#!/usr/bin/env node
/**
 * 整仓备份 → 单个 bundle 文件 → AES-256-GCM 加密 → WebDAV 上传到 OpenList。
 *
 * 为什么是 bundle 而不是直接推 git：
 *   WebDAV 不支持原子的 rename/lock，把 bare repo 挂上去直接 `git push` 会让对象写坏
 *   （表面成功、实际随机损坏，可能几个月后才发现）。bundle 是单文件顺序写，安全。
 *
 * 为什么默认加密：
 *   本仓库历史里含 .env、TLS 私钥、GITEA_SECRETS.md。目标介质是手机内部存储，
 *   未加密等于把密钥明文放在一台可能被刷机/丢失/他人访问的设备上。
 *
 * 为什么不用 gpg：
 *   本机 gpg 2.4.9 在 Windows 下已损坏（反复 `removing stale lockfile`，node spawn 直接 EBUSY）。
 *   改用 Node 内置 crypto 的 AES-256-GCM：零外部依赖、带认证标签（能检测篡改/截断）、
 *   可流式处理 600 MB 不爆内存。加密格式见下方注释，解密由本脚本 `--decrypt` 完成。
 *
 * 用法：
 *   node scripts/backup-bundle.mjs                 # 加密 + 上传 + 比对字节数
 *   node scripts/backup-bundle.mjs --verify        # 额外下载回来比对 sha256（慢，但端到端最可靠）
 *   node scripts/backup-bundle.mjs --dry           # 只打包加密，不上传
 *   node scripts/backup-bundle.mjs --keep 7        # 远端保留最近 7 份（默认）
 *   node scripts/backup-bundle.mjs --no-encrypt    # 不加密（仅当历史里的敏感文件已洗净）
 *   node scripts/backup-bundle.mjs --decrypt <文件> [--out x.bundle]    # 解密（恢复用）
 *   node scripts/backup-bundle.mjs --list          # 列出远端现有备份
 *
 * 配置（按此顺序查找，先找到的生效）：
 *   1. 环境变量  OPENLIST_URL / OPENLIST_USER / OPENLIST_PASS / BACKUP_PASSPHRASE / OPENLIST_DIR
 *   2. ~/.openlist-backup.env
 *   3. .workbuddy-backup/openlist-backup.env   （已在 .gitignore 内）
 *
 * 加密文件布局：  magic(8) | salt(16) | iv(12) | 密文(...) | GCM tag(16)
 */

import fs from 'node:fs';
import path from 'node:path';
import os from 'node:os';
import crypto from 'node:crypto';
import http from 'node:http';
import https from 'node:https';
import { execFileSync } from 'node:child_process';
import { pipeline } from 'node:stream/promises';
import { fileURLToPath } from 'node:url';

const REPO = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
const MAGIC = Buffer.from('BLOGBKP1', 'ascii');
const SCRYPT = { N: 1 << 15, r: 8, p: 1, maxmem: 128 * 1024 * 1024 };
const HEAD = MAGIC.length + 16 + 12;

function arg(name, def) {
  const i = process.argv.indexOf('--' + name);
  if (i < 0) return def;
  const next = process.argv[i + 1];
  return next && !next.startsWith('--') ? next : true;
}
const has = (n) => process.argv.includes('--' + n);

function log(...a) {
  console.log('[' + new Date().toTimeString().slice(0, 8) + ']', ...a);
}
const mb = (n) => (n / 1048576).toFixed(1) + ' MB';

function loadEnvFile(p) {
  if (!fs.existsSync(p)) return {};
  const out = {};
  for (const line of fs.readFileSync(p, 'utf8').split(/\r?\n/)) {
    if (line.trim().startsWith('#')) continue;
    const m = /^\s*([A-Za-z0-9_]+)\s*=\s*(.*?)\s*$/.exec(line);
    if (m) out[m[1]] = m[2].replace(/^["']|["']$/g, '');
  }
  return out;
}

const cfg = {
  ...loadEnvFile(path.join(REPO, '.workbuddy-backup', 'openlist-backup.env')),
  ...loadEnvFile(path.join(os.homedir(), '.openlist-backup.env')),
  ...Object.fromEntries(
    ['OPENLIST_URL', 'OPENLIST_USER', 'OPENLIST_PASS', 'BACKUP_PASSPHRASE', 'OPENLIST_DIR']
      .filter((k) => process.env[k])
      .map((k) => [k, process.env[k]])
  ),
};

