#!/usr/bin/env node
/**
 * 飞书文档 → Markdown 转换工具（含图片本地化）
 *
 * 流程：
 *   1. wiki +node-get  → 解析 obj_token
 *   2. drive +export markdown → 拿到含 feishu.cn/file/<token> 的 Markdown
 *   3. docs +media-preview  → 逐张下载图片到本地
 *   4. 替换图片链接为相对路径，保存最终 Markdown
 *
 * 用法：node feishu-to-md.mjs <wiki_url_or_token> [输出目录]
 */
import { execSync } from 'child_process';
import { writeFileSync, readFileSync, mkdirSync, existsSync, unlinkSync } from 'fs';
import { resolve, join, basename } from 'path';

const argv = process.argv.slice(2);
if (!argv[0] || argv[0] === '--help' || argv[0] === '-h') {
  console.log(`
用法：node feishu-to-md.mjs <wiki_url_or_token> [输出目录]

示例：
  node feishu-to-md.mjs https://your-tenant.feishu.cn/wiki/WikiNodeTokenExample
  FEISHU_TENANT=your-tenant node feishu-to-md.mjs WikiNodeTokenExample
`);
  process.exit(0);
}

const input   = argv[0].trim();
const outDir  = argv[1] ? resolve(argv[1]) : resolve('./output');
let wikiUrl;
if (input.startsWith('http')) {
  wikiUrl = input;
} else {
  const tenant = process.env.FEISHU_TENANT;
  if (!tenant) {
    console.error('❌ 传入纯 token 时需设置 FEISHU_TENANT 环境变量，例如：');
    console.error('   FEISHU_TENANT=your-tenant node feishu-to-md.mjs <token>');
    process.exit(1);
  }
  wikiUrl = `https://${tenant}.feishu.cn/wiki/${input}`;
}

// lark-cli 命令必须在 outDir 下执行（+media-preview 只接受相对路径）
process.chdir(outDir);

console.log('╔════════════════════════════════════════════╗');
console.log('║  飞书文档 → Markdown 转换工具              ║');
console.log('╚════════════════════════════════════════════╝');
console.log(`📎 URL: ${wikiUrl}\n`);

// ── 1. 解析 wiki node → obj_token ────────────────────────────────────────────
console.log('🔍 正在获取 wiki 节点信息...');
const nodeInfo = larkJson(`lark-cli wiki +node-get --node-token "${wikiUrl}"`);
if (!nodeInfo.ok) die('获取 wiki 节点失败', nodeInfo);

const { obj_token, title } = nodeInfo.data;
console.log(`✅ 标题：${title}`);
console.log(`✅ obj_token：${obj_token}\n`);

const safeTitle = title.replace(/[/\\:*?"<>|]/g, '_').trim();
const imgDir    = join(outDir, `${safeTitle}_files`);
if (!existsSync(imgDir)) mkdirSync(imgDir, { recursive: true });

// ── 2. 导出 Markdown ──────────────────────────────────────────────────────────
console.log('📄 正在导出 Markdown...');
const exportResult = larkJson(
  `lark-cli drive +export --token ${obj_token} --doc-type docx --file-extension markdown --output-dir . --overwrite`
);
if (!exportResult.ok) die('导出失败', exportResult);

const mdPath = exportResult.data.saved_path;
let mdContent = readFileSync(mdPath, 'utf-8');
console.log(`✅ 导出成功（${mdContent.length} 字符）\n`);

// ── 3. 下载图片 ────────────────────────────────────────────────────────────────
const TOKEN_RE = /!\[[^\]]*\]\(https:\/\/feishu\.cn\/file\/([A-Za-z0-9]+)\)/g;
const tokens = [...new Set([...mdContent.matchAll(TOKEN_RE)].map(m => m[1]))];
console.log(`🖼️  发现 ${tokens.length} 张图片，开始下载...`);

const tokenToLocal = new Map();
let n = 0;
for (const token of tokens) {
  n++;
  const relPath  = `${safeTitle}_files/image_${n}.png`;
  try {
    execSync(`lark-cli docs +media-preview --token ${token} --output "${relPath}" --overwrite`, {
      stdio: 'ignore',
    });
    tokenToLocal.set(token, relPath);
    console.log(`  ✓ image_${n}.png`);
  } catch {
    tokenToLocal.set(token, `https://feishu.cn/file/${token}`);
    console.log(`  ✗ image_${n}.png（下载失败，保留原链接）`);
  }
}
console.log('');

// ── 4. 替换图片链接并清理 ─────────────────────────────────────────────────────
mdContent = mdContent.replace(
  /!\[([^\]]*)\]\(https:\/\/feishu\.cn\/file\/([A-Za-z0-9]+)\)/g,
  (_, alt, token) => `![${alt}](${tokenToLocal.get(token) ?? `https://feishu.cn/file/${token}`})`
);

// 清理 <title> 标签和 <grid>/<column> 残留
mdContent = mdContent
  .replace(/<title>[\s\S]*?<\/title>\n?/g, '')
  .replace(/<\/?grid[^>]*>\n?/g, '')
  .replace(/<\/?column[^>]*>\n?/g, '')
  .replace(/\n{3,}/g, '\n\n')
  .trim();

// 加首行标题和来源
const finalContent = `# ${title}\n\n> Source: ${wikiUrl}\n\n${mdContent}`;
writeFileSync(mdPath, finalContent, 'utf-8');

console.log('╔════════════════════════════════════════════╗');
console.log(`║  ✅ 完成！共 ${finalContent.length} 字符`);
console.log(`║  📄 ${mdPath}`);
console.log(`║  🖼️  ${imgDir} (${tokens.length} 张)`);
console.log('╚════════════════════════════════════════════╝');

// ── helpers ──────────────────────────────────────────────────────────────────
function larkJson(cmd) {
  try {
    return JSON.parse(execSync(cmd, { encoding: 'utf-8' }));
  } catch (e) {
    // lark-cli 失败时把 JSON 输出到 stderr
    try { return JSON.parse(e.stderr || e.stdout || '{}'); } catch { return {}; }
  }
}

function die(msg, info) {
  console.error(`❌ ${msg}:`, info?.error?.message || JSON.stringify(info));
  process.exit(1);
}