function slugify(value) {
  return String(value || '')
    .toLowerCase()
    .trim()
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-+|-+$/g, '')
    .replace(/-{2,}/g, '-');
}

async function uniqueScreenSlug(pool, baseSlug, excludeId) {
  const start = baseSlug || `screen-${Date.now()}`;
  let candidate = start;
  let counter = 2;
  while (true) {
    const params = [candidate];
    let sql = 'SELECT id FROM screens WHERE slug = ?';
    if (excludeId !== undefined && excludeId !== null) {
      sql += ' AND id <> ?';
      params.push(excludeId);
    }
    const [rows] = await pool.query(sql, params);
    if (!rows.length) {
      return candidate;
    }
    candidate = `${start}-${counter}`;
    counter += 1;
  }
}

async function fetchScreenById(pool, id) {
  const [rows] = await pool.query(`
    SELECT s.id, s.name, s.slug, s.playlist_id, s.created_at, s.modified_at, s.created_by, s.modified_by, p.name AS playlist_name
    FROM screens s
    LEFT JOIN playlists p ON p.id = s.playlist_id
    WHERE s.id = ?
  `, [id]);
  return rows[0] || null;
}

async function fetchScreenEditData(pool) {
  const [playlists] = await pool.query('SELECT id, name, fade_between_slides, skip_unavailable_rtmp, created_at, modified_at, created_by, modified_by FROM playlists ORDER BY id DESC');
  return { playlists };
}

module.exports = {
  slugify,
  uniqueScreenSlug,
  fetchScreenById,
  fetchScreenEditData
};