// Bundles the repository docs/ tree into a generated TS module so the docs
// browser renders instantly and offline. The GitHub sync layer refreshes it
// at runtime when network is available.
import { readdirSync, readFileSync, statSync, writeFileSync, mkdirSync } from 'node:fs';
import { join, relative } from 'node:path';
import { fileURLToPath } from 'node:url';

const root = join(fileURLToPath(new URL('.', import.meta.url)), '..', '..', '..');
const docsDir = join(root, 'docs');
const outFile = join(root, 'app/frontend/src/generated/docs-snapshot.ts');

// Directories that are internal working notes rather than user documentation.
const SKIP_DIRS = new Set(['archive', 'design', 'superpowers']);

function walk(dir) {
  const entries = [];
  for (const name of readdirSync(dir)) {
    const full = join(dir, name);
    const stat = statSync(full);
    if (stat.isDirectory()) {
      if (!SKIP_DIRS.has(name)) entries.push(...walk(full));
    } else if (name.toLowerCase().endsWith('.md')) {
      entries.push(full);
    }
  }
  return entries;
}

function titleOf(markdown, fallback) {
  const match = markdown.match(/^#\s+(.+)$/m);
  if (match) return match[1].replace(/[#*`]/g, '').trim();
  return fallback
    .replace(/\.md$/i, '')
    .replace(/[-_]+/g, ' ')
    .replace(/\b\w/g, (c) => c.toUpperCase());
}

const files = walk(docsDir).sort();
const docs = files.map((full) => {
  const rel = relative(docsDir, full).replace(/\\/g, '/');
  const markdown = readFileSync(full, 'utf8');
  const section = rel.includes('/') ? rel.split('/')[0] : 'docs';
  return {
    path: rel,
    section,
    title: titleOf(markdown, rel.split('/').pop() ?? rel),
    markdown,
  };
});

const banner = `/**\n * Auto-generated by scripts/generate-docs-snapshot.mjs.\n * Bundled copy of the repository docs tree — the offline fallback for the\n * docs browser. Regenerate with \`npm run generate:docs\`.\n */\n\nexport type BundledDoc = {\n  path: string;\n  section: string;\n  title: string;\n  markdown: string;\n};\n\n`;

mkdirSync(join(outFile, '..'), { recursive: true });
writeFileSync(outFile, `${banner}export const bundledDocs: BundledDoc[] = ${JSON.stringify(docs, null, 2)};\n`);
console.log(`docs snapshot: ${docs.length} files → ${relative(root, outFile)}`);