<?php
/**
 * SecureHeaders.php
 * Copyright (c) 2019 james@firefly-iii.org
 *
 * This file is part of Firefly III (https://github.com/firefly-iii).
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

declare(strict_types=1);

namespace FireflyIII\Http\Middleware;

use Closure;
use Exception;
use Illuminate\Http\Request;

/**
 *
 * Class SecureHeaders
 */
class SecureHeaders
{
    /**
     * Handle an incoming request.
     *
     * @param Request $request
     * @param Closure $next
     *
     * @throws Exception
     * @return mixed
     */
    public function handle(Request $request, Closure $next)
    {
        // generate and share nonce.
        $nonce = base64_encode(random_bytes(16));
        app('view')->share('JS_NONCE', $nonce);

        $response          = $next($request);
        $trackingScriptSrc = $this->getTrackingScriptSource();
        $csp               = [
            "default-src 'none'",
            "object-src 'self'",
            sprintf("script-src 'unsafe-inline' 'nonce-%1s' %2s", $nonce, $trackingScriptSrc),
            "style-src 'self' 'unsafe-inline'",
            "base-uri 'self'",
            "font-src 'self' data:",
            "connect-src 'self'",
            sprintf("img-src 'self' data: https://a.tile.openstreetmap.org https://b.tile.openstreetmap.org https://c.tile.openstreetmap.org https://api.tiles.mapbox.com %s", $trackingScriptSrc),
            "manifest-src 'self'",
        ];

        $route = $request->route();
        if (null !== $route && 'oauth/authorize' !== $route->uri) {
            $csp[] = "form-action 'self'";
        }

        $featurePolicies = [
            "geolocation 'none'",
            "midi 'none'",
            //"notifications 'none'",
            //"push 'self'",
            "sync-xhr 'self'",
            "microphone 'none'",
            "camera 'none'",
            "magnetometer 'none'",
            "gyroscope 'none'",
            "speaker 'none'",
            //"vibrate 'none'",
            "fullscreen 'self'",
            "payment 'none'",
        ];

        $disableFrameHeader = config('firefly.disable_frame_header');
        $disableCSP         = config('firefly.disable_csp_header');
        if (false === $disableFrameHeader) {
            $response->header('X-Frame-Options', 'deny');
        }
        if (false === $disableCSP && !$response->headers->has('Content-Security-Policy')) {
            $response->header('Content-Security-Policy', implode('; ', $csp));
        }
        $response->header('X-XSS-Protection', '1; mode=block');
        $response->header('X-Content-Type-Options', 'nosniff');
        $response->header('Referrer-Policy', 'no-referrer');
        $response->header('Feature-Policy', implode('; ', $featurePolicies));

        return $response;
    }

    /**
     * Return part of a CSP header allowing scripts from Google.
     *
     * @return string
     */
    private function getTrackingScriptSource(): string
    {
        if ('' !== (string) config('firefly.tracker_site_id') && '' !== (string) config('firefly.tracker_url')) {
            return (string) config('firefly.tracker_url');
        }

        return '';
    }
}