<?php namespace Common\Core\Middleware;

use Closure;
use Common\Core\Controllers\HomeController;
use Illuminate\Http\Request;
use Illuminate\Support\Str;

class PrerenderIfCrawler
{
    protected array $crawlerUserAgents = [
        'Yahoo! Slurp',
        'bingbot',
        'yandex',
        'baiduspider',
        'facebookexternalhit',
        'twitterbot',
        'rogerbot',
        'linkedinbot',
        'embedly',
        'quora link preview',
        'showyoubot',
        'outbrain',
        'pinterest/0.',
        'slackbot',
        'vkShare',
        'W3C_Validator',
        'redditbot',
        'Applebot',
        'WhatsApp',
        'flipboard',
        'tumblr',
        'bitlybot',
        'SkypeUriPreview',
        'nuzzel',
        'Discordbot',
        'Qwantify',
        'pinterestbot',
        'Bitrix link preview',
        'XING-contenttabreceiver',
        'developers.google.com/+/web/snippet',
    ];

    public function handle(
        Request $request,
        Closure $next,
        string $routeName = null
    ) {
        if ($this->shouldPrerender($request)) {
            define('SHOULD_PRERENDER', true);

            // Always fallback to client routes if not prerendering
            // otherwise prerender routes will override client side routing
        } elseif ($routeName !== 'homepage') {
            return app(HomeController::class)->show();
        }

        return $next($request);
    }

    protected function shouldPrerender(Request $request): bool
    {
        $userAgent = strtolower($request->server->get('HTTP_USER_AGENT'));
        $bufferAgent = $request->server->get('X-BUFFERBOT');

        $shouldPrerender = false;

        if (!$userAgent) {
            return false;
        }
        if (!$request->isMethod('GET')) {
            return false;
        }

        // prerender if _escaped_fragment_ is in the query string
        if ($request->query->has('_escaped_fragment_')) {
            $shouldPrerender = true;
        }

        // prerender if a crawler is detected
        foreach ($this->crawlerUserAgents as $crawlerUserAgent) {
            if (Str::contains($userAgent, strtolower($crawlerUserAgent))) {
                $shouldPrerender = true;
            }
        }

        if ($bufferAgent) {
            $shouldPrerender = true;
        }

        return $shouldPrerender;
    }
}