/* ---------- 加密 ---------- */

async function encryptFile(src, dst, passphrase) {
  const salt = crypto.randomBytes(16);
  const iv = crypto.randomBytes(12);
  const key = crypto.scryptSync(passphrase, salt, 32, SCRYPT);
  const cipher = crypto.createCipheriv('aes-256-gcm', key, iv);
  fs.writeFileSync(dst, Buffer.concat([MAGIC, salt, iv]));
  await pipeline(fs.createReadStream(src), cipher, fs.createWriteStream(dst, { flags: 'a' }));
  fs.appendFileSync(dst, cipher.getAuthTag());
}

async function decryptFile(src, passphrase, out) {
  const size = fs.statSync(src).size;
  if (size < HEAD + 16) throw new Error('文件太小，不是有效备份');
  const fd = fs.openSync(src, 'r');
  const head = Buffer.alloc(HEAD);
  fs.readSync(fd, head, 0, HEAD, 0);
  const tag = Buffer.alloc(16);
  fs.readSync(fd, tag, 0, 16, size - 16);
  fs.closeSync(fd);
  if (!head.subarray(0, 8).equals(MAGIC)) throw new Error('magic 不匹配，不是本脚本产生的备份');
  const salt = head.subarray(8, 24);
  const iv = head.subarray(24, 36);
  const key = crypto.scryptSync(passphrase, salt, 32, SCRYPT);
  const decipher = crypto.createDecipheriv('aes-256-gcm', key, iv);
  decipher.setAuthTag(tag);
  await pipeline(
    fs.createReadStream(src, { start: HEAD, end: size - 17 }),
    decipher,
    fs.createWriteStream(out)
  );
}

/* ---------- WebDAV ---------- */

const BASE = new URL(String(cfg.OPENLIST_URL || 'http://127.0.0.1').replace(/\/+$/, ''));
const AUTH = 'Basic ' + Buffer.from((cfg.OPENLIST_USER || '') + ':' + (cfg.OPENLIST_PASS || '')).toString('base64');
const isHttps = BASE.protocol === 'https:';
const transport = isHttps ? https : http;
const DAVDIR = cfg.OPENLIST_DIR || '/本地/git-backup';
// ★ OpenList 的 WebDAV 端点挂在 /dav 下。少了这个前缀会打到普通 HTTP 路由上，
//   表现是 MKCOL/PUT 全部返回 405 Method Not Allowed（很容易误以为是权限问题）。
const DAV_PREFIX = cfg.OPENLIST_DAV_PREFIX || '/dav';

function davReq(method, urlPath, { file, extraHeaders = {} } = {}) {
  return new Promise((resolve, reject) => {
    const u = new URL(BASE.href.replace(/\/+$/, '') + urlPath.replace(/ /g, '%20'));
    const headers = { Authorization: AUTH, ...extraHeaders };
    if (file) headers['Content-Length'] = fs.statSync(file).size;
    const req = transport.request(
      { hostname: u.hostname, port: u.port || (isHttps ? 443 : 80), path: u.pathname + u.search, method, headers },
      (res) => {
        const chunks = [];
        res.on('data', (c) => chunks.push(c));
        res.on('end', () => resolve({ status: res.statusCode, headers: res.headers, body: Buffer.concat(chunks).toString('utf8') }));
      }
    );
    req.on('error', reject);
    if (file) {
      const rs = fs.createReadStream(file);
      rs.on('error', reject);
      rs.pipe(req);
    } else req.end();
  });
}

