#!/usr/bin/env node
/**
 * Patch W7: health-check.js 时间回拨防护
 * 注入 safeAge(t) 统一处理 Date.now() - mtime，max(0, diff) 防负值
 * 幂等: sentinel W7_SAFE_AGE_v1
 */
const fs = require('fs');
const path = require('path');

const TARGET = path.join(__dirname, '..', 'health-check.js');
const SENTINEL = 'W7_SAFE_AGE_v1';

function main() {
  if (!fs.existsSync(TARGET)) { console.error('[patch-w7] missing target'); process.exit(2); }
  const src = fs.readFileSync(TARGET, 'utf8');
  if (src.includes(SENTINEL)) { console.error('[patch-w7] already applied, skip'); process.exit(0); }

  // 1) 注入 safeAge helper (在 JSON_MODE 声明后)
  const anchor1 = "const JSON_MODE = process.argv.includes('--json');";
  if (!src.includes(anchor1)) { console.error('[patch-w7] anchor1 missing'); process.exit(3); }
  const helperBlock =
    anchor1 + "\n\n" +
    "// " + SENTINEL + ": 时间回拨防护 (NTP 回跳/跨时区/休眠恢复)\n" +
    "function safeAge(t) {\n" +
    "  const ts = typeof t === 'number' ? t : (t && t.getTime ? t.getTime() : 0);\n" +
    "  const d = Date.now() - ts;\n" +
    "  return d < 0 ? 0 : d;\n" +
    "}\n";

  let patched = src.replace(anchor1, helperBlock);

  // 2) 替换 4 处 Date.now() - X 调用点
  const replacements = [
    {
      from: "const lockAge = (Date.now() - fs.statSync(lockFile).mtimeMs) / 3600000;",
      to: "const lockAge = safeAge(fs.statSync(lockFile).mtimeMs) / 3600000;"
    },
    {
      from: "const daysSince = genDate ? Math.floor((Date.now() - genDate.getTime()) / 86400000) : -1;",
      to: "const daysSince = genDate ? Math.floor(safeAge(genDate) / 86400000) : -1;",
      all: true
    },
    {
      from: "return (Date.now() - created) > 30 * 60 * 1000;",
      to: "return safeAge(created) > 30 * 60 * 1000;"
    }
  ];

  let hitCount = 0;
  for (const r of replacements) {
    if (r.all) {
      while (patched.includes(r.from)) {
        patched = patched.replace(r.from, r.to);
        hitCount++;
      }
    } else {
      if (!patched.includes(r.from)) { console.error('[patch-w7] miss:', r.from.slice(0,60)); process.exit(4); }
      patched = patched.replace(r.from, r.to);
      hitCount++;
    }
  }
  if (hitCount < 4) { console.error('[patch-w7] expected 4 hits, got', hitCount); process.exit(5); }
  if (patched === src) { console.error('[patch-w7] nothing changed'); process.exit(6); }

  const bakDir = path.join(path.dirname(TARGET), 'patches', 'bak');
  if (!fs.existsSync(bakDir)) fs.mkdirSync(bakDir, { recursive: true });
  const bak = path.join(bakDir, 'health-check.js.bak.w7.' + Date.now());
  fs.writeFileSync(bak, src);
  const tmp = TARGET + '.tmp.' + process.pid;
  fs.writeFileSync(tmp, patched);
  fs.renameSync(tmp, TARGET);
  console.error('[patch-w7] applied, hits=' + hitCount + ', bak=' + bak);
}
main();