server.js

var express = require('express');
var bodyParser = require('body-parser');
var fs = require('fs');
var path = require('path');
var marked = require('marked');

var app = express();
var PORT = process.env.PORT || 3000;
var NOTES_DIR = path.join(__dirname, 'notes');

if (!fs.existsSync(NOTES_DIR)) {
  fs.mkdirSync(NOTES_DIR);
}

app.use(bodyParser.json());
app.use(express.static(path.join(__dirname, 'public')));

function sanitizeName(name) {
  return name.replace(/[^a-z0-9-_ ]/gi, '').trim();
}

app.get('/api/notes', function (req, res) {
  fs.readdir(NOTES_DIR, function (err, files) {
    if (err) {
      return res.status(500).json({ error: 'Unable to read notes' });
    }

    var notes = files
      .filter(function (file) {
        return file.endsWith('.md');
      })
      .map(function (file) {
        return file.replace('.md', '');
      });

    res.json(notes);
  });
});

app.get('/api/notes/:name', function (req, res) {
  var name = sanitizeName(req.params.name);
  var filePath = path.join(NOTES_DIR, name + '.md');

  fs.readFile(filePath, 'utf8', function (err, data) {
    if (err) {
      return res.status(404).json({ error: 'Note not found' });
    }

    res.json({
      name: name,
      content: data,
      html: marked(data)
    });
  });
});

app.post('/api/notes/:name', function (req, res) {
  var name = sanitizeName(req.params.name);

  if (!name) {
    return res.status(400).json({ error: 'Invalid note name' });
  }

  var filePath = path.join(NOTES_DIR, name + '.md');
  var content = req.body.content || '';

  fs.writeFile(filePath, content, function (err) {
    if (err) {
      return res.status(500).json({ error: 'Unable to save note' });
    }

    res.json({ success: true });
  });
});

app.delete('/api/notes/:name', function (req, res) {
  var name = sanitizeName(req.params.name);
  var filePath = path.join(NOTES_DIR, name + '.md');

  fs.unlink(filePath, function (err) {
    if (err) {
      return res.status(404).json({ error: 'Note not found' });
    }

    res.json({ success: true });
  });
});

app.listen(PORT, function () {
  console.log('Server running on http://localhost:' + PORT);
});

// polish

// tidy up

// small fix