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

module.exports = function() {
  const raw = fs.readFileSync(path.join(__dirname, '../../CHANGELOG.md'), 'utf8');
  const lines = raw.split('\n');
  const versions = [];
  let current = null;
  let currentSection = null;

  for (const line of lines) {
    const versionMatch = line.match(/^## \[([^\]]+)\] - (\d{4}-\d{2}-\d{2})/);
    if (versionMatch) {
      if (current) versions.push(current);
      if (versions.length >= 3) break;
      current = { version: versionMatch[1], date: versionMatch[2], sections: [], intro: '' };
      currentSection = null;
      continue;
    }

    const sectionMatch = line.match(/^### (.+)/);
    if (sectionMatch && current) {
      currentSection = { type: sectionMatch[1], items: [] };
      current.sections.push(currentSection);
      continue;
    }

    const itemMatch = line.match(/^- (.+)/);
    if (itemMatch && current) {
      if (currentSection) {
        currentSection.items.push(itemMatch[1]);
      }
      continue;
    }

    // Free-form text before first section (e.g. v1.0.0 intro paragraph)
    if (line.trim() && current && !currentSection && !line.startsWith('#')) {
      current.intro = current.intro ? current.intro + ' ' + line.trim() : line.trim();
    }
  }
  if (current && versions.length < 3) versions.push(current);

  return versions;
};