#!/usr/bin/env node
/**
 * dshlog.mjs — DSH 平台「多节点日志采集 / 实时巡检 / 事后溯源」单一入口（方案 C：零新增常驻服务）
 *
 * 设计边界（2026-09-18 定）
 *   · 服务器侧**零安装**：远端只用系统自带的 `journalctl`，采集靠 ssh 一次性拉取，不装 agent、不开监听口
 *   · 归档在**本机**：`E:/dsh-logs/<host>/<YYYY-MM-DD>.ndjson.gz`（可按天清理）
 *   · 日志原文**保真**：`msg` 字段逐字节原样落盘（本项目大量判据依赖日志原文的行数/字节数）
 *   · 失败**可分**：远端元信息走 stderr 哨兵 `__DSHLOG_EOF__`，与 stdout 的纯数据分离
 *     ⇒ "拉取失败" 与 "确无日志" 永不混淆（这是本项目反复踩过的坑）
 *
 * 子命令
 *   collect  拉取归档（增量，默认只拉「上次游标之后」）
 *   ls       列出归档分片
 *   q        关键词/正则查询（跨机跨单元）
 *   timeline 时间线重建（多机日志按时间戳合并，用于事后溯源）
 *   watch    实时巡检（规则命中 → 判据表 + 非零退出码，可挂 automation）
 *   stats    归档统计
 *
 * 约定
 *   · 时间一律走 epoch（`--since @<epoch>`；⛔ journalctl 不吃 date -Is 的时区偏移）
 *   · 归档根可用 `DSHLOG_ROOT` 覆盖，默认 `E:/dsh-logs`
 */

import { spawnSync } from "node:child_process";
import {
  appendFileSync, existsSync, mkdirSync, readdirSync, readFileSync, statSync, unlinkSync, writeFileSync,
} from "node:fs";
import { createGunzip, gzipSync } from "node:zlib";
import { createReadStream } from "node:fs";
import { createInterface } from "node:readline";
import path from "node:path";

// ───────────────────────────── 配置 ─────────────────────────────

const ROOT = process.env.DSHLOG_ROOT || "E:/dsh-logs";
const STATE = path.join(ROOT, "state.json");
const HOSTS_FILE = path.join(ROOT, "hosts.json");

// 主机表从配置读取（⛔ 不在代码里写死地址 / ssh 别名）：
//   DSHLOG_HOSTS='{"mgr":{"ssh":["-p","22","root@10.0.0.1"],"label":"manager"}}'
// 未配置 ⇒ 空表，`hosts` 子命令会提示先配置。
const DEFAULT_HOSTS = (() => {
  const raw = process.env.DSHLOG_HOSTS ?? "";
  if (raw.trim() === "") return {};
  try {
    return JSON.parse(raw);
  } catch (e) {
    console.error("DSHLOG_HOSTS 不是合法 JSON：", String(e));
    return {};
  }
})();

// 巡检规则：只认**指向本项目自身故障**的信号。
// ⚠️ 每条规则都是误报与漏报的取舍 —— 下面两组是实测调过的：
//   · WATCH-01 不能只写 `fatal`：sshd 的 `ssh_dispatch_run_fatal`（客户端网络断）会天天命中
//   · WATCH-08 不能写 `Stopped .*`：实例正常退出、用户主动停会话都会打 `Stopped /usr/bin/bwrap …`
const SEV_RULES = [
  ["WATCH-01", "进程级致命", /PANIC|FATAL ERROR|unhandledRejection|uncaughtException|SIGSEGV|core dumped|segfault/i],
  ["WATCH-02", "内存/被杀", /out of memory|oom-kill|oom_reaper|Killed process|ENOMEM/i],
  ["WATCH-03", "端口/连接失败", /EADDRINUSE|ECONNREFUSED|ECONNRESET|ETIMEDOUT|EHOSTUNREACH|EPIPE/i],
  ["WATCH-04", "权限/属主异常", /EACCES|EPERM|permission denied/i],
  ["WATCH-05", "磁盘/写入失败", /ENOSPC|no space left|read-only file system|EROFS/i],
  ["WATCH-06", "覆盖网络信任链被拒", /no-trusted-keys|取目录全部失败|信任链被拒|reject.{0,12}trust/i],
  ["WATCH-07", "HTTP 5xx", /"statusCode":5\d\d|status=5\d\d/i],
  ["WATCH-08", "服务异常终止", /Failed with result|start request repeated|Main process exited, code=(exited|killed)|crash|panic exit/i],
];

