<?php namespace Clockwork\Support\Vanilla;

use Http\Discovery\Psr17Factory;
use Psr\Http\Message\{ResponseFactoryInterface, ResponseInterface, ServerRequestInterface};
use Psr\Http\Server\{MiddlewareInterface, RequestHandlerInterface};

// Generic Clockwork middleware for use with PSR-compatible applications
class ClockworkMiddleware implements MiddlewareInterface
{
	// The underlying vanilla Clockwork support class instance
	protected $clockwork;

	// Whether this middleware should handle routing for Clockwork REST api and Web interface
	protected $handleRouting = true;
	
	// PSR-17 request factory instance
	protected $responseFactory;
	
	// Creates new middleware instance, takes a vanilla Clockwork support class instance as an argument
	public function __construct(Clockwork $clockwork)
	{
		$this->clockwork = $clockwork;
	}
	
	// Returns a new middleware instance with a default singleton Clockwork instance, takes an additional configuration as argument
	public static function init($config = [])
	{
		return new static(Clockwork::init($config));
	}
	
	// Sets a PSR-17 compatible response factory. When using the middleware with routing enabled, response factory must be manually set
	// or the php-http/discovery has to be intalled for zero-configuration use
	public function withResponseFactory(ResponseFactoryInterface $responseFactory)
	{
		$this->responseFactory = $responseFactory;
		return $this;
	}
	
	// Disables routing handling in the middleware. When disabled additional manual configuration of the application router is required.
	public function withoutRouting()
	{
		$this->handleRouting = false;
		return $this;
	}
	
	// Process the middleware
	public function process(ServerRequestInterface $request, RequestHandlerInterface $handler) :ResponseInterface
	{
		$request = $request->withAttribute('clockwork', $this->clockwork);
		
		$this->clockwork->event('Controller')->begin();

		if ($response = $this->handleApiRequest($request)) return $response;
		if ($response = $this->handleWebRequest($request)) return $response;

		$response = $handler->handle($request);

		return $this->clockwork->usePsrMessage($request, $response)->requestProcessed();
	}

	// Handle a Clockwork REST api request if routing is enabled
	protected function handleApiRequest(ServerRequestInterface $request)
	{
		$path = $this->clockwork->getConfig()['api'];

		if (! $this->handleRouting) return;
		if (! preg_match("#^{$path}.*#", $request->getUri()->getPath())) return;
		
		return $this->clockwork->usePsrMessage($request, $this->prepareResponse())->handleMetadata();
	}

	// Handle a Clockwork Web interface request if routing is enabled
	protected function handleWebRequest(ServerRequestInterface $request)
	{
		$path = is_string($this->clockwork->getConfig()['web']['enable']) ? $this->clockwork->getConfig()['web']['enable'] : '/clockwork';

		if (! $this->handleRouting) return;
		if (! preg_match("#^{$path}(/.*)?#", $request->getUri()->getPath())) return;

		return $this->clockwork->usePsrMessage($request, $this->prepareResponse())->returnWeb();
	}

	protected function prepareResponse()
	{
		if (! $this->responseFactory && ! class_exists(Psr17Factory::class)) {
			throw new \Exception('The Clockwork vanilla middleware requires a response factory or the php-http/discovery package to be installed.');
		}

		return ($this->responseFactory ?: new Psr17Factory)->createResponse();
	}
}