// prefixEncoded: 已带好并已存在的端点前缀（如 /dav），不参与创建
// relEncoded:    前缀之下、各段已编码的相对目录
async function ensureDir(prefixEncoded, relEncoded) {
  let cur = prefixEncoded;
  for (const seg of relEncoded.split('/').filter(Boolean)) {
    cur += '/' + seg;
    const r = await davReq('MKCOL', cur);
    if (r.status === 201) { log('  建目录', decodeURIComponent(cur)); continue; }
    // 405 在 WebDAV 里表示「已存在」，但不能无脑相信 —— 真回到普通 HTTP 路由也会给 405。
    // 所以补一次 PROPFIND 确认，避免把路径写错（例如漏了 /dav 前缀）当成「目录已存在」而静默放过。
    if ([405, 301, 200].includes(r.status)) {
      const chk = await davReq('PROPFIND', cur, { extraHeaders: { Depth: '0' } });
      if (chk.status >= 400) {
        throw new Error(`目录 ${decodeURIComponent(cur)} 既没建成也不存在（MKCOL ${r.status} / PROPFIND ${chk.status}）—— 检查 OPENLIST_DIR 与 /dav 前缀`);
      }
      continue;
    }
    throw new Error(`建目录失败 ${decodeURIComponent(cur)} → HTTP ${r.status}`);
  }
}

function linkNames(xml) {
  const out = [];
  const re = /<(?:D:|d:)?href>([^<]+)<\/(?:D:|d:)?href>/g;
  let m;
  while ((m = re.exec(xml))) {
    const name = decodeURIComponent(m[1]).replace(/\/+$/, '').split('/').pop();
    if (name) out.push(name);
  }
  return out;
}

function sha256File(p) {
  return new Promise((resolve, reject) => {
    const h = crypto.createHash('sha256');
    const rs = fs.createReadStream(p);
    rs.on('data', (c) => h.update(c));
    rs.on('end', () => resolve(h.digest('hex')));
    rs.on('error', reject);
  });
}

const relDirEncoded = DAVDIR.split('/').filter(Boolean).map(encodeURIComponent).join('/');
const davDirPath = DAV_PREFIX + '/' + relDirEncoded;
const RE_BACKUP = /^blog-\d{8}-\d{6}\.bundle(\.enc)?$/;

/* ---------- 子命令：解密 / 列出 ---------- */

const decArg = arg('decrypt', null);
if (decArg) {
  const src = path.resolve(String(decArg));
  const out = String(arg('out', src.replace(/\.enc$/, '')));
  if (!cfg.BACKUP_PASSPHRASE) { console.error('缺少 BACKUP_PASSPHRASE'); process.exit(2); }
  await decryptFile(src, cfg.BACKUP_PASSPHRASE, out);
  log('解密完成 →', out, mb(fs.statSync(out).size));
  log('恢复仓库：  git clone "' + out + '" blog-restored');
  process.exit(0);
}

if (has('list')) {
  await ensureDir(DAV_PREFIX, relDirEncoded);
  const ls = await davReq('PROPFIND', davDirPath, { extraHeaders: { Depth: '1' } });
  const files = linkNames(ls.body).filter((n) => RE_BACKUP.test(n)).sort().reverse();
  log('远端目录', DAVDIR);
  for (const f of files) {
    const st = await davReq('HEAD', davDirPath + '/' + encodeURIComponent(f));
    const when = new Date(st.headers['last-modified'] || Date.now()).toISOString().replace('T', ' ').slice(0, 19);
    log('  ' + f + '  ' + mb(Number(st.headers['content-length'] || 0)) + '  ' + when);
  }
  if (!files.length) log('  (无备份)');
  process.exit(0);
}

/* ---------- 主流程 ---------- */

if (!cfg.OPENLIST_URL || !cfg.OPENLIST_USER || !cfg.OPENLIST_PASS) {
  console.error('缺少 OpenList 配置（OPENLIST_URL / OPENLIST_USER / OPENLIST_PASS）');
  process.exit(2);
}
const ENCRYPT = !has('no-encrypt');
if (ENCRYPT && !cfg.BACKUP_PASSPHRASE) {
  console.error('缺少 BACKUP_PASSPHRASE —— 加密备份必须有口令（确实要明文存放请显式加 --no-encrypt）');
  process.exit(2);
}

const KEEP = Number(arg('keep', 7)) || 7;
const VERIFY = has('verify');
const DRY = has('dry');

const stamp = new Date().toISOString().replace(/[-:]/g, '').replace(/\..+/, '').replace('T', '-');
const tmpRoot = path.join(REPO, '.workbuddy-backup', 'tmp');
fs.mkdirSync(tmpRoot, { recursive: true });
const tmpDir = fs.mkdtempSync(path.join(tmpRoot, 'run-'));
const rawBundle = path.join(tmpDir, `blog-${stamp}.bundle`);