// 登录/编排类噪声单元：命中规则也不计（否则 sshd 连接超时会天天冒充"故障"）
const NOISE_UNITS = /^sshd\.service$|^crond\.service$|^systemd-logind\.service$/;

// ───────────────────────────── 小工具 ─────────────────────────────

const nowSec = () => Math.floor(Date.now() / 1000);
const pad = (n) => String(n).padStart(2, "0");
const dayStr = (d = new Date()) => `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())}`;
const tsLocal = (ms) => {
  const d = new Date(ms);
  return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())} ${pad(d.getHours())}:${pad(d.getMinutes())}:${pad(d.getSeconds())}`;
};

/** `--k v` / `--flag` 两种形态都吃 */
function parseArgs(argv) {
  const o = { _: [] };
  for (let i = 0; i < argv.length; i++) {
    const a = argv[i];
    if (a.startsWith("--")) {
      const k = a.slice(2);
      const nxt = argv[i + 1];
      if (nxt === undefined || nxt.startsWith("--")) o[k] = true;
      else { o[k] = nxt; i++; }
    } else o._.push(a);
  }
  return o;
}

/** `1h` / `30m` / `2d` / 纯秒 ⇒ 秒数 */
function dur2sec(s) {
  if (s === undefined || s === true) return null;
  const m = String(s).match(/^(\d+(?:\.\d+)?)([smhd]?)$/);
  if (!m) return null;
  const n = parseFloat(m[1]);
  return Math.round(n * ({ s: 1, m: 60, h: 3600, d: 86400 }[m[2] || "s"]));
}

function readJson(f, dflt) {
  try { return JSON.parse(readFileSync(f, "utf8")); } catch { return dflt; }
}
function loadHosts() {
  const h = readJson(HOSTS_FILE, null);
  return h && Object.keys(h).length ? h : DEFAULT_HOSTS;
}

// ───────────────────────── ssh（数据走 stdout，元信息走 stderr 哨兵） ─────────────────────────

/**
 * 远端执行的脚本：⛔ 只用 journalctl；⛔ 不写服务器任何文件（数据直出 stdout）。
 * 数据走 stdout（纯），元信息走 stderr（哨兵 + 行数 + 错误原文）⇒ 两条通道物理分离。
 * ⚠️ `awk` 既转发 stdout 又把行数写 stderr：这样"拉取失败"与"确无日志"永远可分。
 */
function remoteCollectScript({ sinceEpoch, untilEpoch, afterCursor, units, priority }) {
  const parts = [
    "set -u",
    "set -o pipefail",
    'J="journalctl --no-pager -o json"',
  ];
  // ⚠️ 239 也支持 --output-fields（实测：能砍掉约一半体积）
  //    版本号解析必须 `NR==1` —— `journalctl --version` 是**多行**输出，
  //    不加限定会让 V 变成 "239\n0" ⇒ `[: integer expression expected` ⇒ 静默退回全字段（体积翻倍）
  parts.push('V=$(journalctl --version 2>/dev/null | awk \'NR==1{print $2+0}\')');
  parts.push('if [ "${V:-0}" -ge 236 ] 2>/dev/null; then J="$J --output-fields=__REALTIME_TIMESTAMP,__CURSOR,_SYSTEMD_UNIT,_HOSTNAME,SYSLOG_IDENTIFIER,_PID,PRIORITY,MESSAGE"; fi');
  if (sinceEpoch) parts.push(`J="$J --since @${sinceEpoch}"`);
  if (untilEpoch) parts.push(`J="$J --until @${untilEpoch}"`);
  if (afterCursor) parts.push(`J="$J --after-cursor='${afterCursor}'"`);
  if (priority) parts.push(`J="$J -p ${priority}"`);
  if (units && units.length) parts.push(`J="$J ${units.map((u) => `-u ${u}`).join(" ")}"`);
  parts.push(
    'eval "$J" 2>/tmp/.dshlog_err.$$ | awk \'{n++} {print} END{printf "__DSHLOG_LINES__ %d\\n", n > "/dev/stderr"}\'',
    "RC=$?",
    'EB=$(wc -c < /tmp/.dshlog_err.$$ 2>/dev/null || echo 0)',
    'head -c 2000 /tmp/.dshlog_err.$$ >&2',
    "rm -f /tmp/.dshlog_err.$$",
    'echo "__DSHLOG_EOF__ rc=$RC errbytes=$EB" >&2',
  );
  return parts.join("\n");
}

