<?php

namespace JoopSchilder\Http2;

use RuntimeException;

/**
 * Class Http2
 */
class Http2
{
	/** @var resource */
	private $multihandle;

	/** @var callable */
	private $responseHandler;


	/**
	 * Http2 constructor.
	 */
	public function __construct()
	{
		$this->multihandle = curl_multi_init();
		curl_multi_setopt($this->multihandle, CURLMOPT_PIPELINING, CURLPIPE_MULTIPLEX);
		curl_multi_setopt($this->multihandle, CURLMOPT_MAX_HOST_CONNECTIONS, 1);
		curl_multi_setopt($this->multihandle, CURLMOPT_MAX_TOTAL_CONNECTIONS, 1);
	}


	/**
	 * Http2 destructor.
	 */
	public function __destruct()
	{
		if (is_resource($this->multihandle)) {
			curl_multi_close($this->multihandle);
		}
	}


	/**
	 * @param string $url
	 * @param bool   $priorKnowledge
	 * @return Request
	 */
	public function createRequest(string $url, bool $priorKnowledge = true): Request
	{
		return (new Request($url))->setOptions([
			CURLOPT_AUTOREFERER    => 1,
			CURLOPT_FOLLOWLOCATION => 1,
			CURLOPT_HEADER         => 1,
			CURLOPT_HTTP_VERSION   => ($priorKnowledge ? CURL_HTTP_VERSION_2_PRIOR_KNOWLEDGE : CURL_HTTP_VERSION_2),
			CURLOPT_MAXREDIRS      => 5,
			CURLOPT_PIPEWAIT       => 1,
			CURLOPT_RETURNTRANSFER => 1,
			CURLOPT_SSL_VERIFYPEER => 0,
			CURLOPT_TIMEOUT        => 10,
		]);
	}


	/**
	 * @param Request $request
	 */
	public function addRequest(Request $request): void
	{
		$handle = curl_init($request->getUri());
		curl_setopt_array($handle, $request->getOptions());
		curl_multi_add_handle($this->multihandle, $handle);
	}


	/**
	 * @param callable $responseHandler
	 */
	public function onResponse(callable $responseHandler): void
	{
		$this->responseHandler = $responseHandler;
	}


	/**
	 *
	 */
	public function execute(): void
	{
		$this->guardNoResponseHandler();
		do {
			curl_multi_exec($this->multihandle, $stillRunning);
			while (false !== ($message = curl_multi_info_read($this->multihandle))) {
				$handle = $message['handle'];
				$content = curl_multi_getcontent($handle);

				$header = substr($content, 0, curl_getinfo($handle, CURLINFO_HEADER_SIZE));
				$content = str_replace($header, '', $content);
				$url = curl_getinfo($handle, CURLINFO_EFFECTIVE_URL);
				call_user_func($this->responseHandler, new Response($url, $header, $content));
				curl_multi_remove_handle($this->multihandle, $handle);
				curl_close($handle);
			}
			usleep(5);
		} while ($stillRunning > 0);
	}


	/**
	 *
	 */
	private function guardNoResponseHandler(): void
	{
		if (!is_callable($this->responseHandler)) {
			throw new RuntimeException('No valid response handler found');
		}
	}

}