<?php

declare(strict_types=1);

namespace Evomedien\Vitec\Middleware;

use Evomedien\Vitec\Service\SsrFlagService;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface;

/**
 * Self-healing sync of the SSR routing flag (see SsrFlagService).
 *
 * Registered for BOTH stacks: backend, so flipping the Site Set switch
 * takes effect with the very next backend request (the module reload
 * right after saving), and frontend, so /_json traffic repairs the flag
 * even if nobody is logged into the backend. When flag and setting
 * agree - the normal case - this costs a single file_exists() per
 * request.
 */
final class SyncSsrFlag implements MiddlewareInterface
{
    public function __construct(private readonly SsrFlagService $ssrFlagService)
    {
    }

    public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
    {
        $this->ssrFlagService->syncQuietly();
        return $handler->handle($request);
    }
}