function sshRun(hostCfg, script, { timeoutMs = 120000 } = {}) {
  // 🔴 `-C` 不可省：47 的出方向未压缩带宽实测 ~20 KB/s（1.6 MB 要 84 s），
  //    开压缩后同样的数据 11 s（7.6×）。日志是 JSON ⇒ 压缩率极高，这是最大的单一杠杆。
  const r = spawnSync("ssh", ["-C", ...hostCfg.ssh, "bash -s"], {
    input: script, encoding: "utf8", timeout: timeoutMs, maxBuffer: 256 * 1024 * 1024,
  });
  const stderr = r.stderr || "";
  const sentinel = stderr.split("\n").filter((l) => l.startsWith("__DSHLOG_EOF__")).pop() || "";
  const m = sentinel.match(/rc=(\d+)\s+errbytes=(\d+)/);
  const rc = m ? parseInt(m[1], 10) : null;
  const errbytes = m ? parseInt(m[2], 10) : null;
  // 远端 journalctl 自己报告的输出行数（权威计数，用于与本地解析数对账）
  const lm = stderr.split("\n").filter((l) => l.startsWith("__DSHLOG_LINES__")).pop() || "";
  const lm2 = lm.match(/__DSHLOG_LINES__ (\d+)/);
  const remoteLines = lm2 ? parseInt(lm2[1], 10) : null;
  // 远端 journalctl 自身的错误（剔除 ssh 噪声与自家哨兵行）
  const remoteErr = stderr.split("\n")
    .filter((l) => l.trim() && !l.startsWith("__DSHLOG_EOF__") && !l.startsWith("__DSHLOG_LINES__")
      && !/post-quantum|store now, decrypt later|openssh.com\/pq|WARNING: connection is not using/i.test(l))
    .join("\n").trim();
  return {
    stdout: r.stdout || "",
    rc, errbytes, remoteLines, remoteErr,
    sshStatus: r.status,
    sshError: r.error ? String(r.error.message || r.error) : null,
  };
}

// ───────────────────────────── 归档读写 ─────────────────────────────

function hostDir(host) { return path.join(ROOT, host); }
function shardPath(host, day) { return path.join(hostDir(host), `${day}.ndjson.gz`); }

function appendShard(host, day, lines) {
  if (!lines.length) return 0;
  mkdirSync(hostDir(host), { recursive: true });
  const f = shardPath(host, day);
  // ⚠️ 必须同步写：异步 stream 在进程收尾时可能未 flush（会静默丢最后一批）
  // gzip 多成员文件可被 `gunzip` / `createGunzip` 顺序读回 ⇒ 追加安全
  appendFileSync(f, gzipSync(Buffer.from(lines.join("\n") + "\n", "utf8"), { level: 6 }));
  return lines.length;
}

async function* readShard(host, day) {
  const f = shardPath(host, day);
  if (!existsSync(f)) return;
  const rl = createInterface({ input: createReadStream(f).pipe(createGunzip()), crlfDelay: Infinity });
  for await (const line of rl) {
    if (!line.trim()) continue;
    try { yield JSON.parse(line); } catch { /* 损坏行跳过（不静默吞：由 stats 统计） */ }
  }
}

function listDays(host) {
  const d = hostDir(host);
  if (!existsSync(d)) return [];
  return readdirSync(d).filter((f) => f.endsWith(".ndjson.gz")).map((f) => f.replace(".ndjson.gz", "")).sort();
}

