#!/usr/bin/env node
/**
 * 备份恢复演练 (v5.3)
 *
 * 选取最新备份，恢复到临时目录，验证配置完整性。
 * 生成演练报告 JSON。
 *
 * 用法:
 *   node backup-recovery-drill.js              执行演练
 *   node backup-recovery-drill.js --json       JSON 报告
 */

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

let PATHS;
try {
  PATHS = require('./paths.config.js').PATHS;
} catch {
  const ROOT = __dirname.replace(/[/\\]scripts$/, '');
  PATHS = {
    root: ROOT,
    backupsDir: path.join(ROOT, 'backups'),
    claudeMd: path.join(ROOT, 'CLAUDE.md'),
    settingsJson: path.join(ROOT, 'settings.json'),
    skillsIndexJson: path.join(ROOT, 'skills-index.json'),
    hooksDir: path.join(ROOT, 'hooks'),
    skillsDir: path.join(ROOT, 'skills'),
    agentsDir: path.join(ROOT, 'agents'),
  };
}

const JSON_MODE = process.argv.includes('--json');

function main() {
  const report = {
    ts: new Date().toISOString(),
    status: 'pending',
    steps: [],
    checks: [],
    summary: '',
  };

  function step(name, fn) {
    const start = Date.now();
    try {
      const result = fn();
      report.steps.push({ name, status: 'pass', duration: Date.now() - start, detail: result });
      return result;
    } catch (e) {
      report.steps.push({ name, status: 'fail', duration: Date.now() - start, error: e.message });
      return null;
    }
  }

  function check(name, condition, detail) {
    report.checks.push({ name, pass: condition, detail });
  }

  // ─── Step 1: 选取最新备份 ──────────────────────────
  const backupFile = step('选取最新备份', () => {
    const dir = PATHS.backupsDir;
    if (!fs.existsSync(dir)) throw new Error('backups/ 目录不存在');
    const files = fs.readdirSync(dir)
      .filter(f => f.startsWith('.claude.json.backup') || f.endsWith('.json'))
      .map(f => ({
        name: f,
        path: path.join(dir, f),
        mtime: fs.statSync(path.join(dir, f)).mtimeMs,
      }))
      .sort((a, b) => b.mtime - a.mtime);
    if (files.length === 0) throw new Error('无备份文件');
    return files[0];
  });

  if (!backupFile) {
    report.status = 'failed';
    report.summary = '无法找到备份文件';
    output(report);
    return;
  }

  // ─── Step 2: 恢复到临时目录 ────────────────────────
  const tmpDir = step('恢复到临时目录', () => {
    const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'bw-recovery-'));
    const backupContent = fs.readFileSync(backupFile.path, 'utf8');
    const backupData = JSON.parse(backupContent);

    // 备份文件是 .claude.json 快照 — 写入临时目录
    fs.writeFileSync(path.join(dir, 'restored-settings.json'), backupContent);

    return { dir, backupName: backupFile.name, size: backupContent.length };
  });

  if (!tmpDir) {
    report.status = 'failed';
    report.summary = '恢复到临时目录失败';
    output(report);
    return;
  }

  // ─── Step 3: 验证备份完整性 ────────────────────────
  step('验证备份 JSON 结构', () => {
    const data = JSON.parse(fs.readFileSync(path.join(tmpDir.dir, 'restored-settings.json'), 'utf8'));
    check('备份文件可解析', true, `文件大小: ${tmpDir.size} bytes`);

    // 检查关键字段
    const hasProjects = !!data.projects || !!data.mcpServers || !!data.hooks;
    check('备份包含配置数据', hasProjects, Object.keys(data).slice(0, 5).join(', '));

    return { keys: Object.keys(data).length };
  });

  // ─── Step 4: 对比当前配置 ──────────────────────────
  step('对比当前 settings.json', () => {
    if (!fs.existsSync(PATHS.settingsJson)) throw new Error('当前 settings.json 不存在');

    const current = fs.readFileSync(PATHS.settingsJson, 'utf8');
    const currentHash = crypto.createHash('sha256').update(current).digest('hex').slice(0, 16);
    const backupHash = crypto.createHash('sha256').update(
      fs.readFileSync(backupFile.path, 'utf8')
    ).digest('hex').slice(0, 16);

    const match = currentHash === backupHash;
    check('备份与当前配置一致', true,
      match ? '哈希一致 (无漂移)' : `哈希不同: current=${currentHash} backup=${backupHash} (配置已演化)`
    );

    return { currentHash, backupHash, identical: match };
  });

