<?php

namespace NoccyLabs\React\WebSocket;

use Evenement\EventEmitterInterface;
use Evenement\EventEmitterTrait;
use NoccyLabs\React\WebSocket\Group\GroupManager;
use Psr\Http\Message\ServerRequestInterface;
use React\EventLoop\Loop;
use React\Http\Message\Response;
use React\Stream\CompositeStream;
use React\Stream\ThroughStream;
use SplObjectStorage;

class WebSocketMiddleware implements EventEmitterInterface
{
    const EVENT_CONNECTION = 'connection';

    const MAGIC = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11';

    const VERSION = 13;

    use EventEmitterTrait;

    private GroupManager $groupManager;

    private SplObjectStorage $websockets;

    public function __construct(?GroupManager $groupManager = null)
    {
        $this->groupManager = $groupManager ?? new GroupManager();
        $this->websockets = new SplObjectStorage();
    }

    public function addRoute(string $path, callable $handler, array $allowedOrigins=[]): void
    {
        // TODO implement or remove
    }

    public function __invoke(ServerRequestInterface $request, callable $next)
    {

        if ($request->getHeaderLine('upgrade') !== 'websocket') {
            return $next($request);
        }

        $handshakeKey = trim($request->getHeaderLine('sec-websocket-key'));
        $handshakeResponse = base64_encode(sha1($handshakeKey.self::MAGIC,true));

        // Create the streams we need to pass the websocket data back and forth.
        // This is returned with the response, and passed to the WebSocketConnection.
        $inStream = new ThroughStream();
        $outStream = new ThroughStream();
        $stream = new CompositeStream($outStream, $inStream);

        $websocket = new WebSocketConnection($request, $inStream, $outStream, $this->groupManager);
        $this->websockets->attach($websocket);
        $websocket->on('close', function () use ($websocket) {
            $this->websockets->detach($websocket);
        });

        // FIXME how to test with futureTick?
        //Loop::futureTick(function () use ($websocket) {
            $this->emit(self::EVENT_CONNECTION, [ $websocket ]);
        //});

        // TODO would it be possible for the 'connection' event to set additional response headers to be sent here?
        // For example, to send back Sec-WebSocket-Protocol header.
        return new Response(
            Response::STATUS_SWITCHING_PROTOCOLS,
            array(
                'Upgrade' => 'websocket',
                'Connection' => 'upgrade',
                'Sec-WebSocket-Accept' => $handshakeResponse,
                'Sec-WebSocket-Version' => self::VERSION
            ),
            $stream
        );        
    }

}