/** 归一：journald JSON ⇒ 统一记录（msg 保真） */
function normalize(rec, host) {
  const tsUs = rec.__REALTIME_TIMESTAMP ? Number(rec.__REALTIME_TIMESTAMP) : 0;
  let msg = rec.MESSAGE;
  if (Array.isArray(msg)) {
    // journald 对非 UTF-8 字节会给数组 ⇒ 转义回可读文本（保真：字节以 \xNN 形式保留）
    msg = msg.map((b) => (b >= 32 && b < 127 ? String.fromCharCode(b) : `\\x${b.toString(16).padStart(2, "0")}`)).join("");
  }
  return {
    ts: Math.floor(tsUs / 1000),
    host,
    unit: rec._SYSTEMD_UNIT || "",
    ident: rec.SYSLOG_IDENTIFIER || "",
    pid: rec._PID ? Number(rec._PID) : 0,
    pri: rec.PRIORITY ? Number(rec.PRIORITY) : 6,
    cursor: rec.__CURSOR || "",
    msg: typeof msg === "string" ? msg : JSON.stringify(msg ?? ""),
  };
}

// ───────────────────────────── collect ─────────────────────────────

/**
 * 校时：**以远端 NTP 同步状态为权威判据**，RTT 估算只作参考。
 * ⚠️ 别用"ssh 往返估算"当权威 —— 实测 47 的 ssh RTT 达 3.7s 且往返不对称，
 *    单次估算能给出 1.3s 的假偏移（比真实时钟差还大）⇒ 那样的校正会**制造**错序。
 */
function probeClock(cfg) {
  const r = sshRun(cfg, [
    'echo "__DSHLOG_NTP__ $(timedatectl show -p NTPSynchronized --value 2>/dev/null || echo unknown)"',
    'echo "__DSHLOG_OFF__ $(timedatectl show -p Offset --value 2>/dev/null || echo unknown)"',
    'echo "__DSHLOG_TM__ $(date +%s%N)"',
  ].join("\n"), { timeoutMs: 20000 });
  const all = `${r.stdout}\n${r.stderr}`;
  const synced = (all.match(/__DSHLOG_NTP__ (\S+)/) || [])[1] || "unknown";
  const offRaw = (all.match(/__DSHLOG_OFF__ (\S+)/) || [])[1] || "unknown";
  const tms = (all.match(/__DSHLOG_TM__ (\d+)/) || [])[1];
  return {
    ntpSynced: synced,
    ntpOffsetMs: offRaw !== "unknown" ? Math.round(Number(offRaw) / 1000) : null,
    remoteNowMs: tms ? Number(tms) / 1e6 : null,
    measuredAt: Date.now(),
  };
}

async function cmdCollect(args) {
  mkdirSync(ROOT, { recursive: true });
  const hosts = loadHosts();
  const want = args.hosts && args.hosts !== true ? String(args.hosts).split(",").map((s) => s.trim()) : Object.keys(hosts);
  const st = readJson(STATE, { hosts: {} });
  st.hosts = st.hosts || {};
  const since = dur2sec(args.since);
  const full = !!args.full;
  const backfill = !!since;                                   // 回填 = 显式给 --since（与"续拉"是两种语义）
  const chunk = args.chunk ? dur2sec(args.chunk) : Math.max(3600, Math.ceil((since || 3600) / 8));
  const rows = [];

  for (const h of want) {
    const cfg = hosts[h];
    if (!cfg) { rows.push([h, "SKIP", "hosts.json 无此节点", ""]); continue; }
    const prev = st.hosts[h] || {};

    // 回填必须去重（同一 cursor 已在归档里则跳过），否则重复落盘会污染行数类判据
    const seen = new Set();
    if (backfill) {
      for (const d of listDays(h)) for await (const r of readShard(h, d)) if (r.cursor) seen.add(r.cursor);
    }

    // 时间窗切块：单次 ssh 只搬一块 ⇒ 内存/传输受控，且任何一块失败可单独重试
    let windows;
    if (backfill) {
      const end = nowSec();
      windows = [];
      for (let t = end - since; t < end; t += chunk) windows.push([t, Math.min(t + chunk, end)]);
      if (!windows.length) windows = [[end - 60, end]];
    } else if (!full && prev.cursor) {
      windows = [[null, null]];                               // cursor 续拉（精确、不重不漏）
    } else {
      windows = [[nowSec() - 3600, nowSec()]];
    }

    const clock = probeClock(cfg);
    let ok = 0, bad = 0, dup = 0, written = 0, firstErr = "", jrcBad = null, mismatch = false, remoteReported = 0;
    let lastCursor = prev.cursor || "", lastTs = prev.lastTs || 0;
    const dayMap = {};

