import jwt from 'jsonwebtoken';
import { sql } from '@vercel/postgres';

export async function verifyToken(token) {
  if (!token) {
    return null;
  }

  try {
    const jwtSecret = process.env.JWT_SECRET || 'fallback-secret-change-in-production';
    const decoded = jwt.verify(token, jwtSecret);
    
    // Get user from database
    const result = await sql.query(`
      SELECT 
        up.user_id,
        up.username,
        up.email,
        up.first_name,
        up.last_name,
        up.avatar_url,
        up.roles,
        up.created_at,
        up.updated_at
      FROM user_preferences up
      WHERE up.user_id = $1
    `, [decoded.userId]);

    if (result.rows.length === 0) {
      return null;
    }

    const user = result.rows[0];
    return {
      id: user.user_id,
      username: user.username,
      email: user.email,
      firstName: user.first_name,
      lastName: user.last_name,
      avatarUrl: user.avatar_url,
      roles: user.roles || [],
      createdAt: user.created_at,
      updatedAt: user.updated_at
    };
  } catch (error) {
    console.error('Token verification failed:', error);
    return null;
  }
}

export function isAdmin(user) {
  return user && user.roles && user.roles.includes('admin');
}