<?php

use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpKernel\HttpKernelInterface;

// The firewall is an array of associative arrays containing the rules for which
// the authentication middleware should be concerned.
$firewall = [
    ['path' => '/', 'anonymous' => true],
    ['path' => '/protected'],
];

$challenge = function (Response $response) {
    // Assumptions that can be made:
    // * 401 status code
    // * WWW-Authenticate header with a value of "Stack"
    //
    // Expectations:
    // * MAY set WWW-Authenticate header to another value
    // * MAY return a brand new response (does not have to be
    //   the original response)
    // * MUST return a response
    return $response;
};

$authenticate = function (HttpKernelInterface $app, $anonymous) {
    // Assumptions that can be made:
    // * The $app can be delegated to at any time
    // * The anonymous boolean indicates whether or not we
    //   SHOULD allow anonymous requests through or if we
    //   should challenge immediately.
    // * Additional state, like $request, $type, and $catch
    //   should be passed via use statement if they are needed.
    //
    // Expectations:
    // * SHOULD set 'stack.authn.token' attribute on the request
    //   when authentication is successful.
    // * MAY delegate to the passed $app
    // * MAY return a custom response of any status (for example
    //   returning a 302 or 400 status response is allowed)
    // * MUST return a response
};

$app = new Firewall($app, [
    'challenge' => $challenge,
    'authenticate' => $authenticate,
    'firewall' => $firewall,
]);