    for (const [from, to] of windows) {
      if (process.env.DSHLOG_VERBOSE) console.error(`  [${h}] 拉块 ${from === null ? "cursor" : tsLocal(from * 1000)} → ${to === null ? "now" : tsLocal(to * 1000)} …`);
      const res = sshRun(cfg, remoteCollectScript({
        sinceEpoch: from, untilEpoch: to, afterCursor: from === null ? prev.cursor : null,
      }), { timeoutMs: 600000 });
      const sshFailed = res.rc === null && res.sshStatus !== 0;
      if (sshFailed) { if (!firstErr) firstErr = res.sshError || "ssh 失败"; continue; }
      if (res.rc !== null && res.rc !== 0 && res.rc !== 1) { jrcBad = res.rc; }
      if (res.remoteLines !== null) remoteReported += res.remoteLines;
      if (res.remoteErr && !firstErr) firstErr = res.remoteErr.slice(0, 160);

      let chunkOk = 0, chunkBad = 0;
      for (const l of res.stdout.split("\n")) {
        if (!l.trim()) continue;
        let rec;
        try { rec = JSON.parse(l); } catch { bad++; chunkBad++; continue; }
        const n = normalize(rec, h);
        ok++; chunkOk++;
        if (backfill && n.cursor && seen.has(n.cursor)) { dup++; continue; }
        if (n.cursor) seen.add(n.cursor);
        if (n.cursor) lastCursor = n.cursor;
        if (n.ts > lastTs) lastTs = n.ts;
        const d = dayStr(new Date(n.ts));
        (dayMap[d] = dayMap[d] || []).push(JSON.stringify(n));
      }
      if (res.remoteLines !== null && res.remoteLines !== chunkOk + chunkBad) mismatch = true;
    }

    for (const [d, ls] of Object.entries(dayMap)) written += appendShard(h, d, ls);

    const state = firstErr && ok === 0 ? "FAIL"
      : jrcBad !== null ? `JOURNALCTL_RC${jrcBad}`
        : mismatch ? "MISMATCH"
          : ok === 0 ? "EMPTY" : "OK";
    st.hosts[h] = {
      cursor: lastCursor, lastTs, lastRun: Date.now(),
      ntpSynced: clock.ntpSynced, ntpOffsetMs: clock.ntpOffsetMs,
      lastState: state, lastLines: ok, lastWritten: written, lastDup: dup, lastRemoteLines: remoteReported,
    };
    let detail = `拉取 ${ok} 行`;
    if (remoteReported) detail += ` / 远端报 ${remoteReported}`;
    if (dup) detail += ` · 去重跳 ${dup}`;
    if (written) detail += ` · 落盘 ${written}`;
    if (bad) detail += ` · 解析失败 ${bad}`;
    if (firstErr) detail += ` · err: ${firstErr.slice(0, 120)}`;
    rows.push([h, state, detail,
      `${windows.length} 块` + (backfill ? ` since @${nowSec() - since}` : " cursor 续拉")
      + ` · NTP ${clock.ntpSynced}` + (clock.ntpOffsetMs === null ? "" : `(${clock.ntpOffsetMs}ms)`)]);
  }
  writeFileSync(STATE, JSON.stringify(st, null, 2), "utf8");
  if (!args.quiet) printTable(["节点", "状态", "结果", "方式"], rows, args);
  const badRows = rows.filter((r) => !["OK", "EMPTY", "SKIP"].includes(r[1]));
  if (badRows.length) process.exitCode = 2;
  return rows;
}

// ───────────────────────────── prune（保留策略） ─────────────────────────────

function cmdPrune(args) {
  const keep = args.keep ? Number(args.keep) : 3;   // 与服务器侧口径一致：3 天
  const cut = dayStr(new Date(Date.now() - keep * 86400e3));
  const hosts = loadHosts();
  const rows = [];
  let total = 0;
  for (const h of Object.keys(hosts)) {
    for (const d of listDays(h)) {
      if (d >= cut) continue;
      const p = shardPath(h, d);
      const sz = statSync(p).size;
      total += sz;
      if (args.apply) { try { unlinkSync(p); rows.push([h, d, "已删除", `${(sz / 1e6).toFixed(2)} MB`]); } catch (e) { rows.push([h, d, "删除失败", String(e.message).slice(0, 60)]); } }
      else rows.push([h, d, "待删（干跑）", `${(sz / 1e6).toFixed(2)} MB`]);
    }
  }
  printTable(["节点", "日期", "动作", "大小"], rows, args);
  console.log(`保留 ${keep} 天 ⇒ 截止 ${cut}${args.apply ? " · 已执行" : " · 干跑（加 --apply 才真删）"}｜涉及 ${(total / 1e6).toFixed(2)} MB`);
}

