listSidebar.ts

import path from 'path';
import fs from 'fs';
import matter from 'gray-matter';

interface StarlightSidebarFolder {
  label: string;
  items: StarlightSidebarList;
  collapsed?: boolean;
}

type StarlightSidebarFile = string;

export type StarlightSidebarList = Array<StarlightSidebarFile | StarlightSidebarFolder>;

/**
 * Recursively walk through a documentation directory and build a sidebar structure.
 * Handles both folders (nested sections) and Markdown files.
 */
export function walkDocsRecursive(dir: string): StarlightSidebarList {
  const entries = fs.readdirSync(dir);
  const result: StarlightSidebarList = [];

  // Sort all entry file (If named index.*, it will be first)
  entries.sort((a, b) => {
    const aIsIndex = a.startsWith('index.');
    const bIsIndex = b.startsWith('index.');
    if (aIsIndex && !bIsIndex) return -1;
    if (!aIsIndex && bIsIndex) return 1;
    return a.localeCompare(b);
  });

  for (const entry of entries) {
    const entryPath = path.join(dir, entry);
    const stat = fs.statSync(entryPath);

    if (stat.isDirectory()) {
      // Clean label by removing numeric prefix (if present)
      const label = entry.replace(/^\d+\s+/, ''); // Remove leading numbers and spaces

      result.push({
        label,
        items: walkDocsRecursive(entryPath) // Recurse into subdirectory
      });
    } else {
      // Read file contents and extract frontmatter using gray-matter
      const fileContent = fs.readFileSync(entryPath, 'utf8');
      const parsed = matter(fileContent);

      if (parsed.data.hideInSidebar && parsed.data.hideInSidebar === true) continue;
      if (import.meta.env.PROD && parsed.data.draft && parsed.data.draft === true) continue;

      result.push(String(parsed.data.slug ?? ''));
    }
  }

  return result;
}