<?php
$config = require 'config.php';

$params = [
    'client_id'     => $config['client_id'],
    'response_type' => 'code',
    'redirect_uri'  => $config['redirect_uri'],
    'response_mode' => 'query',
    'scope'         => $config['scopes'],
];

$authUrl = $config['auth_url'] . '?' . http_build_query($params);
header("Location: $authUrl");
exit;