// ───────────────────────────── ls / stats ─────────────────────────────

function cmdLs(args) {
  const hosts = loadHosts();
  const rows = [];
  for (const h of Object.keys(hosts)) {
    for (const d of listDays(h)) {
      const p = shardPath(h, d);
      rows.push([h, d, `${(statSync(p).size / 1024 / 1024).toFixed(2)} MB`]);
    }
  }
  printTable(["节点", "日期", "大小"], rows, args);
}

async function cmdStats(args) {
  const hosts = loadHosts();
  const st = readJson(STATE, { hosts: {} });
  const rows = [];
  for (const h of Object.keys(hosts)) {
    const s = (st.hosts || {})[h] || {};
    rows.push([h, s.lastState || "-", String(s.lastLines ?? "-"),
      s.lastRun ? tsLocal(s.lastRun) : "-",
      s.ntpSynced ? `${s.ntpSynced}${s.ntpOffsetMs === null || s.ntpOffsetMs === undefined ? "" : ` (${s.ntpOffsetMs}ms)`}` : "-",
      s.cursor ? s.cursor.slice(0, 24) + "…" : "-"]);
  }
  printTable(["节点", "末次状态", "行数", "末次拉取", "NTP", "游标"], rows, args);
  if (args.detail) {
    for (const h of Object.keys(hosts)) {
      for (const d of listDays(h)) {
        let n = 0; const units = new Map();
        for await (const r of readShard(h, d)) { n++; units.set(r.unit, (units.get(r.unit) || 0) + 1); }
        const top = [...units.entries()].sort((a, b) => b[1] - a[1]).slice(0, 4)
          .map(([u, c]) => `${u.replace(/\.service|\.scope/g, "")}=${c}`).join(" ");
        console.log(`  ${h} ${d}: ${n} 行 · ${top}`);
      }
    }
  }
}

// ───────────────────────────── q（查询） ─────────────────────────────

async function cmdQ(args) {
  const pat = args._[0];
  if (!pat) { console.error("用法: dshlog q <关键词|/正则/> [--since 6h] [--host 47] [--unit dshs] [--limit 100] [--json]"); process.exitCode = 2; return; }
  const re = pat.startsWith("/") && pat.endsWith("/") ? new RegExp(pat.slice(1, -1), "i") : new RegExp(pat.replace(/[.*+?^${}()|[\]\\]/g, "\\$&"), "i");
  const hosts = args.host && args.host !== true ? String(args.host).split(",") : Object.keys(loadHosts());
  const sinceMs = args.since ? Date.now() - dur2sec(args.since) * 1000 : 0;
  const untilMs = args.until ? Date.now() - dur2sec(args.until) * 1000 : Infinity;
  const unitRe = args.unit && args.unit !== true ? new RegExp(String(args.unit), "i") : null;
  const limit = args.limit ? Number(args.limit) : 100;
  const hits = [];
  let scanned = 0;
  for (const h of hosts) {
    for (const d of listDays(h)) {
      for await (const r of readShard(h, d)) {
        scanned++;
        if (r.ts < sinceMs || r.ts > untilMs) continue;
        if (unitRe && !unitRe.test(r.unit)) continue;
        if (!re.test(r.msg)) continue;
        hits.push(r);
        if (hits.length >= limit * 20) break;
      }
    }
  }
  hits.sort((a, b) => a.ts - b.ts);
  const show = hits.slice(-limit);
  if (args.json) console.log(JSON.stringify(show, null, 1));
  else {
    console.log(`命中 ${hits.length} 条（扫描 ${scanned} 行）⇒ 显示末 ${show.length} 条`);
    for (const r of show) console.log(`${tsLocal(r.ts)} [${r.host}/${r.unit.replace(/\.service|\.scope/g, "")}] ${r.msg.slice(0, 300)}`);
  }
  if (!show.length) process.exitCode = 1;
}