try {
  log('仓库:', REPO);
  log('1/6 打包 bundle（git bundle create --all）…');
  let t = Date.now();
  execFileSync('git', ['-C', REPO, 'bundle', 'create', rawBundle, '--all'], { stdio: ['ignore', 'inherit', 'inherit'] });
  log(`   完成 ${mb(fs.statSync(rawBundle).size)}  用时 ${((Date.now() - t) / 1000).toFixed(1)}s`);

  let upload = rawBundle;
  let finalName = path.basename(rawBundle);

  if (ENCRYPT) {
    log('2/6 AES-256-GCM 加密（scrypt 派生密钥）…');
    const enc = rawBundle + '.enc';
    t = Date.now();
    await encryptFile(rawBundle, enc, cfg.BACKUP_PASSPHRASE);
    fs.unlinkSync(rawBundle);
    upload = enc;
    finalName = path.basename(enc);
    log(`   完成 ${mb(fs.statSync(upload).size)}  用时 ${((Date.now() - t) / 1000).toFixed(1)}s`);
  } else {
    log('2/6 跳过加密（--no-encrypt）—— 请确认历史里已无敏感文件');
  }

  const size = fs.statSync(upload).size;
  const sha = await sha256File(upload);
  log(`   本地 sha256 = ${sha}`);

  if (DRY) {
    log('--dry：不上传。文件留在', upload);
    process.exit(0);
  }

  log('3/6 准备远端目录', DAVDIR);
  await ensureDir(DAV_PREFIX, relDirEncoded);

  log('4/6 上传中…');
  t = Date.now();
  const put = await davReq('PUT', davDirPath + '/' + encodeURIComponent(finalName), {
    file: upload, extraHeaders: { 'Content-Type': 'application/octet-stream' },
  });
  const secs = (Date.now() - t) / 1000;
  if (![200, 201, 204].includes(put.status)) throw new Error('上传失败 HTTP ' + put.status);
  log(`   完成 ${mb(size)} / ${secs.toFixed(1)}s  →  ${(size / 1048576 / secs).toFixed(1)} MB/s`);

  log('5/6 校验远端');
  const stat = await davReq('HEAD', davDirPath + '/' + encodeURIComponent(finalName));
  const remoteLen = Number(stat.headers['content-length'] || 0);
  if (remoteLen !== size) log(`   ★ 远端字节数不一致（本地 ${size} / 远端 ${remoteLen}）`);
  else log(`   远端字节数一致 (${mb(remoteLen)})`);

  if (VERIFY) {
    log('   下载回来比对 sha256…');
    const back = path.join(tmpDir, 'readback.bin');
    await new Promise((res, rej) => {
      const req = transport.request(
        { hostname: BASE.hostname, port: BASE.port || (isHttps ? 443 : 80),
          path: davDirPath + '/' + encodeURIComponent(finalName), method: 'GET', headers: { Authorization: AUTH } },
        (r) => {
          if (r.statusCode !== 200) return rej(new Error('GET ' + r.statusCode));
          const ws = fs.createWriteStream(back);
          r.pipe(ws); ws.on('finish', res); ws.on('error', rej);
        }
      );
      req.on('error', rej); req.end();
    });
    const sha2 = await sha256File(back);
    log('   ' + (sha2 === sha ? '✓ 读回 sha256 一致 —— 数据完整' : '★ 读回 sha256 不一致 —— 备份已损坏'));
    fs.unlinkSync(back);
  }

  log(`6/6 清理旧份（保留最近 ${KEEP} 份）`);
  const ls = await davReq('PROPFIND', davDirPath, { extraHeaders: { Depth: '1' } });
  const files = linkNames(ls.body).filter((n) => RE_BACKUP.test(n)).sort().reverse();
  log('   远端现有:', files.join(', ') || '(无)');
  for (const old of files.slice(KEEP)) {
    const r = await davReq('DELETE', davDirPath + '/' + encodeURIComponent(old));
    log(`   删除 ${old} → HTTP ${r.status}`);
  }

  log('完成。备份文件:', DAVDIR + '/' + finalName);
  fs.rmSync(tmpDir, { recursive: true, force: true });
} catch (e) {
  console.error('\n失败:', e.message);
  console.error('（临时文件保留在 ' + tmpDir + ' 便于排查）');
  process.exit(1);
}