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

const ROOT = path.resolve(__dirname, '..');

function parseFrontmatter(content) {
  const m = content.match(/^---\n([\s\S]*?)\n---/);
  if (!m) return {};
  const fm = {};
  for (const line of m[1].split('\n')) {
    const idx = line.indexOf(':');
    if (idx === -1) continue;
    const key = line.slice(0, idx).trim();
    let val = line.slice(idx + 1).trim();
    // Remove quotes
    if ((val.startsWith('"') && val.endsWith('"')) || (val.startsWith("'") && val.endsWith("'")))
      val = val.slice(1, -1);
    fm[key] = val;
  }
  return fm;
}

function guessTag(folderName) {
  if (folderName.startsWith('dgx-spark')) return 'DGX Spark';
  if (folderName.startsWith('gitea')) return 'Gitea';
  if (folderName.startsWith('searxng')) return 'SearXNG';
  if (folderName.startsWith('ollama')) return 'Ollama';
  if (folderName.startsWith('browser')) return 'Browser';
  if (folderName.startsWith('game')) return 'Game';
  return 'Tech';
}

function getTag(fm, folderName, defaultTag) {
  if (fm.tag) return fm.tag;
  if (fm.tags) return fm.tags.replace(/[\[\]]/g, '').split(',')[0].trim();
  if (defaultTag === 'blog') return 'AI';
  return guessTag(folderName);
}

function scanDir(dir, urlPrefix, isBlog) {
  if (!fs.existsSync(dir)) return [];
  const entries = fs.readdirSync(dir, { withFileTypes: true });
  const posts = [];
  for (const e of entries) {
    if (!e.isDirectory()) continue;
    const indexPath = path.join(dir, e.name, 'index.md');
    if (!fs.existsSync(indexPath)) continue;
    const content = fs.readFileSync(indexPath, 'utf8');
    const fm = parseFrontmatter(content);
    const title = fm.title || e.name;
    const tag = getTag(fm, e.name, isBlog ? 'blog' : 'tech');

    // Extract date
    let date = null;
    const dateMatch = e.name.match(/^(\d{4}-\d{2}-\d{2})/);
    if (dateMatch) {
      date = dateMatch[1];
    } else if (fm.date) {
      date = fm.date.slice(0, 10);
    } else {
      // Use file mtime
      const stat = fs.statSync(indexPath);
      date = stat.mtime.toISOString().slice(0, 10);
    }

    posts.push({ title, date, tag, url: `${urlPrefix}${e.name}` });
  }
  posts.sort((a, b) => b.date.localeCompare(a.date));
  return posts.slice(0, 5);
}

const tech = scanDir(path.join(ROOT, 'docs-tech'), '/tech/', false);
const blog = scanDir(path.join(ROOT, 'docs'), '/blog/', true);

const outPath = path.join(ROOT, 'src', 'data', 'recent-posts.json');
fs.writeFileSync(outPath, JSON.stringify({ tech, blog }, null, 2));
console.log(`Generated ${outPath} (tech: ${tech.length}, blog: ${blog.length})`);