// ───────────────────────────── timeline（事后溯源） ─────────────────────────────

async function cmdTimeline(args) {
  const hosts = args.host && args.host !== true ? String(args.host).split(",") : Object.keys(loadHosts());
  const st = readJson(STATE, { hosts: {} });
  const from = args.from ? new Date(args.from).getTime() : Date.now() - 3600e3;
  const to = args.to ? new Date(args.to).getTime() : Date.now() + 60e3;
  const grep = args.grep && args.grep !== true ? new RegExp(String(args.grep), "i") : null;
  const priMax = args.pri ? Number(args.pri) : 7;
  const fix = !!args["fix-clock"];      // 默认不校正：NTP 偏差是"系统事实"，掩盖它反而会误导溯源
  const all = [];
  for (const h of hosts) {
    const hs = (st.hosts || {})[h] || {};
    const off = fix ? (hs.ntpOffsetMs || 0) : 0;
    for (const d of listDays(h)) {
      for await (const r of readShard(h, d)) {
        const t = r.ts - off;
        if (t < from || t > to) continue;
        if (r.pri > priMax) continue;
        if (grep && !grep.test(r.msg)) continue;
        all.push({ ...r, ts: t });
      }
    }
  }
  all.sort((a, b) => a.ts - b.ts || a.host.localeCompare(b.host));
  const out = args.out && args.out !== true ? args.out : null;
  const lines = all.map((r) =>
    `${tsLocal(r.ts)}.${String(r.ts % 1000).padStart(3, "0")} [${r.host.padEnd(3)}/${(r.unit || "-").replace(/\.service|\.scope/g, "").padEnd(16)}] pri=${r.pri} ${r.msg}`);
  if (out) { writeFileSync(out, lines.join("\n") + "\n", "utf8"); console.log(`已写 ${all.length} 行 ⇒ ${out}`); }
  else { console.log(`时间线 ${all.length} 行（${tsLocal(from)} → ${tsLocal(to)}）`); for (const l of lines) console.log(l); }
  const ntpNote = hosts.map((h) => {
    const hs = (st.hosts || {})[h] || {};
    return `${h}: NTP=${hs.ntpSynced || "?"}${hs.ntpOffsetMs === undefined || hs.ntpOffsetMs === null ? "" : `(偏差${hs.ntpOffsetMs}ms)`}`;
  }).join(" · ");
  console.log(`# 时钟状态 ${ntpNote}${fix ? " · 已按偏差校正（--fix-clock）" : " · 未校正（原始系统时间戳）"}`);
}

