const express = require('express');
const router  = express.Router();
const fs      = require('fs');
const path    = require('path');

const HISTORY_PATH = path.join(__dirname, '..', 'HISTORY.md');
let pkg;
try { pkg = require('../package.json'); } catch { pkg = { version: '0.1.0' }; }

/**
 * Parses HISTORY.md and returns the latest version's structured notes.
 * Reads from disk on every call so the file can be updated without restart.
 */
function parseHistory() {
  if (!fs.existsSync(HISTORY_PATH)) {
    return { version: '0.1', notes: [] };
  }

  const content = fs.readFileSync(HISTORY_PATH, 'utf8');

  // Match first (topmost) version block
  const blockMatch = content.match(/## (v[\d.]+)\n([\s\S]*?)(?=\n## v|\s*$)/);
  if (!blockMatch) return { version: '0.1', notes: [] };

  const version = blockMatch[1].slice(1); // strip the 'v'
  const body    = blockMatch[2];

  // Parse ### Added / Changed / Fixed / Removed sections
  const notes = [];
  const sectionRe = /### (Added|Changed|Fixed|Removed|Deprecated|Security)\n([\s\S]*?)(?=###|\s*$)/g;
  let m;
  while ((m = sectionRe.exec(body)) !== null) {
    const category = m[1];
    const items = m[2]
      .split('\n')
      .filter(l => l.trim().startsWith('- '))
      .map(l => ({ category, text: l.trim().slice(2).trim() }));
    notes.push(...items);
  }

  return { version, notes };
}

// GET /api/version
router.get('/', (req, res) => {
  res.json(parseHistory());
});

// GET /api/version/history
router.get('/history', (req, res) => {
  try {
    if (!fs.existsSync(HISTORY_PATH)) {
      return res.status(404).json({
        error: 'Release history not found',
        version: pkg.version,
        history: '',
        updated_at: null,
      });
    }

    const history = fs.readFileSync(HISTORY_PATH, 'utf8');
    let updatedAt = null;
    try {
      updatedAt = fs.statSync(HISTORY_PATH).mtime.toISOString();
    } catch {
      updatedAt = null;
    }

    res.json({
      version: pkg.version,
      history,
      updated_at: updatedAt,
    });
  } catch (err) {
    res.status(500).json({ error: err.message || 'Failed to read release history' });
  }
});

module.exports = router;