger_wxid, e,
            )