#!/usr/bin/env node
/**
 * patch-p1-fast-cache-lib.js
 *
 * P1.5: 创建 hooks/lib/fast-cache.js
 *
 * 启动性能优化: 通过 mtime 签名缓存合并多次 readFileSync。
 * 对齐 OpenClaw entry.version-fast-path + module.enableCompileCache 思路。
 *
 * Bookworm 的 hooks 每次冷启动都读 stats-compiled / settings / route-stats /
 * SESSION_LOCK / STATE_FILE，2 次 statSync + 缓存命中可省 15-30ms/次。
 */

'use strict';
const fs = require('fs');
const path = require('path');

const TARGET = path.join(__dirname, '..', '..', 'hooks', 'lib', 'fast-cache.js');
const SENTINEL = 'P1-FAST-CACHE-V1';

const CONTENT = `'use strict';
/**
 * fast-cache.js — 启动期热数据快路径缓存 (${SENTINEL})
 *
 * 通过 mtime 签名: 所有源文件未变 → 直接返回上次缓存。
 * 仅缓存只读字段子集，避免缓存整个大 JSON 文件。
 *
 * 借鉴: OpenClaw entry.version-fast-path.ts (零模块加载快退出)
 *
 * Usage:
 *   const { readFastCache } = require('./lib/fast-cache.js');
 *   const cache = readFastCache() || {};
 *   const skillCount = cache.skillCount || 0;
 */

const fs = require('fs');
const path = require('path');

const ROOT = path.join(__dirname, '..', '..');
const CACHE_FILE = path.join(ROOT, 'debug', '.hook-fast-cache.json');

const SOURCES = [
  { file: path.join(ROOT, 'stats-compiled.json'), fields: ['summary', 'version'] },
  { file: path.join(ROOT, 'settings.json'),       fields: ['mcpServers'] },
];

function readFastCache() {
  try {
    const mtimes = SOURCES.map(function(s) {
      try { return fs.statSync(s.file).mtimeMs; } catch (_) { return 0; }
    });
    const sig = mtimes.join(':');

    if (fs.existsSync(CACHE_FILE)) {
      try {
        const cache = JSON.parse(fs.readFileSync(CACHE_FILE, 'utf8'));
        if (cache && cache._sig === sig) return cache;
      } catch (_) { /* malformed cache, rebuild */ }
    }

    const rebuilt = { _sig: sig, _builtAt: Date.now() };
    for (let i = 0; i < SOURCES.length; i++) {
      const { file, fields } = SOURCES[i];
      try {
        const data = JSON.parse(fs.readFileSync(file, 'utf8'));
        for (let j = 0; j < fields.length; j++) {
          rebuilt[fields[j]] = data[fields[j]];
        }
      } catch (_) { /* missing file ok */ }
    }
    rebuilt.mcpCount = Object.keys(rebuilt.mcpServers || {}).length;
    rebuilt.skillCount = (rebuilt.summary || {}).skills || 0;
    rebuilt.hookCount = (rebuilt.summary || {}).hooksRegistered || (rebuilt.summary || {}).hooks || 0;
    rebuilt.agentCount = (rebuilt.summary || {}).agents || 0;

    // 异步写回 (不阻塞主流程)
    setImmediate(function() {
      try {
        const cacheDir = path.dirname(CACHE_FILE);
        if (!fs.existsSync(cacheDir)) fs.mkdirSync(cacheDir, { recursive: true });
        const tmp = CACHE_FILE + '.tmp.' + process.pid;
        fs.writeFileSync(tmp, JSON.stringify(rebuilt));
        fs.renameSync(tmp, CACHE_FILE);
      } catch (_) { /* best effort */ }
    });

    return rebuilt;
  } catch (_) {
    return null;
  }
}

function enableCompileCacheBestEffort() {
  try {
    const mod = require('node:module');
    if (mod.enableCompileCache && !process.env.NODE_DISABLE_COMPILE_CACHE) {
      mod.enableCompileCache();
      return true;
    }
  } catch (_) { /* unsupported */ }
  return false;
}

module.exports = {
  readFastCache,
  enableCompileCacheBestEffort,
  __sentinel: '${SENTINEL}',
};
`;

function main() {
  const dir = path.dirname(TARGET);
  if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });

  if (fs.existsSync(TARGET)) {
    const cur = fs.readFileSync(TARGET, 'utf8');
    if (cur.includes(SENTINEL)) {
      process.stdout.write('[SKIP] already deployed\n');
      process.exit(0);
    }
    const ts = new Date().toISOString().replace(/[:.]/g, '-');
    fs.copyFileSync(TARGET, TARGET + '.bak.' + ts);
    process.stdout.write('[BACKUP] ' + TARGET + '.bak.' + ts + '\n');
  }

  const tmpPath = TARGET + '.tmp.' + process.pid;
  fs.writeFileSync(tmpPath, CONTENT);

  try {
    delete require.cache[require.resolve(tmpPath)];
    const mod = require(tmpPath);

    // 自检 1: readFastCache 工作
    const c = mod.readFastCache();
    if (c === null) throw new Error('readFastCache returned null');
    if (typeof c.skillCount !== 'number') throw new Error('skillCount not number');

    // 自检 2: enableCompileCache 不抛
    const enabled = mod.enableCompileCacheBestEffort();
    process.stdout.write('     compile cache: ' + (enabled ? 'ENABLED' : 'unavailable') + '\n');

    fs.renameSync(tmpPath, TARGET);
    process.stdout.write('[OK] hooks/lib/fast-cache.js deployed\n');
    process.stdout.write('     skills=' + c.skillCount + ' hooks=' + c.hookCount + ' mcp=' + c.mcpCount + '\n');
  } catch (e) {
    fs.unlinkSync(tmpPath);
    process.stderr.write('[ERROR] self-test failed: ' + e.message + '\n');
    process.exit(1);
  }
}

if (require.main === module) main();