<?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();
        // Providers may contribute routes during boot; ensure dispatcher is built after container init
        $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();
        $middleware = [
            new Middleware\ProblemDetailsMiddleware(
                \Phred\Support\Config::get('APP_DEBUG', 'false') === 'true',
                null,
                null,
                filter_var(\Phred\Support\Config::get('API_PROBLEM_DETAILS', 'true'), FILTER_VALIDATE_BOOLEAN)
            ),
            // Perform extension-based content negotiation hinting before standard negotiation
            new Middleware\UrlExtensionNegotiationMiddleware(),
            new Middleware\ContentNegotiationMiddleware(),
            new Middleware\RoutingMiddleware($this->dispatcher, $psr17),
            new Middleware\DispatchMiddleware($psr17),
        ];
        $relay = new Relay($middleware);
        return $relay->handle($request);
    }

    private function buildContainer(): Container
    {
        $builder = new ContainerBuilder();

        // Allow service providers to register definitions before defaults
        $configAdapter = new \Phred\Support\DefaultConfig();
        $providers = new \Phred\Support\ProviderRepository($configAdapter);
        $providers->load();
        $providers->registerAll($builder);

        // Add core definitions/bindings
        $builder->addDefinitions([
            \Phred\Support\Contracts\ConfigInterface::class => \DI\autowire(\Phred\Support\DefaultConfig::class),
            \Phred\Http\Contracts\ErrorFormatNegotiatorInterface::class => \DI\autowire(\Phred\Http\Support\DefaultErrorFormatNegotiator::class),
            \Phred\Http\Contracts\RequestIdProviderInterface::class => \DI\autowire(\Phred\Http\Support\DefaultRequestIdProvider::class),
            \Phred\Http\Contracts\ExceptionToStatusMapperInterface::class => \DI\autowire(\Phred\Http\Support\DefaultExceptionToStatusMapper::class),
            \Phred\Http\Contracts\ApiResponseFactoryInterface::class => \DI\autowire(\Phred\Http\Responses\DelegatingApiResponseFactory::class),
            \Phred\Http\Responses\RestResponseFactory::class => \DI\autowire(\Phred\Http\Responses\RestResponseFactory::class),
            \Phred\Http\Responses\JsonApiResponseFactory::class => \DI\autowire(\Phred\Http\Responses\JsonApiResponseFactory::class),
        ]);
        $container = $builder->build();

        // Reset provider-registered routes to avoid duplicates across multiple kernel instantiations (e.g., tests)
        \Phred\Http\Routing\RouteRegistry::clear();
        // Boot providers after container is available
        $providers->bootAll($container);

        return $container;
    }

    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);
                }
            }

            // Allow providers to contribute routes
            \Phred\Http\Routing\RouteRegistry::apply($r, $router);

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

        return simpleDispatcher($collector);
    }
}