const router = require('express').Router();
const { query } = require('../db');

// GET /api/user-names
router.get('/', async (req, res, next) => {
  try {
    const { limit = 50, offset = 0 } = req.query;
    const result = await query(
      `SELECT * FROM user_names ORDER BY created_at DESC LIMIT $1 OFFSET $2`,
      [Math.min(parseInt(limit), 500), parseInt(offset)]
    );
    res.json(result.rows);
  } catch (err) { next(err); }
});

// GET /api/user-names/:id
router.get('/:id', async (req, res, next) => {
  try {
    const result = await query('SELECT * FROM user_names WHERE id = $1', [req.params.id]);
    if (!result.rows.length) return res.status(404).json({ error: 'Not found' });
    res.json(result.rows[0]);
  } catch (err) { next(err); }
});

// POST /api/user-names
router.post('/', async (req, res, next) => {
  try {
    const { username } = req.body;
    if (!username) return res.status(400).json({ error: 'username is required' });
    const result = await query(
      `INSERT INTO user_names (username, username_lowercase) VALUES ($1, $2) RETURNING *`,
      [username, username.toLowerCase()]
    );
    res.status(201).json(result.rows[0]);
  } catch (err) {
    if (err.code === '23505') return res.status(409).json({ error: 'Username already taken' });
    next(err);
  }
});

// PATCH /api/user-names/:id
router.patch('/:id', async (req, res, next) => {
  try {
    const { username } = req.body;
    if (!username) return res.status(400).json({ error: 'No valid fields provided' });
    const result = await query(
      `UPDATE user_names SET username = $1, username_lowercase = $2 WHERE id = $3 RETURNING *`,
      [username, username.toLowerCase(), req.params.id]
    );
    if (!result.rows.length) return res.status(404).json({ error: 'Not found' });
    res.json(result.rows[0]);
  } catch (err) {
    if (err.code === '23505') return res.status(409).json({ error: 'Username already taken' });
    next(err);
  }
});

// DELETE /api/user-names/:id
router.delete('/:id', async (req, res, next) => {
  try {
    const result = await query('DELETE FROM user_names WHERE id = $1 RETURNING id', [req.params.id]);
    if (!result.rows.length) return res.status(404).json({ error: 'Not found' });
    res.status(204).end();
  } catch (err) { next(err); }
});

module.exports = router;