// ───────────────────────────── watch（实时巡检） ─────────────────────────────

async function cmdWatch(args) {
  const since = args.since ? dur2sec(args.since) : 900;          // 默认 15 分钟窗口
  const hosts = args.host && args.host !== true ? String(args.host).split(",") : Object.keys(loadHosts());
  // 默认先增量续拉（cursor 只搬新行，代价极小）⇒ 挂 automation 时只需这一条命令
  if (!args["no-collect"]) {
    try { await cmdCollect({ hosts: args.host, quiet: !args.verbose, json: args.json }); }
    catch (e) { console.error(`⚠ 预拉取失败（继续按现有归档巡检）: ${e.message}`); }
  }
  const from = Date.now() - since * 1000;
  const counts = new Map();   // ruleId -> [{host,ts,msg}]
  const byUnit = new Map();
  let total = 0, priErr = 0;
  for (const h of hosts) {
    for (const d of listDays(h)) {
      for await (const r of readShard(h, d)) {
        if (r.ts < from) continue;
        total++;
        if (r.pri <= 3) priErr++;
        byUnit.set(`${h}/${r.unit}`, (byUnit.get(`${h}/${r.unit}`) || 0) + 1);
        if (NOISE_UNITS.test(r.unit)) continue;
        for (const [id, , re] of SEV_RULES) {
          if (re.test(r.msg)) {
            if (!counts.has(id)) counts.set(id, []);
            const arr = counts.get(id);
            if (arr.length < 200) arr.push({ host: h, ts: r.ts, msg: r.msg, unit: r.unit });
          }
        }
      }
    }
  }
  const maxHit = args.threshold ? Number(args.threshold) : 0;    // 0 = 命中即 FAIL（告警模式）
  const rows = [];
  for (const [id, name] of SEV_RULES) {
    const hits = counts.get(id) || [];
    const verdict = hits.length > maxHit ? "FAIL" : "PASS";
    const sample = hits.slice(-1)[0];
    rows.push([id, name, verdict, String(hits.length),
      sample ? `${tsLocal(sample.ts)} ${sample.host} ${sample.msg.slice(0, 90)}` : "—"]);
  }
  console.log(`巡检窗口 = 近 ${Math.round(since / 60)} 分钟 · 归档内 ${total} 行 · pri≤3 计 ${priErr} 行`);
  printTable(["判据", "含义", "结果", "命中", "最近一条"], rows, args);
  const fails = rows.filter((r) => r[2] === "FAIL");
  if (args.report) {
    const f = path.join(ROOT, "reports", `watch-${dayStr()}-${new Date().getHours()}${pad(new Date().getMinutes())}.md`);
    mkdirSync(path.dirname(f), { recursive: true });
    writeFileSync(f, [
      `# 日志巡检报告 ${tsLocal(Date.now())}`, "",
      `窗口 = 近 ${Math.round(since / 60)} 分钟 ｜ 归档行数 ${total} ｜ pri≤3 = ${priErr}`, "",
      "| 判据 | 含义 | 结果 | 命中 | 最近一条 |", "|---|---|---|---|---|",
      ...rows.map((r) => `| ${r[0]} | ${r[1]} | ${r[2]} | ${r[3]} | ${String(r[4]).replace(/\|/g, "\\|")} |`), "",
    ].join("\n"), "utf8");
    console.log(`报告 ⇒ ${f}`);
  }
  if (fails.length) process.exitCode = 2;
}

// ───────────────────────────── 输出 ─────────────────────────────

function printTable(head, rows, args) {
  if (args.json) { console.log(JSON.stringify(rows.map((r) => Object.fromEntries(head.map((h, i) => [h, r[i]]))), null, 1)); return; }
  const w = head.map((h, i) => Math.max(strw(h), ...rows.map((r) => strw(String(r[i])))));
  const line = (cells) => cells.map((c, i) => String(c) + " ".repeat(Math.max(0, w[i] - strw(String(c))))).join("  ");
  console.log(line(head));
  console.log(w.map((n) => "─".repeat(n)).join("  "));
  for (const r of rows) console.log(line(r));
}
/** 中文按 2 列宽计 */
function strw(s) { let n = 0; for (const ch of String(s)) n += ch.charCodeAt(0) > 0x2e7f ? 2 : 1; return n; }

// ───────────────────────────── main ─────────────────────────────

const argv = process.argv.slice(2);
const cmd = argv[0];
const args = parseArgs(argv.slice(1));
const cmds = { collect: cmdCollect, ls: cmdLs, stats: cmdStats, q: cmdQ, timeline: cmdTimeline, watch: cmdWatch, prune: cmdPrune };

if (!cmd || cmd === "help" || args.help) {
  console.log(`dshlog — DSH 多节点日志采集 / 巡检 / 溯源（归档根 ${ROOT}）

  collect   [--hosts 47,106] [--since 1h [--chunk 30m]|--full] [--json]
            拉取归档：无 --since = cursor 续拉（增量、不重不漏）；有 --since = 回填（自动去重）
  ls                                                        列出归档分片
  stats     [--detail]                                      归档与末次拉取状态
  q <词|/正则/> [--since 6h] [--host 47] [--unit dshs] [--limit 100] [--json]
  timeline  [--from ISO] [--to ISO] [--host ..] [--grep ..] [--pri 3] [--out f] [--fix-clock]
  watch     [--since 15m] [--threshold N] [--report] [--no-collect] [--json]
            巡检：默认先增量续拉再判据；有 FAIL ⇒ 退出码 2（可被自动化当判据）
  prune     [--keep 3] [--apply]                            归档保留策略（默认 3 天 · 与服务器同口径 · 干跑）

环境变量：DSHLOG_ROOT（归档根，默认 E:/dsh-logs）· DSHLOG_VERBOSE=1（打印每块进度）
`);
  process.exit(0);
}
if (!cmds[cmd]) { console.error(`未知子命令: ${cmd}`); process.exit(2); }
await cmds[cmd](args);