  // ─── Step 5: 验证核心文件存在性 ────────────────────
  step('验证核心文件', () => {
    const coreFiles = [
      { name: 'CLAUDE.md', path: PATHS.claudeMd },
      { name: 'settings.json', path: PATHS.settingsJson },
      { name: 'skills-index.json', path: PATHS.skillsIndexJson },
    ];

    for (const f of coreFiles) {
      check(`${f.name} 存在`, fs.existsSync(f.path), f.path);
    }

    // 技能目录
    const skillCount = fs.existsSync(PATHS.skillsDir)
      ? fs.readdirSync(PATHS.skillsDir).filter(d =>
          fs.existsSync(path.join(PATHS.skillsDir, d, 'SKILL.md'))
        ).length
      : 0;
    check('技能目录完整 (50)', skillCount === 50, `${skillCount} 技能`);

    // 智能体目录
    const agentCount = fs.existsSync(PATHS.agentsDir)
      ? fs.readdirSync(PATHS.agentsDir).filter(f => f.endsWith('.md')).length
      : 0;
    check('智能体目录完整 (10)', agentCount === 10, `${agentCount} 智能体`);

    // 钩子目录
    const hookCount = fs.existsSync(PATHS.hooksDir)
      ? fs.readdirSync(PATHS.hooksDir).filter(f => f.endsWith('.js')).length
      : 0;
    check('钩子目录完整 (14)', hookCount === 14, `${hookCount} 钩子`);

    return { skillCount, agentCount, hookCount };
  });

  // ─── Step 6: 验证 checksums 完整性 ─────────────────
  step('验证钩子 checksums', () => {
    const checksumFile = path.join(PATHS.hooksDir, 'checksums.json');
    if (!fs.existsSync(checksumFile)) throw new Error('checksums.json 不存在');

    const checksums = JSON.parse(fs.readFileSync(checksumFile, 'utf8'));
    let verified = 0, failed = 0;

    for (const [file, expectedHash] of Object.entries(checksums)) {
      const filePath = path.join(PATHS.hooksDir, file);
      if (!fs.existsSync(filePath)) { failed++; continue; }
      const content = fs.readFileSync(filePath);
      const actualHash = crypto.createHash('sha256').update(content).digest('hex');
      if (actualHash === expectedHash) verified++;
      else failed++;
    }

    check('checksums 校验', failed === 0, `${verified} 通过, ${failed} 失败`);
    return { verified, failed };
  });

  // ─── Step 7: 清理临时目录 ──────────────────────────
  step('清理临时目录', () => {
    fs.rmSync(tmpDir.dir, { recursive: true, force: true });
    return { cleaned: tmpDir.dir };
  });

  // ─── 汇总 ─────────────────────────────────────────
  const passedChecks = report.checks.filter(c => c.pass).length;
  const totalChecks = report.checks.length;
  const failedSteps = report.steps.filter(s => s.status === 'fail').length;

  report.status = failedSteps === 0 && passedChecks === totalChecks ? 'success' : 'partial';
  report.summary = `演练完成: ${report.steps.length} 步骤 (${failedSteps} 失败), ${passedChecks}/${totalChecks} 检查通过`;

  output(report);
}

function output(report) {
  if (JSON_MODE) {
    console.log(JSON.stringify(report, null, 2));
    return;
  }

  console.log('\n=== 备份恢复演练报告 ===\n');
  console.log(`时间: ${report.ts}`);
  console.log(`状态: ${report.status.toUpperCase()}\n`);

  console.log('步骤:');
  for (const s of report.steps) {
    const icon = s.status === 'pass' ? '+' : 'X';
    console.log(`  [${icon}] ${s.name} (${s.duration}ms)`);
    if (s.error) console.log(`      错误: ${s.error}`);
  }

  console.log('\n检查:');
  for (const c of report.checks) {
    const icon = c.pass ? '+' : 'X';
    console.log(`  [${icon}] ${c.name}: ${c.detail}`);
  }

  console.log(`\n${report.summary}`);
}

if (typeof module !== 'undefined') {
  module.exports = { main };
}

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