<?php
declare(strict_types=1);

namespace Phred\Http;

use DI\Container;
use DI\ContainerBuilder;
use FastRoute\Dispatcher;
use FastRoute\RouteCollector;
use Nyholm\Psr7\Factory\Psr17Factory;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface as ServerRequest;
use Relay\Relay;

use function FastRoute\simpleDispatcher;

/**
 * Core HTTP Kernel builds container, routes, and PSR-15 pipeline and processes requests.
 */
final class Kernel
{
    private Container $container;
    private Dispatcher $dispatcher;

    public function __construct(?Container $container = null, ?Dispatcher $dispatcher = null)
    {
        $this->container = $container ?? $this->buildContainer();
        $this->dispatcher = $dispatcher ?? $this->buildDispatcher();
    }

    public function container(): Container
    {
        return $this->container;
    }

    public function dispatcher(): Dispatcher
    {
        return $this->dispatcher;
    }

    public function handle(ServerRequest $request): ResponseInterface
    {
        $psr17 = new Psr17Factory();
        $middleware = [
            new Middleware\RoutingMiddleware($this->dispatcher, $psr17),
            new Middleware\DispatchMiddleware($this->container, $psr17),
        ];
        $relay = new Relay($middleware);
        return $relay->handle($request);
    }

    private function buildContainer(): Container
    {
        $builder = new ContainerBuilder();
        // Add definitions/bindings here as needed.
        return $builder->build();
    }

    private function buildDispatcher(): Dispatcher
    {
        $routesPath = dirname(__DIR__, 2) . '/routes';
        $collector = static function (RouteCollector $r) use ($routesPath): void {
            // Load user-defined routes if present
            $router = new Router($r);
            foreach (['web.php', 'api.php'] as $file) {
                $path = $routesPath . '/' . $file;
                if (is_file($path)) {
                    /** @noinspection PhpIncludeInspection */
                    (static function ($router) use ($path) { require $path; })($router);
                }
            }

            // Ensure a default health route exists for acceptance/demo
            $r->addRoute('GET', '/_phred/health', [Controllers\HealthController::class, '__invoke']);
        };

        return simpleDispatcher($collector);
    }
}